From 34586d29f8dfc4ae30642c5b9a4db8a4a7af6869 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Wed, 31 Aug 2022 08:27:07 -0700 Subject: libbpf: Add new BPF_PROG2 macro To support struct arguments in trampoline based programs, existing BPF_PROG doesn't work any more since the type size is needed to find whether a parameter takes one or two registers. So this patch added a new BPF_PROG2 macro to support such trampoline programs. The idea is suggested by Andrii. For example, if the to-be-traced function has signature like typedef struct { void *x; int t; } sockptr; int blah(sockptr x, char y); In the new BPF_PROG2 macro, the argument can be represented as __bpf_prog_call( ({ union { struct { __u64 x, y; } ___z; sockptr x; } ___tmp = { .___z = { ctx[0], ctx[1] }}; ___tmp.x; }), ({ union { struct { __u8 x; } ___z; char y; } ___tmp = { .___z = { ctx[2] }}; ___tmp.y; })); In the above, the values stored on the stack are properly assigned to the actual argument type value by using 'union' magic. Note that the macro also works even if no arguments are with struct types. Note that new BPF_PROG2 works for both llvm16 and pre-llvm16 compilers where llvm16 supports bpf target passing value with struct up to 16 byte size and pre-llvm16 will pass by reference by storing values on the stack. With static functions with struct argument as always inline, the compiler is able to optimize and remove additional stack saving of struct values. Signed-off-by: Yonghong Song Link: https://lore.kernel.org/r/20220831152707.2079473-1-yhs@fb.com Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/bpf_tracing.h | 79 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index 5fdb93da423b..8d4bdd18cb3d 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -438,6 +438,85 @@ typeof(name(0)) name(unsigned long long *ctx) \ static __always_inline typeof(name(0)) \ ____##name(unsigned long long *ctx, ##args) +#ifndef ____bpf_nth +#define ____bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N +#endif +#ifndef ____bpf_narg +#define ____bpf_narg(...) ____bpf_nth(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) +#endif + +#define BPF_REG_CNT(t) \ + (__builtin_choose_expr(sizeof(t) == 1 || sizeof(t) == 2 || sizeof(t) == 4 || sizeof(t) == 8, 1, \ + __builtin_choose_expr(sizeof(t) == 16, 2, \ + (void)0))) + +#define ____bpf_reg_cnt0() (0) +#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + BPF_REG_CNT(t)) +#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, ____bpf_narg(args))(args) + +#define ____bpf_union_arg(t, x, n) \ + __builtin_choose_expr(sizeof(t) == 1, ({ union { struct { __u8 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 2, ({ union { struct { __u16 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 4, ({ union { struct { __u32 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 8, ({ union { struct { __u64 x; } ___z; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ + __builtin_choose_expr(sizeof(t) == 16, ({ union { struct { __u64 x, y; } ___z; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ + (void)0))))) + +#define ____bpf_ctx_arg0(n, args...) +#define ____bpf_ctx_arg1(n, t, x) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt1(t, x)) +#define ____bpf_ctx_arg2(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt2(t, x, args)) ____bpf_ctx_arg1(n, args) +#define ____bpf_ctx_arg3(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt3(t, x, args)) ____bpf_ctx_arg2(n, args) +#define ____bpf_ctx_arg4(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt4(t, x, args)) ____bpf_ctx_arg3(n, args) +#define ____bpf_ctx_arg5(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt5(t, x, args)) ____bpf_ctx_arg4(n, args) +#define ____bpf_ctx_arg6(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt6(t, x, args)) ____bpf_ctx_arg5(n, args) +#define ____bpf_ctx_arg7(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt7(t, x, args)) ____bpf_ctx_arg6(n, args) +#define ____bpf_ctx_arg8(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt8(t, x, args)) ____bpf_ctx_arg7(n, args) +#define ____bpf_ctx_arg9(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt9(t, x, args)) ____bpf_ctx_arg8(n, args) +#define ____bpf_ctx_arg10(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt10(t, x, args)) ____bpf_ctx_arg9(n, args) +#define ____bpf_ctx_arg11(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt11(t, x, args)) ____bpf_ctx_arg10(n, args) +#define ____bpf_ctx_arg12(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt12(t, x, args)) ____bpf_ctx_arg11(n, args) +#define ____bpf_ctx_arg(n, args...) ___bpf_apply(____bpf_ctx_arg, ____bpf_narg(args))(n, args) + +#define ____bpf_ctx_decl0() +#define ____bpf_ctx_decl1(t, x) , t x +#define ____bpf_ctx_decl2(t, x, args...) , t x ____bpf_ctx_decl1(args) +#define ____bpf_ctx_decl3(t, x, args...) , t x ____bpf_ctx_decl2(args) +#define ____bpf_ctx_decl4(t, x, args...) , t x ____bpf_ctx_decl3(args) +#define ____bpf_ctx_decl5(t, x, args...) , t x ____bpf_ctx_decl4(args) +#define ____bpf_ctx_decl6(t, x, args...) , t x ____bpf_ctx_decl5(args) +#define ____bpf_ctx_decl7(t, x, args...) , t x ____bpf_ctx_decl6(args) +#define ____bpf_ctx_decl8(t, x, args...) , t x ____bpf_ctx_decl7(args) +#define ____bpf_ctx_decl9(t, x, args...) , t x ____bpf_ctx_decl8(args) +#define ____bpf_ctx_decl10(t, x, args...) , t x ____bpf_ctx_decl9(args) +#define ____bpf_ctx_decl11(t, x, args...) , t x ____bpf_ctx_decl10(args) +#define ____bpf_ctx_decl12(t, x, args...) , t x ____bpf_ctx_decl11(args) +#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, ____bpf_narg(args))(args) + +/* + * BPF_PROG2 can handle struct arguments. + */ +#define BPF_PROG2(name, args...) \ +name(unsigned long long *ctx); \ +static __always_inline typeof(name(0)) \ +____##name(unsigned long long *ctx ____bpf_ctx_decl(args)); \ +typeof(name(0)) name(unsigned long long *ctx) \ +{ \ + return ____##name(ctx ____bpf_ctx_arg(____bpf_reg_cnt(args), args)); \ +} \ +static __always_inline typeof(name(0)) \ +____##name(unsigned long long *ctx ____bpf_ctx_decl(args)) + struct pt_regs; #define ___bpf_kprobe_args0() ctx -- cgit v1.3-18-gd494 From 665f5d3577ef43e929d59cf39683037887c351bf Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 9 Sep 2022 16:15:11 +0200 Subject: libbpf: Remove gcc support for bpf_tail_call_static for now This reverts commit 14e5ce79943a ("libbpf: Add GCC support for bpf_tail_call_static"). Reason is that gcc invented their own BPF asm which is not conform with LLVM one, and going forward this would be more painful to maintain here and in other areas of the library. Thus remove it; ask to gcc folks is to align with LLVM one to use exact same syntax. Fixes: 14e5ce79943a ("libbpf: Add GCC support for bpf_tail_call_static") Signed-off-by: Daniel Borkmann Cc: James Hilliard Cc: Jose E. Marchesi --- tools/lib/bpf/bpf_helpers.h | 19 ++++++------------- 1 file changed, 6 insertions(+), 13 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 867b734839dd..7349b16b8e2f 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -131,7 +131,7 @@ /* * Helper function to perform a tail call with a constant/immediate map slot. */ -#if (!defined(__clang__) || __clang_major__ >= 8) && defined(__bpf__) +#if __clang_major__ >= 8 && defined(__bpf__) static __always_inline void bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) { @@ -139,8 +139,8 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) __bpf_unreachable(); /* - * Provide a hard guarantee that the compiler won't optimize setting r2 - * (map pointer) and r3 (constant map index) from _different paths_ ending + * Provide a hard guarantee that LLVM won't optimize setting r2 (map + * pointer) and r3 (constant map index) from _different paths_ ending * up at the _same_ call insn as otherwise we won't be able to use the * jmpq/nopl retpoline-free patching by the x86-64 JIT in the kernel * given they mismatch. See also d2e4c1e6c294 ("bpf: Constant map key @@ -148,19 +148,12 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) * * Note on clobber list: we need to stay in-line with BPF calling * convention, so even if we don't end up using r0, r4, r5, we need - * to mark them as clobber so that the compiler doesn't end up using - * them before / after the call. + * to mark them as clobber so that LLVM doesn't end up using them + * before / after the call. */ - asm volatile( -#ifdef __clang__ - "r1 = %[ctx]\n\t" + asm volatile("r1 = %[ctx]\n\t" "r2 = %[map]\n\t" "r3 = %[slot]\n\t" -#else - "mov %%r1,%[ctx]\n\t" - "mov %%r2,%[map]\n\t" - "mov %%r3,%[slot]\n\t" -#endif "call 12" :: [ctx]"r"(ctx), [map]"r"(map), [slot]"i"(slot) : "r0", "r1", "r2", "r3", "r4", "r5"); -- cgit v1.3-18-gd494 From 749c202cb6ea40f4d7ac95c4a1217a7b506f43a8 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 9 Sep 2022 12:30:52 -0700 Subject: libbpf: Fix crash if SEC("freplace") programs don't have attach_prog_fd set Fix SIGSEGV caused by libbpf trying to find attach type in vmlinux BTF for freplace programs. It's wrong to search in vmlinux BTF and libbpf doesn't even mark vmlinux BTF as required for freplace programs. So trying to search anything in obj->vmlinux_btf might cause NULL dereference if nothing else in BPF object requires vmlinux BTF. Instead, error out if freplace (EXT) program doesn't specify attach_prog_fd during at the load time. Fixes: 91abb4a6d79d ("libbpf: Support attachment of BPF tracing programs to kernel modules") Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Link: https://lore.kernel.org/bpf/20220909193053.577111-3-andrii@kernel.org --- tools/lib/bpf/libbpf.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 3ad139285fad..2ca30ccc774c 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -9084,11 +9084,15 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac int err = 0; /* BPF program's BTF ID */ - if (attach_prog_fd) { + if (prog->type == BPF_PROG_TYPE_EXT || attach_prog_fd) { + if (!attach_prog_fd) { + pr_warn("prog '%s': attach program FD is not set\n", prog->name); + return -EINVAL; + } err = libbpf_find_prog_btf_id(attach_name, attach_prog_fd); if (err < 0) { - pr_warn("failed to find BPF program (FD %d) BTF ID for '%s': %d\n", - attach_prog_fd, attach_name, err); + pr_warn("prog '%s': failed to find BPF program (FD %d) BTF ID for '%s': %d\n", + prog->name, attach_prog_fd, attach_name, err); return err; } *btf_obj_fd = 0; @@ -9105,7 +9109,8 @@ static int libbpf_find_attach_btf_id(struct bpf_program *prog, const char *attac err = find_kernel_btf_id(prog->obj, attach_name, attach_type, btf_obj_fd, btf_type_id); } if (err) { - pr_warn("failed to find kernel BTF type ID of '%s': %d\n", attach_name, err); + pr_warn("prog '%s': failed to find kernel BTF type ID of '%s': %d\n", + prog->name, attach_name, err); return err; } return 0; -- cgit v1.3-18-gd494 From dc567045f1590f6460d3e9a6ea6ad5e600b58b84 Mon Sep 17 00:00:00 2001 From: Xin Liu Date: Tue, 13 Sep 2022 15:36:43 +0800 Subject: libbpf: Clean up legacy bpf maps declaration in bpf_helpers Legacy BPF map declarations are no longer supported in libbpf v1.0 [0]. Only BTF-defined maps are supported starting from v1.0, so it is time to remove the definition of bpf_map_def in bpf_helpers.h. [0] https://github.com/libbpf/libbpf/wiki/Libbpf:-the-road-to-v1.0 Signed-off-by: Xin Liu Signed-off-by: Daniel Borkmann Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20220913073643.19960-1-liuxin350@huawei.com --- tools/lib/bpf/bpf_helpers.h | 12 ------------ 1 file changed, 12 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 7349b16b8e2f..d37c4fe2849d 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -160,18 +160,6 @@ bpf_tail_call_static(void *ctx, const void *map, const __u32 slot) } #endif -/* - * Helper structure used by eBPF C program - * to describe BPF map attributes to libbpf loader - */ -struct bpf_map_def { - unsigned int type; - unsigned int key_size; - unsigned int value_size; - unsigned int max_entries; - unsigned int map_flags; -} __attribute__((deprecated("use BTF-defined maps in .maps section"))); - enum libbpf_pin_type { LIBBPF_PIN_NONE, /* PIN_BY_NAME: pin maps by name (in /sys/fs/bpf by default) */ -- cgit v1.3-18-gd494 From 7620bffbf72cd66a5d18e444a143b5b5989efa87 Mon Sep 17 00:00:00 2001 From: Xin Liu Date: Sat, 17 Sep 2022 16:48:09 +0800 Subject: libbpf: Fix NULL pointer exception in API btf_dump__dump_type_data We found that function btf_dump__dump_type_data can be called by the user as an API, but in this function, the `opts` parameter may be used as a null pointer.This causes `opts->indent_str` to trigger a NULL pointer exception. Fixes: 2ce8450ef5a3 ("libbpf: add bpf_object__open_{file, mem} w/ extensible opts") Signed-off-by: Xin Liu Signed-off-by: Weibin Kong Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220917084809.30770-1-liuxin350@huawei.com --- tools/lib/bpf/btf_dump.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c index 627edb5bb6de..4221f73a74d0 100644 --- a/tools/lib/bpf/btf_dump.c +++ b/tools/lib/bpf/btf_dump.c @@ -2385,7 +2385,7 @@ int btf_dump__dump_type_data(struct btf_dump *d, __u32 id, d->typed_dump->indent_lvl = OPTS_GET(opts, indent_level, 0); /* default indent string is a tab */ - if (!opts->indent_str) + if (!OPTS_GET(opts, indent_str, NULL)) d->typed_dump->indent_str[0] = '\t'; else libbpf_strlcpy(d->typed_dump->indent_str, opts->indent_str, -- cgit v1.3-18-gd494 From 583c1f420173f7d84413a1a1fbf5109d798b4faa Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 19 Sep 2022 19:00:57 -0500 Subject: bpf: Define new BPF_MAP_TYPE_USER_RINGBUF map type We want to support a ringbuf map type where samples are published from user-space, to be consumed by BPF programs. BPF currently supports a kernel -> user-space circular ring buffer via the BPF_MAP_TYPE_RINGBUF map type. We'll need to define a new map type for user-space -> kernel, as none of the helpers exported for BPF_MAP_TYPE_RINGBUF will apply to a user-space producer ring buffer, and we'll want to add one or more helper functions that would not apply for a kernel-producer ring buffer. This patch therefore adds a new BPF_MAP_TYPE_USER_RINGBUF map type definition. The map type is useless in its current form, as there is no way to access or use it for anything until we one or more BPF helpers. A follow-on patch will therefore add a new helper function that allows BPF programs to run callbacks on samples that are published to the ring buffer. Signed-off-by: David Vernet Signed-off-by: Andrii Nakryiko Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220920000100.477320-2-void@manifault.com --- include/linux/bpf_types.h | 1 + include/uapi/linux/bpf.h | 1 + kernel/bpf/ringbuf.c | 62 ++++++++++++++++++++++--- kernel/bpf/verifier.c | 3 ++ tools/bpf/bpftool/Documentation/bpftool-map.rst | 2 +- tools/bpf/bpftool/map.c | 2 +- tools/include/uapi/linux/bpf.h | 1 + tools/lib/bpf/libbpf.c | 1 + 8 files changed, 65 insertions(+), 8 deletions(-) (limited to 'tools/lib') diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 2b9112b80171..2c6a4f2562a7 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -126,6 +126,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops) #endif BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_BLOOM_FILTER, bloom_filter_map_ops) +BPF_MAP_TYPE(BPF_MAP_TYPE_USER_RINGBUF, user_ringbuf_map_ops) BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint) BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 3df78c56c1bf..e18c85324db6 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -928,6 +928,7 @@ enum bpf_map_type { BPF_MAP_TYPE_INODE_STORAGE, BPF_MAP_TYPE_TASK_STORAGE, BPF_MAP_TYPE_BLOOM_FILTER, + BPF_MAP_TYPE_USER_RINGBUF, }; /* Note that tracing related programs such as diff --git a/kernel/bpf/ringbuf.c b/kernel/bpf/ringbuf.c index b483aea35f41..754e915748fb 100644 --- a/kernel/bpf/ringbuf.c +++ b/kernel/bpf/ringbuf.c @@ -38,10 +38,27 @@ struct bpf_ringbuf { struct page **pages; int nr_pages; spinlock_t spinlock ____cacheline_aligned_in_smp; - /* Consumer and producer counters are put into separate pages to allow - * mapping consumer page as r/w, but restrict producer page to r/o. - * This protects producer position from being modified by user-space - * application and ruining in-kernel position tracking. + /* Consumer and producer counters are put into separate pages to + * allow each position to be mapped with different permissions. + * This prevents a user-space application from modifying the + * position and ruining in-kernel tracking. The permissions of the + * pages depend on who is producing samples: user-space or the + * kernel. + * + * Kernel-producer + * --------------- + * The producer position and data pages are mapped as r/o in + * userspace. For this approach, bits in the header of samples are + * used to signal to user-space, and to other producers, whether a + * sample is currently being written. + * + * User-space producer + * ------------------- + * Only the page containing the consumer position is mapped r/o in + * user-space. User-space producers also use bits of the header to + * communicate to the kernel, but the kernel must carefully check and + * validate each sample to ensure that they're correctly formatted, and + * fully contained within the ring buffer. */ unsigned long consumer_pos __aligned(PAGE_SIZE); unsigned long producer_pos __aligned(PAGE_SIZE); @@ -224,7 +241,7 @@ static int ringbuf_map_get_next_key(struct bpf_map *map, void *key, return -ENOTSUPP; } -static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) +static int ringbuf_map_mmap_kern(struct bpf_map *map, struct vm_area_struct *vma) { struct bpf_ringbuf_map *rb_map; @@ -242,6 +259,26 @@ static int ringbuf_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) vma->vm_pgoff + RINGBUF_PGOFF); } +static int ringbuf_map_mmap_user(struct bpf_map *map, struct vm_area_struct *vma) +{ + struct bpf_ringbuf_map *rb_map; + + rb_map = container_of(map, struct bpf_ringbuf_map, map); + + if (vma->vm_flags & VM_WRITE) { + if (vma->vm_pgoff == 0) + /* Disallow writable mappings to the consumer pointer, + * and allow writable mappings to both the producer + * position, and the ring buffer data itself. + */ + return -EPERM; + } else { + vma->vm_flags &= ~VM_MAYWRITE; + } + /* remap_vmalloc_range() checks size and offset constraints */ + return remap_vmalloc_range(vma, rb_map->rb, vma->vm_pgoff + RINGBUF_PGOFF); +} + static unsigned long ringbuf_avail_data_sz(struct bpf_ringbuf *rb) { unsigned long cons_pos, prod_pos; @@ -269,7 +306,7 @@ const struct bpf_map_ops ringbuf_map_ops = { .map_meta_equal = bpf_map_meta_equal, .map_alloc = ringbuf_map_alloc, .map_free = ringbuf_map_free, - .map_mmap = ringbuf_map_mmap, + .map_mmap = ringbuf_map_mmap_kern, .map_poll = ringbuf_map_poll, .map_lookup_elem = ringbuf_map_lookup_elem, .map_update_elem = ringbuf_map_update_elem, @@ -278,6 +315,19 @@ const struct bpf_map_ops ringbuf_map_ops = { .map_btf_id = &ringbuf_map_btf_ids[0], }; +BTF_ID_LIST_SINGLE(user_ringbuf_map_btf_ids, struct, bpf_ringbuf_map) +const struct bpf_map_ops user_ringbuf_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc = ringbuf_map_alloc, + .map_free = ringbuf_map_free, + .map_mmap = ringbuf_map_mmap_user, + .map_lookup_elem = ringbuf_map_lookup_elem, + .map_update_elem = ringbuf_map_update_elem, + .map_delete_elem = ringbuf_map_delete_elem, + .map_get_next_key = ringbuf_map_get_next_key, + .map_btf_id = &user_ringbuf_map_btf_ids[0], +}; + /* Given pointer to ring buffer record metadata and struct bpf_ringbuf itself, * calculate offset from record metadata to ring buffer in pages, rounded * down. This page offset is stored as part of record metadata and allows to diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 8c6fbcd0afaf..83710b60e708 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -6240,6 +6240,8 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env, func_id != BPF_FUNC_ringbuf_discard_dynptr) goto error; break; + case BPF_MAP_TYPE_USER_RINGBUF: + goto error; case BPF_MAP_TYPE_STACK_TRACE: if (func_id != BPF_FUNC_get_stackid) goto error; @@ -12635,6 +12637,7 @@ static int check_map_prog_compatibility(struct bpf_verifier_env *env, case BPF_MAP_TYPE_ARRAY_OF_MAPS: case BPF_MAP_TYPE_HASH_OF_MAPS: case BPF_MAP_TYPE_RINGBUF: + case BPF_MAP_TYPE_USER_RINGBUF: case BPF_MAP_TYPE_INODE_STORAGE: case BPF_MAP_TYPE_SK_STORAGE: case BPF_MAP_TYPE_TASK_STORAGE: diff --git a/tools/bpf/bpftool/Documentation/bpftool-map.rst b/tools/bpf/bpftool/Documentation/bpftool-map.rst index 7c188a598444..7f3b67a8b48f 100644 --- a/tools/bpf/bpftool/Documentation/bpftool-map.rst +++ b/tools/bpf/bpftool/Documentation/bpftool-map.rst @@ -55,7 +55,7 @@ MAP COMMANDS | | **devmap** | **devmap_hash** | **sockmap** | **cpumap** | **xskmap** | **sockhash** | | **cgroup_storage** | **reuseport_sockarray** | **percpu_cgroup_storage** | | **queue** | **stack** | **sk_storage** | **struct_ops** | **ringbuf** | **inode_storage** -| | **task_storage** | **bloom_filter** } +| | **task_storage** | **bloom_filter** | **user_ringbuf** } DESCRIPTION =========== diff --git a/tools/bpf/bpftool/map.c b/tools/bpf/bpftool/map.c index 38b6bc9c26c3..9a6ca9f31133 100644 --- a/tools/bpf/bpftool/map.c +++ b/tools/bpf/bpftool/map.c @@ -1459,7 +1459,7 @@ static int do_help(int argc, char **argv) " devmap | devmap_hash | sockmap | cpumap | xskmap | sockhash |\n" " cgroup_storage | reuseport_sockarray | percpu_cgroup_storage |\n" " queue | stack | sk_storage | struct_ops | ringbuf | inode_storage |\n" - " task_storage | bloom_filter }\n" + " task_storage | bloom_filter | user_ringbuf }\n" " " HELP_SPEC_OPTIONS " |\n" " {-f|--bpffs} | {-n|--nomount} }\n" "", diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 3df78c56c1bf..e18c85324db6 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -928,6 +928,7 @@ enum bpf_map_type { BPF_MAP_TYPE_INODE_STORAGE, BPF_MAP_TYPE_TASK_STORAGE, BPF_MAP_TYPE_BLOOM_FILTER, + BPF_MAP_TYPE_USER_RINGBUF, }; /* Note that tracing related programs such as diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 2ca30ccc774c..d480da05b6de 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -163,6 +163,7 @@ static const char * const map_type_name[] = { [BPF_MAP_TYPE_INODE_STORAGE] = "inode_storage", [BPF_MAP_TYPE_TASK_STORAGE] = "task_storage", [BPF_MAP_TYPE_BLOOM_FILTER] = "bloom_filter", + [BPF_MAP_TYPE_USER_RINGBUF] = "user_ringbuf", }; static const char * const prog_type_name[] = { -- cgit v1.3-18-gd494 From b66ccae01f1ddce47fe2c7f393a3a5c5ab3d7f06 Mon Sep 17 00:00:00 2001 From: David Vernet Date: Mon, 19 Sep 2022 19:00:59 -0500 Subject: bpf: Add libbpf logic for user-space ring buffer Now that all of the logic is in place in the kernel to support user-space produced ring buffers, we can add the user-space logic to libbpf. This patch therefore adds the following public symbols to libbpf: struct user_ring_buffer * user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts); void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample); void user_ring_buffer__discard(struct user_ring_buffer *rb, void user_ring_buffer__free(struct user_ring_buffer *rb); A user-space producer must first create a struct user_ring_buffer * object with user_ring_buffer__new(), and can then reserve samples in the ring buffer using one of the following two symbols: void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms); With user_ring_buffer__reserve(), a pointer to a 'size' region of the ring buffer will be returned if sufficient space is available in the buffer. user_ring_buffer__reserve_blocking() provides similar semantics, but will block for up to 'timeout_ms' in epoll_wait if there is insufficient space in the buffer. This function has the guarantee from the kernel that it will receive at least one event-notification per invocation to bpf_ringbuf_drain(), provided that at least one sample is drained, and the BPF program did not pass the BPF_RB_NO_WAKEUP flag to bpf_ringbuf_drain(). Once a sample is reserved, it must either be committed to the ring buffer with user_ring_buffer__submit(), or discarded with user_ring_buffer__discard(). Signed-off-by: David Vernet Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220920000100.477320-4-void@manifault.com --- tools/lib/bpf/libbpf.c | 10 +- tools/lib/bpf/libbpf.h | 107 ++++++++++++++++ tools/lib/bpf/libbpf.map | 10 ++ tools/lib/bpf/libbpf_probes.c | 1 + tools/lib/bpf/libbpf_version.h | 2 +- tools/lib/bpf/ringbuf.c | 271 +++++++++++++++++++++++++++++++++++++++++ 6 files changed, 398 insertions(+), 3 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index d480da05b6de..67bc18506150 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2373,6 +2373,12 @@ static size_t adjust_ringbuf_sz(size_t sz) return sz; } +static bool map_is_ringbuf(const struct bpf_map *map) +{ + return map->def.type == BPF_MAP_TYPE_RINGBUF || + map->def.type == BPF_MAP_TYPE_USER_RINGBUF; +} + static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) { map->def.type = def->map_type; @@ -2387,7 +2393,7 @@ static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def map->btf_value_type_id = def->value_type_id; /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ - if (map->def.type == BPF_MAP_TYPE_RINGBUF) + if (map_is_ringbuf(map)) map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); if (def->parts & MAP_DEF_MAP_TYPE) @@ -4370,7 +4376,7 @@ int bpf_map__set_max_entries(struct bpf_map *map, __u32 max_entries) map->def.max_entries = max_entries; /* auto-adjust BPF ringbuf map max_entries to be a multiple of page size */ - if (map->def.type == BPF_MAP_TYPE_RINGBUF) + if (map_is_ringbuf(map)) map->def.max_entries = adjust_ringbuf_sz(map->def.max_entries); return 0; diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 88a1ac34b12a..e2d8c17f2e85 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -1011,6 +1011,7 @@ LIBBPF_API int bpf_tc_query(const struct bpf_tc_hook *hook, /* Ring buffer APIs */ struct ring_buffer; +struct user_ring_buffer; typedef int (*ring_buffer_sample_fn)(void *ctx, void *data, size_t size); @@ -1030,6 +1031,112 @@ LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms); LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb); LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb); +struct user_ring_buffer_opts { + size_t sz; /* size of this struct, for forward/backward compatibility */ +}; + +#define user_ring_buffer_opts__last_field sz + +/* @brief **user_ring_buffer__new()** creates a new instance of a user ring + * buffer. + * + * @param map_fd A file descriptor to a BPF_MAP_TYPE_USER_RINGBUF map. + * @param opts Options for how the ring buffer should be created. + * @return A user ring buffer on success; NULL and errno being set on a + * failure. + */ +LIBBPF_API struct user_ring_buffer * +user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts); + +/* @brief **user_ring_buffer__reserve()** reserves a pointer to a sample in the + * user ring buffer. + * @param rb A pointer to a user ring buffer. + * @param size The size of the sample, in bytes. + * @return A pointer to an 8-byte aligned reserved region of the user ring + * buffer; NULL, and errno being set if a sample could not be reserved. + * + * This function is *not* thread safe, and callers must synchronize accessing + * this function if there are multiple producers. If a size is requested that + * is larger than the size of the entire ring buffer, errno will be set to + * E2BIG and NULL is returned. If the ring buffer could accommodate the size, + * but currently does not have enough space, errno is set to ENOSPC and NULL is + * returned. + * + * After initializing the sample, callers must invoke + * **user_ring_buffer__submit()** to post the sample to the kernel. Otherwise, + * the sample must be freed with **user_ring_buffer__discard()**. + */ +LIBBPF_API void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size); + +/* @brief **user_ring_buffer__reserve_blocking()** reserves a record in the + * ring buffer, possibly blocking for up to @timeout_ms until a sample becomes + * available. + * @param rb The user ring buffer. + * @param size The size of the sample, in bytes. + * @param timeout_ms The amount of time, in milliseconds, for which the caller + * should block when waiting for a sample. -1 causes the caller to block + * indefinitely. + * @return A pointer to an 8-byte aligned reserved region of the user ring + * buffer; NULL, and errno being set if a sample could not be reserved. + * + * This function is *not* thread safe, and callers must synchronize + * accessing this function if there are multiple producers + * + * If **timeout_ms** is -1, the function will block indefinitely until a sample + * becomes available. Otherwise, **timeout_ms** must be non-negative, or errno + * is set to EINVAL, and NULL is returned. If **timeout_ms** is 0, no blocking + * will occur and the function will return immediately after attempting to + * reserve a sample. + * + * If **size** is larger than the size of the entire ring buffer, errno is set + * to E2BIG and NULL is returned. If the ring buffer could accommodate + * **size**, but currently does not have enough space, the caller will block + * until at most **timeout_ms** has elapsed. If insufficient space is available + * at that time, errno is set to ENOSPC, and NULL is returned. + * + * The kernel guarantees that it will wake up this thread to check if + * sufficient space is available in the ring buffer at least once per + * invocation of the **bpf_ringbuf_drain()** helper function, provided that at + * least one sample is consumed, and the BPF program did not invoke the + * function with BPF_RB_NO_WAKEUP. A wakeup may occur sooner than that, but the + * kernel does not guarantee this. If the helper function is invoked with + * BPF_RB_FORCE_WAKEUP, a wakeup event will be sent even if no sample is + * consumed. + * + * When a sample of size **size** is found within **timeout_ms**, a pointer to + * the sample is returned. After initializing the sample, callers must invoke + * **user_ring_buffer__submit()** to post the sample to the ring buffer. + * Otherwise, the sample must be freed with **user_ring_buffer__discard()**. + */ +LIBBPF_API void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, + __u32 size, + int timeout_ms); + +/* @brief **user_ring_buffer__submit()** submits a previously reserved sample + * into the ring buffer. + * @param rb The user ring buffer. + * @param sample A reserved sample. + * + * It is not necessary to synchronize amongst multiple producers when invoking + * this function. + */ +LIBBPF_API void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample); + +/* @brief **user_ring_buffer__discard()** discards a previously reserved sample. + * @param rb The user ring buffer. + * @param sample A reserved sample. + * + * It is not necessary to synchronize amongst multiple producers when invoking + * this function. + */ +LIBBPF_API void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample); + +/* @brief **user_ring_buffer__free()** frees a ring buffer that was previously + * created with **user_ring_buffer__new()**. + * @param rb The user ring buffer being freed. + */ +LIBBPF_API void user_ring_buffer__free(struct user_ring_buffer *rb); + /* Perf buffer APIs */ struct perf_buffer; diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 2b928dc21af0..c1d6aa7c82b6 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -368,3 +368,13 @@ LIBBPF_1.0.0 { libbpf_bpf_prog_type_str; perf_buffer__buffer; }; + +LIBBPF_1.1.0 { + global: + user_ring_buffer__discard; + user_ring_buffer__free; + user_ring_buffer__new; + user_ring_buffer__reserve; + user_ring_buffer__reserve_blocking; + user_ring_buffer__submit; +} LIBBPF_1.0.0; diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c index 6d495656f554..f3a8e8e74eb8 100644 --- a/tools/lib/bpf/libbpf_probes.c +++ b/tools/lib/bpf/libbpf_probes.c @@ -231,6 +231,7 @@ static int probe_map_create(enum bpf_map_type map_type) return btf_fd; break; case BPF_MAP_TYPE_RINGBUF: + case BPF_MAP_TYPE_USER_RINGBUF: key_size = 0; value_size = 0; max_entries = 4096; diff --git a/tools/lib/bpf/libbpf_version.h b/tools/lib/bpf/libbpf_version.h index 2fb2f4290080..e944f5bce728 100644 --- a/tools/lib/bpf/libbpf_version.h +++ b/tools/lib/bpf/libbpf_version.h @@ -4,6 +4,6 @@ #define __LIBBPF_VERSION_H #define LIBBPF_MAJOR_VERSION 1 -#define LIBBPF_MINOR_VERSION 0 +#define LIBBPF_MINOR_VERSION 1 #endif /* __LIBBPF_VERSION_H */ diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c index 8bc117bcc7bc..d285171d4b69 100644 --- a/tools/lib/bpf/ringbuf.c +++ b/tools/lib/bpf/ringbuf.c @@ -16,6 +16,7 @@ #include #include #include +#include #include "libbpf.h" #include "libbpf_internal.h" @@ -39,6 +40,23 @@ struct ring_buffer { int ring_cnt; }; +struct user_ring_buffer { + struct epoll_event event; + unsigned long *consumer_pos; + unsigned long *producer_pos; + void *data; + unsigned long mask; + size_t page_size; + int map_fd; + int epoll_fd; +}; + +/* 8-byte ring buffer header structure */ +struct ringbuf_hdr { + __u32 len; + __u32 pad; +}; + static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r) { if (r->consumer_pos) { @@ -300,3 +318,256 @@ int ring_buffer__epoll_fd(const struct ring_buffer *rb) { return rb->epoll_fd; } + +static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb) +{ + if (rb->consumer_pos) { + munmap(rb->consumer_pos, rb->page_size); + rb->consumer_pos = NULL; + } + if (rb->producer_pos) { + munmap(rb->producer_pos, rb->page_size + 2 * (rb->mask + 1)); + rb->producer_pos = NULL; + } +} + +void user_ring_buffer__free(struct user_ring_buffer *rb) +{ + if (!rb) + return; + + user_ringbuf_unmap_ring(rb); + + if (rb->epoll_fd >= 0) + close(rb->epoll_fd); + + free(rb); +} + +static int user_ringbuf_map(struct user_ring_buffer *rb, int map_fd) +{ + struct bpf_map_info info; + __u32 len = sizeof(info); + void *tmp; + struct epoll_event *rb_epoll; + int err; + + memset(&info, 0, sizeof(info)); + + err = bpf_obj_get_info_by_fd(map_fd, &info, &len); + if (err) { + err = -errno; + pr_warn("user ringbuf: failed to get map info for fd=%d: %d\n", map_fd, err); + return err; + } + + if (info.type != BPF_MAP_TYPE_USER_RINGBUF) { + pr_warn("user ringbuf: map fd=%d is not BPF_MAP_TYPE_USER_RINGBUF\n", map_fd); + return -EINVAL; + } + + rb->map_fd = map_fd; + rb->mask = info.max_entries - 1; + + /* Map read-only consumer page */ + tmp = mmap(NULL, rb->page_size, PROT_READ, MAP_SHARED, map_fd, 0); + if (tmp == MAP_FAILED) { + err = -errno; + pr_warn("user ringbuf: failed to mmap consumer page for map fd=%d: %d\n", + map_fd, err); + return err; + } + rb->consumer_pos = tmp; + + /* Map read-write the producer page and data pages. We map the data + * region as twice the total size of the ring buffer to allow the + * simple reading and writing of samples that wrap around the end of + * the buffer. See the kernel implementation for details. + */ + tmp = mmap(NULL, rb->page_size + 2 * info.max_entries, + PROT_READ | PROT_WRITE, MAP_SHARED, map_fd, rb->page_size); + if (tmp == MAP_FAILED) { + err = -errno; + pr_warn("user ringbuf: failed to mmap data pages for map fd=%d: %d\n", + map_fd, err); + return err; + } + + rb->producer_pos = tmp; + rb->data = tmp + rb->page_size; + + rb_epoll = &rb->event; + rb_epoll->events = EPOLLOUT; + if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, rb_epoll) < 0) { + err = -errno; + pr_warn("user ringbuf: failed to epoll add map fd=%d: %d\n", map_fd, err); + return err; + } + + return 0; +} + +struct user_ring_buffer * +user_ring_buffer__new(int map_fd, const struct user_ring_buffer_opts *opts) +{ + struct user_ring_buffer *rb; + int err; + + if (!OPTS_VALID(opts, user_ring_buffer_opts)) + return errno = EINVAL, NULL; + + rb = calloc(1, sizeof(*rb)); + if (!rb) + return errno = ENOMEM, NULL; + + rb->page_size = getpagesize(); + + rb->epoll_fd = epoll_create1(EPOLL_CLOEXEC); + if (rb->epoll_fd < 0) { + err = -errno; + pr_warn("user ringbuf: failed to create epoll instance: %d\n", err); + goto err_out; + } + + err = user_ringbuf_map(rb, map_fd); + if (err) + goto err_out; + + return rb; + +err_out: + user_ring_buffer__free(rb); + return errno = -err, NULL; +} + +static void user_ringbuf_commit(struct user_ring_buffer *rb, void *sample, bool discard) +{ + __u32 new_len; + struct ringbuf_hdr *hdr; + uintptr_t hdr_offset; + + hdr_offset = rb->mask + 1 + (sample - rb->data) - BPF_RINGBUF_HDR_SZ; + hdr = rb->data + (hdr_offset & rb->mask); + + new_len = hdr->len & ~BPF_RINGBUF_BUSY_BIT; + if (discard) + new_len |= BPF_RINGBUF_DISCARD_BIT; + + /* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + __atomic_exchange_n(&hdr->len, new_len, __ATOMIC_ACQ_REL); +} + +void user_ring_buffer__discard(struct user_ring_buffer *rb, void *sample) +{ + user_ringbuf_commit(rb, sample, true); +} + +void user_ring_buffer__submit(struct user_ring_buffer *rb, void *sample) +{ + user_ringbuf_commit(rb, sample, false); +} + +void *user_ring_buffer__reserve(struct user_ring_buffer *rb, __u32 size) +{ + __u32 avail_size, total_size, max_size; + /* 64-bit to avoid overflow in case of extreme application behavior */ + __u64 cons_pos, prod_pos; + struct ringbuf_hdr *hdr; + + /* Synchronizes with smp_store_release() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + cons_pos = smp_load_acquire(rb->consumer_pos); + /* Synchronizes with smp_store_release() in user_ringbuf_commit() */ + prod_pos = smp_load_acquire(rb->producer_pos); + + max_size = rb->mask + 1; + avail_size = max_size - (prod_pos - cons_pos); + /* Round up total size to a multiple of 8. */ + total_size = (size + BPF_RINGBUF_HDR_SZ + 7) / 8 * 8; + + if (total_size > max_size) + return errno = E2BIG, NULL; + + if (avail_size < total_size) + return errno = ENOSPC, NULL; + + hdr = rb->data + (prod_pos & rb->mask); + hdr->len = size | BPF_RINGBUF_BUSY_BIT; + hdr->pad = 0; + + /* Synchronizes with smp_load_acquire() in __bpf_user_ringbuf_peek() in + * the kernel. + */ + smp_store_release(rb->producer_pos, prod_pos + total_size); + + return (void *)rb->data + ((prod_pos + BPF_RINGBUF_HDR_SZ) & rb->mask); +} + +static __u64 ns_elapsed_timespec(const struct timespec *start, const struct timespec *end) +{ + __u64 start_ns, end_ns, ns_per_s = 1000000000; + + start_ns = (__u64)start->tv_sec * ns_per_s + start->tv_nsec; + end_ns = (__u64)end->tv_sec * ns_per_s + end->tv_nsec; + + return end_ns - start_ns; +} + +void *user_ring_buffer__reserve_blocking(struct user_ring_buffer *rb, __u32 size, int timeout_ms) +{ + void *sample; + int err, ms_remaining = timeout_ms; + struct timespec start; + + if (timeout_ms < 0 && timeout_ms != -1) + return errno = EINVAL, NULL; + + if (timeout_ms != -1) { + err = clock_gettime(CLOCK_MONOTONIC, &start); + if (err) + return NULL; + } + + do { + int cnt, ms_elapsed; + struct timespec curr; + __u64 ns_per_ms = 1000000; + + sample = user_ring_buffer__reserve(rb, size); + if (sample) + return sample; + else if (errno != ENOSPC) + return NULL; + + /* The kernel guarantees at least one event notification + * delivery whenever at least one sample is drained from the + * ring buffer in an invocation to bpf_ringbuf_drain(). Other + * additional events may be delivered at any time, but only one + * event is guaranteed per bpf_ringbuf_drain() invocation, + * provided that a sample is drained, and the BPF program did + * not pass BPF_RB_NO_WAKEUP to bpf_ringbuf_drain(). If + * BPF_RB_FORCE_WAKEUP is passed to bpf_ringbuf_drain(), a + * wakeup event will be delivered even if no samples are + * drained. + */ + cnt = epoll_wait(rb->epoll_fd, &rb->event, 1, ms_remaining); + if (cnt < 0) + return NULL; + + if (timeout_ms == -1) + continue; + + err = clock_gettime(CLOCK_MONOTONIC, &curr); + if (err) + return NULL; + + ms_elapsed = ns_elapsed_timespec(&start, &curr) / ns_per_ms; + ms_remaining = timeout_ms - ms_elapsed; + } while (ms_remaining > 0); + + /* Try one more time to reserve a sample after the specified timeout has elapsed. */ + return user_ring_buffer__reserve(rb, size); +} -- cgit v1.3-18-gd494 From 9f2f5d7830ddfeeca147595f473e14eadbeb3db1 Mon Sep 17 00:00:00 2001 From: Yonghong Song Date: Fri, 9 Sep 2022 19:52:14 -0700 Subject: libbpf: Improve BPF_PROG2 macro code quality and description Commit 34586d29f8df ("libbpf: Add new BPF_PROG2 macro") added BPF_PROG2 macro for trampoline based programs with struct arguments. Andrii made a few suggestions to improve code quality and description. This patch implemented these suggestions including better internal macro name, consistent usage pattern for __builtin_choose_expr(), simpler macro definition for always-inline func arguments and better macro description. Signed-off-by: Yonghong Song Signed-off-by: Andrii Nakryiko Acked-by: Stanislav Fomichev Link: https://lore.kernel.org/bpf/20220910025214.1536510-1-yhs@fb.com --- tools/lib/bpf/bpf_tracing.h | 154 ++++++++++++++++++++++++++------------------ 1 file changed, 91 insertions(+), 63 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h index 8d4bdd18cb3d..2972dc25ff72 100644 --- a/tools/lib/bpf/bpf_tracing.h +++ b/tools/lib/bpf/bpf_tracing.h @@ -438,84 +438,112 @@ typeof(name(0)) name(unsigned long long *ctx) \ static __always_inline typeof(name(0)) \ ____##name(unsigned long long *ctx, ##args) -#ifndef ____bpf_nth -#define ____bpf_nth(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N +#ifndef ___bpf_nth2 +#define ___bpf_nth2(_, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, \ + _14, _15, _16, _17, _18, _19, _20, _21, _22, _23, _24, N, ...) N #endif -#ifndef ____bpf_narg -#define ____bpf_narg(...) ____bpf_nth(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) +#ifndef ___bpf_narg2 +#define ___bpf_narg2(...) \ + ___bpf_nth2(_, ##__VA_ARGS__, 12, 12, 11, 11, 10, 10, 9, 9, 8, 8, 7, 7, \ + 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 1, 1, 0) #endif -#define BPF_REG_CNT(t) \ - (__builtin_choose_expr(sizeof(t) == 1 || sizeof(t) == 2 || sizeof(t) == 4 || sizeof(t) == 8, 1, \ - __builtin_choose_expr(sizeof(t) == 16, 2, \ - (void)0))) - -#define ____bpf_reg_cnt0() (0) -#define ____bpf_reg_cnt1(t, x) (____bpf_reg_cnt0() + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt2(t, x, args...) (____bpf_reg_cnt1(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt3(t, x, args...) (____bpf_reg_cnt2(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt4(t, x, args...) (____bpf_reg_cnt3(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt5(t, x, args...) (____bpf_reg_cnt4(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt6(t, x, args...) (____bpf_reg_cnt5(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt7(t, x, args...) (____bpf_reg_cnt6(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt8(t, x, args...) (____bpf_reg_cnt7(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt9(t, x, args...) (____bpf_reg_cnt8(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt10(t, x, args...) (____bpf_reg_cnt9(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt11(t, x, args...) (____bpf_reg_cnt10(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt12(t, x, args...) (____bpf_reg_cnt11(args) + BPF_REG_CNT(t)) -#define ____bpf_reg_cnt(args...) ___bpf_apply(____bpf_reg_cnt, ____bpf_narg(args))(args) - -#define ____bpf_union_arg(t, x, n) \ - __builtin_choose_expr(sizeof(t) == 1, ({ union { struct { __u8 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]}}; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 2, ({ union { struct { __u16 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 4, ({ union { struct { __u32 x; } ___z; t x; } ___tmp = { .___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 8, ({ union { struct { __u64 x; } ___z; t x; } ___tmp = {.___z = {ctx[n]} }; ___tmp.x; }), \ - __builtin_choose_expr(sizeof(t) == 16, ({ union { struct { __u64 x, y; } ___z; t x; } ___tmp = {.___z = {ctx[n], ctx[n + 1]} }; ___tmp.x; }), \ +#define ___bpf_treg_cnt(t) \ + __builtin_choose_expr(sizeof(t) == 1, 1, \ + __builtin_choose_expr(sizeof(t) == 2, 1, \ + __builtin_choose_expr(sizeof(t) == 4, 1, \ + __builtin_choose_expr(sizeof(t) == 8, 1, \ + __builtin_choose_expr(sizeof(t) == 16, 2, \ (void)0))))) -#define ____bpf_ctx_arg0(n, args...) -#define ____bpf_ctx_arg1(n, t, x) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt1(t, x)) -#define ____bpf_ctx_arg2(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt2(t, x, args)) ____bpf_ctx_arg1(n, args) -#define ____bpf_ctx_arg3(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt3(t, x, args)) ____bpf_ctx_arg2(n, args) -#define ____bpf_ctx_arg4(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt4(t, x, args)) ____bpf_ctx_arg3(n, args) -#define ____bpf_ctx_arg5(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt5(t, x, args)) ____bpf_ctx_arg4(n, args) -#define ____bpf_ctx_arg6(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt6(t, x, args)) ____bpf_ctx_arg5(n, args) -#define ____bpf_ctx_arg7(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt7(t, x, args)) ____bpf_ctx_arg6(n, args) -#define ____bpf_ctx_arg8(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt8(t, x, args)) ____bpf_ctx_arg7(n, args) -#define ____bpf_ctx_arg9(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt9(t, x, args)) ____bpf_ctx_arg8(n, args) -#define ____bpf_ctx_arg10(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt10(t, x, args)) ____bpf_ctx_arg9(n, args) -#define ____bpf_ctx_arg11(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt11(t, x, args)) ____bpf_ctx_arg10(n, args) -#define ____bpf_ctx_arg12(n, t, x, args...) , ____bpf_union_arg(t, x, n - ____bpf_reg_cnt12(t, x, args)) ____bpf_ctx_arg11(n, args) -#define ____bpf_ctx_arg(n, args...) ___bpf_apply(____bpf_ctx_arg, ____bpf_narg(args))(n, args) - -#define ____bpf_ctx_decl0() -#define ____bpf_ctx_decl1(t, x) , t x -#define ____bpf_ctx_decl2(t, x, args...) , t x ____bpf_ctx_decl1(args) -#define ____bpf_ctx_decl3(t, x, args...) , t x ____bpf_ctx_decl2(args) -#define ____bpf_ctx_decl4(t, x, args...) , t x ____bpf_ctx_decl3(args) -#define ____bpf_ctx_decl5(t, x, args...) , t x ____bpf_ctx_decl4(args) -#define ____bpf_ctx_decl6(t, x, args...) , t x ____bpf_ctx_decl5(args) -#define ____bpf_ctx_decl7(t, x, args...) , t x ____bpf_ctx_decl6(args) -#define ____bpf_ctx_decl8(t, x, args...) , t x ____bpf_ctx_decl7(args) -#define ____bpf_ctx_decl9(t, x, args...) , t x ____bpf_ctx_decl8(args) -#define ____bpf_ctx_decl10(t, x, args...) , t x ____bpf_ctx_decl9(args) -#define ____bpf_ctx_decl11(t, x, args...) , t x ____bpf_ctx_decl10(args) -#define ____bpf_ctx_decl12(t, x, args...) , t x ____bpf_ctx_decl11(args) -#define ____bpf_ctx_decl(args...) ___bpf_apply(____bpf_ctx_decl, ____bpf_narg(args))(args) +#define ___bpf_reg_cnt0() (0) +#define ___bpf_reg_cnt1(t, x) (___bpf_reg_cnt0() + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt2(t, x, args...) (___bpf_reg_cnt1(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt3(t, x, args...) (___bpf_reg_cnt2(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt4(t, x, args...) (___bpf_reg_cnt3(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt5(t, x, args...) (___bpf_reg_cnt4(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt6(t, x, args...) (___bpf_reg_cnt5(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt7(t, x, args...) (___bpf_reg_cnt6(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt8(t, x, args...) (___bpf_reg_cnt7(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt9(t, x, args...) (___bpf_reg_cnt8(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt10(t, x, args...) (___bpf_reg_cnt9(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt11(t, x, args...) (___bpf_reg_cnt10(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt12(t, x, args...) (___bpf_reg_cnt11(args) + ___bpf_treg_cnt(t)) +#define ___bpf_reg_cnt(args...) ___bpf_apply(___bpf_reg_cnt, ___bpf_narg2(args))(args) + +#define ___bpf_union_arg(t, x, n) \ + __builtin_choose_expr(sizeof(t) == 1, ({ union { __u8 z[1]; t x; } ___t = { .z = {ctx[n]}}; ___t.x; }), \ + __builtin_choose_expr(sizeof(t) == 2, ({ union { __u16 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \ + __builtin_choose_expr(sizeof(t) == 4, ({ union { __u32 z[1]; t x; } ___t = { .z = {ctx[n]} }; ___t.x; }), \ + __builtin_choose_expr(sizeof(t) == 8, ({ union { __u64 z[1]; t x; } ___t = {.z = {ctx[n]} }; ___t.x; }), \ + __builtin_choose_expr(sizeof(t) == 16, ({ union { __u64 z[2]; t x; } ___t = {.z = {ctx[n], ctx[n + 1]} }; ___t.x; }), \ + (void)0))))) + +#define ___bpf_ctx_arg0(n, args...) +#define ___bpf_ctx_arg1(n, t, x) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt1(t, x)) +#define ___bpf_ctx_arg2(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt2(t, x, args)) ___bpf_ctx_arg1(n, args) +#define ___bpf_ctx_arg3(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt3(t, x, args)) ___bpf_ctx_arg2(n, args) +#define ___bpf_ctx_arg4(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt4(t, x, args)) ___bpf_ctx_arg3(n, args) +#define ___bpf_ctx_arg5(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt5(t, x, args)) ___bpf_ctx_arg4(n, args) +#define ___bpf_ctx_arg6(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt6(t, x, args)) ___bpf_ctx_arg5(n, args) +#define ___bpf_ctx_arg7(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt7(t, x, args)) ___bpf_ctx_arg6(n, args) +#define ___bpf_ctx_arg8(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt8(t, x, args)) ___bpf_ctx_arg7(n, args) +#define ___bpf_ctx_arg9(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt9(t, x, args)) ___bpf_ctx_arg8(n, args) +#define ___bpf_ctx_arg10(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt10(t, x, args)) ___bpf_ctx_arg9(n, args) +#define ___bpf_ctx_arg11(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt11(t, x, args)) ___bpf_ctx_arg10(n, args) +#define ___bpf_ctx_arg12(n, t, x, args...) , ___bpf_union_arg(t, x, n - ___bpf_reg_cnt12(t, x, args)) ___bpf_ctx_arg11(n, args) +#define ___bpf_ctx_arg(args...) ___bpf_apply(___bpf_ctx_arg, ___bpf_narg2(args))(___bpf_reg_cnt(args), args) + +#define ___bpf_ctx_decl0() +#define ___bpf_ctx_decl1(t, x) , t x +#define ___bpf_ctx_decl2(t, x, args...) , t x ___bpf_ctx_decl1(args) +#define ___bpf_ctx_decl3(t, x, args...) , t x ___bpf_ctx_decl2(args) +#define ___bpf_ctx_decl4(t, x, args...) , t x ___bpf_ctx_decl3(args) +#define ___bpf_ctx_decl5(t, x, args...) , t x ___bpf_ctx_decl4(args) +#define ___bpf_ctx_decl6(t, x, args...) , t x ___bpf_ctx_decl5(args) +#define ___bpf_ctx_decl7(t, x, args...) , t x ___bpf_ctx_decl6(args) +#define ___bpf_ctx_decl8(t, x, args...) , t x ___bpf_ctx_decl7(args) +#define ___bpf_ctx_decl9(t, x, args...) , t x ___bpf_ctx_decl8(args) +#define ___bpf_ctx_decl10(t, x, args...) , t x ___bpf_ctx_decl9(args) +#define ___bpf_ctx_decl11(t, x, args...) , t x ___bpf_ctx_decl10(args) +#define ___bpf_ctx_decl12(t, x, args...) , t x ___bpf_ctx_decl11(args) +#define ___bpf_ctx_decl(args...) ___bpf_apply(___bpf_ctx_decl, ___bpf_narg2(args))(args) /* - * BPF_PROG2 can handle struct arguments. + * BPF_PROG2 is an enhanced version of BPF_PROG in order to handle struct + * arguments. Since each struct argument might take one or two u64 values + * in the trampoline stack, argument type size is needed to place proper number + * of u64 values for each argument. Therefore, BPF_PROG2 has different + * syntax from BPF_PROG. For example, for the following BPF_PROG syntax: + * + * int BPF_PROG(test2, int a, int b) { ... } + * + * the corresponding BPF_PROG2 syntax is: + * + * int BPF_PROG2(test2, int, a, int, b) { ... } + * + * where type and the corresponding argument name are separated by comma. + * + * Use BPF_PROG2 macro if one of the arguments might be a struct/union larger + * than 8 bytes: + * + * int BPF_PROG2(test_struct_arg, struct bpf_testmod_struct_arg_1, a, int, b, + * int, c, int, d, struct bpf_testmod_struct_arg_2, e, int, ret) + * { + * // access a, b, c, d, e, and ret directly + * ... + * } */ #define BPF_PROG2(name, args...) \ name(unsigned long long *ctx); \ static __always_inline typeof(name(0)) \ -____##name(unsigned long long *ctx ____bpf_ctx_decl(args)); \ +____##name(unsigned long long *ctx ___bpf_ctx_decl(args)); \ typeof(name(0)) name(unsigned long long *ctx) \ { \ - return ____##name(ctx ____bpf_ctx_arg(____bpf_reg_cnt(args), args)); \ + return ____##name(ctx ___bpf_ctx_arg(args)); \ } \ static __always_inline typeof(name(0)) \ -____##name(unsigned long long *ctx ____bpf_ctx_decl(args)) +____##name(unsigned long long *ctx ___bpf_ctx_decl(args)) struct pt_regs; -- cgit v1.3-18-gd494 From 01f2e36c959c813a532ae836db49b2ac9de46de4 Mon Sep 17 00:00:00 2001 From: Tao Chen Date: Tue, 13 Sep 2022 00:43:00 +0800 Subject: libbpf: Support raw BTF placed in the default search path Currently, the default vmlinux files at '/boot/vmlinux-*', '/lib/modules/*/vmlinux-*' etc. are parsed with 'btf__parse_elf()' to extract BTF. It is possible that these files are actually raw BTF files similar to /sys/kernel/btf/vmlinux. So parse these files with 'btf__parse' which tries both raw format and ELF format. This might be useful in some scenarios where users put their custom BTF into known locations and don't want to specify btf_custom_path option. Signed-off-by: Tao Chen Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song Link: https://lore.kernel.org/bpf/3f59fb5a345d2e4f10e16fe9e35fbc4c03ecaa3e.1662999860.git.chentao.kernel@linux.alibaba.com --- tools/lib/bpf/btf.c | 30 ++++++++++++------------------ 1 file changed, 12 insertions(+), 18 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 361131518d63..b4d9a96c3c1b 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -4642,20 +4642,17 @@ static int btf_dedup_remap_types(struct btf_dedup *d) */ struct btf *btf__load_vmlinux_btf(void) { - struct { - const char *path_fmt; - bool raw_btf; - } locations[] = { + const char *locations[] = { /* try canonical vmlinux BTF through sysfs first */ - { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, - /* fall back to trying to find vmlinux ELF on disk otherwise */ - { "/boot/vmlinux-%1$s" }, - { "/lib/modules/%1$s/vmlinux-%1$s" }, - { "/lib/modules/%1$s/build/vmlinux" }, - { "/usr/lib/modules/%1$s/kernel/vmlinux" }, - { "/usr/lib/debug/boot/vmlinux-%1$s" }, - { "/usr/lib/debug/boot/vmlinux-%1$s.debug" }, - { "/usr/lib/debug/lib/modules/%1$s/vmlinux" }, + "/sys/kernel/btf/vmlinux", + /* fall back to trying to find vmlinux on disk otherwise */ + "/boot/vmlinux-%1$s", + "/lib/modules/%1$s/vmlinux-%1$s", + "/lib/modules/%1$s/build/vmlinux", + "/usr/lib/modules/%1$s/kernel/vmlinux", + "/usr/lib/debug/boot/vmlinux-%1$s", + "/usr/lib/debug/boot/vmlinux-%1$s.debug", + "/usr/lib/debug/lib/modules/%1$s/vmlinux", }; char path[PATH_MAX + 1]; struct utsname buf; @@ -4665,15 +4662,12 @@ struct btf *btf__load_vmlinux_btf(void) uname(&buf); for (i = 0; i < ARRAY_SIZE(locations); i++) { - snprintf(path, PATH_MAX, locations[i].path_fmt, buf.release); + snprintf(path, PATH_MAX, locations[i], buf.release); if (access(path, R_OK)) continue; - if (locations[i].raw_btf) - btf = btf__parse_raw(path); - else - btf = btf__parse_elf(path, NULL); + btf = btf__parse(path, NULL); err = libbpf_get_error(btf); pr_debug("loading kernel BTF '%s': %d\n", path, err); if (err) -- cgit v1.3-18-gd494 From e588c116df6ca64a295017571151992c76d03132 Mon Sep 17 00:00:00 2001 From: Wang Yufen Date: Thu, 22 Sep 2022 14:28:44 +0800 Subject: libbpf: Add pathname_concat() helper Move snprintf and len check to common helper pathname_concat() to make the code simpler. Signed-off-by: Wang Yufen Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/1663828124-10437-1-git-send-email-wangyufen@huawei.com --- tools/lib/bpf/libbpf.c | 76 +++++++++++++++++++------------------------------- 1 file changed, 29 insertions(+), 47 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 67bc18506150..e691f08a297f 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2097,19 +2097,30 @@ static bool get_map_field_int(const char *map_name, const struct btf *btf, return true; } +static int pathname_concat(char *buf, size_t buf_sz, const char *path, const char *name) +{ + int len; + + len = snprintf(buf, buf_sz, "%s/%s", path, name); + if (len < 0) + return -EINVAL; + if (len >= buf_sz) + return -ENAMETOOLONG; + + return 0; +} + static int build_map_pin_path(struct bpf_map *map, const char *path) { char buf[PATH_MAX]; - int len; + int err; if (!path) path = "/sys/fs/bpf"; - len = snprintf(buf, PATH_MAX, "%s/%s", path, bpf_map__name(map)); - if (len < 0) - return -EINVAL; - else if (len >= PATH_MAX) - return -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return err; return bpf_map__set_pin_path(map, buf); } @@ -7968,17 +7979,9 @@ int bpf_object__pin_maps(struct bpf_object *obj, const char *path) continue; if (path) { - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) { - err = -EINVAL; - goto err_unpin_maps; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) goto err_unpin_maps; - } sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { @@ -8016,14 +8019,9 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) char buf[PATH_MAX]; if (path) { - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, - bpf_map__name(map)); - if (len < 0) - return libbpf_err(-EINVAL); - else if (len >= PATH_MAX) - return libbpf_err(-ENAMETOOLONG); + err = pathname_concat(buf, sizeof(buf), path, bpf_map__name(map)); + if (err) + return libbpf_err(err); sanitize_pin_path(buf); pin_path = buf; } else if (!map->pin_path) { @@ -8041,6 +8039,7 @@ int bpf_object__unpin_maps(struct bpf_object *obj, const char *path) int bpf_object__pin_programs(struct bpf_object *obj, const char *path) { struct bpf_program *prog; + char buf[PATH_MAX]; int err; if (!obj) @@ -8052,17 +8051,9 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path) } bpf_object__for_each_program(prog, obj) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name); - if (len < 0) { - err = -EINVAL; - goto err_unpin_programs; - } else if (len >= PATH_MAX) { - err = -ENAMETOOLONG; + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) goto err_unpin_programs; - } err = bpf_program__pin(prog, buf); if (err) @@ -8073,13 +8064,7 @@ int bpf_object__pin_programs(struct bpf_object *obj, const char *path) err_unpin_programs: while ((prog = bpf_object__prev_program(obj, prog))) { - char buf[PATH_MAX]; - int len; - - len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name); - if (len < 0) - continue; - else if (len >= PATH_MAX) + if (pathname_concat(buf, sizeof(buf), path, prog->name)) continue; bpf_program__unpin(prog, buf); @@ -8098,13 +8083,10 @@ int bpf_object__unpin_programs(struct bpf_object *obj, const char *path) bpf_object__for_each_program(prog, obj) { char buf[PATH_MAX]; - int len; - len = snprintf(buf, PATH_MAX, "%s/%s", path, prog->name); - if (len < 0) - return libbpf_err(-EINVAL); - else if (len >= PATH_MAX) - return libbpf_err(-ENAMETOOLONG); + err = pathname_concat(buf, sizeof(buf), path, prog->name); + if (err) + return libbpf_err(err); err = bpf_program__unpin(prog, buf); if (err) -- cgit v1.3-18-gd494 From dbdea9b36fb61da3b9a1be0dd63542e2bfd3e5d7 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 23 Sep 2022 16:05:59 -0700 Subject: libbpf: restore memory layout of bpf_object_open_opts When attach_prog_fd field was removed in libbpf 1.0 and replaced with `long: 0` placeholder, it actually shifted all the subsequent fields by 8 byte. This is due to `long: 0` promising to adjust next field's offset to long-aligned offset. But in this case we were already long-aligned as pin_root_path is a pointer. So `long: 0` had no effect, and thus didn't feel the gap created by removed attach_prog_fd. Non-zero bitfield should have been used instead. I validated using pahole. Originally kconfig field was at offset 40. With `long: 0` it's at offset 32, which is wrong. With this change it's back at offset 40. While technically libbpf 1.0 is allowed to break backwards compatibility and applications should have been recompiled against libbpf 1.0 headers, but given how trivial it is to preserve memory layout, let's fix this. Reported-by: Grant Seltzer Richman Fixes: 146bf811f5ac ("libbpf: remove most other deprecated high-level APIs") Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/r/20220923230559.666608-1-andrii@kernel.org Signed-off-by: Martin KaFai Lau --- tools/lib/bpf/libbpf.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index e2d8c17f2e85..eee883f007f9 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -118,7 +118,9 @@ struct bpf_object_open_opts { * auto-pinned to that path on load; defaults to "/sys/fs/bpf". */ const char *pin_root_path; - long :0; + + __u32 :32; /* stub out now removed attach_prog_fd */ + /* Additional kernel config content that augments and overrides * system Kconfig for CONFIG_xxx externs. */ -- cgit v1.3-18-gd494 From 6a4ab8869d0bfcf83d7c5184561df8235553cf28 Mon Sep 17 00:00:00 2001 From: Jon Doron Date: Sun, 25 Sep 2022 10:04:31 +0300 Subject: libbpf: Fix the case of running as non-root with capabilities When running rootless with special capabilities like: FOWNER / DAC_OVERRIDE / DAC_READ_SEARCH The "access" API will not make the proper check if there is really access to a file or not. >From the access man page: " The check is done using the calling process's real UID and GID, rather than the effective IDs as is done when actually attempting an operation (e.g., open(2)) on the file. Similarly, for the root user, the check uses the set of permitted capabilities rather than the set of effective capabilities; ***and for non-root users, the check uses an empty set of capabilities.*** " What that means is that for non-root user the access API will not do the proper validation if the process really has permission to a file or not. To resolve this this patch replaces all the access API calls with faccessat with AT_EACCESS flag. Signed-off-by: Jon Doron Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220925070431.1313680-1-arilou@gmail.com --- tools/lib/bpf/btf.c | 2 +- tools/lib/bpf/libbpf.c | 6 +++--- tools/lib/bpf/usdt.c | 2 +- 3 files changed, 5 insertions(+), 5 deletions(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index b4d9a96c3c1b..d88647da2c7f 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -4664,7 +4664,7 @@ struct btf *btf__load_vmlinux_btf(void) for (i = 0; i < ARRAY_SIZE(locations); i++) { snprintf(path, PATH_MAX, locations[i], buf.release); - if (access(path, R_OK)) + if (faccessat(AT_FDCWD, path, R_OK, AT_EACCESS)) continue; btf = btf__parse(path, NULL); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e691f08a297f..184ce1684dcd 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -884,7 +884,7 @@ __u32 get_kernel_version(void) __u32 major, minor, patch; struct utsname info; - if (access(ubuntu_kver_file, R_OK) == 0) { + if (faccessat(AT_FDCWD, ubuntu_kver_file, R_OK, AT_EACCESS) == 0) { FILE *f; f = fopen(ubuntu_kver_file, "r"); @@ -9904,7 +9904,7 @@ static bool use_debugfs(void) static int has_debugfs = -1; if (has_debugfs < 0) - has_debugfs = access(DEBUGFS, F_OK) == 0; + has_debugfs = faccessat(AT_FDCWD, DEBUGFS, F_OK, AT_EACCESS) == 0; return has_debugfs == 1; } @@ -10721,7 +10721,7 @@ static int resolve_full_path(const char *file, char *result, size_t result_sz) continue; snprintf(result, result_sz, "%.*s/%s", seg_len, s, file); /* ensure it has required permissions */ - if (access(result, perm) < 0) + if (faccessat(AT_FDCWD, result, perm, AT_EACCESS) < 0) continue; pr_debug("resolved '%s' to '%s'\n", file, result); return 0; diff --git a/tools/lib/bpf/usdt.c b/tools/lib/bpf/usdt.c index d18e37982344..e83b497c2245 100644 --- a/tools/lib/bpf/usdt.c +++ b/tools/lib/bpf/usdt.c @@ -282,7 +282,7 @@ struct usdt_manager *usdt_manager_new(struct bpf_object *obj) * If this is not supported, USDTs with semaphores will not be supported. * Added in: a6ca88b241d5 ("trace_uprobe: support reference counter in fd-based uprobe") */ - man->has_sema_refcnt = access(ref_ctr_sysfs_path, F_OK) == 0; + man->has_sema_refcnt = faccessat(AT_FDCWD, ref_ctr_sysfs_path, F_OK, AT_EACCESS) == 0; return man; } -- cgit v1.3-18-gd494 From 87dbdc230d162bf9ee1ac77c8ade178b6b1e199e Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Mon, 26 Sep 2022 21:29:39 -0700 Subject: libbpf: Don't require full struct enum64 in UAPI headers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Drop the requirement for system-wide kernel UAPI headers to provide full struct btf_enum64 definition. This is an unexpected requirement that slipped in libbpf 1.0 and put unnecessary pressure ([0]) on users to have a bleeding-edge kernel UAPI header from unreleased Linux 6.0. To achieve this, we forward declare struct btf_enum64. But that's not enough as there is btf_enum64_value() helper that expects to know the layout of struct btf_enum64. So we get a bit creative with reinterpreting memory layout as array of __u32 and accesing lo32/hi32 fields as array elements. Alternative way would be to have a local pointer variable for anonymous struct with exactly the same layout as struct btf_enum64, but that gets us into C++ compiler errors complaining about invalid type casts. So play it safe, if ugly. [0] Closes: https://github.com/libbpf/libbpf/issues/562 Fixes: d90ec262b35b ("libbpf: Add enum64 support for btf_dump") Reported-by: Toke Høiland-Jørgensen Signed-off-by: Andrii Nakryiko Signed-off-by: Daniel Borkmann Acked-by: Toke Høiland-Jørgensen Link: https://lore.kernel.org/bpf/20220927042940.147185-1-andrii@kernel.org --- tools/lib/bpf/btf.h | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h index ae543144ee30..8e6880d91c84 100644 --- a/tools/lib/bpf/btf.h +++ b/tools/lib/bpf/btf.h @@ -486,6 +486,8 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t) return (struct btf_enum *)(t + 1); } +struct btf_enum64; + static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) { return (struct btf_enum64 *)(t + 1); @@ -493,7 +495,28 @@ static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) static inline __u64 btf_enum64_value(const struct btf_enum64 *e) { - return ((__u64)e->val_hi32 << 32) | e->val_lo32; + /* struct btf_enum64 is introduced in Linux 6.0, which is very + * bleeding-edge. Here we are avoiding relying on struct btf_enum64 + * definition coming from kernel UAPI headers to support wider range + * of system-wide kernel headers. + * + * Given this header can be also included from C++ applications, that + * further restricts C tricks we can use (like using compatible + * anonymous struct). So just treat struct btf_enum64 as + * a three-element array of u32 and access second (lo32) and third + * (hi32) elements directly. + * + * For reference, here is a struct btf_enum64 definition: + * + * const struct btf_enum64 { + * __u32 name_off; + * __u32 val_lo32; + * __u32 val_hi32; + * }; + */ + const __u32 *e64 = (const __u32 *)e; + + return ((__u64)e64[2] << 32) | e64[1]; } static inline struct btf_member *btf_members(const struct btf_type *t) -- cgit v1.3-18-gd494 From 51e05a8cf8eb34da7473823b7f236a77adfef0b4 Mon Sep 17 00:00:00 2001 From: Xin Liu Date: Fri, 30 Sep 2022 17:07:08 +0800 Subject: libbpf: Fix overrun in netlink attribute iteration I accidentally found that a change in commit 1045b03e07d8 ("netlink: fix overrun in attribute iteration") was not synchronized to the function `nla_ok` in tools/lib/bpf/nlattr.c, I think it is necessary to modify, this patch will do it. Signed-off-by: Xin Liu Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20220930090708.62394-1-liuxin350@huawei.com --- tools/lib/bpf/nlattr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'tools/lib') diff --git a/tools/lib/bpf/nlattr.c b/tools/lib/bpf/nlattr.c index f57e77a6e40f..3900d052ed19 100644 --- a/tools/lib/bpf/nlattr.c +++ b/tools/lib/bpf/nlattr.c @@ -32,7 +32,7 @@ static struct nlattr *nla_next(const struct nlattr *nla, int *remaining) static int nla_ok(const struct nlattr *nla, int remaining) { - return remaining >= sizeof(*nla) && + return remaining >= (int)sizeof(*nla) && nla->nla_len >= sizeof(*nla) && nla->nla_len <= remaining; } -- cgit v1.3-18-gd494