diff options
Diffstat (limited to 'kernel/bpf/core.c')
| -rw-r--r-- | kernel/bpf/core.c | 257 |
1 files changed, 222 insertions, 35 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 6377225b2082..38de580abcc2 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c @@ -21,12 +21,14 @@ * Kris Katterjohn - Added many additional checks in bpf_check_classic() */ +#include <uapi/linux/btf.h> #include <linux/filter.h> #include <linux/skbuff.h> #include <linux/vmalloc.h> #include <linux/random.h> #include <linux/moduleloader.h> #include <linux/bpf.h> +#include <linux/btf.h> #include <linux/frame.h> #include <linux/rbtree_latch.h> #include <linux/kallsyms.h> @@ -103,6 +105,91 @@ struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags) } EXPORT_SYMBOL_GPL(bpf_prog_alloc); +int bpf_prog_alloc_jited_linfo(struct bpf_prog *prog) +{ + if (!prog->aux->nr_linfo || !prog->jit_requested) + return 0; + + prog->aux->jited_linfo = kcalloc(prog->aux->nr_linfo, + sizeof(*prog->aux->jited_linfo), + GFP_KERNEL | __GFP_NOWARN); + if (!prog->aux->jited_linfo) + return -ENOMEM; + + return 0; +} + +void bpf_prog_free_jited_linfo(struct bpf_prog *prog) +{ + kfree(prog->aux->jited_linfo); + prog->aux->jited_linfo = NULL; +} + +void bpf_prog_free_unused_jited_linfo(struct bpf_prog *prog) +{ + if (prog->aux->jited_linfo && !prog->aux->jited_linfo[0]) + bpf_prog_free_jited_linfo(prog); +} + +/* The jit engine is responsible to provide an array + * for insn_off to the jited_off mapping (insn_to_jit_off). + * + * The idx to this array is the insn_off. Hence, the insn_off + * here is relative to the prog itself instead of the main prog. + * This array has one entry for each xlated bpf insn. + * + * jited_off is the byte off to the last byte of the jited insn. + * + * Hence, with + * insn_start: + * The first bpf insn off of the prog. The insn off + * here is relative to the main prog. + * e.g. if prog is a subprog, insn_start > 0 + * linfo_idx: + * The prog's idx to prog->aux->linfo and jited_linfo + * + * jited_linfo[linfo_idx] = prog->bpf_func + * + * For i > linfo_idx, + * + * jited_linfo[i] = prog->bpf_func + + * insn_to_jit_off[linfo[i].insn_off - insn_start - 1] + */ +void bpf_prog_fill_jited_linfo(struct bpf_prog *prog, + const u32 *insn_to_jit_off) +{ + u32 linfo_idx, insn_start, insn_end, nr_linfo, i; + const struct bpf_line_info *linfo; + void **jited_linfo; + + if (!prog->aux->jited_linfo) + /* Userspace did not provide linfo */ + return; + + linfo_idx = prog->aux->linfo_idx; + linfo = &prog->aux->linfo[linfo_idx]; + insn_start = linfo[0].insn_off; + insn_end = insn_start + prog->len; + + jited_linfo = &prog->aux->jited_linfo[linfo_idx]; + jited_linfo[0] = prog->bpf_func; + + nr_linfo = prog->aux->nr_linfo - linfo_idx; + + for (i = 1; i < nr_linfo && linfo[i].insn_off < insn_end; i++) + /* The verifier ensures that linfo[i].insn_off is + * strictly increasing + */ + jited_linfo[i] = prog->bpf_func + + insn_to_jit_off[linfo[i].insn_off - insn_start - 1]; +} + +void bpf_prog_free_linfo(struct bpf_prog *prog) +{ + bpf_prog_free_jited_linfo(prog); + kvfree(prog->aux->linfo); +} + struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size, gfp_t gfp_extra_flags) { @@ -292,6 +379,26 @@ static int bpf_adj_branches(struct bpf_prog *prog, u32 pos, u32 delta, return ret; } +static void bpf_adj_linfo(struct bpf_prog *prog, u32 off, u32 delta) +{ + struct bpf_line_info *linfo; + u32 i, nr_linfo; + + nr_linfo = prog->aux->nr_linfo; + if (!nr_linfo || !delta) + return; + + linfo = prog->aux->linfo; + + for (i = 0; i < nr_linfo; i++) + if (off < linfo[i].insn_off) + break; + + /* Push all off < linfo[i].insn_off by delta */ + for (; i < nr_linfo; i++) + linfo[i].insn_off += delta; +} + struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, const struct bpf_insn *patch, u32 len) { @@ -347,6 +454,8 @@ struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off, */ BUG_ON(bpf_adj_branches(prog_adj, off, insn_delta, false)); + bpf_adj_linfo(prog_adj, off, insn_delta); + return prog_adj; } @@ -365,13 +474,11 @@ void bpf_prog_kallsyms_del_all(struct bpf_prog *fp) } #ifdef CONFIG_BPF_JIT -# define BPF_JIT_LIMIT_DEFAULT (PAGE_SIZE * 40000) - /* All BPF JIT sysctl knobs here. */ int bpf_jit_enable __read_mostly = IS_BUILTIN(CONFIG_BPF_JIT_ALWAYS_ON); int bpf_jit_harden __read_mostly; int bpf_jit_kallsyms __read_mostly; -int bpf_jit_limit __read_mostly = BPF_JIT_LIMIT_DEFAULT; +long bpf_jit_limit __read_mostly; static __always_inline void bpf_get_prog_addr_region(const struct bpf_prog *prog, @@ -390,6 +497,8 @@ bpf_get_prog_addr_region(const struct bpf_prog *prog, static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) { const char *end = sym + KSYM_NAME_LEN; + const struct btf_type *type; + const char *func_name; BUILD_BUG_ON(sizeof("bpf_prog_") + sizeof(prog->tag) * 2 + @@ -404,6 +513,16 @@ static void bpf_get_prog_name(const struct bpf_prog *prog, char *sym) sym += snprintf(sym, KSYM_NAME_LEN, "bpf_prog_"); sym = bin2hex(sym, prog->tag, sizeof(prog->tag)); + + /* prog->aux->name will be ignored if full btf name is available */ + if (prog->aux->func_info_cnt) { + type = btf_type_by_id(prog->aux->btf, + prog->aux->func_info[prog->aux->func_idx].type_id); + func_name = btf_name_by_offset(prog->aux->btf, type->name_off); + snprintf(sym, (size_t)(end - sym), "_%s", func_name); + return; + } + if (prog->aux->name[0]) snprintf(sym, (size_t)(end - sym), "_%s", prog->aux->name); else @@ -553,7 +672,6 @@ bool is_bpf_text_address(unsigned long addr) int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, char *sym) { - unsigned long symbol_start, symbol_end; struct bpf_prog_aux *aux; unsigned int it = 0; int ret = -ERANGE; @@ -566,10 +684,9 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, if (it++ != symnum) continue; - bpf_get_prog_addr_region(aux->prog, &symbol_start, &symbol_end); bpf_get_prog_name(aux->prog, sym); - *value = symbol_start; + *value = (unsigned long)aux->prog->bpf_func; *type = BPF_SYM_ELF_TYPE; ret = 0; @@ -582,16 +699,27 @@ int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type, static atomic_long_t bpf_jit_current; +/* Can be overridden by an arch's JIT compiler if it has a custom, + * dedicated BPF backend memory area, or if neither of the two + * below apply. + */ +u64 __weak bpf_jit_alloc_exec_limit(void) +{ #if defined(MODULES_VADDR) + return MODULES_END - MODULES_VADDR; +#else + return VMALLOC_END - VMALLOC_START; +#endif +} + static int __init bpf_jit_charge_init(void) { /* Only used as heuristic here to derive limit. */ - bpf_jit_limit = min_t(u64, round_up((MODULES_END - MODULES_VADDR) >> 2, - PAGE_SIZE), INT_MAX); + bpf_jit_limit = min_t(u64, round_up(bpf_jit_alloc_exec_limit() >> 2, + PAGE_SIZE), LONG_MAX); return 0; } pure_initcall(bpf_jit_charge_init); -#endif static int bpf_jit_charge_modmem(u32 pages) { @@ -611,6 +739,16 @@ static void bpf_jit_uncharge_modmem(u32 pages) atomic_long_sub(pages, &bpf_jit_current); } +void *__weak bpf_jit_alloc_exec(unsigned long size) +{ + return module_alloc(size); +} + +void __weak bpf_jit_free_exec(void *addr) +{ + module_memfree(addr); +} + struct bpf_binary_header * bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, unsigned int alignment, @@ -628,7 +766,7 @@ bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr, if (bpf_jit_charge_modmem(pages)) return NULL; - hdr = module_alloc(size); + hdr = bpf_jit_alloc_exec(size); if (!hdr) { bpf_jit_uncharge_modmem(pages); return NULL; @@ -652,7 +790,7 @@ void bpf_jit_binary_free(struct bpf_binary_header *hdr) { u32 pages = hdr->pages; - module_memfree(hdr); + bpf_jit_free_exec(hdr); bpf_jit_uncharge_modmem(pages); } @@ -674,6 +812,40 @@ void __weak bpf_jit_free(struct bpf_prog *fp) bpf_prog_unlock_free(fp); } +int bpf_jit_get_func_addr(const struct bpf_prog *prog, + const struct bpf_insn *insn, bool extra_pass, + u64 *func_addr, bool *func_addr_fixed) +{ + s16 off = insn->off; + s32 imm = insn->imm; + u8 *addr; + + *func_addr_fixed = insn->src_reg != BPF_PSEUDO_CALL; + if (!*func_addr_fixed) { + /* Place-holder address till the last pass has collected + * all addresses for JITed subprograms in which case we + * can pick them up from prog->aux. + */ + if (!extra_pass) + addr = NULL; + else if (prog->aux->func && + off >= 0 && off < prog->aux->func_cnt) + addr = (u8 *)prog->aux->func[off]->bpf_func; + else + return -EINVAL; + } else { + /* Address of a BPF helper call. Since part of the core + * kernel, it's always at a fixed location. __bpf_call_base + * and the helper with imm relative to it are both in core + * kernel. + */ + addr = (u8 *)__bpf_call_base + imm; + } + + *func_addr = (unsigned long)addr; + return 0; +} + static int bpf_jit_blind_insn(const struct bpf_insn *from, const struct bpf_insn *aux, struct bpf_insn *to_buff) @@ -877,32 +1049,34 @@ EXPORT_SYMBOL_GPL(__bpf_call_base); #define BPF_INSN_MAP(INSN_2, INSN_3) \ /* 32 bit ALU operations. */ \ /* Register based. */ \ - INSN_3(ALU, ADD, X), \ - INSN_3(ALU, SUB, X), \ - INSN_3(ALU, AND, X), \ - INSN_3(ALU, OR, X), \ - INSN_3(ALU, LSH, X), \ - INSN_3(ALU, RSH, X), \ - INSN_3(ALU, XOR, X), \ - INSN_3(ALU, MUL, X), \ - INSN_3(ALU, MOV, X), \ - INSN_3(ALU, DIV, X), \ - INSN_3(ALU, MOD, X), \ + INSN_3(ALU, ADD, X), \ + INSN_3(ALU, SUB, X), \ + INSN_3(ALU, AND, X), \ + INSN_3(ALU, OR, X), \ + INSN_3(ALU, LSH, X), \ + INSN_3(ALU, RSH, X), \ + INSN_3(ALU, XOR, X), \ + INSN_3(ALU, MUL, X), \ + INSN_3(ALU, MOV, X), \ + INSN_3(ALU, ARSH, X), \ + INSN_3(ALU, DIV, X), \ + INSN_3(ALU, MOD, X), \ INSN_2(ALU, NEG), \ INSN_3(ALU, END, TO_BE), \ INSN_3(ALU, END, TO_LE), \ /* Immediate based. */ \ - INSN_3(ALU, ADD, K), \ - INSN_3(ALU, SUB, K), \ - INSN_3(ALU, AND, K), \ - INSN_3(ALU, OR, K), \ - INSN_3(ALU, LSH, K), \ - INSN_3(ALU, RSH, K), \ - INSN_3(ALU, XOR, K), \ - INSN_3(ALU, MUL, K), \ - INSN_3(ALU, MOV, K), \ - INSN_3(ALU, DIV, K), \ - INSN_3(ALU, MOD, K), \ + INSN_3(ALU, ADD, K), \ + INSN_3(ALU, SUB, K), \ + INSN_3(ALU, AND, K), \ + INSN_3(ALU, OR, K), \ + INSN_3(ALU, LSH, K), \ + INSN_3(ALU, RSH, K), \ + INSN_3(ALU, XOR, K), \ + INSN_3(ALU, MUL, K), \ + INSN_3(ALU, MOV, K), \ + INSN_3(ALU, ARSH, K), \ + INSN_3(ALU, DIV, K), \ + INSN_3(ALU, MOD, K), \ /* 64 bit ALU operations. */ \ /* Register based. */ \ INSN_3(ALU64, ADD, X), \ @@ -1081,6 +1255,12 @@ select_insn: DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32; insn++; CONT; + ALU_ARSH_X: + DST = (u64) (u32) ((*(s32 *) &DST) >> SRC); + CONT; + ALU_ARSH_K: + DST = (u64) (u32) ((*(s32 *) &DST) >> IMM); + CONT; ALU64_ARSH_X: (*(s64 *) &DST) >>= SRC; CONT; @@ -1527,13 +1707,20 @@ struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err) * be JITed, but falls back to the interpreter. */ if (!bpf_prog_is_dev_bound(fp->aux)) { + *err = bpf_prog_alloc_jited_linfo(fp); + if (*err) + return fp; + fp = bpf_int_jit_compile(fp); -#ifdef CONFIG_BPF_JIT_ALWAYS_ON if (!fp->jited) { + bpf_prog_free_jited_linfo(fp); +#ifdef CONFIG_BPF_JIT_ALWAYS_ON *err = -ENOTSUPP; return fp; - } #endif + } else { + bpf_prog_free_unused_jited_linfo(fp); + } } else { *err = bpf_prog_offload_compile(fp); if (*err) |