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| author |   Jiri Olsa <jolsa@kernel.org> | 2022-10-18 09:59:34 +0200 |
|---|---|---|
| committer |   Alexei Starovoitov <ast@kernel.org> | 2022-10-20 18:57:51 -0700 |
| commit | dbe69b29988465b011f198f2797b1c2b6980b50e (patch) | |
| tree | d060772885a0e15050fe1e1eb96697e61ee25ef3 /include/linux | |
| parent | bpf: prevent decl_tag from being referenced in func_proto (diff) | |
| download | linux-dev-dbe69b29988465b011f198f2797b1c2b6980b50e.tar.xz linux-dev-dbe69b29988465b011f198f2797b1c2b6980b50e.zip | |
bpf: Fix dispatcher patchable function entry to 5 bytes nop
The patchable_function_entry(5) might output 5 single nop
instructions (depends on toolchain), which will clash with
bpf_arch_text_poke check for 5 bytes nop instruction.
Adding early init call for dispatcher that checks and change
the patchable entry into expected 5 nop instruction if needed.
There's no need to take text_mutex, because we are using it
in early init call which is called at pre-smp time.
Fixes: ceea991a019c ("bpf: Move bpf_dispatcher function out of ftrace locations")
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20221018075934.574415-1-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/bpf.h | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 9e7d46d16032..0566705c1d4e 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -27,6 +27,7 @@ #include <linux/bpfptr.h> #include <linux/btf.h> #include <linux/rcupdate_trace.h> +#include <linux/init.h> struct bpf_verifier_env; struct bpf_verifier_log; @@ -970,6 +971,8 @@ struct bpf_trampoline *bpf_trampoline_get(u64 key, struct bpf_attach_target_info *tgt_info); void bpf_trampoline_put(struct bpf_trampoline *tr); int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_funcs); +int __init bpf_arch_init_dispatcher_early(void *ip); + #define BPF_DISPATCHER_INIT(_name) { \ .mutex = __MUTEX_INITIALIZER(_name.mutex), \ .func = &_name##_func, \ @@ -983,6 +986,13 @@ int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_func }, \ } +#define BPF_DISPATCHER_INIT_CALL(_name) \ + static int __init _name##_init(void) \ + { \ + return bpf_arch_init_dispatcher_early(_name##_func); \ + } \ + early_initcall(_name##_init) + #ifdef CONFIG_X86_64 #define BPF_DISPATCHER_ATTRIBUTES __attribute__((patchable_function_entry(5))) #else @@ -1000,7 +1010,9 @@ int arch_prepare_bpf_dispatcher(void *image, void *buf, s64 *funcs, int num_func } \ EXPORT_SYMBOL(bpf_dispatcher_##name##_func); \ struct bpf_dispatcher bpf_dispatcher_##name = \ - BPF_DISPATCHER_INIT(bpf_dispatcher_##name); + BPF_DISPATCHER_INIT(bpf_dispatcher_##name); \ + BPF_DISPATCHER_INIT_CALL(bpf_dispatcher_##name); + #define DECLARE_BPF_DISPATCHER(name) \ unsigned int bpf_dispatcher_##name##_func( \ const void *ctx, \ |