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authorJiri Olsa <jolsa@kernel.org>2022-10-18 10:59:34 +0300
committerAlexei Starovoitov <ast@kernel.org>2022-10-21 04:57:51 +0300
commitdbe69b29988465b011f198f2797b1c2b6980b50e (patch)
treed060772885a0e15050fe1e1eb96697e61ee25ef3 /include
parentea68376c8bed5cd156900852aada20c3a0874d17 (diff)
downloadlinux-dbe69b29988465b011f198f2797b1c2b6980b50e.tar.xz
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')
-rw-r--r--include/linux/bpf.h14
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, \