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authorJiri Olsa2022-10-18 09:59:34 +0200
committerAlexei Starovoitov2022-10-20 18:57:51 -0700
commitdbe69b29988465b011f198f2797b1c2b6980b50e (patch)
treed060772885a0e15050fe1e1eb96697e61ee25ef3 /arch
parentea68376c8bed5cd156900852aada20c3a0874d17 (diff)
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 'arch')
-rw-r--r--arch/x86/net/bpf_jit_comp.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c
index 99620428ad78..00127abd89ee 100644
--- a/arch/x86/net/bpf_jit_comp.c
+++ b/arch/x86/net/bpf_jit_comp.c
@@ -11,6 +11,7 @@
#include <linux/bpf.h>
#include <linux/memory.h>
#include <linux/sort.h>
+#include <linux/init.h>
#include <asm/extable.h>
#include <asm/set_memory.h>
#include <asm/nospec-branch.h>
@@ -388,6 +389,18 @@ out:
return ret;
}
+int __init bpf_arch_init_dispatcher_early(void *ip)
+{
+ const u8 *nop_insn = x86_nops[5];
+
+ if (is_endbr(*(u32 *)ip))
+ ip += ENDBR_INSN_SIZE;
+
+ if (memcmp(ip, nop_insn, X86_PATCH_SIZE))
+ text_poke_early(ip, nop_insn, X86_PATCH_SIZE);
+ return 0;
+}
+
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *old_addr, void *new_addr)
{