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| author | Peter Zijlstra <peterz@infradead.org> | 2022-06-14 23:15:40 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-25 11:26:37 +0200 |
| commit | 00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb (patch) | |
| tree | 466b5a36265c65fc97a1477f3eff6ea32fd4e541 | |
| parent | 7723edf5edfdfdabd8234e45142be86598a04cad (diff) | |
| download | linux-stable-00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb.tar.gz linux-stable-00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb.tar.bz2 linux-stable-00b136bb6254e0abf6aaafe62c4da5f6c4fea4cb.zip | |
x86/ftrace: Use alternative RET encoding
commit 1f001e9da6bbf482311e45e48f53c2bd2179e59c upstream.
Use the return thunk in ftrace trampolines, if needed.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
[cascardo: still copy return from ftrace_stub]
[cascardo: use memcpy(text_gen_insn) as there is no __text_gen_insn]
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/kernel/ftrace.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c index fbcd144260ac..dca5cf82144c 100644 --- a/arch/x86/kernel/ftrace.c +++ b/arch/x86/kernel/ftrace.c @@ -308,7 +308,7 @@ union ftrace_op_code_union { } __attribute__((packed)); }; -#define RET_SIZE 1 + IS_ENABLED(CONFIG_SLS) +#define RET_SIZE (IS_ENABLED(CONFIG_RETPOLINE) ? 5 : 1 + IS_ENABLED(CONFIG_SLS)) static unsigned long create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) @@ -367,7 +367,10 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size) /* The trampoline ends with ret(q) */ retq = (unsigned long)ftrace_stub; - ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE); + if (cpu_feature_enabled(X86_FEATURE_RETHUNK)) + memcpy(ip, text_gen_insn(JMP32_INSN_OPCODE, ip, &__x86_return_thunk), JMP32_INSN_SIZE); + else + ret = copy_from_kernel_nofault(ip, (void *)retq, RET_SIZE); if (WARN_ON(ret < 0)) goto fail; |