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| author | Peter Zijlstra <peterz@infradead.org> | 2020-06-17 18:21:16 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2020-06-25 13:45:39 +0200 |
| commit | e3a9e681adb779b39565a28b3252c3be1033f994 (patch) | |
| tree | 1f613b0aca09f5304ee45af45ef14f28f17f7a36 | |
| parent | 734d099ba644f5a92c70efa3d54d0ba2500ce162 (diff) | |
| download | linux-e3a9e681adb779b39565a28b3252c3be1033f994.tar.gz | |
x86/entry: Fixup bad_iret vs noinstr
vmlinux.o: warning: objtool: fixup_bad_iret()+0x8e: call to memcpy() leaves .noinstr.text section
Worse, when KASAN there is no telling what memcpy() actually is. Force
the use of __memcpy() which is our assmebly implementation.
Reported-by: Marco Elver <elver@google.com>
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marco Elver <elver@google.com>
Link: https://lkml.kernel.org/r/20200618144801.760070502@infradead.org
| -rw-r--r-- | arch/x86/kernel/traps.c | 6 | ||||
| -rw-r--r-- | arch/x86/lib/memcpy_64.S | 4 |
2 files changed, 7 insertions, 3 deletions
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index af75109485c263..a7d1570905727e 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -690,13 +690,13 @@ struct bad_iret_stack *fixup_bad_iret(struct bad_iret_stack *s) (struct bad_iret_stack *)__this_cpu_read(cpu_tss_rw.x86_tss.sp0) - 1; /* Copy the IRET target to the temporary storage. */ - memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8); + __memcpy(&tmp.regs.ip, (void *)s->regs.sp, 5*8); /* Copy the remainder of the stack from the current stack. */ - memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip)); + __memcpy(&tmp, s, offsetof(struct bad_iret_stack, regs.ip)); /* Update the entry stack */ - memcpy(new_stack, &tmp, sizeof(tmp)); + __memcpy(new_stack, &tmp, sizeof(tmp)); BUG_ON(!user_mode(&new_stack->regs)); return new_stack; diff --git a/arch/x86/lib/memcpy_64.S b/arch/x86/lib/memcpy_64.S index 56b243b14c3a26..bbcc05bcefadb2 100644 --- a/arch/x86/lib/memcpy_64.S +++ b/arch/x86/lib/memcpy_64.S @@ -8,6 +8,8 @@ #include <asm/alternative-asm.h> #include <asm/export.h> +.pushsection .noinstr.text, "ax" + /* * We build a jump to memcpy_orig by default which gets NOPped out on * the majority of x86 CPUs which set REP_GOOD. In addition, CPUs which @@ -184,6 +186,8 @@ SYM_FUNC_START_LOCAL(memcpy_orig) retq SYM_FUNC_END(memcpy_orig) +.popsection + #ifndef CONFIG_UML MCSAFE_TEST_CTL |