From 1ef0199a1a698d82ecd39d11d1daa3f4ab006c75 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Mon, 12 Sep 2016 15:05:50 -0700 Subject: [PATCH] selftests/x86/sigreturn: Use CX, not AX, as the scratch register RAX is handled specially in ESPFIX64. Use CX as our scratch register so that, if something goes wrong with RAX handling, we'll notice. Signed-off-by: Andy Lutomirski Reviewed-by: Borislav Petkov Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Shuah Khan Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/9ceeb24ea56925586c330dc46306f757ddea9fb5.1473717910.git.luto@kernel.org Signed-off-by: Ingo Molnar --- tools/testing/selftests/x86/sigreturn.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c index 8a577e7070c6..246145b84a12 100644 --- a/tools/testing/selftests/x86/sigreturn.c +++ b/tools/testing/selftests/x86/sigreturn.c @@ -106,7 +106,7 @@ asm (".pushsection .text\n\t" ".type int3, @function\n\t" ".align 4096\n\t" "int3:\n\t" - "mov %ss,%eax\n\t" + "mov %ss,%ecx\n\t" "int3\n\t" ".size int3, . - int3\n\t" ".align 4096, 0xcc\n\t" @@ -306,7 +306,7 @@ static volatile sig_atomic_t sig_corrupt_final_ss; #ifdef __x86_64__ # define REG_IP REG_RIP # define REG_SP REG_RSP -# define REG_AX REG_RAX +# define REG_CX REG_RCX struct selectors { unsigned short cs, gs, fs, ss; @@ -326,7 +326,7 @@ static unsigned short *csptr(ucontext_t *ctx) #else # define REG_IP REG_EIP # define REG_SP REG_ESP -# define REG_AX REG_EAX +# define REG_CX REG_ECX static greg_t *ssptr(ucontext_t *ctx) { @@ -457,10 +457,10 @@ static void sigusr1(int sig, siginfo_t *info, void *ctx_void) ctx->uc_mcontext.gregs[REG_IP] = sig_cs == code16_sel ? 0 : (unsigned long)&int3; ctx->uc_mcontext.gregs[REG_SP] = (unsigned long)0x8badf00d5aadc0deULL; - ctx->uc_mcontext.gregs[REG_AX] = 0; + ctx->uc_mcontext.gregs[REG_CX] = 0; memcpy(&requested_regs, &ctx->uc_mcontext.gregs, sizeof(gregset_t)); - requested_regs[REG_AX] = *ssptr(ctx); /* The asm code does this. */ + requested_regs[REG_CX] = *ssptr(ctx); /* The asm code does this. */ return; } @@ -482,7 +482,7 @@ static void sigtrap(int sig, siginfo_t *info, void *ctx_void) unsigned short ss; asm ("mov %%ss,%0" : "=r" (ss)); - greg_t asm_ss = ctx->uc_mcontext.gregs[REG_AX]; + greg_t asm_ss = ctx->uc_mcontext.gregs[REG_CX]; if (asm_ss != sig_ss && sig == SIGTRAP) { /* Sanity check failure. */ printf("[FAIL]\tSIGTRAP: ss = %hx, frame ss = %hx, ax = %llx\n", @@ -654,8 +654,8 @@ static int test_valid_sigreturn(int cs_bits, bool use_16bit_ss, int force_ss) #endif /* Sanity check on the kernel */ - if (i == REG_AX && requested_regs[i] != resulting_regs[i]) { - printf("[FAIL]\tAX (saved SP) mismatch: requested 0x%llx; got 0x%llx\n", + if (i == REG_CX && requested_regs[i] != resulting_regs[i]) { + printf("[FAIL]\tCX (saved SP) mismatch: requested 0x%llx; got 0x%llx\n", (unsigned long long)requested_regs[i], (unsigned long long)resulting_regs[i]); nerrs++; -- 2.20.1