diff options
Diffstat (limited to 'tools/testing/selftests/x86/syscall_arg_fault.c')
-rw-r--r-- | tools/testing/selftests/x86/syscall_arg_fault.c | 132 |
1 files changed, 116 insertions, 16 deletions
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c index 7db4fc9fa09f..bc0ecc2e862e 100644 --- a/tools/testing/selftests/x86/syscall_arg_fault.c +++ b/tools/testing/selftests/x86/syscall_arg_fault.c @@ -1,15 +1,7 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * syscall_arg_fault.c - tests faults 32-bit fast syscall stack args * Copyright (c) 2015 Andrew Lutomirski - * - * This program is free software; you can redistribute it and/or modify - * it under the terms and conditions of the GNU General Public License, - * version 2, as published by the Free Software Foundation. - * - * This program is distributed in the hope it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * General Public License for more details. */ #define _GNU_SOURCE @@ -23,9 +15,30 @@ #include <setjmp.h> #include <errno.h> +#ifdef __x86_64__ +# define WIDTH "q" +#else +# define WIDTH "l" +#endif + /* Our sigaltstack scratch space. */ static unsigned char altstack_data[SIGSTKSZ]; +static unsigned long get_eflags(void) +{ + unsigned long eflags; + asm volatile ("pushf" WIDTH "\n\tpop" WIDTH " %0" : "=rm" (eflags)); + return eflags; +} + +static void set_eflags(unsigned long eflags) +{ + asm volatile ("push" WIDTH " %0\n\tpopf" WIDTH + : : "rm" (eflags) : "flags"); +} + +#define X86_EFLAGS_TF (1UL << 8) + static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -43,13 +56,22 @@ static sigjmp_buf jmpbuf; static volatile sig_atomic_t n_errs; -static void sigsegv(int sig, siginfo_t *info, void *ctx_void) +#ifdef __x86_64__ +#define REG_AX REG_RAX +#define REG_IP REG_RIP +#else +#define REG_AX REG_EAX +#define REG_IP REG_EIP +#endif + +static void sigsegv_or_sigbus(int sig, siginfo_t *info, void *ctx_void) { ucontext_t *ctx = (ucontext_t*)ctx_void; + long ax = (long)ctx->uc_mcontext.gregs[REG_AX]; - if (ctx->uc_mcontext.gregs[REG_EAX] != -EFAULT) { - printf("[FAIL]\tAX had the wrong value: 0x%x\n", - ctx->uc_mcontext.gregs[REG_EAX]); + if (ax != -EFAULT && ax != -ENOSYS) { + printf("[FAIL]\tAX had the wrong value: 0x%lx\n", + (unsigned long)ax); n_errs++; } else { printf("[OK]\tSeems okay\n"); @@ -58,9 +80,42 @@ static void sigsegv(int sig, siginfo_t *info, void *ctx_void) siglongjmp(jmpbuf, 1); } +static volatile sig_atomic_t sigtrap_consecutive_syscalls; + +static void sigtrap(int sig, siginfo_t *info, void *ctx_void) +{ + /* + * KVM has some bugs that can cause us to stop making progress. + * detect them and complain, but don't infinite loop or fail the + * test. + */ + + ucontext_t *ctx = (ucontext_t*)ctx_void; + unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP]; + + if (*ip == 0x340f || *ip == 0x050f) { + /* The trap was on SYSCALL or SYSENTER */ + sigtrap_consecutive_syscalls++; + if (sigtrap_consecutive_syscalls > 3) { + printf("[WARN]\tGot stuck single-stepping -- you probably have a KVM bug\n"); + siglongjmp(jmpbuf, 1); + } + } else { + sigtrap_consecutive_syscalls = 0; + } +} + static void sigill(int sig, siginfo_t *info, void *ctx_void) { - printf("[SKIP]\tIllegal instruction\n"); + ucontext_t *ctx = (ucontext_t*)ctx_void; + unsigned short *ip = (unsigned short *)ctx->uc_mcontext.gregs[REG_IP]; + + if (*ip == 0x0b0f) { + /* one of the ud2 instructions faulted */ + printf("[OK]\tSYSCALL returned normally\n"); + } else { + printf("[SKIP]\tIllegal instruction\n"); + } siglongjmp(jmpbuf, 1); } @@ -73,7 +128,13 @@ int main() if (sigaltstack(&stack, NULL) != 0) err(1, "sigaltstack"); - sethandler(SIGSEGV, sigsegv, SA_ONSTACK); + sethandler(SIGSEGV, sigsegv_or_sigbus, SA_ONSTACK); + /* + * The actual exception can vary. On Atom CPUs, we get #SS + * instead of #PF when the vDSO fails to access the stack when + * ESP is too close to 2^32, and #SS causes SIGBUS. + */ + sethandler(SIGBUS, sigsegv_or_sigbus, SA_ONSTACK); sethandler(SIGILL, sigill, SA_ONSTACK); /* @@ -122,9 +183,48 @@ int main() "movl $-1, %%ebp\n\t" "movl $-1, %%esp\n\t" "syscall\n\t" - "pushl $0" /* make sure we segfault cleanly */ + "ud2" /* make sure we recover cleanly */ + : : : "memory", "flags"); + } + + printf("[RUN]\tSYSENTER with TF and invalid state\n"); + sethandler(SIGTRAP, sigtrap, SA_ONSTACK); + + if (sigsetjmp(jmpbuf, 1) == 0) { + sigtrap_consecutive_syscalls = 0; + set_eflags(get_eflags() | X86_EFLAGS_TF); + asm volatile ( + "movl $-1, %%eax\n\t" + "movl $-1, %%ebx\n\t" + "movl $-1, %%ecx\n\t" + "movl $-1, %%edx\n\t" + "movl $-1, %%esi\n\t" + "movl $-1, %%edi\n\t" + "movl $-1, %%ebp\n\t" + "movl $-1, %%esp\n\t" + "sysenter" + : : : "memory", "flags"); + } + set_eflags(get_eflags() & ~X86_EFLAGS_TF); + + printf("[RUN]\tSYSCALL with TF and invalid state\n"); + if (sigsetjmp(jmpbuf, 1) == 0) { + sigtrap_consecutive_syscalls = 0; + set_eflags(get_eflags() | X86_EFLAGS_TF); + asm volatile ( + "movl $-1, %%eax\n\t" + "movl $-1, %%ebx\n\t" + "movl $-1, %%ecx\n\t" + "movl $-1, %%edx\n\t" + "movl $-1, %%esi\n\t" + "movl $-1, %%edi\n\t" + "movl $-1, %%ebp\n\t" + "movl $-1, %%esp\n\t" + "syscall\n\t" + "ud2" /* make sure we recover cleanly */ : : : "memory", "flags"); } + set_eflags(get_eflags() & ~X86_EFLAGS_TF); return 0; } |