diff options
Diffstat (limited to 'tools/testing/selftests/x86')
-rw-r--r-- | tools/testing/selftests/x86/Makefile | 2 | ||||
-rw-r--r-- | tools/testing/selftests/x86/fsgsbase.c | 41 | ||||
-rw-r--r-- | tools/testing/selftests/x86/ldt_gdt.c | 46 |
3 files changed, 82 insertions, 7 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index a89f80a5b711..6300c1a41ff6 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -5,7 +5,7 @@ include ../lib.mk .PHONY: all all_32 all_64 warn_32bit_failure clean TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall test_mremap_vdso \ - check_initial_reg_state sigreturn ldt_gdt iopl \ + check_initial_reg_state sigreturn ldt_gdt iopl mpx-mini-test \ protection_keys TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault test_syscall_vdso unwind_vdso \ test_FCMOV test_FCOMI test_FISTTP \ diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c index 5b2b4b3c634c..9b4610c6d3fb 100644 --- a/tools/testing/selftests/x86/fsgsbase.c +++ b/tools/testing/selftests/x86/fsgsbase.c @@ -285,9 +285,12 @@ static void *threadproc(void *ctx) } } -static void set_gs_and_switch_to(unsigned long local, unsigned long remote) +static void set_gs_and_switch_to(unsigned long local, + unsigned short force_sel, + unsigned long remote) { unsigned long base; + unsigned short sel_pre_sched, sel_post_sched; bool hard_zero = false; if (local == HARD_ZERO) { @@ -297,6 +300,8 @@ static void set_gs_and_switch_to(unsigned long local, unsigned long remote) printf("[RUN]\tARCH_SET_GS(0x%lx)%s, then schedule to 0x%lx\n", local, hard_zero ? " and clear gs" : "", remote); + if (force_sel) + printf("\tBefore schedule, set selector to 0x%hx\n", force_sel); if (syscall(SYS_arch_prctl, ARCH_SET_GS, local) != 0) err(1, "ARCH_SET_GS"); if (hard_zero) @@ -307,18 +312,35 @@ static void set_gs_and_switch_to(unsigned long local, unsigned long remote) printf("[FAIL]\tGSBASE wasn't set as expected\n"); } + if (force_sel) { + asm volatile ("mov %0, %%gs" : : "rm" (force_sel)); + sel_pre_sched = force_sel; + local = read_base(GS); + + /* + * Signal delivery seems to mess up weird selectors. Put it + * back. + */ + asm volatile ("mov %0, %%gs" : : "rm" (force_sel)); + } else { + asm volatile ("mov %%gs, %0" : "=rm" (sel_pre_sched)); + } + remote_base = remote; ftx = 1; syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0); while (ftx != 0) syscall(SYS_futex, &ftx, FUTEX_WAIT, 1, NULL, NULL, 0); + asm volatile ("mov %%gs, %0" : "=rm" (sel_post_sched)); base = read_base(GS); - if (base == local) { - printf("[OK]\tGSBASE remained 0x%lx\n", local); + if (base == local && sel_pre_sched == sel_post_sched) { + printf("[OK]\tGS/BASE remained 0x%hx/0x%lx\n", + sel_pre_sched, local); } else { nerrs++; - printf("[FAIL]\tGSBASE changed to 0x%lx\n", base); + printf("[FAIL]\tGS/BASE changed from 0x%hx/0x%lx to 0x%hx/0x%lx\n", + sel_pre_sched, local, sel_post_sched, base); } } @@ -381,8 +403,15 @@ int main() for (int local = 0; local < 4; local++) { for (int remote = 0; remote < 4; remote++) { - set_gs_and_switch_to(bases_with_hard_zero[local], - bases_with_hard_zero[remote]); + for (unsigned short s = 0; s < 5; s++) { + unsigned short sel = s; + if (s == 4) + asm ("mov %%ss, %0" : "=rm" (sel)); + set_gs_and_switch_to( + bases_with_hard_zero[local], + sel, + bases_with_hard_zero[remote]); + } } } diff --git a/tools/testing/selftests/x86/ldt_gdt.c b/tools/testing/selftests/x86/ldt_gdt.c index 4af47079cf04..e717fed80219 100644 --- a/tools/testing/selftests/x86/ldt_gdt.c +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -403,6 +403,51 @@ static void *threadproc(void *ctx) } } +#ifdef __i386__ + +#ifndef SA_RESTORE +#define SA_RESTORER 0x04000000 +#endif + +/* + * The UAPI header calls this 'struct sigaction', which conflicts with + * glibc. Sigh. + */ +struct fake_ksigaction { + void *handler; /* the real type is nasty */ + unsigned long sa_flags; + void (*sa_restorer)(void); + unsigned char sigset[8]; +}; + +static void fix_sa_restorer(int sig) +{ + struct fake_ksigaction ksa; + + if (syscall(SYS_rt_sigaction, sig, NULL, &ksa, 8) == 0) { + /* + * glibc has a nasty bug: it sometimes writes garbage to + * sa_restorer. This interacts quite badly with anything + * that fiddles with SS because it can trigger legacy + * stack switching. Patch it up. See: + * + * https://sourceware.org/bugzilla/show_bug.cgi?id=21269 + */ + if (!(ksa.sa_flags & SA_RESTORER) && ksa.sa_restorer) { + ksa.sa_restorer = NULL; + if (syscall(SYS_rt_sigaction, sig, &ksa, NULL, + sizeof(ksa.sigset)) != 0) + err(1, "rt_sigaction"); + } + } +} +#else +static void fix_sa_restorer(int sig) +{ + /* 64-bit glibc works fine. */ +} +#endif + static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), int flags) { @@ -414,6 +459,7 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), if (sigaction(sig, &sa, 0)) err(1, "sigaction"); + fix_sa_restorer(sig); } static jmp_buf jmpbuf; |