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-rw-r--r--tools/testing/selftests/x86/Makefile2
-rw-r--r--tools/testing/selftests/x86/fsgsbase.c41
-rw-r--r--tools/testing/selftests/x86/ldt_gdt.c46
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;