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authorAndy Lutomirski <luto@kernel.org>2020-06-26 10:21:16 -0700
committerThomas Gleixner <tglx@linutronix.de>2020-07-01 10:00:27 +0200
commitcced0b24bb545bfe74fea96de84adc23c0146b05 (patch)
tree4cf94eb54ae3f64b4c4b54c696f0e5fabd081078
parenta61fa2799ef9bf6c4f54cf7295036577cececc72 (diff)
selftests/x86: Consolidate and fix get/set_eflags() helpers
There are several copies of get_eflags() and set_eflags() and they all are buggy. Consolidate them and fix them. The fixes are: Add memory clobbers. These are probably unnecessary but they make sure that the compiler doesn't move something past one of these calls when it shouldn't. Respect the redzone on x86_64. There has no failure been observed related to this, but it's definitely a bug. Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/982ce58ae8dea2f1e57093ee894760e35267e751.1593191971.git.luto@kernel.org
-rw-r--r--tools/testing/selftests/x86/Makefile4
-rw-r--r--tools/testing/selftests/x86/helpers.h41
-rw-r--r--tools/testing/selftests/x86/single_step_syscall.c17
-rw-r--r--tools/testing/selftests/x86/syscall_arg_fault.c21
-rw-r--r--tools/testing/selftests/x86/syscall_nt.c20
-rw-r--r--tools/testing/selftests/x86/test_vsyscall.c15
-rw-r--r--tools/testing/selftests/x86/unwind_vdso.c23
7 files changed, 51 insertions, 90 deletions
diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 5f16821c7f63..d2796ea98c5a 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -70,10 +70,10 @@ all_64: $(BINARIES_64)
EXTRA_CLEAN := $(BINARIES_32) $(BINARIES_64)
-$(BINARIES_32): $(OUTPUT)/%_32: %.c
+$(BINARIES_32): $(OUTPUT)/%_32: %.c helpers.h
$(CC) -m32 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl -lm
-$(BINARIES_64): $(OUTPUT)/%_64: %.c
+$(BINARIES_64): $(OUTPUT)/%_64: %.c helpers.h
$(CC) -m64 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl
# x86_64 users should be encouraged to install 32-bit libraries
diff --git a/tools/testing/selftests/x86/helpers.h b/tools/testing/selftests/x86/helpers.h
new file mode 100644
index 000000000000..f5ff2a2615df
--- /dev/null
+++ b/tools/testing/selftests/x86/helpers.h
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef __SELFTESTS_X86_HELPERS_H
+#define __SELFTESTS_X86_HELPERS_H
+
+#include <asm/processor-flags.h>
+
+static inline unsigned long get_eflags(void)
+{
+ unsigned long eflags;
+
+ asm volatile (
+#ifdef __x86_64__
+ "subq $128, %%rsp\n\t"
+ "pushfq\n\t"
+ "popq %0\n\t"
+ "addq $128, %%rsp"
+#else
+ "pushfl\n\t"
+ "popl %0"
+#endif
+ : "=r" (eflags) :: "memory");
+
+ return eflags;
+}
+
+static inline void set_eflags(unsigned long eflags)
+{
+ asm volatile (
+#ifdef __x86_64__
+ "subq $128, %%rsp\n\t"
+ "pushq %0\n\t"
+ "popfq\n\t"
+ "addq $128, %%rsp"
+#else
+ "pushl %0\n\t"
+ "popfl"
+#endif
+ :: "r" (eflags) : "flags", "memory");
+}
+
+#endif /* __SELFTESTS_X86_HELPERS_H */
diff --git a/tools/testing/selftests/x86/single_step_syscall.c b/tools/testing/selftests/x86/single_step_syscall.c
index 1063328e275c..120ac741fe44 100644
--- a/tools/testing/selftests/x86/single_step_syscall.c
+++ b/tools/testing/selftests/x86/single_step_syscall.c
@@ -31,6 +31,8 @@
#include <sys/ptrace.h>
#include <sys/user.h>
+#include "helpers.h"
+
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
int flags)
{
@@ -67,21 +69,6 @@ static unsigned char altstack_data[SIGSTKSZ];
# define INT80_CLOBBERS
#endif
-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 sigtrap(int sig, siginfo_t *info, void *ctx_void)
{
ucontext_t *ctx = (ucontext_t*)ctx_void;
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index bc0ecc2e862e..5b7abebbcbb9 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -15,30 +15,11 @@
#include <setjmp.h>
#include <errno.h>
-#ifdef __x86_64__
-# define WIDTH "q"
-#else
-# define WIDTH "l"
-#endif
+#include "helpers.h"
/* 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)
{
diff --git a/tools/testing/selftests/x86/syscall_nt.c b/tools/testing/selftests/x86/syscall_nt.c
index 5fc82b9cebed..970e5e14d96d 100644
--- a/tools/testing/selftests/x86/syscall_nt.c
+++ b/tools/testing/selftests/x86/syscall_nt.c
@@ -13,29 +13,11 @@
#include <signal.h>
#include <err.h>
#include <sys/syscall.h>
-#include <asm/processor-flags.h>
-#ifdef __x86_64__
-# define WIDTH "q"
-#else
-# define WIDTH "l"
-#endif
+#include "helpers.h"
static unsigned int nerrs;
-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");
-}
-
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
int flags)
{
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index a4f4d4cf22c3..c41f24b517f4 100644
--- a/tools/testing/selftests/x86/test_vsyscall.c
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -20,6 +20,8 @@
#include <setjmp.h>
#include <sys/uio.h>
+#include "helpers.h"
+
#ifdef __x86_64__
# define VSYS(x) (x)
#else
@@ -493,21 +495,8 @@ static int test_process_vm_readv(void)
}
#ifdef __x86_64__
-#define X86_EFLAGS_TF (1UL << 8)
static volatile sig_atomic_t num_vsyscall_traps;
-static unsigned long get_eflags(void)
-{
- unsigned long eflags;
- asm volatile ("pushfq\n\tpopq %0" : "=rm" (eflags));
- return eflags;
-}
-
-static void set_eflags(unsigned long eflags)
-{
- asm volatile ("pushq %0\n\tpopfq" : : "rm" (eflags) : "flags");
-}
-
static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
{
ucontext_t *ctx = (ucontext_t *)ctx_void;
diff --git a/tools/testing/selftests/x86/unwind_vdso.c b/tools/testing/selftests/x86/unwind_vdso.c
index 0075ccd65407..4c311e1af4c7 100644
--- a/tools/testing/selftests/x86/unwind_vdso.c
+++ b/tools/testing/selftests/x86/unwind_vdso.c
@@ -11,6 +11,8 @@
#include <features.h>
#include <stdio.h>
+#include "helpers.h"
+
#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16
int main()
@@ -53,27 +55,6 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
err(1, "sigaction");
}
-#ifdef __x86_64__
-# define WIDTH "q"
-#else
-# define WIDTH "l"
-#endif
-
-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 volatile sig_atomic_t nerrs;
static unsigned long sysinfo;
static bool got_sysinfo = false;