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
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
--- /dev/null
+// 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 */
#include <sys/ptrace.h>
#include <sys/user.h>
+#include "helpers.h"
+
static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
int flags)
{
# 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;
#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)
{
#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)
{
#include <setjmp.h>
#include <sys/uio.h>
+#include "helpers.h"
+
#ifdef __x86_64__
# define VSYS(x) (x)
#else
}
#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;
#include <features.h>
#include <stdio.h>
+#include "helpers.h"
+
#if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 16
int main()
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;