selftests: vDSO: vdso_standalone_test_x86: Switch to nolibc
vdso_standalone_test_x86 provides its own ASM syscall wrappers and _start() implementation. The in-tree nolibc library already provides this functionality for multiple architectures. By making use of nolibc, the standalone testcase can be built from the exact same codebase as the non-standalone version. Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> Acked-by: Shuah Khan <skhan@linuxfoundation.org> Link: https://lore.kernel.org/all/20250226-parse_vdso-nolibc-v2-16-28e14e031ed8@linutronix.depull/838/merge
Thomas Weißschuh
Thomas Gleixner
parent
4f65df6a58
commit
8770a9183f
|
|
@ -22,13 +22,17 @@ include ../lib.mk
|
|||
|
||||
CFLAGS += $(TOOLS_INCLUDES)
|
||||
|
||||
CFLAGS_NOLIBC := -nostdlib -nostdinc -ffreestanding -fno-asynchronous-unwind-tables \
|
||||
-fno-stack-protector -include $(top_srcdir)/tools/include/nolibc/nolibc.h \
|
||||
-I$(top_srcdir)/tools/include/nolibc/ $(KHDR_INCLUDES)
|
||||
|
||||
$(OUTPUT)/vdso_test_gettimeofday: parse_vdso.c vdso_test_gettimeofday.c
|
||||
$(OUTPUT)/vdso_test_getcpu: parse_vdso.c vdso_test_getcpu.c
|
||||
$(OUTPUT)/vdso_test_abi: parse_vdso.c vdso_test_abi.c
|
||||
$(OUTPUT)/vdso_test_clock_getres: vdso_test_clock_getres.c
|
||||
|
||||
$(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c
|
||||
$(OUTPUT)/vdso_standalone_test_x86: CFLAGS +=-nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector
|
||||
$(OUTPUT)/vdso_standalone_test_x86: vdso_standalone_test_x86.c parse_vdso.c | headers
|
||||
$(OUTPUT)/vdso_standalone_test_x86: CFLAGS:=$(CFLAGS_NOLIBC) $(CFLAGS)
|
||||
|
||||
$(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c
|
||||
$(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl
|
||||
|
|
|
|||
|
|
@ -1,167 +1,58 @@
|
|||
// SPDX-License-Identifier: GPL-2.0-only
|
||||
/*
|
||||
* vdso_test.c: Sample code to test parse_vdso.c on x86
|
||||
* Copyright (c) 2011-2014 Andy Lutomirski
|
||||
* vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and
|
||||
* vDSO gettimeofday()
|
||||
* Copyright (c) 2014 Andy Lutomirski
|
||||
*
|
||||
* You can amuse yourself by compiling with:
|
||||
* gcc -std=gnu99 -nostdlib
|
||||
* -Os -fno-asynchronous-unwind-tables -flto -lgcc_s
|
||||
* vdso_standalone_test_x86.c parse_vdso.c
|
||||
* to generate a small binary. On x86_64, you can omit -lgcc_s
|
||||
* if you want the binary to be completely standalone.
|
||||
* Compile with:
|
||||
* gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c
|
||||
*
|
||||
* Tested on x86, 32-bit and 64-bit. It may work on other architectures, too.
|
||||
*/
|
||||
|
||||
#include <sys/syscall.h>
|
||||
#include <stdio.h>
|
||||
#ifndef NOLIBC
|
||||
#include <sys/auxv.h>
|
||||
#include <sys/time.h>
|
||||
#include <unistd.h>
|
||||
#include <stdint.h>
|
||||
#include <linux/auxvec.h>
|
||||
#endif
|
||||
|
||||
#include "../kselftest.h"
|
||||
#include "parse_vdso.h"
|
||||
#include "vdso_config.h"
|
||||
#include "vdso_call.h"
|
||||
|
||||
/* We need some libc functions... */
|
||||
int strcmp(const char *a, const char *b)
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
/* This implementation is buggy: it never returns -1. */
|
||||
while (*a || *b) {
|
||||
if (*a != *b)
|
||||
return 1;
|
||||
if (*a == 0 || *b == 0)
|
||||
return 1;
|
||||
a++;
|
||||
b++;
|
||||
const char *version = versions[VDSO_VERSION];
|
||||
const char **name = (const char **)&names[VDSO_NAMES];
|
||||
|
||||
unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
|
||||
if (!sysinfo_ehdr) {
|
||||
printf("AT_SYSINFO_EHDR is not present!\n");
|
||||
return KSFT_SKIP;
|
||||
}
|
||||
|
||||
vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
|
||||
|
||||
/* Find gettimeofday. */
|
||||
typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
|
||||
gtod_t gtod = (gtod_t)vdso_sym(version, name[0]);
|
||||
|
||||
if (!gtod) {
|
||||
printf("Could not find %s\n", name[0]);
|
||||
return KSFT_SKIP;
|
||||
}
|
||||
|
||||
struct timeval tv;
|
||||
long ret = VDSO_CALL(gtod, 2, &tv, 0);
|
||||
|
||||
if (ret == 0) {
|
||||
printf("The time is %lld.%06lld\n",
|
||||
(long long)tv.tv_sec, (long long)tv.tv_usec);
|
||||
} else {
|
||||
printf("%s failed\n", name[0]);
|
||||
return KSFT_FAIL;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* The clang build needs this, although gcc does not.
|
||||
* Stolen from lib/string.c.
|
||||
*/
|
||||
void *memcpy(void *dest, const void *src, size_t count)
|
||||
{
|
||||
char *tmp = dest;
|
||||
const char *s = src;
|
||||
|
||||
while (count--)
|
||||
*tmp++ = *s++;
|
||||
return dest;
|
||||
}
|
||||
|
||||
/* ...and two syscalls. This is x86-specific. */
|
||||
static inline long x86_syscall3(long nr, long a0, long a1, long a2)
|
||||
{
|
||||
long ret;
|
||||
#ifdef __x86_64__
|
||||
asm volatile ("syscall" : "=a" (ret) : "a" (nr),
|
||||
"D" (a0), "S" (a1), "d" (a2) :
|
||||
"cc", "memory", "rcx",
|
||||
"r8", "r9", "r10", "r11" );
|
||||
#else
|
||||
asm volatile ("int $0x80" : "=a" (ret) : "a" (nr),
|
||||
"b" (a0), "c" (a1), "d" (a2) :
|
||||
"cc", "memory" );
|
||||
#endif
|
||||
return ret;
|
||||
}
|
||||
|
||||
static inline long linux_write(int fd, const void *data, size_t len)
|
||||
{
|
||||
return x86_syscall3(__NR_write, fd, (long)data, (long)len);
|
||||
}
|
||||
|
||||
static inline void linux_exit(int code)
|
||||
{
|
||||
x86_syscall3(__NR_exit, code, 0, 0);
|
||||
}
|
||||
|
||||
void to_base10(char *lastdig, time_t n)
|
||||
{
|
||||
while (n) {
|
||||
*lastdig = (n % 10) + '0';
|
||||
n /= 10;
|
||||
lastdig--;
|
||||
}
|
||||
}
|
||||
|
||||
unsigned long getauxval(const unsigned long *auxv, unsigned long type)
|
||||
{
|
||||
unsigned long ret;
|
||||
|
||||
if (!auxv)
|
||||
return 0;
|
||||
|
||||
while (1) {
|
||||
if (!auxv[0] && !auxv[1]) {
|
||||
ret = 0;
|
||||
break;
|
||||
}
|
||||
|
||||
if (auxv[0] == type) {
|
||||
ret = auxv[1];
|
||||
break;
|
||||
}
|
||||
|
||||
auxv += 2;
|
||||
}
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
void c_main(void **stack)
|
||||
{
|
||||
/* Parse the stack */
|
||||
long argc = (long)*stack;
|
||||
stack += argc + 2;
|
||||
|
||||
/* Now we're pointing at the environment. Skip it. */
|
||||
while(*stack)
|
||||
stack++;
|
||||
stack++;
|
||||
|
||||
/* Now we're pointing at auxv. Initialize the vDSO parser. */
|
||||
vdso_init_from_sysinfo_ehdr(getauxval((unsigned long *)stack, AT_SYSINFO_EHDR));
|
||||
|
||||
/* Find gettimeofday. */
|
||||
typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
|
||||
gtod_t gtod = (gtod_t)vdso_sym("LINUX_2.6", "__vdso_gettimeofday");
|
||||
|
||||
if (!gtod)
|
||||
linux_exit(1);
|
||||
|
||||
struct timeval tv;
|
||||
long ret = gtod(&tv, 0);
|
||||
|
||||
if (ret == 0) {
|
||||
char buf[] = "The time is .000000\n";
|
||||
to_base10(buf + 31, tv.tv_sec);
|
||||
to_base10(buf + 38, tv.tv_usec);
|
||||
linux_write(1, buf, sizeof(buf) - 1);
|
||||
} else {
|
||||
linux_exit(ret);
|
||||
}
|
||||
|
||||
linux_exit(0);
|
||||
}
|
||||
|
||||
/*
|
||||
* This is the real entry point. It passes the initial stack into
|
||||
* the C entry point.
|
||||
*/
|
||||
asm (
|
||||
".text\n"
|
||||
".global _start\n"
|
||||
".type _start,@function\n"
|
||||
"_start:\n\t"
|
||||
#ifdef __x86_64__
|
||||
"mov %rsp,%rdi\n\t"
|
||||
"and $-16,%rsp\n\t"
|
||||
"sub $8,%rsp\n\t"
|
||||
"jmp c_main"
|
||||
#else
|
||||
"push %esp\n\t"
|
||||
"call c_main\n\t"
|
||||
"int $3"
|
||||
#endif
|
||||
);
|
||||
|
|
|
|||
Loading…
Reference in New Issue