github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-09-23 13:14:02 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

selftests: vDSO: vdso_standalone_test_x86: Switch to nolibc

Browse Source 
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.de
This commit is contained in:
Thomas Weißschuh 2025-02-26 12:44:55 +01:00 committed by Thomas Gleixner
parent 4f65df6a58
commit 8770a9183f
2 changed files with 50 additions and 155 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
tools/testing/selftests/vDSO/Makefile
View File

@ -22,13 +22,17 @@ include ../lib.mk
CFLAGS += $(TOOLS_INCLUDES) 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_gettimeofday: parse_vdso.c vdso_test_gettimeofday.c
$(OUTPUT)/vdso_test_getcpu: parse_vdso.c vdso_test_getcpu.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_abi: parse_vdso.c vdso_test_abi.c
$(OUTPUT)/vdso_test_clock_getres: vdso_test_clock_getres.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: vdso_standalone_test_x86.c parse_vdso.c | headers
$(OUTPUT)/vdso_standalone_test_x86: CFLAGS +=-nostdlib -fno-asynchronous-unwind-tables -fno-stack-protector $(OUTPUT)/vdso_standalone_test_x86: CFLAGS:=$(CFLAGS_NOLIBC) $(CFLAGS)
$(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c $(OUTPUT)/vdso_test_correctness: vdso_test_correctness.c
$(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl $(OUTPUT)/vdso_test_correctness: LDFLAGS += -ldl

179
tools/testing/selftests/vDSO/vdso_standalone_test_x86.c
View File

@ -1,167 +1,58 @@
// SPDX-License-Identifier: GPL-2.0-only // SPDX-License-Identifier: GPL-2.0-only
/* /*
* vdso_test.c: Sample code to test parse_vdso.c on x86 * vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and
* Copyright (c) 2011-2014 Andy Lutomirski * vDSO gettimeofday()
* Copyright (c) 2014 Andy Lutomirski
* *
* You can amuse yourself by compiling with: * Compile with:
* gcc -std=gnu99 -nostdlib * gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c
* -Os -fno-asynchronous-unwind-tables -flto -lgcc_s *
* vdso_standalone_test_x86.c parse_vdso.c * Tested on x86, 32-bit and 64-bit. It may work on other architectures, too.
* to generate a small binary. On x86_64, you can omit -lgcc_s
* if you want the binary to be completely standalone.
*/ */
#include <sys/syscall.h> #include <stdio.h>
#ifndef NOLIBC
#include <sys/auxv.h>
#include <sys/time.h> #include <sys/time.h>
#include <unistd.h>
#include <stdint.h>
#include <linux/auxvec.h>
#include "parse_vdso.h"
/* We need some libc functions... */
int strcmp(const char *a, const char *b)
{
/* 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++;
}
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 #endif
return ret;
}
static inline long linux_write(int fd, const void *data, size_t len) #include "../kselftest.h"
#include "parse_vdso.h"
#include "vdso_config.h"
#include "vdso_call.h"
int main(int argc, char **argv)
{ {
return x86_syscall3(__NR_write, fd, (long)data, (long)len); 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;
} }
static inline void linux_exit(int code) vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
{
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. */ /* Find gettimeofday. */
typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz); typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
gtod_t gtod = (gtod_t)vdso_sym("LINUX_2.6", "__vdso_gettimeofday"); gtod_t gtod = (gtod_t)vdso_sym(version, name[0]);
if (!gtod) if (!gtod) {
linux_exit(1); printf("Could not find %s\n", name[0]);
return KSFT_SKIP;
}
struct timeval tv; struct timeval tv;
long ret = gtod(&tv, 0); long ret = VDSO_CALL(gtod, 2, &tv, 0);
if (ret == 0) { if (ret == 0) {
char buf[] = "The time is .000000\n"; printf("The time is %lld.%06lld\n",
to_base10(buf + 31, tv.tv_sec); (long long)tv.tv_sec, (long long)tv.tv_usec);
to_base10(buf + 38, tv.tv_usec);
linux_write(1, buf, sizeof(buf) - 1);
} else { } else {
linux_exit(ret); printf("%s failed\n", name[0]);
return KSFT_FAIL;
} }
linux_exit(0); return 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
);