vdso_test_correctness test fails on powerpc:
~ # ./vdso_test_correctness ... [RUN] Testing clock_gettime for clock CLOCK_REALTIME_ALARM (8)... [FAIL] No such clock, but __vdso_clock_gettime returned 22 [RUN] Testing clock_gettime for clock CLOCK_BOOTTIME_ALARM (9)... [FAIL] No such clock, but __vdso_clock_gettime returned 22 [RUN] Testing clock_gettime for clock CLOCK_SGI_CYCLE (10)... [FAIL] No such clock, but __vdso_clock_gettime returned 22 ... [RUN] Testing clock_gettime for clock invalid (-1)... [FAIL] No such clock, but __vdso_clock_gettime returned 22 [RUN] Testing clock_gettime for clock invalid (-2147483648)... [FAIL] No such clock, but __vdso_clock_gettime returned 22 [RUN] Testing clock_gettime for clock invalid (2147483647)... [FAIL] No such clock, but __vdso_clock_gettime returned 22
On powerpc, a call to a VDSO function is not an ordinary C function call. Unlike several architectures which returns a negative error code in case of an error, powerpc sets CR[SO] and returns the error code as a positive value.
Define and use a macro called VDSO_CALL() which takes a pointer to the function to call, the number of arguments and the arguments.
Also update ABI vdso documentation to reflect this subtlety.
Provide a specific version of VDSO_CALL() for powerpc that negates the error code on return when CR[SO] is set.
Fixes: c7e5789b24d3 ("kselftest: Move test_vdso to the vDSO test suite") Fixes: 2e9a97256616 ("selftests: vdso: Add a selftest for vDSO getcpu()") Fixes: 693f5ca08ca0 ("kselftest: Extend vDSO selftest") Fixes: b2f1c3db2887 ("kselftest: Extend vdso correctness test to clock_gettime64") Fixes: 4920a2590e91 ("selftests/vDSO: add tests for vgetrandom") Signed-off-by: Christophe Leroy christophe.leroy@csgroup.eu --- Documentation/ABI/stable/vdso | 8 ++- tools/testing/selftests/vDSO/vdso_call.h | 70 +++++++++++++++++++ tools/testing/selftests/vDSO/vdso_test_abi.c | 9 +-- .../selftests/vDSO/vdso_test_correctness.c | 15 ++-- .../testing/selftests/vDSO/vdso_test_getcpu.c | 3 +- .../selftests/vDSO/vdso_test_getrandom.c | 5 +- .../selftests/vDSO/vdso_test_gettimeofday.c | 3 +- 7 files changed, 95 insertions(+), 18 deletions(-) create mode 100644 tools/testing/selftests/vDSO/vdso_call.h
diff --git a/Documentation/ABI/stable/vdso b/Documentation/ABI/stable/vdso index 951838d42781..85dbb6a160df 100644 --- a/Documentation/ABI/stable/vdso +++ b/Documentation/ABI/stable/vdso @@ -9,9 +9,11 @@ maps an ELF DSO into that program's address space. This DSO is called the vDSO and it often contains useful and highly-optimized alternatives to real syscalls.
-These functions are called just like ordinary C function according to -your platform's ABI. Call them from a sensible context. (For example, -if you set CS on x86 to something strange, the vDSO functions are +These functions are called according to your platform's ABI. On many +platforms they are called just like ordinary C function. On other platforms +(ex: powerpc) they are called with the same convention as system calls which +is different from ordinary C functions. Call them from a sensible context. +(For example, if you set CS on x86 to something strange, the vDSO functions are within their rights to crash.) In addition, if you pass a bad pointer to a vDSO function, you might get SIGSEGV instead of -EFAULT.
diff --git a/tools/testing/selftests/vDSO/vdso_call.h b/tools/testing/selftests/vDSO/vdso_call.h new file mode 100644 index 000000000000..bb237d771051 --- /dev/null +++ b/tools/testing/selftests/vDSO/vdso_call.h @@ -0,0 +1,70 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Macro to call vDSO functions + * + * Copyright (C) 2024 Christophe Leroy christophe.leroy@csgroup.eu, CS GROUP France + */ +#ifndef __VDSO_CALL_H__ +#define __VDSO_CALL_H__ + +#ifdef __powerpc__ + +#define LOADARGS_1(fn, __arg1) do { \ + _r0 = fn; \ + _r3 = (long)__arg1; \ +} while (0) + +#define LOADARGS_2(fn, __arg1, __arg2) do { \ + _r0 = fn; \ + _r3 = (long)__arg1; \ + _r4 = (long)__arg2; \ +} while (0) + +#define LOADARGS_3(fn, __arg1, __arg2, __arg3) do { \ + _r0 = fn; \ + _r3 = (long)__arg1; \ + _r4 = (long)__arg2; \ + _r5 = (long)__arg3; \ +} while (0) + +#define LOADARGS_5(fn, __arg1, __arg2, __arg3, __arg4, __arg5) do { \ + _r0 = fn; \ + _r3 = (long)__arg1; \ + _r4 = (long)__arg2; \ + _r5 = (long)__arg3; \ + _r6 = (long)__arg4; \ + _r7 = (long)__arg5; \ +} while (0) + +#define VDSO_CALL(fn, nr, args...) ({ \ + register void *_r0 asm ("r0"); \ + register long _r3 asm ("r3"); \ + register long _r4 asm ("r4"); \ + register long _r5 asm ("r5"); \ + register long _r6 asm ("r6"); \ + register long _r7 asm ("r7"); \ + register long _r8 asm ("r8"); \ + register long _rval asm ("r3"); \ + \ + LOADARGS_##nr(fn, args); \ + \ + asm volatile( \ + " mtctr %0\n" \ + " bctrl\n" \ + " bns+ 1f\n" \ + " neg 3, 3\n" \ + "1:" \ + : "+r" (_r0), "=r" (_r3), "+r" (_r4), "+r" (_r5), \ + "+r" (_r6), "+r" (_r7), "+r" (_r8) \ + : "r" (_rval) \ + : "r9", "r10", "r11", "r12", "cr0", "cr1", "cr5", \ + "cr6", "cr7", "xer", "lr", "ctr", "memory" \ + ); \ + _rval; \ +}) + +#else +#define VDSO_CALL(fn, nr, args...) fn(args) +#endif + +#endif diff --git a/tools/testing/selftests/vDSO/vdso_test_abi.c b/tools/testing/selftests/vDSO/vdso_test_abi.c index 96d32fd65b42..00034208c4c6 100644 --- a/tools/testing/selftests/vDSO/vdso_test_abi.c +++ b/tools/testing/selftests/vDSO/vdso_test_abi.c @@ -20,6 +20,7 @@
#include "../kselftest.h" #include "vdso_config.h" +#include "vdso_call.h"
extern void *vdso_sym(const char *version, const char *name); extern void vdso_init_from_sysinfo_ehdr(uintptr_t base); @@ -61,7 +62,7 @@ static void vdso_test_gettimeofday(void) }
struct timeval tv; - long ret = vdso_gettimeofday(&tv, 0); + long ret = VDSO_CALL(vdso_gettimeofday, 2, &tv, 0);
if (ret == 0) { ksft_print_msg("The time is %lld.%06lld\n", @@ -86,7 +87,7 @@ static void vdso_test_clock_gettime(clockid_t clk_id) }
struct timespec ts; - long ret = vdso_clock_gettime(clk_id, &ts); + long ret = VDSO_CALL(vdso_clock_gettime, 2, clk_id, &ts);
if (ret == 0) { ksft_print_msg("The time is %lld.%06lld\n", @@ -111,7 +112,7 @@ static void vdso_test_time(void) return; }
- long ret = vdso_time(NULL); + long ret = VDSO_CALL(vdso_time, 1, NULL);
if (ret > 0) { ksft_print_msg("The time in hours since January 1, 1970 is %lld\n", @@ -138,7 +139,7 @@ static void vdso_test_clock_getres(clockid_t clk_id) }
struct timespec ts, sys_ts; - long ret = vdso_clock_getres(clk_id, &ts); + long ret = VDSO_CALL(vdso_clock_getres, 2, clk_id, &ts);
if (ret == 0) { ksft_print_msg("The vdso resolution is %lld %lld\n", diff --git a/tools/testing/selftests/vDSO/vdso_test_correctness.c b/tools/testing/selftests/vDSO/vdso_test_correctness.c index cdb697ae8343..5fb97ad67eea 100644 --- a/tools/testing/selftests/vDSO/vdso_test_correctness.c +++ b/tools/testing/selftests/vDSO/vdso_test_correctness.c @@ -20,6 +20,7 @@ #include <limits.h>
#include "vdso_config.h" +#include "vdso_call.h" #include "../kselftest.h"
static const char **name; @@ -186,7 +187,7 @@ static void test_getcpu(void)
ret_sys = sys_getcpu(&cpu_sys, &node_sys, 0); if (vdso_getcpu) - ret_vdso = vdso_getcpu(&cpu_vdso, &node_vdso, 0); + ret_vdso = VDSO_CALL(vdso_getcpu, 3, &cpu_vdso, &node_vdso, 0); if (vgetcpu) ret_vsys = vgetcpu(&cpu_vsys, &node_vsys, 0);
@@ -269,7 +270,7 @@ static void test_one_clock_gettime(int clock, const char *name)
if (sys_clock_gettime(clock, &start) < 0) { if (errno == EINVAL) { - vdso_ret = vdso_clock_gettime(clock, &vdso); + vdso_ret = VDSO_CALL(vdso_clock_gettime, 2, clock, &vdso); if (vdso_ret == -EINVAL) { printf("[OK]\tNo such clock.\n"); } else { @@ -282,7 +283,7 @@ static void test_one_clock_gettime(int clock, const char *name) return; }
- vdso_ret = vdso_clock_gettime(clock, &vdso); + vdso_ret = VDSO_CALL(vdso_clock_gettime, 2, clock, &vdso); end_ret = sys_clock_gettime(clock, &end);
if (vdso_ret != 0 || end_ret != 0) { @@ -331,7 +332,7 @@ static void test_one_clock_gettime64(int clock, const char *name)
if (sys_clock_gettime64(clock, &start) < 0) { if (errno == EINVAL) { - vdso_ret = vdso_clock_gettime64(clock, &vdso); + vdso_ret = VDSO_CALL(vdso_clock_gettime64, 2, clock, &vdso); if (vdso_ret == -EINVAL) { printf("[OK]\tNo such clock.\n"); } else { @@ -344,7 +345,7 @@ static void test_one_clock_gettime64(int clock, const char *name) return; }
- vdso_ret = vdso_clock_gettime64(clock, &vdso); + vdso_ret = VDSO_CALL(vdso_clock_gettime64, 2, clock, &vdso); end_ret = sys_clock_gettime64(clock, &end);
if (vdso_ret != 0 || end_ret != 0) { @@ -401,7 +402,7 @@ static void test_gettimeofday(void) return; }
- vdso_ret = vdso_gettimeofday(&vdso, &vdso_tz); + vdso_ret = VDSO_CALL(vdso_gettimeofday, 2, &vdso, &vdso_tz); end_ret = sys_gettimeofday(&end, NULL);
if (vdso_ret != 0 || end_ret != 0) { @@ -431,7 +432,7 @@ static void test_gettimeofday(void) }
/* And make sure that passing NULL for tz doesn't crash. */ - vdso_gettimeofday(&vdso, NULL); + VDSO_CALL(vdso_gettimeofday, 2, &vdso, NULL); }
int main(int argc, char **argv) diff --git a/tools/testing/selftests/vDSO/vdso_test_getcpu.c b/tools/testing/selftests/vDSO/vdso_test_getcpu.c index b758f68c6c9c..cdeaed45fb26 100644 --- a/tools/testing/selftests/vDSO/vdso_test_getcpu.c +++ b/tools/testing/selftests/vDSO/vdso_test_getcpu.c @@ -14,6 +14,7 @@ #include "../kselftest.h" #include "parse_vdso.h" #include "vdso_config.h" +#include "vdso_call.h"
struct getcpu_cache; typedef long (*getcpu_t)(unsigned int *, unsigned int *, @@ -42,7 +43,7 @@ int main(int argc, char **argv) return KSFT_SKIP; }
- ret = get_cpu(&cpu, &node, 0); + ret = VDSO_CALL(get_cpu, 3, &cpu, &node, 0); if (ret == 0) { printf("Running on CPU %u node %u\n", cpu, node); } else { diff --git a/tools/testing/selftests/vDSO/vdso_test_getrandom.c b/tools/testing/selftests/vDSO/vdso_test_getrandom.c index 05122425a873..94aa1cffde52 100644 --- a/tools/testing/selftests/vDSO/vdso_test_getrandom.c +++ b/tools/testing/selftests/vDSO/vdso_test_getrandom.c @@ -21,6 +21,7 @@
#include "../kselftest.h" #include "parse_vdso.h" +#include "vdso_call.h"
#ifndef timespecsub #define timespecsub(tsp, usp, vsp) \ @@ -120,7 +121,7 @@ static void vgetrandom_init(void) printf("__vdso_getrandom is missing!\n"); exit(KSFT_FAIL); } - if (grnd_ctx.fn(NULL, 0, 0, &grnd_ctx.params, ~0UL) != 0) { + if (VDSO_CALL(grnd_ctx.fn, 5, NULL, 0, 0, &grnd_ctx.params, ~0UL) != 0) { printf("failed to fetch vgetrandom params!\n"); exit(KSFT_FAIL); } @@ -143,7 +144,7 @@ static ssize_t vgetrandom(void *buf, size_t len, unsigned long flags) exit(KSFT_FAIL); } } - return grnd_ctx.fn(buf, len, flags, state, grnd_ctx.params.size_of_opaque_state); + return VDSO_CALL(grnd_ctx.fn, 5, buf, len, flags, state, grnd_ctx.params.size_of_opaque_state); }
enum { TRIALS = 25000000, THREADS = 256 }; diff --git a/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c index ee4f1ca56a71..e31b18ffae33 100644 --- a/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c +++ b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c @@ -19,6 +19,7 @@ #include "../kselftest.h" #include "parse_vdso.h" #include "vdso_config.h" +#include "vdso_call.h"
int main(int argc, char **argv) { @@ -43,7 +44,7 @@ int main(int argc, char **argv) }
struct timeval tv; - long ret = gtod(&tv, 0); + long ret = VDSO_CALL(gtod, 2, &tv, 0);
if (ret == 0) { printf("The time is %lld.%06lld\n",