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S390: Do not clobber r7 in clone [BZ #31402]

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Starting with commit e57d8fc97b
"S390: Always use svc 0"
clone clobbers the call-saved register r7 in error case:
function or stack is NULL.

This patch restores the saved registers also in the error case.
Furthermore the existing test misc/tst-clone is extended to check
all error cases and that clone does not clobber registers in this
error case.
This commit is contained in:
Stefan Liebler 2024-02-22 15:03:27 +01:00
parent 9f78a7c1d0
commit 02782fd128
3 changed files with 63 additions and 12 deletions
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1
sysdeps/unix/sysv/linux/s390/s390-32/clone.S
View File

@ -53,6 +53,7 @@ ENTRY(__clone)
br %r14
error:
lhi %r2,-EINVAL
lm %r6,%r7,24(%r15) /* Load registers. */
j SYSCALL_ERROR_LABEL
PSEUDO_END (__clone)

1
sysdeps/unix/sysv/linux/s390/s390-64/clone.S
View File

@ -54,6 +54,7 @@ ENTRY(__clone)
br %r14
error:
lghi %r2,-EINVAL
lmg %r6,%r7,48(%r15) /* Restore registers. */
jg SYSCALL_ERROR_LABEL
PSEUDO_END (__clone)

73
sysdeps/unix/sysv/linux/tst-clone.c
View File

@ -16,12 +16,16 @@
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
/* BZ #2386 */
/* BZ #2386, BZ #31402 */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>
#include <stackinfo.h> /* For _STACK_GROWS_{UP,DOWN}. */
#include <support/check.h>
volatile unsigned v = 0xdeadbeef;
int child_fn(void *arg)
{
@ -30,22 +34,67 @@ int child_fn(void *arg)
}
static int
do_test (void)
__attribute__((noinline))
do_clone (int (*fn)(void *), void *stack)
{
int result;
unsigned int a = v;
unsigned int b = v;
unsigned int c = v;
unsigned int d = v;
unsigned int e = v;
unsigned int f = v;
unsigned int g = v;
unsigned int h = v;
unsigned int i = v;
unsigned int j = v;
unsigned int k = v;
unsigned int l = v;
unsigned int m = v;
unsigned int n = v;
unsigned int o = v;
result = clone (child_fn, NULL, 0, NULL);
result = clone (fn, stack, 0, NULL);
if (errno != EINVAL || result != -1)
{
printf ("FAIL: clone()=%d (wanted -1) errno=%d (wanted %d)\n",
result, errno, EINVAL);
return 1;
}
/* Check that clone does not clobber call-saved registers. */
TEST_VERIFY (a == v && b == v && c == v && d == v && e == v && f == v
&& g == v && h == v && i == v && j == v && k == v && l == v
&& m == v && n == v && o == v);
return result;
}
static void
__attribute__((noinline))
do_test_single (int (*fn)(void *), void *stack)
{
printf ("%s (fn=%p, stack=%p)\n", __FUNCTION__, fn, stack);
errno = 0;
int result = do_clone (fn, stack);
TEST_COMPARE (errno, EINVAL);
TEST_COMPARE (result, -1);
}
static int
do_test (void)
{
char st[128 * 1024] __attribute__ ((aligned));
void *stack = NULL;
#if _STACK_GROWS_DOWN
stack = st + sizeof (st);
#elif _STACK_GROWS_UP
stack = st;
#else
# error "Define either _STACK_GROWS_DOWN or _STACK_GROWS_UP"
#endif
do_test_single (child_fn, NULL);
do_test_single (NULL, stack);
do_test_single (NULL, NULL);
puts ("All OK");
return 0;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"
#include <support/test-driver.c>