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From: Stefan Liebler <stli@sourceware.org> To: glibc-cvs@sourceware.org Subject: [glibc] S390: Do not clobber r7 in clone [BZ #31402] Date: Mon, 26 Feb 2024 12:40:56 +0000 (GMT) [thread overview] Message-ID: <20240226124056.E56873858D28@sourceware.org> (raw) https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=02782fd12849b6673cb5c2728cb750e8ec295aa3 commit 02782fd12849b6673cb5c2728cb750e8ec295aa3 Author: Stefan Liebler <stli@linux.ibm.com> Date: Thu Feb 22 15:03:27 2024 +0100 S390: Do not clobber r7 in clone [BZ #31402] Starting with commit e57d8fc97b90127de4ed3e3a9cdf663667580935 "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. Diff: --- sysdeps/unix/sysv/linux/s390/s390-32/clone.S | 1 + sysdeps/unix/sysv/linux/s390/s390-64/clone.S | 1 + sysdeps/unix/sysv/linux/tst-clone.c | 73 +++++++++++++++++++++++----- 3 files changed, 63 insertions(+), 12 deletions(-) diff --git a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S index 4c882ef2ee..a7a863242c 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-32/clone.S +++ b/sysdeps/unix/sysv/linux/s390/s390-32/clone.S @@ -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) diff --git a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S index 4eb104be71..c552a6b8de 100644 --- a/sysdeps/unix/sysv/linux/s390/s390-64/clone.S +++ b/sysdeps/unix/sysv/linux/s390/s390-64/clone.S @@ -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) diff --git a/sysdeps/unix/sysv/linux/tst-clone.c b/sysdeps/unix/sysv/linux/tst-clone.c index 470676ab2b..2bc7124983 100644 --- a/sysdeps/unix/sysv/linux/tst-clone.c +++ b/sysdeps/unix/sysv/linux/tst-clone.c @@ -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 (fn, stack, 0, NULL); + + /* 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); +} - result = clone (child_fn, NULL, 0, NULL); +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 - if (errno != EINVAL || result != -1) - { - printf ("FAIL: clone()=%d (wanted -1) errno=%d (wanted %d)\n", - result, errno, EINVAL); - return 1; - } + 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>
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