Bug#838574: glibc: FTBFS on hppa - nptl/tst-stack4 fails
Source: glibc
Version: 2.24-3
Severity: normal
Tags: patch
Dear Maintainer,
In the previous change which fixed various cancellation tests on hppa, I
removed nptl/tst-stack4 from the expected fail list. Probably, it should
be added back to the xfail list. However, with the attached change, the
test does not fail on my test system. It optimizes the atomic compare
and exchange code on hppa to avoid conditional branches.
The patch has been submitted upstream:
https://sourceware.org/ml/libc-alpha/2016-09/msg00456.html
Regards,
Dave Anglin
-- System Information:
Debian Release: stretch/sid
APT prefers buildd-unstable
APT policy: (500, 'buildd-unstable'), (500, 'unstable')
Architecture: hppa (parisc64)
Kernel: Linux 4.7.4+ (SMP w/4 CPU cores)
Locale: LANG=C, LC_CTYPE=C (charmap=UTF-8) (ignored: LC_ALL set to en_US.utf8)
Shell: /bin/sh linked to /bin/dash
Init: sysvinit (via /sbin/init)
2016-09-22 John David Anglin
* sysdeps/unix/sysv/linux/hppa/atomic-machine.h: Don't include
abort-instr.h.
(EFAULT): Remove conditional define.
(ENOSYS): Likewise.
(atomic_compare_and_exchange_val_acq): Use instruction nullification
instead of conditional branch instructions.
Index: glibc-2.23/sysdeps/unix/sysv/linux/hppa/atomic-machine.h
===================================================================
--- glibc-2.23.orig/sysdeps/unix/sysv/linux/hppa/atomic-machine.h
+++ glibc-2.23/sysdeps/unix/sysv/linux/hppa/atomic-machine.h
@@ -17,13 +17,6 @@
<http://www.gnu.org/licenses/>. */
#include <stdint.h> /* Required for type definitions e.g. uint8_t. */
-#include <abort-instr.h> /* Required for ABORT_INSTRUCTIUON. */
-
-/* We need EFAULT, ENONSYS */
-#if !defined EFAULT && !defined ENOSYS
-#define EFAULT 14
-#define ENOSYS 251
-#endif
#ifndef _ATOMIC_MACHINE_H
#define _ATOMIC_MACHINE_H 1
@@ -62,7 +55,7 @@ typedef uintmax_t uatomic_max_t;
#define _ASM_EDEADLOCK "-45"
/* The only basic operation needed is compare and exchange. The mem
- pointer must be word aligned. */
+ pointer must be word aligned. We no longer loop on deadlock. */
#define atomic_compare_and_exchange_val_acq(mem, newval, oldval) \
({ \
register long lws_errno asm("r21"); \
@@ -74,20 +67,15 @@ typedef uintmax_t uatomic_max_t;
"0: \n\t" \
"ble " _LWS "(%%sr2, %%r0) \n\t" \
"ldi " _LWS_CAS ", %%r20 \n\t" \
- "ldi " _ASM_EAGAIN ", %%r20 \n\t" \
- "cmpb,=,n %%r20, %%r21, 0b \n\t" \
- "nop \n\t" \
- "ldi " _ASM_EDEADLOCK ", %%r20 \n\t" \
- "cmpb,=,n %%r20, %%r21, 0b \n\t" \
- "nop \n\t" \
+ "cmpiclr,<> " _ASM_EAGAIN ", %%r21, %%r0\n\t" \
+ "b,n 0b \n\t" \
+ "cmpclr,= %%r0, %%r21, %%r0 \n\t" \
+ "iitlbp %%r0,(%%sr0, %%r0) \n\t" \
: "=r" (lws_ret), "=r" (lws_errno) \
: "r" (lws_mem), "r" (lws_old), "r" (lws_new) \
: _LWS_CLOBBER \
); \
\
- if (lws_errno == -EFAULT || lws_errno == -ENOSYS) \
- ABORT_INSTRUCTION; \
- \
(__typeof (oldval)) lws_ret; \
})
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