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- commit 2952c70804b48bb5c87eea21df5e401969dc4ec1
- Author: Kevin Cernekee <cernekee@gmail.com>
- Date: Tue Jun 5 15:05:20 2012 -0700
- MIPS: Use $a0 instead of $v0 for __syscall_error() argument
-
- $a0 is saved across _dl_runtime_resolve(); $v0 is not. Unfortunately,
- __syscall_error() uses $v0 for its argument, not $a0 as is the MIPS ABI
- standard. This means that if lazy binding was used for __syscall_error(),
- the errno value in $v0 could get corrupted.
-
- The problem can be easily seen in testcases where syscalls in librt fail;
- when librt tries to call __syscall_error() in libc, the argument gets
- lost and errno gets set to a bogus value:
-
- # ./tst-mqueue1 ; echo $?
- mq_receive on O_WRONLY mqd_t did not fail with EBADF: Unknown error 2004684208
- 1
- # ./tst-mqueue2 ; echo $?
- mq_timedreceive with too small msg_len did not fail with EMSGSIZE: Unknown error 1997360560
- 1
- # ./tst-mqueue4 ; echo $?
- mq_timedsend did not fail with ETIMEDOUT: Unknown error 2008747440
- 1
-
- When _dl_runtime_resolve() was taken out of the equation, the same test
- cases passed:
-
- # LD_BIND_NOW=y ./tst-mqueue1 ; echo $?
- 0
- # LD_BIND_NOW=y ./tst-mqueue2 ; echo $?
- 0
- # LD_BIND_NOW=y ./tst-mqueue4 ; echo $?
- 0
-
- Changing __syscall_error() to look at $a0 instead of $v0 fixed the
- problem.
-
- (Note that there is also a "__syscall_error.c" file which presumably
- uses the standard C calling conventions, but I do not think it is used
- on MIPS.)
-
- Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
- Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- commit 3c58d95d918c7e2fda374c37a52f81b34b81e4ca
- Author: Kevin Cernekee <cernekee@gmail.com>
- Date: Tue Jun 5 15:05:19 2012 -0700
- MIPS: Convert __syscall_error() callers to use $a0 for argument
-
- Some callers passed the first argument in $v0, while others used $a0.
- Change the callers to use $a0 consistently.
-
- Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
- Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
- --- a/libc/sysdeps/linux/mips/vfork.S
- +++ b/libc/sysdeps/linux/mips/vfork.S
- @@ -84,6 +84,7 @@ NESTED(__vfork,FRAMESZ,sp)
-
- /* Something bad happened -- no child created. */
- L(error):
- + move a0, v0
- #ifdef __PIC__
- PTR_LA t9, __syscall_error
- RESTORE_GP64
- --- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
- +++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/mips64/sysdep-cancel.h
- @@ -31,7 +31,7 @@
- # undef PSEUDO
- # define PSEUDO(name, syscall_name, args) \
- .align 2; \
- - 99: \
- + 99: move a0, v0; \
- PTR_LA t9,__syscall_error; \
- /* manual cpreturn. */ \
- REG_L gp, STKOFF_GP(sp); \
- --- a/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
- +++ b/libpthread/linuxthreads/sysdeps/unix/sysv/linux/mips/vfork.S
- @@ -80,6 +80,7 @@ NESTED(__vfork,FRAMESZ,sp)
-
- /* Something bad happened -- no child created. */
- L(error):
- + move a0, v0
- #ifdef __PIC__
- PTR_LA t9, __syscall_error
- RESTORE_GP64
- --- a/libc/sysdeps/linux/mips/syscall_error.S
- +++ b/libc/sysdeps/linux/mips/syscall_error.S
- @@ -43,7 +43,7 @@ ENTRY(__syscall_error)
- #ifdef __PIC__
- SAVE_GP(GPOFF)
- #endif
- - REG_S v0, V0OFF(sp)
- + REG_S a0, V0OFF(sp)
- REG_S ra, RAOFF(sp)
-
- /* Find our per-thread errno address */
|
