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mmap calls could not be restarted after being interrupted by

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a signal.  The parameters on the stack were corrupted by the
signal handler.
This commit is contained in:
Ulrich Drepper 1999-04-14 13:42:16 +00:00
parent 95084e8a47
commit 45c6c04d8d
1 changed files with 19 additions and 3 deletions
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22
sysdeps/unix/sysv/linux/arm/mmap.S
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@ -26,10 +26,26 @@ ENTRY (__mmap)
mmap() takes six, we need to build a parameter block and pass its
address instead. The 386 port does a similar trick. */
mov ip, sp
stmdb ip!, {a1-a4}
mov a1, ip
/* This code previously moved sp into ip and stored the args using
stmdb ip!, {a1-a4}. It did not modify sp, so the stack never had
to be restored after the syscall completed. It saved an
instruction and meant no stack cleanup work was required.
This will not work in the case of a mmap call being interrupted
by a signal. If the signal handler uses any stack the arguments
to mmap will be trashed. The results of a restart of mmap are
then unpredictable. */
/* store args on the stack */
stmdb sp!, {a1-a4}
/* do the syscall */
mov a1, sp
swi SYS_ify (mmap)
/* pop args off the stack. */
add sp, sp, #16
cmn r0, $4096
bhs PLTJMP(syscall_error);
ret