generic-library/bionic
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Merge "bionic: modify syscall to use 6 registers to pass parameter."

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This commit is contained in:
Elliott Hughes 2012-08-03 13:55:56 -07:00 committed by android code review
commit aea5f00df4
1 changed files with 25 additions and 16 deletions
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41
libc/arch-x86/bionic/syscall.S
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@ -1,15 +1,13 @@
/*
* Generic syscall call.
* Upon entry
* %eax: system call number
* %ebx: arg0 to system call
* %ecx: arg..
* %edx: arg..
* %esi: arg..
* %edi: arg..
* We push these (to save them) load them up with the
* values from the calling frame (not all will actually be valid)
* and make the syscall.
* Upon entry:
* %eax: system call number - caller save
* %ebx: arg0 to system call - callee save
* %ecx: arg1 - caller save
* %edx: arg2 - caller save
* %esi: arg3 - callee save
* %edi: arg4 - callee save
* %ebp: arg5 - callee save
*/
#include <sys/linux-syscalls.h>
@ -20,26 +18,37 @@
.align 4
syscall:
# Push the callee save registers.
push %ebx
push %esi
push %edi
mov 16(%esp),%eax
mov 20(%esp),%ebx
mov 24(%esp),%ecx
mov 28(%esp),%edx
mov 32(%esp),%esi
mov 36(%esp),%edi
push %ebp
# Load all the arguments from the calling frame.
# (Not all will be valid, depending on the syscall.)
mov 20(%esp),%eax
mov 24(%esp),%ebx
mov 28(%esp),%ecx
mov 32(%esp),%edx
mov 36(%esp),%esi
mov 40(%esp),%edi
mov 44(%esp),%ebp
# Make the system call.
int $0x80
# Error?
cmpl $-4095, %eax
jb 1f
# Yes, so set errno.
negl %eax
pushl %eax
call __set_errno
addl $4, %esp
orl $-1, %eax
1:
# Restore the callee save registers.
pop %ebp
pop %edi
pop %esi
pop %ebx