Author: andrew
Date: Sat Aug 4 05:31:26 2012
New Revision: 239032
URL: http://svn.freebsd.org/changeset/base/239032
Log:
Ensure we align the stack to 8 bytes in system calls.
This is not strictly required with the current ABI but will be when we
switch to the ARM EABI. The aapcs requires the stack to be 4 byte aligned
at all times and 8 byte aligned when calling a public subroutine where the
current ABI only requires sp to be a multiple of 4.
Modified:
head/sys/arm/arm/exception.S
Modified: head/sys/arm/arm/exception.S
==============================================================================
--- head/sys/arm/arm/exception.S Sat Aug 4 05:30:20 2012
(r239031)
+++ head/sys/arm/arm/exception.S Sat Aug 4 05:31:26 2012
(r239032)
@@ -80,7 +80,10 @@ ASENTRY_NP(swi_entry)
PUSHFRAME
mov r0, sp /* Pass the frame to any function */
+ mov r6, sp /* Backup the stack pointer */
+ bic sp, sp, #7 /* Align the stack pointer */
bl _C_LABEL(swi_handler) /* It's a SWI ! */
+ mov sp, r6 /* Restore the stack */
DO_AST
PULLFRAME
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