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Stop ARM setjmp/longjmp saving/restoring fpscr (bug 14908)
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: <libc-ports at sourceware dot org>
- Date: Tue, 14 May 2013 17:17:42 +0000
- Subject: Stop ARM setjmp/longjmp saving/restoring fpscr (bug 14908)
This patch fixes bug 14908, ARM setjmp/longjmp wrongly saving and
restoring fpscr. Tested in conjunction with my libc patch
<http://sourceware.org/ml/libc-alpha/2013-05/msg00474.html> to add a
testcase for this issue; will commit once the libc testcase is in.
2013-05-14 Joseph Myers <joseph@codesourcery.com>
[BZ #14908]
* sysdeps/arm/setjmp.S (__sigsetjmp): Don't save fpscr.
* sysdeps/arm/__longjmp.S (__longjmp): Don't restore fpscr.
* sysdeps/arm/bits/setjmp.h (__jmp_buf): Don't mention fpscr in
comment.
diff --git a/ports/sysdeps/arm/__longjmp.S b/ports/sysdeps/arm/__longjmp.S
index 8de9fa1..a5edede 100644
--- a/ports/sysdeps/arm/__longjmp.S
+++ b/ports/sysdeps/arm/__longjmp.S
@@ -83,11 +83,6 @@ ENTRY (__longjmp)
/* Following instruction is vldmia ip!, {d8-d15}. */
sfi_breg r12, \
ldc p11, cr8, [\B], #64
- /* Restore the floating-point status register. */
- sfi_breg ip, \
- ldr a3, [\B], #4
- /* Following instruction is fmxr fpscr, a3. */
- mcr p10, 7, a3, cr1, cr0, 0
.Lno_vfp:
#ifndef ARM_ASSUME_NO_IWMMXT
diff --git a/ports/sysdeps/arm/bits/setjmp.h b/ports/sysdeps/arm/bits/setjmp.h
index 21bbf7f..c8c3a9a 100644
--- a/ports/sysdeps/arm/bits/setjmp.h
+++ b/ports/sysdeps/arm/bits/setjmp.h
@@ -28,9 +28,9 @@
/* The exact set of registers saved may depend on the particular core
in use, as some coprocessor registers may need to be saved. The C
Library ABI requires that the buffer be 8-byte aligned, and
- recommends that the buffer contain 64 words. The first 28 words
- are occupied by v1-v6, sl, fp, sp, pc, d8-d15, and fpscr. (Note
- that d8-15 require 17 words, due to the use of fstmx.) */
+ recommends that the buffer contain 64 words. The first 27 words
+ are occupied by v1-v6, sl, fp, sp, pc, and d8-d15. (Note that
+ d8-15 require 17 words, due to the use of fstmx.) */
typedef int __jmp_buf[64] __attribute__((__aligned__ (8)));
#endif
diff --git a/ports/sysdeps/arm/setjmp.S b/ports/sysdeps/arm/setjmp.S
index f750470..a6c161d 100644
--- a/ports/sysdeps/arm/setjmp.S
+++ b/ports/sysdeps/arm/setjmp.S
@@ -67,11 +67,6 @@ ENTRY (__sigsetjmp)
/* Following instruction is vstmia ip!, {d8-d15}. */
sfi_breg ip, \
stc p11, cr8, [\B], #64
- /* Store the floating-point status register. */
- /* Following instruction is vmrs a4, fpscr. */
- mrc p10, 7, a4, cr1, cr0, 0
- sfi_breg ip, \
- str a4, [\B], #4
.Lno_vfp:
#ifndef ARM_ASSUME_NO_IWMMXT
--
Joseph S. Myers
joseph@codesourcery.com