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From: tip-bot for Luca Barbieri on 12 Aug 2010 02:20
Commit-ID: 30246557a06bb20618bed906a06d1e1e0faa8bb4
Gitweb: http://git.kernel.org/tip/30246557a06bb20618bed906a06d1e1e0faa8bb4
Author: Luca Barbieri <luca(a)luca-barbieri.com>
AuthorDate: Fri, 6 Aug 2010 04:04:38 +0200
Committer: H. Peter Anvin <hpa(a)zytor.com>
CommitDate: Wed, 11 Aug 2010 21:03:28 -0700

x86, asm: Refactor atomic64_386_32.S to support old binutils and be cleaner

The old code didn't work on binutils 2.12 because setting a symbol to
a register apparently requires a fairly recent version.

This commit refactors the code to use the C preprocessor instead, and
in the process makes the whole code a bit easier to understand.

The object code produced is unchanged as expected.

This fixes kernel bugzilla 16506.

Reported-by: Dieter Stussy <kd6lvw+software(a)kd6lvw.ampr.org>
Signed-off-by: Luca Barbieri <luca(a)luca-barbieri.com>
Signed-off-by: H. Peter Anvin <hpa(a)zytor.com>
Cc: <stable(a)kernel.org> 2.6.35
LKML-Reference: <tip-*@git.kernel.org>
---
arch/x86/lib/atomic64_386_32.S | 236 ++++++++++++++++++++++------------------
1 files changed, 128 insertions(+), 108 deletions(-)

diff --git a/arch/x86/lib/atomic64_386_32.S b/arch/x86/lib/atomic64_386_32.S
index 4a5979a..78ee8e0 100644
--- a/arch/x86/lib/atomic64_386_32.S
+++ b/arch/x86/lib/atomic64_386_32.S
@@ -25,150 +25,170 @@
CFI_ADJUST_CFA_OFFSET -4
.endm

-.macro BEGIN func reg
-$v = \reg
-
-ENTRY(atomic64_\func\()_386)
- CFI_STARTPROC
- LOCK $v
-
-.macro RETURN
- UNLOCK $v
+#define BEGIN(op) \
+.macro END; \
+ CFI_ENDPROC; \
+ENDPROC(atomic64_##op##_386); \
+.purgem END; \
+.endm; \
+ENTRY(atomic64_##op##_386); \
+ CFI_STARTPROC; \
+ LOCK v;
+
+#define RET \
+ UNLOCK v; \
ret
-.endm
-
-.macro END_
- CFI_ENDPROC
-ENDPROC(atomic64_\func\()_386)
-.purgem RETURN
-.purgem END_
-.purgem END
-.endm
-
-.macro END
-RETURN
-END_
-.endm
-.endm
-
-BEGIN read %ecx
- movl ($v), %eax
- movl 4($v), %edx
-END
-
-BEGIN set %esi
- movl %ebx, ($v)
- movl %ecx, 4($v)
-END
-
-BEGIN xchg %esi
- movl ($v), %eax
- movl 4($v), %edx
- movl %ebx, ($v)
- movl %ecx, 4($v)
-END
-
-BEGIN add %ecx
- addl %eax, ($v)
- adcl %edx, 4($v)
-END

-BEGIN add_return %ecx
- addl ($v), %eax
- adcl 4($v), %edx
- movl %eax, ($v)
- movl %edx, 4($v)
-END
-
-BEGIN sub %ecx
- subl %eax, ($v)
- sbbl %edx, 4($v)
-END
-
-BEGIN sub_return %ecx
+#define RET_END \
+ RET; \
+ END
+
+#define v %ecx
+BEGIN(read)
+ movl (v), %eax
+ movl 4(v), %edx
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(set)
+ movl %ebx, (v)
+ movl %ecx, 4(v)
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(xchg)
+ movl (v), %eax
+ movl 4(v), %edx
+ movl %ebx, (v)
+ movl %ecx, 4(v)
+RET_END
+#undef v
+
+#define v %ecx
+BEGIN(add)
+ addl %eax, (v)
+ adcl %edx, 4(v)
+RET_END
+#undef v
+
+#define v %ecx
+BEGIN(add_return)
+ addl (v), %eax
+ adcl 4(v), %edx
+ movl %eax, (v)
+ movl %edx, 4(v)
+RET_END
+#undef v
+
+#define v %ecx
+BEGIN(sub)
+ subl %eax, (v)
+ sbbl %edx, 4(v)
+RET_END
+#undef v
+
+#define v %ecx
+BEGIN(sub_return)
negl %edx
negl %eax
sbbl $0, %edx
- addl ($v), %eax
- adcl 4($v), %edx
- movl %eax, ($v)
- movl %edx, 4($v)
-END
-
-BEGIN inc %esi
- addl $1, ($v)
- adcl $0, 4($v)
-END
-
-BEGIN inc_return %esi
- movl ($v), %eax
- movl 4($v), %edx
+ addl (v), %eax
+ adcl 4(v), %edx
+ movl %eax, (v)
+ movl %edx, 4(v)
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(inc)
+ addl $1, (v)
+ adcl $0, 4(v)
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(inc_return)
+ movl (v), %eax
+ movl 4(v), %edx
addl $1, %eax
adcl $0, %edx
- movl %eax, ($v)
- movl %edx, 4($v)
-END
-
-BEGIN dec %esi
- subl $1, ($v)
- sbbl $0, 4($v)
-END
-
-BEGIN dec_return %esi
- movl ($v), %eax
- movl 4($v), %edx
+ movl %eax, (v)
+ movl %edx, 4(v)
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(dec)
+ subl $1, (v)
+ sbbl $0, 4(v)
+RET_END
+#undef v
+
+#define v %esi
+BEGIN(dec_return)
+ movl (v), %eax
+ movl 4(v), %edx
subl $1, %eax
sbbl $0, %edx
- movl %eax, ($v)
- movl %edx, 4($v)
-END
+ movl %eax, (v)
+ movl %edx, 4(v)
+RET_END
+#undef v

-BEGIN add_unless %ecx
+#define v %ecx
+BEGIN(add_unless)
addl %eax, %esi
adcl %edx, %edi
- addl ($v), %eax
- adcl 4($v), %edx
+ addl (v), %eax
+ adcl 4(v), %edx
cmpl %eax, %esi
je 3f
1:
- movl %eax, ($v)
- movl %edx, 4($v)
+ movl %eax, (v)
+ movl %edx, 4(v)
movl $1, %eax
2:
-RETURN
+ RET
3:
cmpl %edx, %edi
jne 1b
xorl %eax, %eax
jmp 2b
-END_
+END
+#undef v

-BEGIN inc_not_zero %esi
- movl ($v), %eax
- movl 4($v), %edx
+#define v %esi
+BEGIN(inc_not_zero)
+ movl (v), %eax
+ movl 4(v), %edx
testl %eax, %eax
je 3f
1:
addl $1, %eax
adcl $0, %edx
- movl %eax, ($v)
- movl %edx, 4($v)
+ movl %eax, (v)
+ movl %edx, 4(v)
movl $1, %eax
2:
-RETURN
+ RET
3:
testl %edx, %edx
jne 1b
jmp 2b
-END_
+END
+#undef v

-BEGIN dec_if_positive %esi
- movl ($v), %eax
- movl 4($v), %edx
+#define v %esi
+BEGIN(dec_if_positive)
+ movl (v), %eax
+ movl 4(v), %edx
subl $1, %eax
sbbl $0, %edx
js 1f
- movl %eax, ($v)
- movl %edx, 4($v)
+ movl %eax, (v)
+ movl %edx, 4(v)
1:
-END
+RET_END
+#undef v
--
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Next: [X86] Fix potential issue on memmove