inconsistent asm macro
In include/asm-mips/interrupt.h, the definition for local_irq_restore is inconsistent in its use of .reorder/.noreorder assembler directives. Other asm macros in interrupt.h are wrapped with '.set push' and '.set pop'.
It doesn't seem to be a problem with the 2.96 mipsel-linux- assembler, but it caused me a problem with my 4.0-based toolchain. (As it was the local_irq_restore left the assembler in 'reorder' mode and a stack pointer post-inc was reordered out of the return delay slot where it belonged.) Luckily we have a sharp compiler guy who figured it out. Thanks.
As usual, there may be a reason for this, but it took me a whole day to find it, and I thought I'd point it out.
Ed Martini
$ diff -uN interrupt.h interrupt-new.h --- interrupt.h 2005-03-29 17:35:02.922362384 -0800 +++ interrupt-new.h 2005-03-29 17:33:26.350770293 -0800 @@ -100,6 +100,7 @@
__asm__ (
".macro\tlocal_irq_restore flags\n\t"
+ ".set\tpush\n\t"
".set\tnoreorder\n\t"
".set\tnoat\n\t"
"mfc0\t$1, $12\n\t"
@@ -109,8 +110,7 @@
"or\t\\flags, $1\n\t"
"mtc0\t\\flags, $12\n\t"
"irq_disable_hazard\n\t"
- ".set\tat\n\t"
- ".set\treorder\n\t"
+ ".set\tpop\n\t"
".endm");Quoted 11 lines · Ed Martini
In
include/asm-mips/interrupt.h, the definition forlocal_irq_restoreis inconsistent in its use of .reorder/.noreorder assembler directives. Other asm macros ininterrupt.hare wrapped with '.set push' and '.set pop'.It doesn't seem to be a problem with the 2.96 mipsel-linux- assembler, but it caused me a problem with my 4.0-based toolchain. (As it was the
local_irq_restoreleft the assembler in 'reorder' mode and a stack pointer post-inc was reordered out of the return delay slot where it belonged.) Luckily we have a sharp compiler guy who figured it out. Thanks.
Quoted 2 lines
As usual, there may be a reason for this, but it took me a whole day to find it, and I thought I'd point it out.
Maciej, since you use gcc 4, can you please review this patch?
Quoted 24 lines
Ed Martini
$ diff -uN interrupt.h interrupt-new.hinterrupt-new.h 2005-03-29 17:33:26.350770293 -0800 renamed from interrupt.h 2005-03-29 17:35:02.922362384 -0800 +0
-0@@ -100,6 +100,7 @@
__asm__(
".macro\tlocal_irq_restore flags\n\t"interrupt-new.h 2005-03-29 17:33:26.350770293 -0800 renamed from interrupt.h 2005-03-29 17:35:02.922362384 -0800 +2
-2+ ".set\tpush\n\t" ".set\tnoreorder\n\t" ".set\tnoat\n\t" "mfc0\t$1, $12\n\t"@@ -109,8 +110,7 @@ "or\t\\flags, $1\n\t" "mtc0\t\\flags, $12\n\t" "irq_disable_hazard\n\t" - ".set\tat\n\t" - ".set\treorder\n\t" + ".set\tpop\n\t" ".endm");
Signature · 2 lines
Martin Michlmayr http://www.cyrius.com/