[PATCH 3.16.y-ckt 128/183] MIPS: asm: asmmacro: Replace "add" instructions with "addu"

Luis Henriques luis.henriques at canonical.com
Fri Mar 6 09:56:59 UTC 2015

3.16.7-ckt8 -stable review patch.  If anyone has any objections, please let me know.


From: Markos Chandras <markos.chandras at imgtec.com>

commit 98a833c1fa4de0695830f77b2d13fd86693da298 upstream.

The "add" instruction is actually a macro in binutils and depending on
the size of the immediate it can expand to an "addi" instruction.
However, the "addi" instruction traps on overflows which is not
something we want on address calculation.

Link: http://www.linux-mips.org/archives/linux-mips/2015-01/msg00121.html
Cc: Paul Burton <paul.burton at imgtec.com>
Cc: Maciej W. Rozycki <macro at linux-mips.org>
Signed-off-by: Markos Chandras <markos.chandras at imgtec.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 arch/mips/include/asm/asmmacro.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h
index 935543f14538..9dbc454ad14e 100644
--- a/arch/mips/include/asm/asmmacro.h
+++ b/arch/mips/include/asm/asmmacro.h
@@ -293,7 +293,7 @@
 	.macro	ld_d	wd, off, base
 	.set	push
 	.set	noat
-	add	$1, \base, \off
+	addu	$1, \base, \off
 	.word	LDD_MSA_INSN | (\wd << 6)
 	.set	pop
@@ -301,7 +301,7 @@
 	.macro	st_d	wd, off, base
 	.set	push
 	.set	noat
-	add	$1, \base, \off
+	addu	$1, \base, \off
 	.word	STD_MSA_INSN | (\wd << 6)
 	.set	pop

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