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MIPS: csum_partial.S CPU_DADDI_WORKAROUNDS bug fix
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This change reverts most of commit
60724ca [MIPS: IP checksums: Remove
unncessary .set pseudos] that introduced warnings with the
CPU_DADDI_WORKAROUNDS option set:

arch/mips/lib/csum_partial.S: Assembler messages:
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3"
[...]
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3"
[and so on, and so on...]

The warnings are benign and good code is produced regardless because no
macros that'd use the assembler's temporary register are involved, however
the `.set noat' directives removed by the commit referred are crucial to
guarantee this is still going to be the case after any changes in the
future.  Therefore they need to be brought back to place which this
change does.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6686/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Maciej W. Rozycki authored and Ralf Baechle committed May 12, 2014
1 parent 465ca5d commit 44ba138
Showing 1 changed file with 9 additions and 0 deletions.
9 changes: 9 additions & 0 deletions arch/mips/lib/csum_partial.S
Original file line number Diff line number Diff line change
Expand Up @@ -56,14 +56,20 @@
#define UNIT(unit) ((unit)*NBYTES)

#define ADDC(sum,reg) \
.set push; \
.set noat; \
ADD sum, reg; \
sltu v1, sum, reg; \
ADD sum, v1; \
.set pop

#define ADDC32(sum,reg) \
.set push; \
.set noat; \
addu sum, reg; \
sltu v1, sum, reg; \
addu sum, v1; \
.set pop

#define CSUM_BIGCHUNK1(src, offset, sum, _t0, _t1, _t2, _t3) \
LOAD _t0, (offset + UNIT(0))(src); \
Expand Down Expand Up @@ -710,6 +716,8 @@ LEAF(csum_partial)
ADDC(sum, t2)
.Ldone\@:
/* fold checksum */
.set push
.set noat
#ifdef USE_DOUBLE
dsll32 v1, sum, 0
daddu sum, v1
Expand All @@ -732,6 +740,7 @@ LEAF(csum_partial)
or sum, sum, t0
1:
#endif
.set pop
.set reorder
ADDC32(sum, psum)
jr ra
Expand Down

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