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| author | Paul Burton <paul.burton@mips.com> | 2018-11-08 23:14:38 +0300 |
|---|---|---|
| committer | Paul Burton <paul.burton@mips.com> | 2018-11-09 21:23:19 +0300 |
| commit | 378ed6f0e3c525e3b12827e7b7fb0a078ee48a32 (patch) | |
| tree | 766bb2bdd18f7aa7fce8a9ccb428cfcad8cf2feb /arch/mips/include/asm/io.h | |
| parent | 183b40f992c8f98082c4d72043ecdeba0e6a4367 (diff) | |
| download | linux-378ed6f0e3c525e3b12827e7b7fb0a078ee48a32.tar.xz | |
MIPS: Avoid using .set mips0 to restore ISA
We currently have 2 commonly used methods for switching ISA within
assembly code, then restoring the original ISA.
1) Using a pair of .set push & .set pop directives. For example:
.set push
.set mips32r2
<some_insn>
.set pop
2) Using .set mips0 to restore the ISA originally specified on the
command line. For example:
.set mips32r2
<some_insn>
.set mips0
Unfortunately method 2 does not work with nanoMIPS toolchains, where the
assembler rejects the .set mips0 directive like so:
Error: cannot change ISA from nanoMIPS to mips0
In preparation for supporting nanoMIPS builds, switch all instances of
method 2 in generic non-platform-specific code to use push & pop as in
method 1 instead. The .set push & .set pop is arguably cleaner anyway,
and if nothing else it's good to consistently use one method.
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/21037/
Cc: linux-mips@linux-mips.org
Diffstat (limited to 'arch/mips/include/asm/io.h')
| -rw-r--r-- | arch/mips/include/asm/io.h | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h index b5322f7386bf..845fbbc7a2e3 100644 --- a/arch/mips/include/asm/io.h +++ b/arch/mips/include/asm/io.h @@ -354,13 +354,14 @@ static inline void pfx##write##bwlq(type val, \ if (irq) \ local_irq_save(__flags); \ __asm__ __volatile__( \ - ".set arch=r4000" "\t\t# __writeq""\n\t" \ + ".set push" "\t\t# __writeq""\n\t" \ + ".set arch=r4000" "\n\t" \ "dsll32 %L0, %L0, 0" "\n\t" \ "dsrl32 %L0, %L0, 0" "\n\t" \ "dsll32 %M0, %M0, 0" "\n\t" \ "or %L0, %L0, %M0" "\n\t" \ "sd %L0, %2" "\n\t" \ - ".set mips0" "\n" \ + ".set pop" "\n" \ : "=r" (__tmp) \ : "0" (__val), "m" (*__mem)); \ if (irq) \ @@ -387,11 +388,12 @@ static inline type pfx##read##bwlq(const volatile void __iomem *mem) \ if (irq) \ local_irq_save(__flags); \ __asm__ __volatile__( \ - ".set arch=r4000" "\t\t# __readq" "\n\t" \ + ".set push" "\t\t# __readq" "\n\t" \ + ".set arch=r4000" "\n\t" \ "ld %L0, %1" "\n\t" \ "dsra32 %M0, %L0, 0" "\n\t" \ "sll %L0, %L0, 0" "\n\t" \ - ".set mips0" "\n" \ + ".set pop" "\n" \ : "=r" (__val) \ : "m" (*__mem)); \ if (irq) \ |