From: James Hogan jhogan@kernel.org
Building 32-bit MIPS64r2 kernels produces warnings like the following on certain toolchains (such as GNU assembler 2.24.90, but not GNU assembler 2.28.51) since commit 22b8ba765a72 ("MIPS: Fix MIPS64 FP save/restore on 32-bit kernels"), due to the exposure of fpu_save_16odd from fpu_save_double and fpu_restore_16odd from fpu_restore_double:
arch/mips/kernel/r4k_fpu.S:47: Warning: float register should be even, was 1 ... arch/mips/kernel/r4k_fpu.S:59: Warning: float register should be even, was 1 ...
This appears to be because .set mips64r2 does not change the FPU ABI to 64-bit when -march=mips64r2 (or e.g. -march=xlp) is provided on the command line on that toolchain, from the default FPU ABI of 32-bit due to the -mabi=32. This makes access to the odd FPU registers invalid.
Fix by explicitly changing the FPU ABI with .set fp=64 directives in fpu_save_16odd and fpu_restore_16odd, and moving the undefine of fp up in asmmacro.h so fp doesn't turn into $30.
Fixes: 22b8ba765a72 ("MIPS: Fix MIPS64 FP save/restore on 32-bit kernels") Signed-off-by: James Hogan jhogan@kernel.org Cc: Ralf Baechle ralf@linux-mips.org Cc: Paul Burton paul.burton@imgtec.com Cc: linux-mips@linux-mips.org Cc: stable@vger.kernel.org # 4.0+: 22b8ba765a72: MIPS: Fix MIPS64 FP save/restore on 32-bit kernels Cc: stable@vger.kernel.org # 4.0+ --- arch/mips/include/asm/asmmacro.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/arch/mips/include/asm/asmmacro.h b/arch/mips/include/asm/asmmacro.h index b815d7b3bd27..feb069cbf44e 100644 --- a/arch/mips/include/asm/asmmacro.h +++ b/arch/mips/include/asm/asmmacro.h @@ -19,6 +19,9 @@ #include <asm/asmmacro-64.h> #endif
+/* preprocessor replaces the fp in ".set fp=64" with $30 otherwise */ +#undef fp + /* * Helper macros for generating raw instruction encodings. */ @@ -105,6 +108,7 @@ .macro fpu_save_16odd thread .set push .set mips64r2 + .set fp=64 SET_HARDFLOAT sdc1 $f1, THREAD_FPR1(\thread) sdc1 $f3, THREAD_FPR3(\thread) @@ -163,6 +167,7 @@ .macro fpu_restore_16odd thread .set push .set mips64r2 + .set fp=64 SET_HARDFLOAT ldc1 $f1, THREAD_FPR1(\thread) ldc1 $f3, THREAD_FPR3(\thread) @@ -234,9 +239,6 @@ .endm
#ifdef TOOLCHAIN_SUPPORTS_MSA -/* preprocessor replaces the fp in ".set fp=64" with $30 otherwise */ -#undef fp - .macro _cfcmsa rd, cs .set push .set mips32r2