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| author | Paul Burton <paul.burton@imgtec.com> | 2014-07-11 16:44:29 +0100 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2014-08-02 00:06:43 +0200 |
| commit | b83406735a4ae0aff4b614664d6a64a0fd6b9917 (patch) | |
| tree | 2fd9b98b88f6f19c421001666b4aaeb943d1e7e7 /arch/mips | |
| parent | f7a46fa7bb0047d3e226702a0c4b786862fe6843 (diff) | |
| download | linux-b83406735a4ae0aff4b614664d6a64a0fd6b9917.tar.gz | |
MIPS: preserve scalar FP CSR when switching vector context
Switching the vector context implicitly saves & restores the state of the aliased scalar FP data registers, however the scalar FP control & status register is distinct from the MSA control & status register. In order to allow scalar FP to function correctly in programs using MSA, the scalar CSR needs to be saved & restored along with the MSA vector context. Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7301/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/kernel/r4k_switch.S | 4 | ||||
| -rw-r--r-- | arch/mips/kernel/traps.c | 5 |
2 files changed, 8 insertions, 1 deletions
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S index 81ca3f70fe29..1a1aef04312d 100644 --- a/arch/mips/kernel/r4k_switch.S +++ b/arch/mips/kernel/r4k_switch.S @@ -64,8 +64,10 @@ /* Check whether we're saving scalar or vector context. */ bgtz a3, 1f - /* Save 128b MSA vector context. */ + /* Save 128b MSA vector context + scalar FP control & status. */ + cfc1 t1, fcr31 msa_save_all a0 + sw t1, THREAD_FCR31(a0) b 2f 1: /* Save 32b/64b scalar FP context. */ diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c index 1a328b1e288b..649c151fe1db 100644 --- a/arch/mips/kernel/traps.c +++ b/arch/mips/kernel/traps.c @@ -1154,6 +1154,11 @@ static int enable_restore_fp_context(int msa) /* We need to restore the vector context. */ restore_msa(current); + + /* Restore the scalar FP control & status register */ + if (!was_fpu_owner) + asm volatile("ctc1 %0, $31" : : "r"(current->thread.fpu.fcr31)); + return 0; } |