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MIPS: disable preemption whilst initialising MSA 

Preemption must be disabled throughout the process of enabling the FPU,
enabling MSA & initialising the vector registers. Without doing so it
is possible to lose the FPU or MSA whilst initialising them causing
that initialisation to fail.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7307/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
hifive-unleashed-5.1
Paul Burton 2014-07-11 16:44:35 +01:00 committed by Ralf Baechle
parent 3587ea888b
commit 762a1f4388
2 changed files with 11 additions and 7 deletions
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4
arch/mips/include/asm/fpu.h
View File

@ -164,8 +164,6 @@ static inline int init_fpu(void)
{
int ret = 0;
preempt_disable();
if (cpu_has_fpu) {
ret = __own_fpu();
if (!ret)
@ -173,8 +171,6 @@ static inline int init_fpu(void)
} else
fpu_emulator_init_fpu();
preempt_enable();
return ret;
}

14
arch/mips/kernel/traps.c
View File

@ -1093,6 +1093,7 @@ static int enable_restore_fp_context(int msa)
if (!used_math()) {
/* First time FP context user. */
preempt_disable();
err = init_fpu();
if (msa && !err) {
enable_msa();
@ -1100,6 +1101,7 @@ static int enable_restore_fp_context(int msa)
set_thread_flag(TIF_USEDMSA);
set_thread_flag(TIF_MSA_CTX_LIVE);
}
preempt_enable();
if (!err)
set_used_math();
return err;
@ -1139,10 +1141,11 @@ static int enable_restore_fp_context(int msa)
* This task is using or has previously used MSA. Thus we require
* that Status.FR == 1.
*/
preempt_disable();
was_fpu_owner = is_fpu_owner();
err = own_fpu(0);
err = own_fpu_inatomic(0);
if (err)
return err;
goto out;
enable_msa();
write_msa_csr(current->thread.fpu.msacsr);
@ -1158,7 +1161,8 @@ static int enable_restore_fp_context(int msa)
prior_msa = test_and_set_thread_flag(TIF_MSA_CTX_LIVE);
if (!prior_msa && was_fpu_owner) {
_init_msa_upper();
return 0;
goto out;
}
if (!prior_msa) {
@ -1182,6 +1186,10 @@ static int enable_restore_fp_context(int msa)
if (!was_fpu_owner)
asm volatile("ctc1 %0, $31" : : "r"(current->thread.fpu.fcr31));
}
out:
preempt_enable();
return 0;
}