diff options
| author | Anton Blanchard <anton@samba.org> | 2015-10-29 11:44:06 +1100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2015-12-01 13:52:26 +1100 |
| commit | 3eb5d5888dc68c9b187998ca4249b8b9fa481eeb (patch) | |
| tree | 16c17e1867d56207321c404f361c1115aac6320e /arch/powerpc/kernel | |
| parent | dc4fbba11e4661a6a77a1f89ba32f9082e6395ff (diff) | |
powerpc: Add ppc_strict_facility_enable boot option
Add a boot option that strictly manages the MSR unavailable bits.
This catches kernel uses of FP/Altivec/SPE that would otherwise
corrupt user state.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 17 |
1 files changed, 15 insertions, 2 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 5cdd35c0b026..1eafceefeac9 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -87,7 +87,19 @@ static void check_if_tm_restore_required(struct task_struct *tsk) static inline void check_if_tm_restore_required(struct task_struct *tsk) { } #endif /* CONFIG_PPC_TRANSACTIONAL_MEM */ -static void msr_check_and_set(unsigned long bits) +bool strict_msr_control; +EXPORT_SYMBOL(strict_msr_control); + +static int __init enable_strict_msr_control(char *str) +{ + strict_msr_control = true; + pr_info("Enabling strict facility control\n"); + + return 0; +} +early_param("ppc_strict_facility_enable", enable_strict_msr_control); + +void msr_check_and_set(unsigned long bits) { unsigned long oldmsr = mfmsr(); unsigned long newmsr; @@ -103,7 +115,7 @@ static void msr_check_and_set(unsigned long bits) mtmsr_isync(newmsr); } -static void msr_check_and_clear(unsigned long bits) +void __msr_check_and_clear(unsigned long bits) { unsigned long oldmsr = mfmsr(); unsigned long newmsr; @@ -118,6 +130,7 @@ static void msr_check_and_clear(unsigned long bits) if (oldmsr != newmsr) mtmsr_isync(newmsr); } +EXPORT_SYMBOL(__msr_check_and_clear); #ifdef CONFIG_PPC_FPU void giveup_fpu(struct task_struct *tsk) |