Michael Ellerman <m...@ellerman.id.au> writes:
> On Thu, 2016-09-06 at 06:19:15 UTC, "Aneesh Kumar K.V" wrote:
>> Updated patch below. MMU_FTRS_POWER4 is inherited by others, hence don't
>> update that.
>>
>> >From 4ed66fd24dc4f976969cc34aca8df2ddbc69fe61 Mon Sep 17 00:00:00 2001
>> From: "Aneesh Kumar K.V" <aneesh.ku...@linux.vnet.ibm.com>
>> Date: Sat, 4 Jun 2016 19:58:26 +0530
>> Subject: [PATCH] powerpc/mm: Clear top 16 bits of va only on older cpus
>>
>> As per ISA, we need to do this only for architecture version 2.02 and
>> earlier. This continued to work even for 2.07. But let's not do this for
>> anything after 2.02
>
> What are the practical effects of this?
For ISA 3.0 we require these top bits to be not cleared. I have updated
the commit message to reflect that.
>
>> diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
>> index e53ebebff474..fa314b1d667e 100644
>> --- a/arch/powerpc/include/asm/mmu.h
>> +++ b/arch/powerpc/include/asm/mmu.h
>> @@ -24,6 +24,11 @@
>> /*
>> * This is individual features
>> */
>> +/*
>> + * We need to clear top 16bits of va (from the remaining 64 bits )in
>> + * tlbie* instructions
>> + */
>> +#define MMU_FTR_TLBIE_CROP_VA ASM_CONST(0x00008000)
>>
>> /* Enable use of high BAT registers */
>> #define MMU_FTR_USE_HIGH_BATS ASM_CONST(0x00010000)
>> @@ -124,7 +129,7 @@ enum {
>> MMU_FTR_USE_TLBRSRV | MMU_FTR_USE_PAIRED_MAS |
>> MMU_FTR_NO_SLBIE_B | MMU_FTR_16M_PAGE | MMU_FTR_TLBIEL |
>> MMU_FTR_LOCKLESS_TLBIE | MMU_FTR_CI_LARGE_PAGE |
>> - MMU_FTR_1T_SEGMENT |
>> + MMU_FTR_1T_SEGMENT | MMU_FTR_TLBIE_CROP_VA |
>> #ifdef CONFIG_PPC_RADIX_MMU
>> MMU_FTR_RADIX |
>> #endif
>> diff --git a/arch/powerpc/kernel/cputable.c b/arch/powerpc/kernel/cputable.c
>> index eeeacf6235a3..d8a0f7ca74e1 100644
>> --- a/arch/powerpc/kernel/cputable.c
>> +++ b/arch/powerpc/kernel/cputable.c
>> @@ -137,7 +137,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
>> .cpu_name = "POWER4 (gp)",
>> .cpu_features = CPU_FTRS_POWER4,
>> .cpu_user_features = COMMON_USER_POWER4,
>> - .mmu_features = MMU_FTRS_POWER4,
>> + .mmu_features = MMU_FTRS_POWER4 |
>> MMU_FTR_TLBIE_CROP_VA,
>> .icache_bsize = 128,
>> .dcache_bsize = 128,
>> .num_pmcs = 8,
>> @@ -152,7 +152,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
>> .cpu_name = "POWER4+ (gq)",
>> .cpu_features = CPU_FTRS_POWER4,
>> .cpu_user_features = COMMON_USER_POWER4,
>> - .mmu_features = MMU_FTRS_POWER4,
>> + .mmu_features = MMU_FTRS_POWER4 |
>> MMU_FTR_TLBIE_CROP_VA,
>> .icache_bsize = 128,
>> .dcache_bsize = 128,
>> .num_pmcs = 8,
>> @@ -168,7 +168,7 @@ static struct cpu_spec __initdata cpu_specs[] = {
>> .cpu_features = CPU_FTRS_PPC970,
>> .cpu_user_features = COMMON_USER_POWER4 |
>> PPC_FEATURE_HAS_ALTIVEC_COMP,
>> - .mmu_features = MMU_FTRS_PPC970,
>> + .mmu_features = MMU_FTRS_PPC970 |
>> MMU_FTR_TLBIE_CROP_VA,
>
> Please add it to MMU_FTRS_PPC970, rather than at every usage.
>
Done
-aneesh
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