Subject: Re: [PATCH v6 07/22] powerpc/book3s64/kuap: Rename MMU_FTR_RADIX_KUAP to MMU_FTR_KUAP

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Wed, 25 Nov 2020 19:22:35 +0530

On 11/25/20 7:13 PM, Christophe Leroy wrote:
> 
> 
> Le 25/11/2020 à 06:16, Aneesh Kumar K.V a écrit :
>> This is in preparate to adding support for kuap with hash translation.
>> In preparation for that rename/move kuap related functions to
>> non radix names. Also move the feature bit closer to MMU_FTR_KUEP.
> 
> It was obvious with MMU_FTR_RADIX_KUAP that it was only for Radix PPC64.
> Now, do we expect it to be applies on PPC32 as well or is it still for 
> PPC64 only ?

Right now this is PPC64 only. I added

+config PPC_PKEY
+	def_bool y
+	depends on PPC_BOOK3S_64
+	depends on PPC_MEM_KEYS || PPC_KUAP || PPC_KUEP

to select the base bits needed for both KUAP and MEM_KEYS. I haven't 
looked at PPC32 to see if we can implement it there also.

> 
>>
>> Signed-off-by: Aneesh Kumar K.V <[email-masked]>
>> ---
>>   arch/powerpc/include/asm/book3s/64/kup.h | 18 +++++++++---------
>>   arch/powerpc/include/asm/mmu.h           | 14 +++++++-------
>>   arch/powerpc/mm/book3s64/pkeys.c         |  2 +-
>>   3 files changed, 17 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/kup.h 
>> b/arch/powerpc/include/asm/book3s/64/kup.h
>> index 39d2e3a0d64d..1d38eab83d48 100644
>> --- a/arch/powerpc/include/asm/book3s/64/kup.h
>> +++ b/arch/powerpc/include/asm/book3s/64/kup.h
>> @@ -24,7 +24,7 @@
>>       mtspr    SPRN_AMR, \gpr2
>>       /* No isync required, see kuap_restore_amr() */
>>   998:
>> -    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
>> +    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_KUAP, 67)
>>   #endif
>>   .endm
>> @@ -37,7 +37,7 @@
>>       sldi    \gpr2, \gpr2, AMR_KUAP_SHIFT
>>   999:    tdne    \gpr1, \gpr2
>>       EMIT_BUG_ENTRY 999b, __FILE__, __LINE__, (BUGFLAG_WARNING | 
>> BUGFLAG_ONCE)
>> -    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
>> +    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_KUAP, 67)
>>   #endif
>>   .endm
>>   #endif
>> @@ -58,7 +58,7 @@
>>       mtspr    SPRN_AMR, \gpr2
>>       isync
>>   99:
>> -    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_RADIX_KUAP, 67)
>> +    END_MMU_FTR_SECTION_NESTED_IFSET(MMU_FTR_KUAP, 67)
>>   #endif
>>   .endm
>> @@ -73,7 +73,7 @@ DECLARE_STATIC_KEY_FALSE(uaccess_flush_key);
>>   static inline void kuap_restore_amr(struct pt_regs *regs, unsigned 
>> long amr)
>>   {
>> -    if (mmu_has_feature(MMU_FTR_RADIX_KUAP) && unlikely(regs->kuap != 
>> amr)) {
>> +    if (mmu_has_feature(MMU_FTR_KUAP) && unlikely(regs->kuap != amr)) {
>>           isync();
>>           mtspr(SPRN_AMR, regs->kuap);
>>           /*
>> @@ -86,7 +86,7 @@ static inline void kuap_restore_amr(struct pt_regs 
>> *regs, unsigned long amr)
>>   static inline unsigned long kuap_get_and_check_amr(void)
>>   {
>> -    if (mmu_has_feature(MMU_FTR_RADIX_KUAP)) {
>> +    if (mmu_has_feature(MMU_FTR_KUAP)) {
>>           unsigned long amr = mfspr(SPRN_AMR);
>>           if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG)) /* kuap_check_amr() */
>>               WARN_ON_ONCE(amr != AMR_KUAP_BLOCKED);
>> @@ -97,7 +97,7 @@ static inline unsigned long 
>> kuap_get_and_check_amr(void)
>>   static inline void kuap_check_amr(void)
>>   {
>> -    if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && 
>> mmu_has_feature(MMU_FTR_RADIX_KUAP))
>> +    if (IS_ENABLED(CONFIG_PPC_KUAP_DEBUG) && 
>> mmu_has_feature(MMU_FTR_KUAP))
>>           WARN_ON_ONCE(mfspr(SPRN_AMR) != AMR_KUAP_BLOCKED);
>>   }
>> @@ -116,7 +116,7 @@ static inline unsigned long get_kuap(void)
>>        * This has no effect in terms of actually blocking things on hash,
>>        * so it doesn't break anything.
>>        */
>> -    if (!early_mmu_has_feature(MMU_FTR_RADIX_KUAP))
>> +    if (!early_mmu_has_feature(MMU_FTR_KUAP))
>>           return AMR_KUAP_BLOCKED;
>>       return mfspr(SPRN_AMR);
>> @@ -124,7 +124,7 @@ static inline unsigned long get_kuap(void)
>>   static inline void set_kuap(unsigned long value)
>>   {
>> -    if (!early_mmu_has_feature(MMU_FTR_RADIX_KUAP))
>> +    if (!early_mmu_has_feature(MMU_FTR_KUAP))
>>           return;
>>       /*
>> @@ -139,7 +139,7 @@ static inline void set_kuap(unsigned long value)
>>   static inline bool
>>   bad_kuap_fault(struct pt_regs *regs, unsigned long address, bool 
>> is_write)
>>   {
>> -    return WARN(mmu_has_feature(MMU_FTR_RADIX_KUAP) &&
>> +    return WARN(mmu_has_feature(MMU_FTR_KUAP) &&
>>               (regs->kuap & (is_write ? AMR_KUAP_BLOCK_WRITE : 
>> AMR_KUAP_BLOCK_READ)),
>>               "Bug: %s fault blocked by AMR!", is_write ? "Write" : 
>> "Read");
>>   }
>> diff --git a/arch/powerpc/include/asm/mmu.h 
>> b/arch/powerpc/include/asm/mmu.h
>> index 255a1837e9f7..f5c7a17c198a 100644
>> --- a/arch/powerpc/include/asm/mmu.h
>> +++ b/arch/powerpc/include/asm/mmu.h
>> @@ -28,6 +28,11 @@
>>    * Individual features below.
>>    */
>> +/*
>> + * Supports KUAP (key 0 controlling userspace addresses) on radix
>> + */
>> +#define MMU_FTR_KUAP            ASM_CONST(0x00000200)
>> +
>>   /*
>>    * Support for KUEP feature.
>>    */
>> @@ -120,11 +125,6 @@
>>    */
>>   #define MMU_FTR_1T_SEGMENT        ASM_CONST(0x40000000)
>> -/*
>> - * Supports KUAP (key 0 controlling userspace addresses) on radix
>> - */
>> -#define MMU_FTR_RADIX_KUAP        ASM_CONST(0x80000000)
>> -
>>   /* MMU feature bit sets for various CPUs */
>>   #define MMU_FTRS_DEFAULT_HPTE_ARCH_V2    \
>>       MMU_FTR_HPTE_TABLE | MMU_FTR_PPCAS_ARCH_V2
>> @@ -187,10 +187,10 @@ enum {
>>   #ifdef CONFIG_PPC_RADIX_MMU
>>           MMU_FTR_TYPE_RADIX |
>>           MMU_FTR_GTSE |
>> +#endif /* CONFIG_PPC_RADIX_MMU */
>>   #ifdef CONFIG_PPC_KUAP
>> -        MMU_FTR_RADIX_KUAP |
>> +    MMU_FTR_KUAP |
>>   #endif /* CONFIG_PPC_KUAP */
>> -#endif /* CONFIG_PPC_RADIX_MMU */
>>   #ifdef CONFIG_PPC_MEM_KEYS
>>       MMU_FTR_PKEY |
>>   #endif
>> diff --git a/arch/powerpc/mm/book3s64/pkeys.c 
>> b/arch/powerpc/mm/book3s64/pkeys.c
>> index 82c722fbce52..bfc27f1f0ab0 100644
>> --- a/arch/powerpc/mm/book3s64/pkeys.c
>> +++ b/arch/powerpc/mm/book3s64/pkeys.c
>> @@ -258,7 +258,7 @@ void __init setup_kuap(bool disabled)
>>       if (smp_processor_id() == boot_cpuid) {
>>           pr_info("Activating Kernel Userspace Access Prevention\n");
>> -        cur_cpu_spec->mmu_features |= MMU_FTR_RADIX_KUAP;
>> +        cur_cpu_spec->mmu_features |= MMU_FTR_KUAP;
>>       }
>>       /*
>>