linux-kernel - Re: [PATCH V2 2/2] arm64/mm: Add remaining TLBI_XXX

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Message-ID: <6e7d0bf3-ddf1-44a0-a0cb-7dc994101878@arm.com>
Date: Mon, 27 Oct 2025 07:06:45 +0530
From: Anshuman Khandual <anshuman.khandual@....com>
To: Jonathan Cameron <jonathan.cameron@...wei.com>
Cc: linux-arm-kernel@...ts.infradead.org, ben.horgan@....com,
 Catalin Marinas <catalin.marinas@....com>, Will Deacon <will@...nel.org>,
 Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>,
 linux-kernel@...r.kernel.org, kvmarm@...ts.linux.dev
Subject: Re: [PATCH V2 2/2] arm64/mm: Add remaining TLBI_XXX_MASK macros



On 24/10/25 4:30 PM, Jonathan Cameron wrote:
> On Fri, 24 Oct 2025 05:02:07 +0100
> Anshuman Khandual <anshuman.khandual@....com> wrote:
> 
>> Add remaining TLBI_XXX_MASK macros and replace current open encoded fields.
>> While here replace hard coded page size based shifts but with derived ones
>> via ilog2() thus adding some required context.
>>
>> TLBI_TTL_MASK has been split into separate TLBI_TTL_MASK and TLBI_TG_MASK
>> as appropriate because currently it simultaneously contains both page size
>> and translation table level information. KVM on arm64 has been updated to
>> accommodate these changes to TLBI_TTL_MASK.
>>
>> Cc: Catalin Marinas <catalin.marinas@....com>
>> Cc: Will Deacon <will@...nel.org>
>> Cc: Marc Zyngier <maz@...nel.org>
>> Cc: Oliver Upton <oliver.upton@...ux.dev>
>> Cc: linux-arm-kernel@...ts.infradead.org
>> Cc: linux-kernel@...r.kernel.org
>> Cc: kvmarm@...ts.linux.dev
>> Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
>> ---
>>  arch/arm64/include/asm/tlbflush.h | 26 ++++++++++++++++++--------
>>  arch/arm64/kvm/nested.c           |  8 +++++---
>>  2 files changed, 23 insertions(+), 11 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
>> index 131096094f5b..cf75fc2a06c3 100644
>> --- a/arch/arm64/include/asm/tlbflush.h
>> +++ b/arch/arm64/include/asm/tlbflush.h
>> @@ -57,9 +57,10 @@
>>  /* This macro creates a properly formatted VA operand for the TLBI */
>>  #define __TLBI_VADDR(addr, asid)				\
>>  	({							\
>> -		unsigned long __ta = (addr) >> 12;		\
>> -		__ta &= GENMASK_ULL(43, 0);			\
>> -		__ta |= (unsigned long)(asid) << 48;		\
>> +		unsigned long __ta = (addr) >> ilog2(SZ_4K);	\
>> +		__ta &= TLBI_BADDR_MASK;			\
>> +		__ta &= ~TLBI_ASID_MASK;			\
>> +		__ta |= FIELD_PREP(TLBI_ASID_MASK, asid);	\
> I think you can replace the two lines above with
> 		FIELD_MODIFY(TLBI_ASID_MASK, &__ta, asid);
> 
> It's a small reduction in code but I don't mind much either way.

Right. FIELD_MODIFY() might be appropriate in this scenario but
there will be some additional code churn needed. I don't have a
strong opinion either way.

--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -55,13 +55,12 @@
 } while (0)

 /* This macro creates a properly formatted VA operand for the TLBI */
-#define __TLBI_VADDR(addr, asid)                               \
-       ({                                                      \
-               unsigned long __ta = (addr) >> ilog2(SZ_4K);    \
-               __ta &= TLBI_BADDR_MASK;                        \
-               __ta &= ~TLBI_ASID_MASK;                        \
-               __ta |= FIELD_PREP(TLBI_ASID_MASK, asid);       \
-               __ta;                                           \
+#define __TLBI_VADDR(addr, asid)                                       \
+       ({                                                              \
+               unsigned long __ta = (addr) >> ilog2(SZ_4K);            \
+               __ta &= TLBI_BADDR_MASK;                                \
+               __ta |= FIELD_MODIFY(TLBI_ASID_MASK, &__ta, asid);      \
+               __ta;                                                   \
        })
 > 
>>  		__ta;						\
>>  	})
>>  
>> @@ -100,8 +101,17 @@ static inline unsigned long get_trans_granule(void)
>>   *
>>   * For Stage-2 invalidation, use the level values provided to that effect
>>   * in asm/stage2_pgtable.h.
>> + *
>> + * +----------+------+-------+--------------------------------------+
>> + * |   ASID   |  TG  |  TTL  |                 BADDR                |
>> + * +-----------------+-------+--------------------------------------+
>> + * |63      48|47  46|45   44|43                                   0|
>> + * +----------+------+-------+--------------------------------------+
>>   */
>> -#define TLBI_TTL_MASK		GENMASK_ULL(47, 44)
>> +#define TLBI_ASID_MASK		GENMASK_ULL(63, 48)
>> +#define TLBI_TG_MASK		GENMASK_ULL(47, 46)
>> +#define TLBI_TTL_MASK		GENMASK_ULL(45, 44)
>> +#define TLBI_BADDR_MASK		GENMASK_ULL(43, 0)
>>  
>>  #define TLBI_TTL_UNKNOWN	INT_MAX
>>  
>> @@ -110,10 +120,10 @@ static inline unsigned long get_trans_granule(void)
>>  									\
>>  	if (alternative_has_cap_unlikely(ARM64_HAS_ARMv8_4_TTL) &&	\
>>  	    level >= 0 && level <= 3) {					\
>> -		u64 ttl = level;					\
>> -		ttl |= get_trans_granule() << 2;			\
>> +		arg &= ~TLBI_TG_MASK;					\
>> +		arg |= FIELD_PREP(TLBI_TG_MASK, get_trans_granule());	\
>>  		arg &= ~TLBI_TTL_MASK;					\
>> -		arg |= FIELD_PREP(TLBI_TTL_MASK, ttl);			\
>> +		arg |= FIELD_PREP(TLBI_TTL_MASK, level);		\
> 
> Similar potential to use FIELD_MODIFY for these.
> 
> Jonathan
>