From: Christophe Leroy <christophe.leroy@csgroup.eu>
To: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 2/8] powerpc/mem: Remove address argument to flush_coherent_icache()
Date: Thu, 8 Apr 2021 17:25:20 +0200 [thread overview]
Message-ID: <8fdbc753-4ed6-ee3f-3317-f0ea5b95bbc9@csgroup.eu> (raw)
In-Reply-To: <87k0pdb1n6.fsf@linux.ibm.com>
Le 08/04/2021 à 10:50, Aneesh Kumar K.V a écrit :
> Christophe Leroy <christophe.leroy@csgroup.eu> writes:
>
>> flush_coherent_icache() can use any valid address as mentionned
>> by the comment.
>>
>> Use PAGE_OFFSET as base address. This allows removing the
>> user access stuff.
>>
>> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>> ---
>> arch/powerpc/mm/mem.c | 13 +++++--------
>> 1 file changed, 5 insertions(+), 8 deletions(-)
>>
>> diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
>> index ce6c81ce4362..19f807b87697 100644
>> --- a/arch/powerpc/mm/mem.c
>> +++ b/arch/powerpc/mm/mem.c
>> @@ -342,10 +342,9 @@ void free_initmem(void)
>>
>> /**
>> * flush_coherent_icache() - if a CPU has a coherent icache, flush it
>> - * @addr: The base address to use (can be any valid address, the whole cache will be flushed)
>> * Return true if the cache was flushed, false otherwise
>> */
>> -static inline bool flush_coherent_icache(unsigned long addr)
>> +static inline bool flush_coherent_icache(void)
>> {
>> /*
>> * For a snooping icache, we still need a dummy icbi to purge all the
>> @@ -355,9 +354,7 @@ static inline bool flush_coherent_icache(unsigned long addr)
>> */
>> if (cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) {
>> mb(); /* sync */
>> - allow_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
>> - icbi((void *)addr);
>> - prevent_read_from_user((const void __user *)addr, L1_CACHE_BYTES);
>> + icbi((void *)PAGE_OFFSET);
>> mb(); /* sync */
>> isync();
>> return true;
>
> do we need that followup sync? Usermanual suggest sync; icbi(any address);
> isync sequence.
I don't know.
The original implementation is here: https://github.com/linuxppc/linux/commit/0ce636700
Christophe
next prev parent reply other threads:[~2021-04-08 15:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-07 17:22 [PATCH v1 1/8] powerpc/mem: Declare __flush_dcache_icache() static Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 2/8] powerpc/mem: Remove address argument to flush_coherent_icache() Christophe Leroy
2021-04-08 8:50 ` Aneesh Kumar K.V
2021-04-08 15:25 ` Christophe Leroy [this message]
2021-04-07 17:22 ` [PATCH v1 3/8] powerpc/mem: Call flush_coherent_icache() at higher level Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 4/8] powerpc/mem: Optimise flush_dcache_icache_hugepage() Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 5/8] powerpc/mem: flush_dcache_icache_phys() is for HIGHMEM pages only Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 6/8] powerpc/mem: Help GCC realise __flush_dcache_icache() flushes single pages Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 7/8] powerpc/mem: Inline flush_dcache_page() Christophe Leroy
2021-04-07 17:22 ` [PATCH v1 8/8] powerpc/mem: Use kmap_local_page() in flushing functions Christophe Leroy
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