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charset="UTF-8" X-Rspamd-Queue-Id: 18BBF180442C0 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 27, 2020 at 11:38 AM Catalin Marinas wrote: > > On Fri, Aug 14, 2020 at 07:27:02PM +0200, Andrey Konovalov wrote: > > diff --git a/arch/arm64/include/asm/mte.h b/arch/arm64/include/asm/mte.h > > index 1c99fcadb58c..733be1cb5c95 100644 > > --- a/arch/arm64/include/asm/mte.h > > +++ b/arch/arm64/include/asm/mte.h > > @@ -5,14 +5,19 @@ > > #ifndef __ASM_MTE_H > > #define __ASM_MTE_H > > > > -#define MTE_GRANULE_SIZE UL(16) > > +#include > > So the reason for this move is to include it in asm/cache.h. Fine by > me but... > > > #define MTE_GRANULE_MASK (~(MTE_GRANULE_SIZE - 1)) > > #define MTE_TAG_SHIFT 56 > > #define MTE_TAG_SIZE 4 > > +#define MTE_TAG_MASK GENMASK((MTE_TAG_SHIFT + (MTE_TAG_SIZE - 1)), MTE_TAG_SHIFT) > > +#define MTE_TAG_MAX (MTE_TAG_MASK >> MTE_TAG_SHIFT) > > ... I'd rather move all these definitions in a file with a more > meaningful name like mte-def.h. The _asm implies being meant for .S > files inclusion which isn't the case. > > > diff --git a/arch/arm64/kernel/mte.c b/arch/arm64/kernel/mte.c > > index eb39504e390a..e2d708b4583d 100644 > > --- a/arch/arm64/kernel/mte.c > > +++ b/arch/arm64/kernel/mte.c > > @@ -72,6 +74,47 @@ int memcmp_pages(struct page *page1, struct page *page2) > > return ret; > > } > > > > +u8 mte_get_mem_tag(void *addr) > > +{ > > + if (system_supports_mte()) > > + addr = mte_assign_valid_ptr_tag(addr); > > The mte_assign_valid_ptr_tag() is slightly misleading. All it does is > read the allocation tag from memory. > > I also think this should be inline asm, possibly using alternatives. > It's just an LDG instruction (and it saves us from having to invent a > better function name). Could you point me to an example of inline asm with alternatives if there's any? I see alternative_if and other similar macros used in arch/arm64/ code, is that what you mean? Those seem to always use static conditions, like config values, but here we have a dynamic system_supports_mte(). Could you elaborate on how I should implement this?