Commit 4beba948 authored by Steven Price's avatar Steven Price Committed by Catalin Marinas
Browse files

mm: Add PG_arch_2 page flag 



For arm64 MTE support it is necessary to be able to mark pages that
contain user space visible tags that will need to be saved/restored e.g.
when swapped out.

To support this add a new arch specific flag (PG_arch_2). This flag is
only available on 64-bit architectures due to the limited number of
spare page flags on the 32-bit ones.

Signed-off-by: default avatarSteven Price <steven.price@arm.com>
[catalin.marinas@arm.com: use CONFIG_64BIT for guarding this new flag]
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
parent 637ec831

fs/proc/page.c

+3 −0
Original line number Diff line number Diff line
@@ -217,6 +217,9 @@ u64 stable_page_flags(struct page *page) 
	u |= kpf_copy_bit(k, KPF_PRIVATE_2,	PG_private_2);

	u |= kpf_copy_bit(k, KPF_OWNER_PRIVATE,	PG_owner_priv_1);

	u |= kpf_copy_bit(k, KPF_ARCH,		PG_arch_1);

#ifdef CONFIG_64BIT

	u |= kpf_copy_bit(k, KPF_ARCH_2,	PG_arch_2);

#endif



	return u;

};

include/linux/kernel-page-flags.h

+1 −0
Original line number Diff line number Diff line
@@ -17,5 +17,6 @@ 
#define KPF_ARCH		38

#define KPF_UNCACHED		39

#define KPF_SOFTDIRTY		40

#define KPF_ARCH_2		41



#endif /* LINUX_KERNEL_PAGE_FLAGS_H */

include/linux/page-flags.h

+3 −0
Original line number Diff line number Diff line
@@ -135,6 +135,9 @@ enum pageflags { 
#if defined(CONFIG_IDLE_PAGE_TRACKING) && defined(CONFIG_64BIT)

	PG_young,

	PG_idle,

#endif

#ifdef CONFIG_64BIT

	PG_arch_2,

#endif

	__NR_PAGEFLAGS,

include/trace/events/mmflags.h

+8 −1
Original line number Diff line number Diff line
@@ -79,6 +79,12 @@ 
#define IF_HAVE_PG_IDLE(flag,string)

#endif



#ifdef CONFIG_64BIT

#define IF_HAVE_PG_ARCH_2(flag,string) ,{1UL << flag, string}

#else

#define IF_HAVE_PG_ARCH_2(flag,string)

#endif



#define __def_pageflag_names						\

	{1UL << PG_locked,		"locked"	},		\

	{1UL << PG_waiters,		"waiters"	},		\
@@ -105,7 +111,8 @@ IF_HAVE_PG_MLOCK(PG_mlocked, "mlocked" ) \ 
IF_HAVE_PG_UNCACHED(PG_uncached,	"uncached"	)		\

IF_HAVE_PG_HWPOISON(PG_hwpoison,	"hwpoison"	)		\

IF_HAVE_PG_IDLE(PG_young,		"young"		)		\

IF_HAVE_PG_IDLE(PG_idle,		"idle"		)

IF_HAVE_PG_IDLE(PG_idle,		"idle"		)		\

IF_HAVE_PG_ARCH_2(PG_arch_2,		"arch_2"	)



#define show_page_flags(flags)						\

	(flags) ? __print_flags(flags, "|",				\

tools/vm/page-types.c

+2 −0
Original line number Diff line number Diff line
@@ -78,6 +78,7 @@ 
#define KPF_ARCH		38

#define KPF_UNCACHED		39

#define KPF_SOFTDIRTY		40

#define KPF_ARCH_2		41



/* [48-] take some arbitrary free slots for expanding overloaded flags

 * not part of kernel API
@@ -135,6 +136,7 @@ static const char * const page_flag_names[] = { 
	[KPF_ARCH]		= "h:arch",

	[KPF_UNCACHED]		= "c:uncached",

	[KPF_SOFTDIRTY]		= "f:softdirty",

	[KPF_ARCH_2]		= "H:arch_2",



	[KPF_READAHEAD]		= "I:readahead",

	[KPF_SLOB_FREE]		= "P:slob_free",