kaiser: allocate pgd with order 0 when pti=off
Subsystems (2)
PATCH 1/1 kaiser: allocate pgd with order 0 when pti=off
The 4.9.77 version of "x86/pti/efi: broken conversion from efi to kernel page table" looked nicer than the 4.4.112 version, but was suboptimal on machines booted with "pti=off" (or on AMD machines): it allocated pgd with an order 1 page whatever the setting of kaiser_enabled.
Fix that by moving the definition of PGD_ALLOCATION_ORDER from asm/pgalloc.h to asm/pgtable.h, which already defines kaiser_enabled.
--- arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)
arch/x86/include/asm/pgalloc.h +0 -11
@@ -27,17 +27,6 @@ static inline void paravirt_release_pud(unsigned long pfn) {}*/ extern gfp_t __userpte_alloc_gfp; -#ifdef CONFIG_PAGE_TABLE_ISOLATION -/* -* Instead of one PGD, we acquire two PGDs. Being order-1, it is -* both 8k in size and 8k-aligned. That lets us just flip bit 12 -* in a pointer to swap between the two 4k halves. -*/ -#define PGD_ALLOCATION_ORDER 1 -#else -#define PGD_ALLOCATION_ORDER 0 -#endif -/* * Allocate and free page tables. */
arch/x86/include/asm/pgtable.h +6 -0
@@ -20,9 +20,15 @@#ifdef CONFIG_PAGE_TABLE_ISOLATION extern int kaiser_enabled; +/* +* Instead of one PGD, we acquire two PGDs. Being order-1, it is +* both 8k in size and 8k-aligned. That lets us just flip bit 12 +* in a pointer to swap between the two 4k halves. +*/ #else #define kaiser_enabled 0#endif +#define PGD_ALLOCATION_ORDER kaiser_enabledvoid ptdump_walk_pgd_level (struct seq_file *m,pgd_t *pgd);void ptdump_walk_pgd_level_checkwx (void );
Signature · 1 line
2.16.0.rc1.238.g530d649a79-goog
Patch "kaiser: allocate pgd with order 0 when pti=off" has been added to the 4.9-stable tree
This is a note to let you know that I've just added the patch titled
kaiser: allocate pgd with order 0 when pti=off
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kaiser-allocate-pgd-with-order-0-when-pti-off.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From [email protected] Mon Feb 5 05:00:13 2018
From: Hugh Dickins <[email protected]>
Date: Mon, 29 Jan 2018 18:17:58 -0800
Subject: kaiser: allocate pgd with order 0 when pti=off
To: Greg Kroah-Hartman <[email protected]>
Cc: Hugh Dickins <[email protected]>, Pavel Tatashin <[email protected]>, Steven Sistare <[email protected]>, Jiri Kosina <[email protected]>, [email protected]
Message-ID: <[email protected]>
From: Hugh Dickins <[email protected]>
The 4.9.77 version of "x86/pti/efi: broken conversion from efi to kernel page table" looked nicer than the 4.4.112 version, but was suboptimal on machines booted with "pti=off" (or on AMD machines): it allocated pgd with an order 1 page whatever the setting of kaiser_enabled.
Fix that by moving the definition of PGD_ALLOCATION_ORDER from asm/pgalloc.h to asm/pgtable.h, which already defines kaiser_enabled.
--- arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)
arch/x86/include/asm/pgalloc.h +0 -11
@@ -27,17 +27,6 @@ static inline void paravirt_release_pud(*/ extern gfp_t __userpte_alloc_gfp; -#ifdef CONFIG_PAGE_TABLE_ISOLATION -/* -* Instead of one PGD, we acquire two PGDs. Being order-1, it is -* both 8k in size and 8k-aligned. That lets us just flip bit 12 -* in a pointer to swap between the two 4k halves. -*/ -#define PGD_ALLOCATION_ORDER 1 -#else -#define PGD_ALLOCATION_ORDER 0 -#endif -/* * Allocate and free page tables. */
arch/x86/include/asm/pgtable.h +6 -0
@@ -20,9 +20,15 @@#ifdef CONFIG_PAGE_TABLE_ISOLATION extern int kaiser_enabled; +/* +* Instead of one PGD, we acquire two PGDs. Being order-1, it is +* both 8k in size and 8k-aligned. That lets us just flip bit 12 +* in a pointer to swap between the two 4k halves. +*/ #else #define kaiser_enabled 0#endif +#define PGD_ALLOCATION_ORDER kaiser_enabledvoid ptdump_walk_pgd_level (struct seq_file *m,pgd_t *pgd);void ptdump_walk_pgd_level_checkwx (void );
Patches currently in stable-queue which might be from [email protected] are
queue-4.9/kaiser-allocate-pgd-with-order-0-when-pti-off.patch queue-4.9/x86-pti-make-unpoison-of-pgd-for-trusted-boot-work-for-real.patch queue-4.9/kaiser-fix-intel_bts-perf-crashes.patch
Quoted 62 lines · Hugh Dickins
The 4.9.77 version of "x86/pti/efi: broken conversion from efi to kernel page table" looked nicer than the 4.4.112 version, but was suboptimal on machines booted with "pti=off" (or on AMD machines): it allocated pgd with an order 1 page whatever the setting of
kaiser_enabled.Fix that by moving the definition of
PGD_ALLOCATION_ORDERfromasm/pgalloc.htoasm/pgtable.h, which already defineskaiser_enabled.Fixes 1b92c48a2eeb ("x86/pti/efi: broken conversion from efi to kernel page table")Cc Pavel Tatashin <[email protected]>Cc Steven Sistare <[email protected]>Cc Jiri Kosina <[email protected]>Signed-off-by Hugh Dickins <[email protected]>--- arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)arch/x86/include/asm/pgalloc.h +0
-11@@ -27,17 +27,6 @@ static inline void paravirt_release_pud(unsigned long pfn) {}*/ extern gfp_t __userpte_alloc_gfp; -#ifdef CONFIG_PAGE_TABLE_ISOLATION -/* -* Instead of one PGD, we acquire two PGDs. Being order-1, it is -* both 8k in size and 8k-aligned. That lets us just flip bit 12 -* in a pointer to swap between the two 4k halves. -*/ -#define PGD_ALLOCATION_ORDER 1 -#else -#define PGD_ALLOCATION_ORDER 0 -#endif -/* * Allocate and free page tables. */ arch/x86/include/asm/pgtable.h +6
-0@@ -20,9 +20,15 @@#ifdef CONFIG_PAGE_TABLE_ISOLATION extern int kaiser_enabled; +/* +* Instead of one PGD, we acquire two PGDs. Being order-1, it is +* both 8k in size and 8k-aligned. That lets us just flip bit 12 +* in a pointer to swap between the two 4k halves. +*/ #else #define kaiser_enabled 0#endif +#define PGD_ALLOCATION_ORDER kaiser_enabledvoid ptdump_walk_pgd_level (struct seq_file *m,pgd_t *pgd);void ptdump_walk_pgd_level_checkwx (void );
Greg Kroah-Hartman
maintainerQuoted 1 line · Pavel Tatashin
Reviewed-by Pavel Tatashin <[email protected]>
Wonderful, thanks for the review.
greg k-h