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.
Fixes: 1b92c48a2eeb ("x86/pti/efi: broken conversion from efi to kernel page table") Cc: Pavel Tatashin pasha.tatashin@oracle.com Cc: Steven Sistare steven.sistare@oracle.com Cc: Jiri Kosina jkosina@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Hugh Dickins hughd@google.com --- arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index 1178a51b77f3..b6d425999f99 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -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. */ diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 2536f90cd30c..5af0401ccff2 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -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_enabled
void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); void ptdump_walk_pgd_level_checkwx(void);
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%3Ba=su...
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 stable@vger.kernel.org know about it.
From hughd@google.com Mon Feb 5 05:00:13 2018
From: Hugh Dickins hughd@google.com Date: Mon, 29 Jan 2018 18:17:58 -0800 Subject: kaiser: allocate pgd with order 0 when pti=off To: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Hugh Dickins hughd@google.com, Pavel Tatashin pasha.tatashin@oracle.com, Steven Sistare steven.sistare@oracle.com, Jiri Kosina jkosina@suse.cz, stable@vger.kernel.org Message-ID: 20180130021758.229507-1-hughd@google.com
From: Hugh Dickins hughd@google.com
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.
Fixes: 1b92c48a2eeb ("x86/pti/efi: broken conversion from efi to kernel page table") Cc: Pavel Tatashin pasha.tatashin@oracle.com Cc: Steven Sistare steven.sistare@oracle.com Cc: Jiri Kosina jkosina@suse.cz Signed-off-by: Hugh Dickins hughd@google.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)
--- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -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. */ --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -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_enabled
void 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 hughd@google.com 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
Reviewed-by: Pavel Tatashin pasha.tatashin@oracle.com
On 01/29/2018 09:17 PM, Hugh Dickins wrote:
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.
Fixes: 1b92c48a2eeb ("x86/pti/efi: broken conversion from efi to kernel page table") Cc: Pavel Tatashin pasha.tatashin@oracle.com Cc: Steven Sistare steven.sistare@oracle.com Cc: Jiri Kosina jkosina@suse.cz Cc: stable@vger.kernel.org Signed-off-by: Hugh Dickins hughd@google.com
arch/x86/include/asm/pgalloc.h | 11 ----------- arch/x86/include/asm/pgtable.h | 6 ++++++ 2 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h index 1178a51b77f3..b6d425999f99 100644 --- a/arch/x86/include/asm/pgalloc.h +++ b/arch/x86/include/asm/pgalloc.h @@ -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.
diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 2536f90cd30c..5af0401ccff2 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -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_enabled void ptdump_walk_pgd_level(struct seq_file *m, pgd_t *pgd); void ptdump_walk_pgd_level_checkwx(void);
On Mon, Feb 05, 2018 at 10:52:00AM -0500, Pavel Tatashin wrote:
Reviewed-by: Pavel Tatashin pasha.tatashin@oracle.com
Wonderful, thanks for the review.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg Kroah-Hartman -
gregkh＠linuxfoundation.org
-
Hugh Dickins -
Pavel Tatashin