@@ -3,11 +3,6 @@
#ifdef __KERNEL__
-#if defined(CONFIG_CPU_USE_DOMAINS) && defined(CONFIG_SMP)
-/* ARM doesn't provide unprivileged exclusive memory accessors */
-#include <asm-generic/futex.h>
-#else
-
#include <linux/futex.h>
#include <linux/uaccess.h>
#include <asm/errno.h>
@@ -164,6 +159,5 @@ futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
return ret;
}
-#endif /* !(CPU_USE_DOMAINS && SMP) */
#endif /* __KERNEL__ */
#endif /* _ASM_ARM_FUTEX_H */
@@ -140,6 +140,7 @@
#define L_PTE_MT_DEV_NONSHARED (_AT(pteval_t, 0x0c) << 2) /* 1100 */
#define L_PTE_MT_DEV_WC (_AT(pteval_t, 0x09) << 2) /* 1001 */
#define L_PTE_MT_DEV_CACHED (_AT(pteval_t, 0x0b) << 2) /* 1011 */
+#define L_PTE_MT_VECTORS (_AT(pteval_t, 0x0f) << 2) /* 1111 */
#define L_PTE_MT_MASK (_AT(pteval_t, 0x0f) << 2)
#ifndef __ASSEMBLY__
@@ -429,7 +429,6 @@ config CPU_32v5
config CPU_32v6
bool
- select CPU_USE_DOMAINS if CPU_V6 && MMU
select TLS_REG_EMUL if !CPU_32v6K && !MMU
config CPU_32v6K
@@ -651,7 +650,7 @@ config ARM_VIRT_EXT
config SWP_EMULATE
bool "Emulate SWP/SWPB instructions"
- depends on !CPU_USE_DOMAINS && CPU_V7
+ depends on CPU_V7
default y if SMP
select HAVE_PROC_CPU if PROC_FS
help
@@ -423,6 +423,16 @@ static void __init build_mem_type_table(void)
vecs_pgprot = kern_pgprot = user_pgprot = cp->pte;
/*
+ * We don't use domains on ARMv6 (since this causes problems with
+ * v6/v7 kernels), so we must use a separate memory type for user
+ * r/o, kernel r/w to map the vectors page.
+ */
+#ifndef CONFIG_ARM_LPAE
+ if (cpu_arch == CPU_ARCH_ARMv6)
+ vecs_pgprot |= L_PTE_MT_VECTORS;
+#endif
+
+ /*
* ARMv6 and above have extended page tables.
*/
if (cpu_arch >= CPU_ARCH_ARMv6 && (cr & CR_XP)) {
@@ -107,13 +107,9 @@
* 100x 1 0 1 r/o no acc
* 10x0 1 0 1 r/o no acc
* 1011 0 0 1 r/w no acc
- * 110x 0 1 0 r/w r/o
- * 11x0 0 1 0 r/w r/o
- * 1111 0 1 1 r/w r/w
- *
- * If !CONFIG_CPU_USE_DOMAINS, the following permissions are changed:
* 110x 1 1 1 r/o r/o
* 11x0 1 1 1 r/o r/o
+ * 1111 0 1 1 r/w r/w
*/
.macro armv6_mt_table pfx
\pfx\()_mt_table:
@@ -132,7 +128,7 @@
.long PTE_EXT_TEX(2) @ L_PTE_MT_DEV_NONSHARED
.long 0x00 @ unused
.long 0x00 @ unused
- .long 0x00 @ unused
+ .long PTE_CACHEABLE | PTE_BUFFERABLE | PTE_EXT_APX @ L_PTE_MT_VECTORS
.endm
.macro armv6_set_pte_ext pfx
@@ -153,24 +149,21 @@
tst r1, #L_PTE_USER
orrne r3, r3, #PTE_EXT_AP1
-#ifdef CONFIG_CPU_USE_DOMAINS
- @ allow kernel read/write access to read-only user pages
tstne r3, #PTE_EXT_APX
- bicne r3, r3, #PTE_EXT_APX | PTE_EXT_AP0
-#endif
+
+ @ user read-only -> kernel read-only
+ bicne r3, r3, #PTE_EXT_AP0
tst r1, #L_PTE_XN
orrne r3, r3, #PTE_EXT_XN
- orr r3, r3, r2
+ eor r3, r3, r2
tst r1, #L_PTE_YOUNG
tstne r1, #L_PTE_PRESENT
moveq r3, #0
-#ifndef CONFIG_CPU_USE_DOMAINS
tstne r1, #L_PTE_NONE
movne r3, #0
-#endif
str r3, [r0]
mcr p15, 0, r0, c7, c10, 1 @ flush_pte
@@ -90,21 +90,14 @@ ENTRY(cpu_v7_set_pte_ext)
tst r1, #L_PTE_USER
orrne r3, r3, #PTE_EXT_AP1
-#ifdef CONFIG_CPU_USE_DOMAINS
- @ allow kernel read/write access to read-only user pages
- tstne r3, #PTE_EXT_APX
- bicne r3, r3, #PTE_EXT_APX | PTE_EXT_AP0
-#endif
tst r1, #L_PTE_XN
orrne r3, r3, #PTE_EXT_XN
tst r1, #L_PTE_YOUNG
tstne r1, #L_PTE_VALID
-#ifndef CONFIG_CPU_USE_DOMAINS
eorne r1, r1, #L_PTE_NONE
tstne r1, #L_PTE_NONE
-#endif
moveq r3, #0
ARM( str r3, [r0, #2048]! )
This is a note to let you know that I have just added a patch titled ARM: 7954/1: mm: remove remaining domain support from ARMv6 to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.22. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 20a052c55fce14a3d35c9d6ff5e4eca91f281647 Mon Sep 17 00:00:00 2001 From: Will Deacon <will.deacon@arm.com> Date: Fri, 7 Feb 2014 19:12:27 +0100 Subject: ARM: 7954/1: mm: remove remaining domain support from ARMv6 commit b6ccb9803e90c16b212cf4ed62913a7591e79a39 upstream. CPU_32v6 currently selects CPU_USE_DOMAINS if CPU_V6 and MMU. This is because ARM 1136 r0pX CPUs lack the v6k extensions, and therefore do not have hardware thread registers. The lack of these registers requires the kernel to update the vectors page at each context switch in order to write a new TLS pointer. This write must be done via the userspace mapping, since aliasing caches can lead to expensive flushing when using kmap. Finally, this requires the vectors page to be mapped r/w for kernel and r/o for user, which has implications for things like put_user which must trigger CoW appropriately when targetting user pages. The upshot of all this is that a v6/v7 kernel makes use of domains to segregate kernel and user memory accesses. This has the nasty side-effect of making device mappings executable, which has been observed to cause subtle bugs on recent cores (e.g. Cortex-A15 performing a speculative instruction fetch from the GIC and acking an interrupt in the process). This patch solves this problem by removing the remaining domain support from ARMv6. A new memory type is added specifically for the vectors page which allows that page (and only that page) to be mapped as user r/o, kernel r/w. All other user r/o pages are mapped also as kernel r/o. Patch co-developed with Russell King. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- arch/arm/include/asm/futex.h | 6 ------ arch/arm/include/asm/pgtable-2level.h | 1 + arch/arm/mm/Kconfig | 3 +-- arch/arm/mm/mmu.c | 10 ++++++++++ arch/arm/mm/proc-macros.S | 19 ++++++------------- arch/arm/mm/proc-v7-2level.S | 7 ------- 6 files changed, 18 insertions(+), 28 deletions(-) -- 1.9.1