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authorBen Dooks <ben-linux@fluff.org>2013-02-11 15:25:06 +0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2013-02-16 21:54:26 +0400
commit9520a5bece13b7382f4b0059180f61530c423c81 (patch)
treeb1ea5eae98171dd61a35964160407abf9c0f18d0 /arch/arm/mm
parent352af7d4dd90bac3640ad2383e4e9f332d3a4537 (diff)
downloadlinux-9520a5bece13b7382f4b0059180f61530c423c81.tar.xz
ARM: 7649/1: mm: mm->context.id fix for big-endian
Since the new ASID code in b5466f8728527a05a493cc4abe9e6f034a1bbaab ("ARM: mm: remove IPI broadcasting on ASID rollover") was changed to use 64bit operations it has broken the BE operation due to an issue with the MM code accessing sub-fields of mm->context.id. When running in BE mode we see the values in mm->context.id are stored with the highest value first, so the LDR in the arch/arm/mm/proc-macros.S reads the wrong part of this field. To resolve this, change the LDR in the mmid macro to load from +4. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mm')
-rw-r--r--arch/arm/mm/context.c3
-rw-r--r--arch/arm/mm/proc-macros.S5
2 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index bc4a5e9ebb78..7a0511191f6b 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -34,6 +34,9 @@
* The ASID is used to tag entries in the CPU caches and TLBs.
* The context ID is used by debuggers and trace logic, and
* should be unique within all running processes.
+ *
+ * In big endian operation, the two 32 bit words are swapped if accesed by
+ * non 64-bit operations.
*/
#define ASID_FIRST_VERSION (1ULL << ASID_BITS)
#define NUM_USER_ASIDS (ASID_FIRST_VERSION - 1)
diff --git a/arch/arm/mm/proc-macros.S b/arch/arm/mm/proc-macros.S
index eb6aa73bc8b7..f9a0aa725ea9 100644
--- a/arch/arm/mm/proc-macros.S
+++ b/arch/arm/mm/proc-macros.S
@@ -38,9 +38,14 @@
/*
* mmid - get context id from mm pointer (mm->context.id)
+ * note, this field is 64bit, so in big-endian the two words are swapped too.
*/
.macro mmid, rd, rn
+#ifdef __ARMEB__
+ ldr \rd, [\rn, #MM_CONTEXT_ID + 4 ]
+#else
ldr \rd, [\rn, #MM_CONTEXT_ID]
+#endif
.endm
/*