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ARM: 7649/1: mm: mm->context.id fix for big-endian 

Since the new ASID code in b5466f8728
("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>
This commit is contained in:
Ben Dooks 2013-02-11 12:25:06 +01:00 committed by Russell King
parent 352af7d4dd
commit 9520a5bece
2 changed files with 8 additions and 0 deletions
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3
arch/arm/mm/context.c
View File

@ -34,6 +34,9 @@
* The ASID is used to tag entries in the CPU caches and TLBs. * The ASID is used to tag entries in the CPU caches and TLBs.
* The context ID is used by debuggers and trace logic, and * The context ID is used by debuggers and trace logic, and
* should be unique within all running processes. * 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 ASID_FIRST_VERSION (1ULL << ASID_BITS)
#define NUM_USER_ASIDS (ASID_FIRST_VERSION - 1) #define NUM_USER_ASIDS (ASID_FIRST_VERSION - 1)

5
arch/arm/mm/proc-macros.S
View File

@ -38,9 +38,14 @@
/* /*
* mmid - get context id from mm pointer (mm->context.id) * 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 .macro mmid, rd, rn
#ifdef __ARMEB__
ldr \rd, [\rn, #MM_CONTEXT_ID + 4 ]
#else
ldr \rd, [\rn, #MM_CONTEXT_ID] ldr \rd, [\rn, #MM_CONTEXT_ID]
#endif
.endm .endm
/* /*