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authorRalf Baechle <ralf@linux-mips.org>2009-10-13 23:23:28 +0200
committerRalf Baechle <ralf@linux-mips.org>2009-11-02 12:00:07 +0100
commitc2ea1d56eaf084c66177eb5658ff4065e79b36ea (patch)
treefcc0a634a194dba00f730b54bdf6cf5f0f3b9de1 /arch
parentcd847b7857b835f9730d6fc93c3f423fcacc50f7 (diff)
MIPS: Avoid potential hazard on Context register
set_saved_sp reads Context register. Avoid reading stale value from earlier incomplete write. Issue found and fixed for head.S by Chris Dearman <chris@mips.com>. Signed-off-by: Chris Dearman <chris@mips.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/include/asm/mmu_context.h3
-rw-r--r--arch/mips/kernel/head.S1
2 files changed, 4 insertions, 0 deletions
diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h
index ed331c2e4882..6083db586500 100644
--- a/arch/mips/include/asm/mmu_context.h
+++ b/arch/mips/include/asm/mmu_context.h
@@ -16,6 +16,7 @@
#include <linux/smp.h>
#include <linux/slab.h>
#include <asm/cacheflush.h>
+#include <asm/hazards.h>
#include <asm/tlbflush.h>
#ifdef CONFIG_MIPS_MT_SMTC
#include <asm/mipsmtregs.h>
@@ -36,11 +37,13 @@ extern unsigned long pgd_current[];
#ifdef CONFIG_32BIT
#define TLBMISS_HANDLER_SETUP() \
write_c0_context((unsigned long) smp_processor_id() << 25); \
+ back_to_back_c0_hazard(); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif
#ifdef CONFIG_64BIT
#define TLBMISS_HANDLER_SETUP() \
write_c0_context((unsigned long) smp_processor_id() << 26); \
+ back_to_back_c0_hazard(); \
TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir)
#endif
diff --git a/arch/mips/kernel/head.S b/arch/mips/kernel/head.S
index 531ce7b16124..ea695d9605e9 100644
--- a/arch/mips/kernel/head.S
+++ b/arch/mips/kernel/head.S
@@ -191,6 +191,7 @@ NESTED(kernel_entry, 16, sp) # kernel entry point
/* Set the SP after an empty pt_regs. */
PTR_LI sp, _THREAD_SIZE - 32 - PT_SIZE
PTR_ADDU sp, $28
+ back_to_back_c0_hazard
set_saved_sp sp, t0, t1
PTR_SUBU sp, 4 * SZREG # init stack pointer