[RFC 09/23] ARM: LPAE: use 64-bit accessors for TTBR registers

From: Cyril Chemparathy
Date: Mon Jul 23 2012 - 21:11:25 EST


This patch adds TTBR accessor macros, and modifies cpu_get_pgd() and
the LPAE version of cpu_set_reserved_ttbr0() to use these instead.

In the process, we also fix these functions to correctly handle cases
where the physical address lies beyond the 4G limit of 32-bit addressing.

Signed-off-by: Cyril Chemparathy <cyril@xxxxxx>
Signed-off-by: Vitaly Andrianov <vitalya@xxxxxx>
---
arch/arm/include/asm/proc-fns.h | 24 +++++++++++++++++++-----
arch/arm/mm/context.c | 13 ++-----------
2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index fa6554e..918b4f9 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -116,13 +116,27 @@ extern void cpu_resume(void);
#define cpu_switch_mm(pgd,mm) cpu_do_switch_mm(virt_to_phys(pgd),mm)

#ifdef CONFIG_ARM_LPAE
+
+#define cpu_get_ttbr(nr) \
+ ({ \
+ u64 ttbr; \
+ __asm__("mrrc p15, " #nr ", %Q0, %R0, c2" \
+ : "=r" (ttbr) \
+ : : "cc"); \
+ ttbr; \
+ })
+
+#define cpu_set_ttbr(nr, val) \
+ do { \
+ u64 ttbr = val; \
+ __asm__("mcrr p15, " #nr ", %Q0, %R0, c2" \
+ : : "r" (ttbr) \
+ : "cc"); \
+ } while (0)
+
#define cpu_get_pgd() \
({ \
- unsigned long pg, pg2; \
- __asm__("mrrc p15, 0, %0, %1, c2" \
- : "=r" (pg), "=r" (pg2) \
- : \
- : "cc"); \
+ u64 pg = cpu_get_ttbr(0); \
pg &= ~(PTRS_PER_PGD*sizeof(pgd_t)-1); \
(pgd_t *)phys_to_virt(pg); \
})
diff --git a/arch/arm/mm/context.c b/arch/arm/mm/context.c
index 806cc4f..ad70bd8 100644
--- a/arch/arm/mm/context.c
+++ b/arch/arm/mm/context.c
@@ -15,6 +15,7 @@

#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
+#include <asm/proc-fns.h>

static DEFINE_RAW_SPINLOCK(cpu_asid_lock);
unsigned int cpu_last_asid = ASID_FIRST_VERSION;
@@ -22,17 +23,7 @@ unsigned int cpu_last_asid = ASID_FIRST_VERSION;
#ifdef CONFIG_ARM_LPAE
void cpu_set_reserved_ttbr0(void)
{
- unsigned long ttbl = __pa(swapper_pg_dir);
- unsigned long ttbh = 0;
-
- /*
- * Set TTBR0 to swapper_pg_dir which contains only global entries. The
- * ASID is set to 0.
- */
- asm volatile(
- " mcrr p15, 0, %0, %1, c2 @ set TTBR0\n"
- :
- : "r" (ttbl), "r" (ttbh));
+ cpu_set_ttbr(0, __pa(swapper_pg_dir));
isb();
}
#else
--
1.7.9.5

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