[PATCH v3 2/4] ARM: Move asm statements accessing TTBCR into C functions

[Linus Walleij]

From: Catalin Marinas <catalin.marinas at arm.com>

This patch implements cpu_get_ttbcr() and cpu_set_ttbcr() and replaces
the corresponding asm statements.

Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
Reviewed-by: Kees Cook <keescook at chromium.org>
Signed-off-by: Linus Walleij <linus.walleij at linaro.org>
---
ChangeLog v1->v3:
- Drop unnecesary volatile from the asm(mcr) call.
---
 arch/arm/include/asm/proc-fns.h | 12 ++++++++++++
 arch/arm/mm/mmu.c               |  7 +++----
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/arm/include/asm/proc-fns.h b/arch/arm/include/asm/proc-fns.h
index 280396483f5d..9b3105a2a5e0 100644
--- a/arch/arm/include/asm/proc-fns.h
+++ b/arch/arm/include/asm/proc-fns.h
@@ -178,6 +178,18 @@ extern void cpu_resume(void);
 	})
 #endif
 
+static inline unsigned int cpu_get_ttbcr(void)
+{
+	unsigned int ttbcr;
+	asm("mrc p15, 0, %0, c2, c0, 2" : "=r" (ttbcr));
+	return ttbcr;
+}
+
+static inline void cpu_set_ttbcr(unsigned int ttbcr)
+{
+	asm("mcr p15, 0, %0, c2, c0, 2" : : "r" (ttbcr));
+}
+
 #else	/*!CONFIG_MMU */
 
 #define cpu_switch_mm(pgd,mm)	{ }
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 674ed71573a8..9a780da6a4e1 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1687,9 +1687,8 @@ static void __init early_paging_init(const struct machine_desc *mdesc)
 	 */
 	cr = get_cr();
 	set_cr(cr & ~(CR_I | CR_C));
-	asm("mrc p15, 0, %0, c2, c0, 2" : "=r" (ttbcr));
-	asm volatile("mcr p15, 0, %0, c2, c0, 2"
-		: : "r" (ttbcr & ~(3 << 8 | 3 << 10)));
+	ttbcr = cpu_get_ttbcr();
+	cpu_set_ttbcr(ttbcr & ~(3 << 8 | 3 << 10));
 	flush_cache_all();
 
 	/*
@@ -1701,7 +1700,7 @@ static void __init early_paging_init(const struct machine_desc *mdesc)
 	lpae_pgtables_remap(offset, pa_pgd);
 
 	/* Re-enable the caches and cacheable TLB walks */
-	asm volatile("mcr p15, 0, %0, c2, c0, 2" : : "r" (ttbcr));
+	cpu_set_ttbcr(ttbcr);
 	set_cr(cr);
 }
 

-- 
2.34.1