[RFC 15/23] ARM: LPAE: allow proc override of TTB setup

[cyril@ti.com (Cyril Chemparathy)]

This patch allows ARM processor setup functions (*_setup in proc-*.S) to
indicate that the page table has already been programmed.  This is
done by setting r4 (page table pointer) to -1 before returning from the
processor setup handler.

This capability is particularly needed on LPAE systems, where the translation
table base needs to be programmed differently with 64-bit control
register operations.

Further, a few of the processors (arm1026, mohawk, xsc3) were programming the
TTB twice.  This patch prevents the main head.S code from programming TTB the
second time on these machines.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
---
 arch/arm/kernel/head.S       |   11 ++++++-----
 arch/arm/mm/proc-arm1026.S   |    1 +
 arch/arm/mm/proc-mohawk.S    |    1 +
 arch/arm/mm/proc-v6.S        |    2 ++
 arch/arm/mm/proc-v7-2level.S |    3 ++-
 arch/arm/mm/proc-v7-3level.S |    1 +
 arch/arm/mm/proc-v7.S        |    1 +
 arch/arm/mm/proc-xsc3.S      |    1 +
 8 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 835898e..692e57f 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -411,17 +411,18 @@ __enable_mmu:
 #ifdef CONFIG_CPU_ICACHE_DISABLE
 	bic	r0, r0, #CR_I
 #endif
-#ifdef CONFIG_ARM_LPAE
-	mov	r5, #0
-	mcrr	p15, 0, r4, r5, c2		@ load TTBR0
-#else
+#ifndef CONFIG_ARM_LPAE
 	mov	r5, #(domain_val(DOMAIN_USER, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_KERNEL, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_TABLE, DOMAIN_MANAGER) | \
 		      domain_val(DOMAIN_IO, DOMAIN_CLIENT))
 	mcr	p15, 0, r5, c3, c0, 0		@ load domain access register
-	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
 #endif
+
+	@ has the processor setup already programmed the page table pointer?
+	adds	r5, r4, #1
+	beq	__turn_mmu_on			@ yes!
+	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
 	b	__turn_mmu_on
 ENDPROC(__enable_mmu)
 
diff --git a/arch/arm/mm/proc-arm1026.S b/arch/arm/mm/proc-arm1026.S
index fbc1d5f..c28070e 100644
--- a/arch/arm/mm/proc-arm1026.S
+++ b/arch/arm/mm/proc-arm1026.S
@@ -404,6 +404,7 @@ __arm1026_setup:
 #ifdef CONFIG_MMU
 	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs on v4
 	mcr	p15, 0, r4, c2, c0		@ load page table pointer
+	mvn	r4, #0				@ do not set page table pointer
 #endif
 #ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
 	mov	r0, #4				@ explicitly disable writeback
diff --git a/arch/arm/mm/proc-mohawk.S b/arch/arm/mm/proc-mohawk.S
index fbb2124..a26303c 100644
--- a/arch/arm/mm/proc-mohawk.S
+++ b/arch/arm/mm/proc-mohawk.S
@@ -390,6 +390,7 @@ __mohawk_setup:
 	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs
 	orr	r4, r4, #0x18			@ cache the page table in L2
 	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
+	mvn	r4, #0				@ do not set page table pointer
 
 	mov	r0, #0				@ don't allow CP access
 	mcr	p15, 0, r0, c15, c1, 0		@ write CP access register
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 566c658..872156e 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -210,7 +210,9 @@ __v6_setup:
 	ALT_UP(orr	r4, r4, #TTB_FLAGS_UP)
 	ALT_SMP(orr	r8, r8, #TTB_FLAGS_SMP)
 	ALT_UP(orr	r8, r8, #TTB_FLAGS_UP)
+	mcr	p15, 0, r4, c2, c0, 0		@ load TTB0
 	mcr	p15, 0, r8, c2, c0, 1		@ load TTB1
+	mvn	r4, #0				@ do not set page table pointer
 #endif /* CONFIG_MMU */
 	adr	r5, v6_crval
 	ldmia	r5, {r5, r6}
diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index 3397803..cc78c0c 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -139,7 +139,7 @@ ENDPROC(cpu_v7_set_pte_ext)
 
 	/*
 	 * Macro for setting up the TTBRx and TTBCR registers.
-	 * - \ttb0 and \ttb1 updated with the corresponding flags.
+	 * - \ttbr0 and \ttbr1 updated with the corresponding flags.
 	 */
 	.macro	v7_ttb_setup, zero, ttbr0, ttbr1, tmp
 	mcr	p15, 0, \zero, c2, c0, 2	@ TTB control register
@@ -147,6 +147,7 @@ ENDPROC(cpu_v7_set_pte_ext)
 	ALT_UP(orr	\ttbr0, \ttbr0, #TTB_FLAGS_UP)
 	ALT_SMP(orr	\ttbr1, \ttbr1, #TTB_FLAGS_SMP)
 	ALT_UP(orr	\ttbr1, \ttbr1, #TTB_FLAGS_UP)
+	mcr	p15, 0, \ttbr0, c2, c0, 0	@ load TTB0
 	mcr	p15, 0, \ttbr1, c2, c0, 1	@ load TTB1
 	.endm
 
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 3b1a745..5e3bed1 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -124,6 +124,7 @@ ENDPROC(cpu_v7_set_pte_ext)
 	mcr	p15, 0, \tmp, c2, c0, 2				@ TTBCR
 	addls	\ttbr1, \ttbr1, #TTBR1_OFFSET
 	mcrr	p15, 1, \ttbr1, \zero, c2			@ load TTBR1
+	mcrr	p15, 0, \ttbr0, \zero, c2			@ load TTBR0
 	.endm
 
 	__CPUINIT
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index c2e2b66..8850194 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -250,6 +250,7 @@ __v7_setup:
 #ifdef CONFIG_MMU
 	mcr	p15, 0, r10, c8, c7, 0		@ invalidate I + D TLBs
 	v7_ttb_setup r10, r4, r8, r5		@ TTBCR, TTBRx setup
+	mvn	r4, #0				@ do not set page table pointer
 	ldr	r5, =PRRR			@ PRRR
 	ldr	r6, =NMRR			@ NMRR
 	mcr	p15, 0, r5, c10, c2, 0		@ write PRRR
diff --git a/arch/arm/mm/proc-xsc3.S b/arch/arm/mm/proc-xsc3.S
index b0d5786..db3836b 100644
--- a/arch/arm/mm/proc-xsc3.S
+++ b/arch/arm/mm/proc-xsc3.S
@@ -455,6 +455,7 @@ __xsc3_setup:
 	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I and D TLBs
 	orr	r4, r4, #0x18			@ cache the page table in L2
 	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
+	mvn	r4, #0				@ do not set page table pointer
 
 	mov	r0, #1 << 6			@ cp6 access for early sched_clock
 	mcr	p15, 0, r0, c15, c1, 0		@ write CP access register
-- 
1.7.9.5