diff mbox

[RFC,16/23] ARM: LPAE: accomodate >32-bit addresses for page table base

Message ID 1343092165-9470-17-git-send-email-cyril@ti.com (mailing list archive)
State New, archived
Headers show

Commit Message

Cyril Chemparathy July 24, 2012, 1:09 a.m. UTC 
This patch redefines the early boot time use of the R4 register to steal a few
low order bits (ARCH_PGD_SHIFT bits), allowing for up to 38-bit physical
addresses.

This is probably not the best means to the end, and a better alternative may
be to modify the head.S register allocations to fit in full register pairs for
pgdir and swapper_pg_dir.  However, squeezing out these extra registers seemed
to be a far greater pain than squeezing out a few low order bits from the page
table addresses.

Signed-off-by: Cyril Chemparathy <cyril@ti.com>
Signed-off-by: Vitaly Andrianov <vitalya@ti.com>
---
 arch/arm/include/asm/cache.h |    9 +++++++++
 arch/arm/kernel/head.S       |    7 +++++--
 arch/arm/kernel/smp.c        |   11 +++++++++--
 arch/arm/mm/proc-arm1026.S   |    2 ++
 arch/arm/mm/proc-mohawk.S    |    2 ++
 arch/arm/mm/proc-v6.S        |    2 ++
 arch/arm/mm/proc-v7-2level.S |    2 ++
 arch/arm/mm/proc-v7-3level.S |    7 +++++++
 arch/arm/mm/proc-v7.S        |    1 +
 arch/arm/mm/proc-xsc3.S      |    2 ++
 10 files changed, 41 insertions(+), 4 deletions(-)
diff mbox

Patch

diff --git a/arch/arm/include/asm/cache.h b/arch/arm/include/asm/cache.h
index 75fe66b..986480c 100644
--- a/arch/arm/include/asm/cache.h
+++ b/arch/arm/include/asm/cache.h
@@ -17,6 +17,15 @@ 
 #define ARCH_DMA_MINALIGN	L1_CACHE_BYTES
 
 /*
+ * Minimum guaranted alignment in pgd_alloc().  The page table pointers passed
+ * around in head.S and proc-*.S are shifted by this amount, in order to
+ * leave spare high bits for systems with physical address extension.  This
+ * does not fully accomodate the 40-bit addressing capability of ARM LPAE, but
+ * gives us about 38-bits or so.
+ */
+#define ARCH_PGD_SHIFT		L1_CACHE_SHIFT
+
+/*
  * With EABI on ARMv5 and above we must have 64-bit aligned slab pointers.
  */
 #if defined(CONFIG_AEABI) && (__LINUX_ARM_ARCH__ >= 5)
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
index 692e57f..6fe1c40 100644
--- a/arch/arm/kernel/head.S
+++ b/arch/arm/kernel/head.S
@@ -22,6 +22,7 @@ 
 #include <asm/memory.h>
 #include <asm/thread_info.h>
 #include <asm/pgtable.h>
+#include <asm/cache.h>
 
 #ifdef CONFIG_DEBUG_LL
 #include <mach/debug-macro.S>
@@ -160,7 +161,7 @@  ENDPROC(stext)
  *
  * Returns:
  *  r0, r3, r5-r7 corrupted
- *  r4 = physical page table address
+ *  r4 = page table (see ARCH_PGD_SHIFT in asm/cache.h)
  */
 __create_page_tables:
 	pgtbl	r4, r8				@ page table address
@@ -320,6 +321,7 @@  __create_page_tables:
 #ifdef CONFIG_ARM_LPAE
 	sub	r4, r4, #0x1000		@ point to the PGD table
 #endif
+	mov	r4, r4, lsr #ARCH_PGD_SHIFT
 	mov	pc, lr
 ENDPROC(__create_page_tables)
 	.ltorg
@@ -392,7 +394,7 @@  __secondary_data:
  *  r0  = cp#15 control register
  *  r1  = machine ID
  *  r2  = atags or dtb pointer
- *  r4  = page table pointer
+ *  r4  = page table (see ARCH_PGD_SHIFT in asm/cache.h)
  *  r9  = processor ID
  *  r13 = *virtual* address to jump to upon completion
  */
@@ -422,6 +424,7 @@  __enable_mmu:
 	@ has the processor setup already programmed the page table pointer?
 	adds	r5, r4, #1
 	beq	__turn_mmu_on			@ yes!
+	mov	r4, r4, lsl #ARCH_PGD_SHIFT
 	mcr	p15, 0, r4, c2, c0, 0		@ load page table pointer
 	b	__turn_mmu_on
 ENDPROC(__enable_mmu)
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 2c7217d..e41e1be 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -42,6 +42,7 @@ 
 #include <asm/ptrace.h>
 #include <asm/localtimer.h>
 #include <asm/smp_plat.h>
+#include <asm/cache.h>
 
 /*
  * as from 2.5, kernels no longer have an init_tasks structure
@@ -62,6 +63,7 @@  static DECLARE_COMPLETION(cpu_running);
 
 int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 {
+	phys_addr_t pgdir;
 	int ret;
 
 	/*
@@ -69,8 +71,13 @@  int __cpuinit __cpu_up(unsigned int cpu, struct task_struct *idle)
 	 * its stack and the page tables.
 	 */
 	secondary_data.stack = task_stack_page(idle) + THREAD_START_SP;
-	secondary_data.pgdir = virt_to_phys(idmap_pgd);
-	secondary_data.swapper_pg_dir = virt_to_phys(swapper_pg_dir);
+
+	pgdir = virt_to_phys(idmap_pgd);
+	secondary_data.pgdir = pgdir >> ARCH_PGD_SHIFT;
+
+	pgdir = virt_to_phys(swapper_pg_dir);
+	secondary_data.swapper_pg_dir = pgdir >> ARCH_PGD_SHIFT;
+
 	__cpuc_flush_dcache_area(&secondary_data, sizeof(secondary_data));
 	outer_clean_range(__pa(&secondary_data), __pa(&secondary_data + 1));
 
diff --git a/arch/arm/mm/proc-arm1026.S b/arch/arm/mm/proc-arm1026.S
index c28070e..4556f77 100644
--- a/arch/arm/mm/proc-arm1026.S
+++ b/arch/arm/mm/proc-arm1026.S
@@ -22,6 +22,7 @@ 
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
 #include <asm/ptrace.h>
+#include <asm/cache.h>
 
 #include "proc-macros.S"
 
@@ -403,6 +404,7 @@  __arm1026_setup:
 	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer on v4
 #ifdef CONFIG_MMU
 	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs on v4
+	mov	r4, r4, lsl #ARCH_PGD_SHIFT
 	mcr	p15, 0, r4, c2, c0		@ load page table pointer
 	mvn	r4, #0				@ do not set page table pointer
 #endif
diff --git a/arch/arm/mm/proc-mohawk.S b/arch/arm/mm/proc-mohawk.S
index a26303c..13fcc67 100644
--- a/arch/arm/mm/proc-mohawk.S
+++ b/arch/arm/mm/proc-mohawk.S
@@ -28,6 +28,7 @@ 
 #include <asm/pgtable.h>
 #include <asm/page.h>
 #include <asm/ptrace.h>
+#include <asm/cache.h>
 #include "proc-macros.S"
 
 /*
@@ -388,6 +389,7 @@  __mohawk_setup:
 	mcr	p15, 0, r0, c7, c7		@ invalidate I,D caches
 	mcr	p15, 0, r0, c7, c10, 4		@ drain write buffer
 	mcr	p15, 0, r0, c8, c7		@ invalidate I,D TLBs
+	mov	r4, r4, lsl #ARCH_PGD_SHIFT
 	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
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index 872156e..4751be7 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -17,6 +17,7 @@ 
 #include <asm/hwcap.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
+#include <asm/cache.h>
 
 #include "proc-macros.S"
 
@@ -206,6 +207,7 @@  __v6_setup:
 #ifdef CONFIG_MMU
 	mcr	p15, 0, r0, c8, c7, 0		@ invalidate I + D TLBs
 	mcr	p15, 0, r0, c2, c0, 2		@ TTB control register
+	mov	r4, r4, lsl #ARCH_PGD_SHIFT
 	ALT_SMP(orr	r4, r4, #TTB_FLAGS_SMP)
 	ALT_UP(orr	r4, r4, #TTB_FLAGS_UP)
 	ALT_SMP(orr	r8, r8, #TTB_FLAGS_SMP)
diff --git a/arch/arm/mm/proc-v7-2level.S b/arch/arm/mm/proc-v7-2level.S
index cc78c0c..f4bc63b 100644
--- a/arch/arm/mm/proc-v7-2level.S
+++ b/arch/arm/mm/proc-v7-2level.S
@@ -143,8 +143,10 @@  ENDPROC(cpu_v7_set_pte_ext)
 	 */
 	.macro	v7_ttb_setup, zero, ttbr0, ttbr1, tmp
 	mcr	p15, 0, \zero, c2, c0, 2	@ TTB control register
+	mov	\ttbr0, \ttbr0, lsl #ARCH_PGD_SHIFT
 	ALT_SMP(orr	\ttbr0, \ttbr0, #TTB_FLAGS_SMP)
 	ALT_UP(orr	\ttbr0, \ttbr0, #TTB_FLAGS_UP)
+	mov	\ttbr1, \ttbr1, lsl #ARCH_PGD_SHIFT
 	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
diff --git a/arch/arm/mm/proc-v7-3level.S b/arch/arm/mm/proc-v7-3level.S
index 5e3bed1..33f322a 100644
--- a/arch/arm/mm/proc-v7-3level.S
+++ b/arch/arm/mm/proc-v7-3level.S
@@ -103,6 +103,7 @@  ENDPROC(cpu_v7_set_pte_ext)
 	 */
 	.macro	v7_ttb_setup, zero, ttbr0, ttbr1, tmp
 	ldr	\tmp, =swapper_pg_dir		@ swapper_pg_dir virtual address
+	mov	\tmp, \tmp, lsr #ARCH_PGD_SHIFT
 	cmp	\ttbr1, \tmp			@ PHYS_OFFSET > PAGE_OFFSET? (branch below)
 	mrc	p15, 0, \tmp, c2, c0, 2		@ TTB control register
 	orr	\tmp, \tmp, #TTB_EAE
@@ -122,8 +123,14 @@  ENDPROC(cpu_v7_set_pte_ext)
 	 */
 	orrls	\tmp, \tmp, #TTBR1_SIZE				@ TTBCR.T1SZ
 	mcr	p15, 0, \tmp, c2, c0, 2				@ TTBCR
+	mov	\tmp, \ttbr1, lsr #(32 - ARCH_PGD_SHIFT)	@ upper bits
+	mov	\ttbr1, \ttbr1, lsl #ARCH_PGD_SHIFT		@ lower bits
 	addls	\ttbr1, \ttbr1, #TTBR1_OFFSET
 	mcrr	p15, 1, \ttbr1, \zero, c2			@ load TTBR1
+	mov	\tmp, \ttbr0, lsr #(32 - ARCH_PGD_SHIFT)	@ upper bits
+	mov	\ttbr0, \ttbr0, lsl #ARCH_PGD_SHIFT		@ lower bits
+	mcrr	p15, 0, \ttbr0, \zero, c2			@ load TTBR0
+	mcrr	p15, 1, \ttbr1, \zero, c2			@ load TTBR1
 	mcrr	p15, 0, \ttbr0, \zero, c2			@ load TTBR0
 	.endm
 
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 8850194..443f602 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -16,6 +16,7 @@ 
 #include <asm/hwcap.h>
 #include <asm/pgtable-hwdef.h>
 #include <asm/pgtable.h>
+#include <asm/cache.h>
 
 #include "proc-macros.S"
 
diff --git a/arch/arm/mm/proc-xsc3.S b/arch/arm/mm/proc-xsc3.S
index db3836b..a43a07d 100644
--- a/arch/arm/mm/proc-xsc3.S
+++ b/arch/arm/mm/proc-xsc3.S
@@ -32,6 +32,7 @@ 
 #include <asm/pgtable-hwdef.h>
 #include <asm/page.h>
 #include <asm/ptrace.h>
+#include <asm/cache.h>
 #include "proc-macros.S"
 
 /*
@@ -453,6 +454,7 @@  __xsc3_setup:
 	mcr	p15, 0, ip, c7, c10, 4		@ data write barrier
 	mcr	p15, 0, ip, c7, c5, 4		@ prefetch flush
 	mcr	p15, 0, ip, c8, c7, 0		@ invalidate I and D TLBs
+	mov	r4, r4, lsl #ARCH_PGD_SHIFT
 	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