[PATCH 2/7] ARM: pm: preallocate a page table for suspend/resume

Russell King - ARM Linux
2011-09-19T16:39:08Z

Preallocate a page table and setup an identity mapping for the MMU
enable code. This means we don't have to "borrow" a page table to
do this, avoiding complexities with L2 cache coherency.

Tested-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
---
arch/arm/include/asm/suspend.h | 17 +-------------
arch/arm/kernel/Makefile | 2 +-
arch/arm/kernel/sleep.S | 33 ++++++++++-----------------
arch/arm/kernel/suspend.c | 48 ++++++++++++++++++++++++++++++++++++++++
arch/arm/mm/proc-arm920.S | 4 ---
arch/arm/mm/proc-arm926.S | 4 ---
arch/arm/mm/proc-sa1100.S | 4 ---
arch/arm/mm/proc-v6.S | 6 -----
arch/arm/mm/proc-v7.S | 6 -----
arch/arm/mm/proc-xsc3.S | 6 -----
arch/arm/mm/proc-xscale.S | 4 ---
11 files changed, 62 insertions(+), 72 deletions(-)
create mode 100644 arch/arm/kernel/suspend.c

diff --git a/arch/arm/include/asm/suspend.h b/arch/arm/include/asm/suspend.h
index b0e4e1a..1c0a551 100644
--- a/arch/arm/include/asm/suspend.h
+++ b/arch/arm/include/asm/suspend.h
@@ -1,22 +1,7 @@
#ifndef __ASM_ARM_SUSPEND_H
#define __ASM_ARM_SUSPEND_H

-#include <asm/memory.h>
-#include <asm/tlbflush.h>
-
extern void cpu_resume(void);
-
-/*
- * Hide the first two arguments to __cpu_suspend - these are an implementation
- * detail which platform code shouldn't have to know about.
- */
-static inline int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
-{
- extern int __cpu_suspend(int, long, unsigned long,
- int (*)(unsigned long));
- int ret = __cpu_suspend(0, PHYS_OFFSET - PAGE_OFFSET, arg, fn);
- flush_tlb_all();
- return ret;
-}
+extern int cpu_suspend(unsigned long, int (*)(unsigned long));

#endif
diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
index f7887dc..787b888 100644
--- a/arch/arm/kernel/Makefile
+++ b/arch/arm/kernel/Makefile
@@ -29,7 +29,7 @@ obj-$(CONFIG_MODULES) += armksyms.o module.o
obj-$(CONFIG_ARTHUR) += arthur.o
obj-$(CONFIG_ISA_DMA) += dma-isa.o
obj-$(CONFIG_PCI) += bios32.o isa.o
-obj-$(CONFIG_PM_SLEEP) += sleep.o
+obj-$(CONFIG_PM_SLEEP) += sleep.o suspend.o
obj-$(CONFIG_HAVE_SCHED_CLOCK) += sched_clock.o
obj-$(CONFIG_SMP) += smp.o smp_tlb.o
obj-$(CONFIG_HAVE_ARM_SCU) += smp_scu.o
diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index 46a9f46..8cf13de 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -27,7 +27,7 @@ ENTRY(__cpu_suspend)
sub sp, sp, r5 @ allocate CPU state on stack
mov r0, sp @ save pointer to CPU save block
add ip, ip, r1 @ convert resume fn to phys
- stmfd sp!, {r1, r6, ip} @ save v:p, virt SP, phys resume fn
+ stmfd sp!, {r6, ip} @ save virt SP, phys resume fn
ldr r5, =sleep_save_sp
add r6, sp, r1 @ convert SP to phys
stmfd sp!, {r2, r3} @ save suspend func arg and pointer
@@ -60,7 +60,7 @@ ENDPROC(__cpu_suspend)
.ltorg

cpu_suspend_abort:
- ldmia sp!, {r1 - r3} @ pop v:p, virt SP, phys resume fn
+ ldmia sp!, {r2 - r3} @ pop virt SP, phys resume fn
teq r0, #0
moveq r0, #1 @ force non-zero value
mov sp, r2
@@ -74,28 +74,19 @@ ENDPROC(cpu_suspend_abort)
* r3 = L1 section flags
*/
ENTRY(cpu_resume_mmu)
- adr r4, cpu_resume_turn_mmu_on
- mov r4, r4, lsr #20
- orr r3, r3, r4, lsl #20
- ldr r5, [r2, r4, lsl #2] @ save old mapping
- str r3, [r2, r4, lsl #2] @ setup 1:1 mapping for mmu code
- sub r2, r2, r1
ldr r3, =cpu_resume_after_mmu
- bic r1, r0, #CR_C @ ensure D-cache is disabled
b cpu_resume_turn_mmu_on
ENDPROC(cpu_resume_mmu)
.ltorg
.align 5
-cpu_resume_turn_mmu_on:
- mcr p15, 0, r1, c1, c0, 0 @ turn on MMU, I-cache, etc
- mrc p15, 0, r1, c0, c0, 0 @ read id reg
- mov r1, r1
- mov r1, r1
+ENTRY(cpu_resume_turn_mmu_on)
+ mcr p15, 0, r0, c1, c0, 0 @ turn on MMU, I-cache, etc
+ mrc p15, 0, r0, c0, c0, 0 @ read id reg
+ mov r0, r0
+ mov r0, r0
mov pc, r3 @ jump to virtual address
ENDPROC(cpu_resume_turn_mmu_on)
cpu_resume_after_mmu:
- str r5, [r2, r4, lsl #2] @ restore old mapping
- mcr p15, 0, r0, c1, c0, 0 @ turn on D-cache
bl cpu_init @ restore the und/abt/irq banked regs
mov r0, #0 @ return zero on success
ldmfd sp!, {r4 - r11, pc}
@@ -121,11 +112,11 @@ ENTRY(cpu_resume)
ldr r0, sleep_save_sp @ stack phys addr
#endif
setmode PSR_I_BIT | PSR_F_BIT | SVC_MODE, r1 @ set SVC, irqs off
- @ load v:p, stack, resume fn
- ARM( ldmia r0!, {r1, sp, pc} )
-THUMB( ldmia r0!, {r1, r2, r3} )
-THUMB( mov sp, r2 )
-THUMB( bx r3 )
+ @ load stack, resume fn
+ ARM( ldmia r0!, {sp, pc} )
+THUMB( ldmia r0!, {r2, r3} )
+THUMB( mov sp, r2 )
+THUMB( bx r3 )
ENDPROC(cpu_resume)

sleep_save_sp:
diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
new file mode 100644
index 0000000..0a33f10
--- /dev/null
+++ b/arch/arm/kernel/suspend.c
@@ -0,0 +1,48 @@
+#include <linux/init.h>
+
+#include <asm/pgalloc.h>
+#include <asm/pgtable.h>
+#include <asm/memory.h>
+#include <asm/suspend.h>
+#include <asm/tlbflush.h>
+
+static pgd_t *suspend_pgd;
+
+extern int __cpu_suspend(int, long, unsigned long, int (*)(unsigned long));
+extern void cpu_resume_turn_mmu_on(void);
+
+/*
+ * Hide the first two arguments to __cpu_suspend - these are an implementation
+ * detail which platform code shouldn't have to know about.
+ */
+int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
+{
+ struct mm_struct *mm = current->active_mm;
+ int ret;
+
+ if (!suspend_pgd)
+ return -EINVAL;
+
+ /*
+ * Temporarily switch the page tables to our suspend page
+ * tables, which contain the temporary identity mapping
+ * required for resuming.
+ */
+ cpu_switch_mm(suspend_pgd, mm);
+ ret = __cpu_suspend(0, PHYS_OFFSET - PAGE_OFFSET, arg, fn);
+ cpu_switch_mm(mm->pgd, mm);
+ local_flush_tlb_all();
+
+ return ret;
+}
+
+static int __init cpu_suspend_init(void)
+{
+ suspend_pgd = pgd_alloc(&init_mm);
+ if (suspend_pgd) {
+ unsigned long addr = virt_to_phys(cpu_resume_turn_mmu_on);
+ identity_mapping_add(suspend_pgd, addr, addr + SECTION_SIZE);
+ }
+ return suspend_pgd ? 0 : -ENOMEM;
+}
+core_initcall(cpu_suspend_init);
diff --git a/arch/arm/mm/proc-arm920.S b/arch/arm/mm/proc-arm920.S
index 2e6849b..035d57b 100644
--- a/arch/arm/mm/proc-arm920.S
+++ b/arch/arm/mm/proc-arm920.S
@@ -400,10 +400,6 @@ ENTRY(cpu_arm920_do_resume)
mcr p15, 0, r5, c3, c0, 0 @ Domain ID
mcr p15, 0, r6, c2, c0, 0 @ TTB address
mov r0, r7 @ control register
- mov r2, r6, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, =PMD_TYPE_SECT | PMD_SECT_BUFFERABLE | \
- PMD_SECT_CACHEABLE | PMD_BIT4 | PMD_SECT_AP_WRITE
b cpu_resume_mmu
ENDPROC(cpu_arm920_do_resume)
#endif
diff --git a/arch/arm/mm/proc-arm926.S b/arch/arm/mm/proc-arm926.S
index cd8f79c..48add84 100644
--- a/arch/arm/mm/proc-arm926.S
+++ b/arch/arm/mm/proc-arm926.S
@@ -415,10 +415,6 @@ ENTRY(cpu_arm926_do_resume)
mcr p15, 0, r5, c3, c0, 0 @ Domain ID
mcr p15, 0, r6, c2, c0, 0 @ TTB address
mov r0, r7 @ control register
- mov r2, r6, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, =PMD_TYPE_SECT | PMD_SECT_BUFFERABLE | \
- PMD_SECT_CACHEABLE | PMD_BIT4 | PMD_SECT_AP_WRITE
b cpu_resume_mmu
ENDPROC(cpu_arm926_do_resume)
#endif
diff --git a/arch/arm/mm/proc-sa1100.S b/arch/arm/mm/proc-sa1100.S
index 69e7f2e..52f73fb 100644
--- a/arch/arm/mm/proc-sa1100.S
+++ b/arch/arm/mm/proc-sa1100.S
@@ -192,10 +192,6 @@ ENTRY(cpu_sa1100_do_resume)
mcr p15, 0, r5, c2, c0, 0 @ translation table base addr
mcr p15, 0, r6, c13, c0, 0 @ PID
mov r0, r7 @ control register
- mov r2, r5, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, =PMD_TYPE_SECT | PMD_SECT_BUFFERABLE | \
- PMD_SECT_CACHEABLE | PMD_SECT_AP_WRITE
b cpu_resume_mmu
ENDPROC(cpu_sa1100_do_resume)
#endif
diff --git a/arch/arm/mm/proc-v6.S b/arch/arm/mm/proc-v6.S
index a923aa0..414e369 100644
--- a/arch/arm/mm/proc-v6.S
+++ b/arch/arm/mm/proc-v6.S
@@ -161,14 +161,8 @@ ENTRY(cpu_v6_do_resume)
mcr p15, 0, ip, c2, c0, 2 @ TTB control register
mcr p15, 0, ip, c7, c5, 4 @ ISB
mov r0, r11 @ control register
- mov r2, r7, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, cpu_resume_l1_flags
b cpu_resume_mmu
ENDPROC(cpu_v6_do_resume)
-cpu_resume_l1_flags:
- ALT_SMP(.long PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_FLAGS_SMP)
- ALT_UP(.long PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_FLAGS_UP)
#endif

string cpu_v6_name, "ARMv6-compatible processor"
diff --git a/arch/arm/mm/proc-v7.S b/arch/arm/mm/proc-v7.S
index 9049c07..21d6910 100644
--- a/arch/arm/mm/proc-v7.S
+++ b/arch/arm/mm/proc-v7.S
@@ -259,14 +259,8 @@ ENTRY(cpu_v7_do_resume)
isb
dsb
mov r0, r9 @ control register
- mov r2, r7, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, cpu_resume_l1_flags
b cpu_resume_mmu
ENDPROC(cpu_v7_do_resume)
-cpu_resume_l1_flags:
- ALT_SMP(.long PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_FLAGS_SMP)
- ALT_UP(.long PMD_TYPE_SECT | PMD_SECT_AP_WRITE | PMD_FLAGS_UP)
#endif

__CPUINIT
diff --git a/arch/arm/mm/proc-xsc3.S b/arch/arm/mm/proc-xsc3.S
index 755e1bf..efd4949 100644
--- a/arch/arm/mm/proc-xsc3.S
+++ b/arch/arm/mm/proc-xsc3.S
@@ -435,13 +435,7 @@ ENTRY(cpu_xsc3_do_resume)
mcr p15, 0, r7, c3, c0, 0 @ domain ID
mcr p15, 0, r8, c2, c0, 0 @ translation table base addr
mcr p15, 0, r9, c1, c0, 1 @ auxiliary control reg
-
- @ temporarily map resume_turn_on_mmu into the page table,
- @ otherwise prefetch abort occurs after MMU is turned on
mov r0, r10 @ control register
- mov r2, r8, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, =0x542e @ section flags
b cpu_resume_mmu
ENDPROC(cpu_xsc3_do_resume)
#endif
diff --git a/arch/arm/mm/proc-xscale.S b/arch/arm/mm/proc-xscale.S
index fbc06e5..37dbada 100644
--- a/arch/arm/mm/proc-xscale.S
+++ b/arch/arm/mm/proc-xscale.S
@@ -548,10 +548,6 @@ ENTRY(cpu_xscale_do_resume)
mcr p15, 0, r8, c2, c0, 0 @ translation table base addr
mcr p15, 0, r9, c1, c1, 0 @ auxiliary control reg
mov r0, r10 @ control register
- mov r2, r8, lsr #14 @ get TTB0 base
- mov r2, r2, lsl #14
- ldr r3, =PMD_TYPE_SECT | PMD_SECT_BUFFERABLE | \
- PMD_SECT_CACHEABLE | PMD_SECT_AP_WRITE
b cpu_resume_mmu
ENDPROC(cpu_xscale_do_resume)
#endif
--
1.7.4.4