ARM: suspend: use idmap_pgd instead of suspend_pgd

The ARM CPU suspend code requires cpu_resume_mmu to be identity mapped
in order to re-enable the MMU when coming out of suspend. Currently,
this is accomplished by maintaining a suspend_pgd with the relevant
mapping put in place at init time.

This patch replaces the use of suspend_pgd with the new idmap_pgd.
cpu_resume_mmu is placed in the .idmap.text section so that it is
included in the identity map.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Dave Martin <dave.martin@linaro.org>
Tested-by: Lorenzo Pieralisi <Lorenzo.Pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

2 files changed, 5 insertions, 15 deletions

diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S
index 020e99c845e7..9e64231c8cfe 100644
--- a/arch/arm/kernel/sleep.S
+++ b/arch/arm/kernel/sleep.S
@@ -54,6 +54,7 @@ ENDPROC(cpu_suspend_abort)
  * r0 = control register value
  */
         .align  5
+        .pushsection    .idmap.text,"ax"
 ENTRY(cpu_resume_mmu)
         ldr     r3, =cpu_resume_after_mmu
         mcr     p15, 0, r0, c1, c0, 0   @ turn on MMU, I-cache, etc
@@ -62,6 +63,7 @@ ENTRY(cpu_resume_mmu)
         mov     r0, r0
         mov     pc, r3                  @ jump to virtual address
 ENDPROC(cpu_resume_mmu)
+        .popsection
 cpu_resume_after_mmu:
         bl      cpu_init                @ restore the und/abt/irq banked regs
         mov     r0, #0                  @ return zero on success
diff --git a/arch/arm/kernel/suspend.c b/arch/arm/kernel/suspend.c
index 93a22d282c16..1794cc3b0f18 100644
--- a/arch/arm/kernel/suspend.c
+++ b/arch/arm/kernel/suspend.c
@@ -1,13 +1,12 @@
 #include <linux/init.h>
 
+#include <asm/idmap.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(unsigned long, int (*)(unsigned long));
 extern void cpu_resume_mmu(void);
 
@@ -21,7 +20,7 @@ void __cpu_suspend_save(u32 *ptr, u32 ptrsz, u32 sp, u32 *save_ptr)
         *save_ptr = virt_to_phys(ptr);
 
         /* This must correspond to the LDM in cpu_resume() assembly */
-        *ptr++ = virt_to_phys(suspend_pgd);
+        *ptr++ = virt_to_phys(idmap_pgd);
         *ptr++ = sp;
         *ptr++ = virt_to_phys(cpu_do_resume);
 
@@ -42,7 +41,7 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
         struct mm_struct *mm = current->active_mm;
         int ret;
 
-        if (!suspend_pgd)
+        if (!idmap_pgd)
                 return -EINVAL;
 
         /*
@@ -59,14 +58,3 @@ int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
 
         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_mmu);
-                identity_mapping_add(suspend_pgd, addr, addr + SECTION_SIZE);
-        }
-        return suspend_pgd ? 0 : -ENOMEM;
-}
-core_initcall(cpu_suspend_init);