forked from Minki/linux
e8ce0eb5e2
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> Tested-by: Shawn Guo <shawn.guo@linaro.org> Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
49 lines
1.2 KiB
C
49 lines
1.2 KiB
C
#include <linux/init.h>
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#include <asm/pgalloc.h>
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#include <asm/pgtable.h>
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#include <asm/memory.h>
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#include <asm/suspend.h>
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#include <asm/tlbflush.h>
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static pgd_t *suspend_pgd;
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extern int __cpu_suspend(int, long, unsigned long, int (*)(unsigned long));
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extern void cpu_resume_turn_mmu_on(void);
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/*
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* Hide the first two arguments to __cpu_suspend - these are an implementation
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* detail which platform code shouldn't have to know about.
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*/
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int cpu_suspend(unsigned long arg, int (*fn)(unsigned long))
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{
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struct mm_struct *mm = current->active_mm;
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int ret;
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if (!suspend_pgd)
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return -EINVAL;
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/*
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* Temporarily switch the page tables to our suspend page
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* tables, which contain the temporary identity mapping
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* required for resuming.
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*/
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cpu_switch_mm(suspend_pgd, mm);
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ret = __cpu_suspend(0, PHYS_OFFSET - PAGE_OFFSET, arg, fn);
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cpu_switch_mm(mm->pgd, mm);
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local_flush_tlb_all();
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return ret;
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}
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static int __init cpu_suspend_init(void)
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{
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suspend_pgd = pgd_alloc(&init_mm);
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if (suspend_pgd) {
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unsigned long addr = virt_to_phys(cpu_resume_turn_mmu_on);
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identity_mapping_add(suspend_pgd, addr, addr + SECTION_SIZE);
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}
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return suspend_pgd ? 0 : -ENOMEM;
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}
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core_initcall(cpu_suspend_init);
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