--- /dev/null
+/*
+ * Suspend support specific for i386 - temporary page tables
+ *
+ * Distribute under GPLv2
+ *
+ * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
+ */
+
+#include <linux/suspend.h>
+#include <linux/bootmem.h>
+
+#include <asm/system.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+
+/* Defined in arch/i386/power/swsusp.S */
+extern int restore_image(void);
+
+/* Pointer to the temporary resume page tables */
+pgd_t *resume_pg_dir;
+
+/* The following three functions are based on the analogous code in
+ * arch/i386/mm/init.c
+ */
+
+/*
+ * Create a middle page table on a resume-safe page and put a pointer to it in
+ * the given global directory entry. This only returns the gd entry
+ * in non-PAE compilation mode, since the middle layer is folded.
+ */
+static pmd_t *resume_one_md_table_init(pgd_t *pgd)
+{
+ pud_t *pud;
+ pmd_t *pmd_table;
+
+#ifdef CONFIG_X86_PAE
+ pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
+ if (!pmd_table)
+ return NULL;
+
+ set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
+ pud = pud_offset(pgd, 0);
+
+ BUG_ON(pmd_table != pmd_offset(pud, 0));
+#else
+ pud = pud_offset(pgd, 0);
+ pmd_table = pmd_offset(pud, 0);
+#endif
+
+ return pmd_table;
+}
+
+/*
+ * Create a page table on a resume-safe page and place a pointer to it in
+ * a middle page directory entry.
+ */
+static pte_t *resume_one_page_table_init(pmd_t *pmd)
+{
+ if (pmd_none(*pmd)) {
+ pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
+ if (!page_table)
+ return NULL;
+
+ set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
+
+ BUG_ON(page_table != pte_offset_kernel(pmd, 0));
+
+ return page_table;
+ }
+
+ return pte_offset_kernel(pmd, 0);
+}
+
+/*
+ * This maps the physical memory to kernel virtual address space, a total
+ * of max_low_pfn pages, by creating page tables starting from address
+ * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
+ */
+static int resume_physical_mapping_init(pgd_t *pgd_base)
+{
+ unsigned long pfn;
+ pgd_t *pgd;
+ pmd_t *pmd;
+ pte_t *pte;
+ int pgd_idx, pmd_idx;
+
+ pgd_idx = pgd_index(PAGE_OFFSET);
+ pgd = pgd_base + pgd_idx;
+ pfn = 0;
+
+ for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
+ pmd = resume_one_md_table_init(pgd);
+ if (!pmd)
+ return -ENOMEM;
+
+ if (pfn >= max_low_pfn)
+ continue;
+
+ for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
+ if (pfn >= max_low_pfn)
+ break;
+
+ /* Map with big pages if possible, otherwise create
+ * normal page tables.
+ * NOTE: We can mark everything as executable here
+ */
+ if (cpu_has_pse) {
+ set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
+ pfn += PTRS_PER_PTE;
+ } else {
+ pte_t *max_pte;
+
+ pte = resume_one_page_table_init(pmd);
+ if (!pte)
+ return -ENOMEM;
+
+ max_pte = pte + PTRS_PER_PTE;
+ for (; pte < max_pte; pte++, pfn++) {
+ if (pfn >= max_low_pfn)
+ break;
+
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+ }
+ }
+ }
+ }
+ return 0;
+}
+
+static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
+{
+#ifdef CONFIG_X86_PAE
+ int i;
+
+ /* Init entries of the first-level page table to the zero page */
+ for (i = 0; i < PTRS_PER_PGD; i++)
+ set_pgd(pg_dir + i,
+ __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
+#endif
+}
+
+int swsusp_arch_resume(void)
+{
+ int error;
+
+ resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
+ if (!resume_pg_dir)
+ return -ENOMEM;
+
+ resume_init_first_level_page_table(resume_pg_dir);
+ error = resume_physical_mapping_init(resume_pg_dir);
+ if (error)
+ return error;
+
+ /* We have got enough memory and from now on we cannot recover */
+ restore_image();
+ return 0;
+}
call swsusp_save
ret
-ENTRY(swsusp_arch_resume)
- movl $swsusp_pg_dir-__PAGE_OFFSET, %ecx
+ENTRY(restore_image)
+ movl resume_pg_dir, %ecx
+ subl $__PAGE_OFFSET, %ecx
movl %ecx, %cr3
movl restore_pblist, %edx
.p2align 4,,7
done:
+ /* go back to the original page tables */
+ movl $swapper_pg_dir, %ecx
+ subl $__PAGE_OFFSET, %ecx
+ movl %ecx, %cr3
/* Flush TLB, including "global" things (vmalloc) */
movl mmu_cr4_features, %eax
movl %eax, %edx
projects / GitHub / LineageOS / android_kernel_motorola_exynos9610.git / commitdiff