On Saturday, 1 of October 2005 21:45, Andi Kleen wrote:
> On Saturday 01 October 2005 18:13, Rafael J. Wysocki wrote:
>
> >
> > This function allocates twice as much memory as needed for the direct
> > mapping page tables and assigns the second half of it to the resume page
> > tables. This area is later marked with PG_nosave by swsusp, so that it is
> > not overwritten during resume.
> >
> I prefered it when the additional page tables were allocated only on demand.
Me too. Let's get back to that patch, then. :-)
Comments etc. will be appreciated.
Greetings,
Rafael
Signed-off-by: Rafael J. Wysocki <[email protected]>
Index: linux-2.6.14-rc3-git1/arch/x86_64/kernel/suspend.c
===================================================================
--- linux-2.6.14-rc3-git1.orig/arch/x86_64/kernel/suspend.c 2005-10-02 10:39:41.000000000 +0200
+++ linux-2.6.14-rc3-git1/arch/x86_64/kernel/suspend.c 2005-10-02 12:12:27.000000000 +0200
@@ -11,6 +11,8 @@
#include <linux/smp.h>
#include <linux/suspend.h>
#include <asm/proto.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
struct saved_context saved_context;
@@ -140,4 +142,132 @@
}
+#ifdef CONFIG_SOFTWARE_SUSPEND
+/* Defined in kernel/power/swsusp.c */
+extern unsigned long get_usable_page(unsigned gfp_mask);
+extern void free_eaten_memory(void);
+/* Defined in arch/x86_64/kernel/suspend_asm.S */
+extern int restore_image(void);
+pgd_t *temp_level4_pgt;
+
+static void **pages;
+
+static inline void *__add_page(void)
+{
+ void **c;
+
+ c = (void **)get_usable_page(GFP_ATOMIC);
+ if (c) {
+ *c = pages;
+ pages = c;
+ }
+ return c;
+}
+
+static inline void *__next_page(void)
+{
+ void **c;
+
+ c = pages;
+ if (c) {
+ pages = *c;
+ *c = NULL;
+ }
+ return c;
+}
+
+/*
+ * Try to allocate as many usable pages as needed and daisy chain them.
+ * If one allocation fails, free the pages allocated so far
+ */
+static int alloc_usable_pages(unsigned long n)
+{
+ void *p;
+
+ pages = NULL;
+ do
+ if (!__add_page())
+ break;
+ while (--n);
+ if (n) {
+ p = __next_page();
+ while (p) {
+ free_page((unsigned long)p);
+ p = __next_page();
+ }
+ return -ENOMEM;
+ }
+ return 0;
+}
+
+static void phys_pud_init(pud_t *pud, unsigned long address, unsigned long end)
+{
+ long i, j;
+
+ i = pud_index(address);
+ pud = pud + i;
+ for (; i < PTRS_PER_PUD; pud++, i++) {
+ unsigned long paddr;
+ pmd_t *pmd;
+
+ paddr = address + i*PUD_SIZE;
+ if (paddr >= end)
+ break;
+
+ pmd = (pmd_t *)__next_page();
+ set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
+ for (j = 0; j < PTRS_PER_PMD; pmd++, j++, paddr += PMD_SIZE) {
+ unsigned long pe;
+
+ if (paddr >= end)
+ break;
+ pe = _PAGE_NX|_PAGE_PSE | _KERNPG_TABLE | _PAGE_GLOBAL | paddr;
+ pe &= __supported_pte_mask;
+ set_pmd(pmd, __pmd(pe));
+ }
+ }
+}
+
+static void set_up_temporary_mappings(void)
+{
+ unsigned long start, end, next;
+
+ temp_level4_pgt = (pgd_t *)__next_page();
+
+ /* It is safe to reuse the original kernel mapping */
+ set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
+ init_level4_pgt[pgd_index(__START_KERNEL_map)]);
+
+ /* Set up the direct mapping from scratch */
+ start = (unsigned long)pfn_to_kaddr(0);
+ end = (unsigned long)pfn_to_kaddr(end_pfn);
+
+ for (; start < end; start = next) {
+ pud_t *pud = (pud_t *)__next_page();
+ next = start + PGDIR_SIZE;
+ if (next > end)
+ next = end;
+ phys_pud_init(pud, __pa(start), __pa(next));
+ set_pgd(temp_level4_pgt + pgd_index(start),
+ mk_kernel_pgd(__pa(pud)));
+ }
+}
+
+int swsusp_arch_resume(void)
+{
+ unsigned long n;
+
+ n = ((end_pfn << PAGE_SHIFT) + PUD_SIZE - 1) >> PUD_SHIFT;
+ n += (n + PTRS_PER_PUD - 1) / PTRS_PER_PUD + 1;
+ pr_debug("swsusp_arch_resume(): pages needed = %lu\n", n);
+ if (alloc_usable_pages(n)) {
+ free_eaten_memory();
+ return -ENOMEM;
+ }
+ /* We have got enough memory and from now on we cannot recover */
+ set_up_temporary_mappings();
+ restore_image();
+ return 0;
+}
+#endif /* CONFIG_SOFTWARE_SUSPEND */
Index: linux-2.6.14-rc3-git1/kernel/power/swsusp.c
===================================================================
--- linux-2.6.14-rc3-git1.orig/kernel/power/swsusp.c 2005-10-02 10:39:41.000000000 +0200
+++ linux-2.6.14-rc3-git1/kernel/power/swsusp.c 2005-10-02 12:11:08.000000000 +0200
@@ -1095,7 +1095,7 @@
*eaten_memory = c;
}
-static unsigned long get_usable_page(unsigned gfp_mask)
+unsigned long get_usable_page(unsigned gfp_mask)
{
unsigned long m;
@@ -1109,7 +1109,7 @@
return m;
}
-static void free_eaten_memory(void)
+void free_eaten_memory(void)
{
unsigned long m;
void **c;
@@ -1481,11 +1481,12 @@
/* Allocate memory for the image and read the data from swap */
error = check_pagedir(pagedir_nosave);
- free_eaten_memory();
+
if (!error)
error = data_read(pagedir_nosave);
if (error) { /* We fail cleanly */
+ free_eaten_memory();
for_each_pbe (p, pagedir_nosave)
if (p->address) {
free_page(p->address);
Index: linux-2.6.14-rc3-git1/arch/x86_64/kernel/suspend_asm.S
===================================================================
--- linux-2.6.14-rc3-git1.orig/arch/x86_64/kernel/suspend_asm.S 2005-10-02 10:39:41.000000000 +0200
+++ linux-2.6.14-rc3-git1/arch/x86_64/kernel/suspend_asm.S 2005-10-02 11:30:55.000000000 +0200
@@ -39,12 +39,13 @@
call swsusp_save
ret
-ENTRY(swsusp_arch_resume)
- /* set up cr3 */
- leaq init_level4_pgt(%rip),%rax
- subq $__START_KERNEL_map,%rax
- movq %rax,%cr3
-
+ENTRY(restore_image)
+ /* switch to temporary page tables */
+ movq $__PAGE_OFFSET, %rdx
+ movq temp_level4_pgt(%rip), %rax
+ subq %rdx, %rax
+ movq %rax, %cr3
+ /* Flush TLB */
movq mmu_cr4_features(%rip), %rax
movq %rax, %rdx
andq $~(1<<7), %rdx # PGE
@@ -69,6 +70,10 @@
movq pbe_next(%rdx), %rdx
jmp loop
done:
+ /* go back to the original page tables */
+ leaq init_level4_pgt(%rip), %rax
+ subq $__START_KERNEL_map, %rax
+ movq %rax, %cr3
/* Flush TLB, including "global" things (vmalloc) */
movq mmu_cr4_features(%rip), %rax
movq %rax, %rdx
-
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