Fix S3 resume when kernel is big

Pavel Machek
2002-11-20T15:11:37Z

Hi!

When kernel is big enough, S3 stops working because page table with
low mappings is not big enough. This fixes it, along with possible %ds
problem. (I believe our method of setting %ds was not robust). Code
from mm/init.c is reused, so this actually deletes code.

Please apply (or tell me to push it to the Linus myself),

Pavel

--- clean/arch/i386/kernel/acpi.c 2002-09-22 23:46:52.000000000 +0200
+++ linux-swsusp/arch/i386/kernel/acpi.c 2002-11-20 15:30:31.000000000 +0100
@@ -446,74 +446,11 @@

#ifdef CONFIG_ACPI_SLEEP

-#define DEBUG
-
-#ifdef DEBUG
-#include <linux/serial.h>
-#endif
-
/* address in low memory of the wakeup routine. */
unsigned long acpi_wakeup_address = 0;

-/* new page directory that we will be using */
-static pmd_t *pmd;
-
-/* saved page directory */
-static pmd_t saved_pmd;
-
-/* page which we'll use for the new page directory */
-static pte_t *ptep;
-
extern unsigned long FASTCALL(acpi_copy_wakeup_routine(unsigned long));

-/*
- * acpi_create_identity_pmd
- *
- * Create a new, identity mapped pmd.
- *
- * Do this by creating new page directory, and marking all the pages as R/W
- * Then set it as the new Page Middle Directory.
- * And, of course, flush the TLB so it takes effect.
- *
- * We save the address of the old one, for later restoration.
- */
-static void acpi_create_identity_pmd (void)
-{
- pgd_t *pgd;
- int i;
-
- ptep = (pte_t*)__get_free_page(GFP_KERNEL);
-
- /* fill page with low mapping */
- for (i = 0; i < PTRS_PER_PTE; i++)
- set_pte(ptep + i, pfn_pte(i, PAGE_SHARED));
-
- pgd = pgd_offset(current->active_mm, 0);
- pmd = pmd_alloc(current->mm,pgd, 0);
-
- /* save the old pmd */
- saved_pmd = *pmd;
-
- /* set the new one */
- set_pmd(pmd, __pmd(_PAGE_TABLE + __pa(ptep)));
-
- /* flush the TLB */
- local_flush_tlb();
-}
-
-/*
- * acpi_restore_pmd
- *
- * Restore the old pmd saved by acpi_create_identity_pmd and
- * free the page that said function alloc'd
- */
-static void acpi_restore_pmd (void)
-{
- set_pmd(pmd, saved_pmd);
- local_flush_tlb();
- free_page((unsigned long)ptep);
-}
-
/**
* acpi_save_state_mem - save kernel state
*
@@ -522,7 +459,15 @@
*/
int acpi_save_state_mem (void)
{
- acpi_create_identity_pmd();
+ if (!cpu_has_pse) {
+ printk(KERN_ERR "You have S3 capable machine without pse? Wow!");
+ return 1;
+ }
+#if CONFIG_X86_PAE
+ panic("S3 and PAE do not like each other for now.");
+ return 1;
+#endif
+ init_physical_mapping(swapper_pg_dir, 0, USER_PTRS_PER_PGD);
acpi_copy_wakeup_routine(acpi_wakeup_address);

return 0;
@@ -542,7 +487,7 @@
*/
void acpi_restore_state_mem (void)
{
- acpi_restore_pmd();
+ zap_low_mappings();
}

/**
@@ -555,7 +500,10 @@
*/
void __init acpi_reserve_bootmem(void)
{
+ extern long wakeup_start, wakeup_end;
acpi_wakeup_address = (unsigned long)alloc_bootmem_low(PAGE_SIZE);
+ if ((&wakeup_end - &wakeup_start) > PAGE_SIZE)
+ printk(KERN_CRIT "ACPI: Wakeup code way too big, will crash on attempt to suspend\n");
printk(KERN_DEBUG "ACPI: have wakeup address 0x%8.8lx\n", acpi_wakeup_address);
}

--- clean/arch/i386/kernel/acpi_wakeup.S 2002-11-19 16:45:58.000000000 +0100
+++ linux-swsusp/arch/i386/kernel/acpi_wakeup.S 2002-11-20 14:56:23.000000000 +0100
@@ -1,12 +1,17 @@
-
.text
#include <linux/linkage.h>
#include <asm/segment.h>
+#include <asm/page.h>

-# Do we need to deal with A20?
+#
+# wakeup_code runs in real mode, and at unknown address (determined at run-time).
+# Therefore it must only use relative jumps/calls.
+#
+# Do we need to deal with A20? It seems okay

ALIGN
-wakeup_start:
+ .align 4096
+ENTRY(wakeup_start)
wakeup_code:
wakeup_code_start = .
.code16
@@ -14,49 +19,73 @@
movw $0xb800, %ax
movw %ax,%fs
movw $0x0e00 + 'L', %fs:(0x10)
+
cli
cld
-
- # setup data segment
- movw %cs, %ax

- addw $(wakeup_data - wakeup_code) >> 4, %ax
- movw %ax, %ds
- movw %ax, %ss
- mov $(wakeup_stack - wakeup_data), %sp # Private stack is needed for ASUS board
+# We are now probably running at something like 0x0000 : 0x1000
+ call here
+here:
+ pop %bx
+ subw $(here-wakeup_start), %bx
+ shrw $4, %bx
+
+ # setup data segment
+ movw %cs, %ax
+ addw %bx, %ax
+ movw %ax, %ds # Make ds:0 point to wakeup_start
+ movw %ax, %ss
+ mov $(wakeup_stack-wakeup_code), %sp # Private stack is needed for ASUS board
movw $0x0e00 + 'S', %fs:(0x12)

- movl real_magic - wakeup_data, %eax
+ pushl $0 # Kill any dangerous flags
+ popfl
+ cli
+ cld
+
+ movl real_magic-wakeup_code, %eax
cmpl $0x12345678, %eax
jne bogus_real_magic
-
- mov video_mode - wakeup_data, %ax
+ mov video_mode, %ax
call mode_set

# set up page table
- movl (real_save_cr3 - wakeup_data), %eax
+# movl real_save_cr3-wakeup_code, %eax
+ movl $swapper_pg_dir-__PAGE_OFFSET,%eax
movl %eax, %cr3

# make sure %cr4 is set correctly (features, etc)
- movl (real_save_cr4 - wakeup_data), %eax
+ movl real_save_cr4-wakeup_code, %eax
movl %eax, %cr4
movw $0xb800, %ax
movw %ax,%fs
movw $0x0e00 + 'i', %fs:(0x12)
-
+
# need a gdt
- lgdt real_save_gdt - wakeup_data
+ lgdt real_save_gdt-wakeup_code

- movl (real_save_cr0 - wakeup_data), %eax
+ movl real_save_cr0-wakeup_code, %eax
movl %eax, %cr0
+ jmp 1f
+1:
movw $0x0e00 + 'n', %fs:(0x14)

- movl real_magic - wakeup_data, %eax
+ movl real_magic-wakeup_code, %eax
cmpl $0x12345678, %eax
jne bogus_real_magic

ljmpl $__KERNEL_CS,$wakeup_pmode_return

+wakeup_data:
+ .word 0
+real_save_gdt: .word 0
+ .long 0
+real_save_cr0: .long 0
+real_save_cr3: .long 0
+real_save_cr4: .long 0
+real_magic: .long 0
+video_mode: .long 0
+
bogus_real_magic:
movw $0x0e00 + 'B', %fs:(0x12)
jmp bogus_real_magic
@@ -129,20 +164,12 @@
.code32
ALIGN

-.org 0x300
-wakeup_data:
- .word 0
-real_save_gdt: .word 0
- .long 0
-real_save_cr0: .long 0
-real_save_cr3: .long 0
-real_save_cr4: .long 0
-real_magic: .long 0
-video_mode: .long 0

-.org 0x500
+.org 0x2000
wakeup_stack:
-wakeup_end:
+.org 0x3000
+ENTRY(wakeup_end)
+.org 0x4000

wakeup_pmode_return:
movl $__KERNEL_DS, %eax
--- clean/arch/i386/mm/init.c 2002-11-19 16:45:26.000000000 +0100
+++ linux-swsusp/arch/i386/mm/init.c 2002-11-20 15:05:29.000000000 +0100
@@ -117,24 +117,18 @@
}
}

-/*
- * 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.
- */
-static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
+void init_physical_mapping(pgd_t *pgd_base, int pgd_ofs, int pgd_limit)
{
unsigned long pfn;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
- int pgd_ofs, pmd_ofs, pte_ofs;
+ int pmd_ofs, pte_ofs;

- pgd_ofs = __pgd_offset(PAGE_OFFSET);
pgd = pgd_base + pgd_ofs;
pfn = 0;

- for (; pgd_ofs < PTRS_PER_PGD && pfn < max_low_pfn; pgd++, pgd_ofs++) {
+ for (; pgd_ofs < pgd_limit && pfn < max_low_pfn; pgd++, pgd_ofs++) {
pmd = one_md_table_init(pgd);
for (pmd_ofs = 0; pmd_ofs < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_ofs++) {
/* Map with big pages if possible, otherwise create normal page tables. */
@@ -151,6 +145,16 @@
}
}

+/*
+ * 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.
+ */
+static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
+{
+ init_physical_mapping(pgd_base, __pgd_offset(PAGE_OFFSET), PTRS_PER_PGD);
+}
+
static inline int page_kills_ppro(unsigned long pagenr)
{
if (pagenr >= 0x70000 && pagenr <= 0x7003F)
@@ -299,7 +303,7 @@
#endif
}

-void __init zap_low_mappings (void)
+void zap_low_mappings (void)
{
int i;
/*

--
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