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x86-32, mm: Add an initial page table for core bootstrapping

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This patch adds an initial page table with low mappings used exclusively
for booting APs/resuming after ACPI suspend/machine restart. After this,
there's no need to add low mappings to swapper_pg_dir and zap them later
or create own swsusp PGD page solely for ACPI sleep needs - we have
initial_page_table for that.

Signed-off-by: Borislav Petkov <bp@alien8.de>
LKML-Reference: <20101020070526.GA9588@liondog.tnic>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This commit is contained in:
Borislav Petkov 2010-08-28 15:58:33 +02:00 committed by H. Peter Anvin
parent d25e6b0b32
commit b40827fa72
11 changed files with 58 additions and 121 deletions
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2
arch/x86/include/asm/pgtable_32.h
View File

@ -26,7 +26,7 @@ struct mm_struct;
struct vm_area_struct;
extern pgd_t swapper_pg_dir[1024];
extern pgd_t trampoline_pg_dir[1024];
extern pgd_t initial_page_table[1024];
static inline void pgtable_cache_init(void) { }
static inline void check_pgt_cache(void) { }

2
arch/x86/include/asm/tlbflush.h
View File

@ -172,6 +172,4 @@ static inline void flush_tlb_kernel_range(unsigned long start,
flush_tlb_all();
}
extern void zap_low_mappings(bool early);
#endif /* _ASM_X86_TLBFLUSH_H */

3
arch/x86/include/asm/trampoline.h
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@ -13,16 +13,13 @@ extern unsigned char *trampoline_base;
extern unsigned long init_rsp;
extern unsigned long initial_code;
extern unsigned long initial_page_table;
extern unsigned long initial_gs;
#define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE)
extern unsigned long setup_trampoline(void);
extern void __init setup_trampoline_page_table(void);
extern void __init reserve_trampoline_memory(void);
#else
static inline void setup_trampoline_page_table(void) {}
static inline void reserve_trampoline_memory(void) {}
#endif /* CONFIG_X86_TRAMPOLINE */

7
arch/x86/kernel/acpi/sleep.c
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@ -12,6 +12,11 @@
#include <asm/segment.h>
#include <asm/desc.h>
#ifdef CONFIG_X86_32
#include <asm/pgtable.h>
#include <asm/pgtable_32.h>
#endif
#include "realmode/wakeup.h"
#include "sleep.h"
@ -90,7 +95,7 @@ int acpi_save_state_mem(void)
#ifndef CONFIG_64BIT
header->pmode_entry = (u32)&wakeup_pmode_return;
header->pmode_cr3 = (u32)(swsusp_pg_dir - __PAGE_OFFSET);
header->pmode_cr3 = (u32)__pa(&initial_page_table);
saved_magic = 0x12345678;
#else /* CONFIG_64BIT */
header->trampoline_segment = setup_trampoline() >> 4;

1
arch/x86/kernel/head32.c
View File

@ -17,6 +17,7 @@
#include <asm/apic.h>
#include <asm/io_apic.h>
#include <asm/bios_ebda.h>
#include <asm/tlbflush.h>
static void __init i386_default_early_setup(void)
{

55
arch/x86/kernel/head_32.S
View File

@ -183,13 +183,12 @@ default_entry:
#ifdef CONFIG_X86_PAE
/*
* In PAE mode swapper_pg_dir is statically defined to contain enough
* entries to cover the VMSPLIT option (that is the top 1, 2 or 3
* entries). The identity mapping is handled by pointing two PGD
* entries to the first kernel PMD.
* In PAE mode initial_page_table is statically defined to contain
* enough entries to cover the VMSPLIT option (that is the top 1, 2 or 3
* entries). The identity mapping is handled by pointing two PGD entries
* to the first kernel PMD.
*
* Note the upper half of each PMD or PTE are always zero at
* this stage.
* Note the upper half of each PMD or PTE are always zero at this stage.
*/
#define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
@ -197,7 +196,7 @@ default_entry:
xorl %ebx,%ebx /* %ebx is kept at zero */
movl $pa(__brk_base), %edi
movl $pa(swapper_pg_pmd), %edx
movl $pa(initial_pg_pmd), %edx
movl $PTE_IDENT_ATTR, %eax
10:
leal PDE_IDENT_ATTR(%edi),%ecx /* Create PMD entry */
@ -226,14 +225,14 @@ default_entry:
movl %eax, pa(max_pfn_mapped)
/* Do early initialization of the fixmap area */
movl $pa(swapper_pg_fixmap)+PDE_IDENT_ATTR,%eax
movl %eax,pa(swapper_pg_pmd+0x1000*KPMDS-8)
movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
movl %eax,pa(initial_pg_pmd+0x1000*KPMDS-8)
#else /* Not PAE */
page_pde_offset = (__PAGE_OFFSET >> 20);
movl $pa(__brk_base), %edi
movl $pa(swapper_pg_dir), %edx
movl $pa(initial_page_table), %edx
movl $PTE_IDENT_ATTR, %eax
10:
leal PDE_IDENT_ATTR(%edi),%ecx /* Create PDE entry */
@ -257,8 +256,8 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
movl %eax, pa(max_pfn_mapped)
/* Do early initialization of the fixmap area */
movl $pa(swapper_pg_fixmap)+PDE_IDENT_ATTR,%eax
movl %eax,pa(swapper_pg_dir+0xffc)
movl $pa(initial_pg_fixmap)+PDE_IDENT_ATTR,%eax
movl %eax,pa(initial_page_table+0xffc)
#endif
jmp 3f
/*
@ -334,7 +333,7 @@ ENTRY(startup_32_smp)
/*
* Enable paging
*/
movl pa(initial_page_table), %eax
movl $pa(initial_page_table), %eax
movl %eax,%cr3 /* set the page table pointer.. */
movl %cr0,%eax
orl $X86_CR0_PG,%eax
@ -614,8 +613,6 @@ ignore_int:
.align 4
ENTRY(initial_code)
.long i386_start_kernel
ENTRY(initial_page_table)
.long pa(swapper_pg_dir)
/*
* BSS section
@ -623,20 +620,18 @@ ENTRY(initial_page_table)
__PAGE_ALIGNED_BSS
.align PAGE_SIZE_asm
#ifdef CONFIG_X86_PAE
swapper_pg_pmd:
initial_pg_pmd:
.fill 1024*KPMDS,4,0
#else
ENTRY(swapper_pg_dir)
ENTRY(initial_page_table)
.fill 1024,4,0
#endif
swapper_pg_fixmap:
initial_pg_fixmap:
.fill 1024,4,0
#ifdef CONFIG_X86_TRAMPOLINE
ENTRY(trampoline_pg_dir)
.fill 1024,4,0
#endif
ENTRY(empty_zero_page)
.fill 4096,1,0
ENTRY(swapper_pg_dir)
.fill 1024,4,0
/*
* This starts the data section.
@ -645,20 +640,20 @@ ENTRY(empty_zero_page)
__PAGE_ALIGNED_DATA
/* Page-aligned for the benefit of paravirt? */
.align PAGE_SIZE_asm
ENTRY(swapper_pg_dir)
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */
ENTRY(initial_page_table)
.long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */
# if KPMDS == 3
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x1000),0
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x2000),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x2000),0
# elif KPMDS == 2
.long 0,0
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x1000),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR+0x1000),0
# elif KPMDS == 1
.long 0,0
.long 0,0
.long pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
.long pa(initial_pg_pmd+PGD_IDENT_ATTR),0
# else
# error "Kernel PMDs should be 1, 2 or 3"
# endif

10
arch/x86/kernel/reboot.c
View File

@ -371,16 +371,10 @@ void machine_real_restart(const unsigned char *code, int length)
CMOS_WRITE(0x00, 0x8f);
spin_unlock(&rtc_lock);
/* Remap the kernel at virtual address zero, as well as offset zero
from the kernel segment. This assumes the kernel segment starts at
virtual address PAGE_OFFSET. */
memcpy(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
sizeof(swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
/*
* Use `swapper_pg_dir' as our page directory.
* Switch back to the initial page table.
*/
load_cr3(swapper_pg_dir);
load_cr3(initial_page_table);
/* Write 0x1234 to absolute memory location 0x472. The BIOS reads
this on booting to tell it to "Bypass memory test (also warm

18
arch/x86/kernel/setup.c
View File

@ -728,6 +728,17 @@ void __init setup_arch(char **cmdline_p)
#ifdef CONFIG_X86_32
memcpy(&boot_cpu_data, &new_cpu_data, sizeof(new_cpu_data));
visws_early_detect();
/*
* copy kernel address range established so far and switch
* to the proper swapper page table
*/
clone_pgd_range(swapper_pg_dir + KERNEL_PGD_BOUNDARY,
initial_page_table + KERNEL_PGD_BOUNDARY,
KERNEL_PGD_PTRS);
load_cr3(swapper_pg_dir);
__flush_tlb_all();
#else
printk(KERN_INFO "Command line: %s\n", boot_command_line);
#endif
@ -1009,7 +1020,12 @@ void __init setup_arch(char **cmdline_p)
paging_init();
x86_init.paging.pagetable_setup_done(swapper_pg_dir);
setup_trampoline_page_table();
#ifdef CONFIG_X86_32
/* sync back kernel address range */
clone_pgd_range(initial_page_table + KERNEL_PGD_BOUNDARY,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
KERNEL_PGD_PTRS);
#endif
tboot_probe();

20
arch/x86/kernel/smpboot.c
View File

@ -298,22 +298,16 @@ notrace static void __cpuinit start_secondary(void *unused)
* fragile that we want to limit the things done here to the
* most necessary things.
*/
#ifdef CONFIG_X86_32
/*
* Switch away from the trampoline page-table
*
* Do this before cpu_init() because it needs to access per-cpu
* data which may not be mapped in the trampoline page-table.
*/
load_cr3(swapper_pg_dir);
__flush_tlb_all();
#endif
cpu_init();
preempt_disable();
smp_callin();
#ifdef CONFIG_X86_32
/* switch away from the initial page table */
load_cr3(swapper_pg_dir);
__flush_tlb_all();
#endif
/* otherwise gcc will move up smp_processor_id before the cpu_init */
barrier();
/*
@ -772,7 +766,6 @@ do_rest:
#ifdef CONFIG_X86_32
/* Stack for startup_32 can be just as for start_secondary onwards */
irq_ctx_init(cpu);
initial_page_table = __pa(&trampoline_pg_dir);
#else
clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
initial_gs = per_cpu_offset(cpu);
@ -921,7 +914,6 @@ int __cpuinit native_cpu_up(unsigned int cpu)
per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
err = do_boot_cpu(apicid, cpu);
if (err) {
pr_debug("do_boot_cpu failed %d\n", err);
return -EIO;

16
arch/x86/kernel/trampoline.c
View File

@ -38,19 +38,3 @@ unsigned long __trampinit setup_trampoline(void)
memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
return virt_to_phys(trampoline_base);
}
void __init setup_trampoline_page_table(void)
{
#ifdef CONFIG_X86_32
/* Copy kernel address range */
clone_pgd_range(trampoline_pg_dir + KERNEL_PGD_BOUNDARY,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
KERNEL_PGD_PTRS);
/* Initialize low mappings */
clone_pgd_range(trampoline_pg_dir,
swapper_pg_dir + KERNEL_PGD_BOUNDARY,
min_t(unsigned long, KERNEL_PGD_PTRS,
KERNEL_PGD_BOUNDARY));
#endif
}

45
arch/x86/mm/init_32.c
View File

@ -548,48 +548,6 @@ static void __init pagetable_init(void)
permanent_kmaps_init(pgd_base);
}
#ifdef CONFIG_ACPI_SLEEP
/*
* ACPI suspend needs this for resume, because things like the intel-agp
* driver might have split up a kernel 4MB mapping.
*/
char swsusp_pg_dir[PAGE_SIZE]
__attribute__ ((aligned(PAGE_SIZE)));
static inline void save_pg_dir(void)
{
copy_page(swsusp_pg_dir, swapper_pg_dir);
}
#else /* !CONFIG_ACPI_SLEEP */
static inline void save_pg_dir(void)
{
}
#endif /* !CONFIG_ACPI_SLEEP */
void zap_low_mappings(bool early)
{
int i;
/*
* Zap initial low-memory mappings.
*
* Note that "pgd_clear()" doesn't do it for
* us, because pgd_clear() is a no-op on i386.
*/
for (i = 0; i < KERNEL_PGD_BOUNDARY; i++) {
#ifdef CONFIG_X86_PAE
set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
#else
set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
}
if (early)
__flush_tlb();
else
flush_tlb_all();
}
pteval_t __supported_pte_mask __read_mostly = ~(_PAGE_NX | _PAGE_GLOBAL | _PAGE_IOMAP);
EXPORT_SYMBOL_GPL(__supported_pte_mask);
@ -958,9 +916,6 @@ void __init mem_init(void)
if (boot_cpu_data.wp_works_ok < 0)
test_wp_bit();
save_pg_dir();
zap_low_mappings(true);
}
#ifdef CONFIG_MEMORY_HOTPLUG