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x86: change static allocation of trampoline area

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Impact: fix trampoline sizing bug, save space

While debugging a suspend-to-RAM related issue it occured to me that
if the trampoline code had grown past 4 KB, we would have been
allocating too little memory for it, since the 4 KB size of the
trampoline is hardcoded into arch/x86/kernel/e820.c .  Change that
by making the kernel compute the trampoline size and allocate as much
memory as necessary.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Rafael J. Wysocki 2008-12-08 00:50:22 +01:00 committed by Ingo Molnar
parent 218d11a8b0
commit 3e1e9002aa
5 changed files with 30 additions and 18 deletions
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7
arch/x86/include/asm/trampoline.h
View file

@ -3,6 +3,7 @@
#ifndef __ASSEMBLY__
#ifdef CONFIG_X86_TRAMPOLINE
/*
* Trampoline 80x86 program as an array.
*/
@ -13,8 +14,14 @@ extern unsigned char *trampoline_base;
extern unsigned long init_rsp;
extern unsigned long initial_code;
#define TRAMPOLINE_SIZE roundup(trampoline_end - trampoline_data, PAGE_SIZE)
#define TRAMPOLINE_BASE 0x6000
extern unsigned long setup_trampoline(void);
extern void __init reserve_trampoline_memory(void);
#else
static inline void reserve_trampoline_memory(void) {};
#endif /* CONFIG_X86_TRAMPOLINE */
#endif /* __ASSEMBLY__ */

16
arch/x86/kernel/e820.c
View file

@ -677,22 +677,6 @@ struct early_res {
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
{ 0, PAGE_SIZE, "BIOS data page" }, /* BIOS data page */
#if defined(CONFIG_X86_64) && defined(CONFIG_X86_TRAMPOLINE)
{ TRAMPOLINE_BASE, TRAMPOLINE_BASE + 2 * PAGE_SIZE, "TRAMPOLINE" },
#endif
#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
/*
* But first pinch a few for the stack/trampoline stuff
* FIXME: Don't need the extra page at 4K, but need to fix
* trampoline before removing it. (see the GDT stuff)
*/
{ PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE" },
/*
* Has to be in very low memory so we can execute
* real-mode AP code.
*/
{ TRAMPOLINE_BASE, TRAMPOLINE_BASE + PAGE_SIZE, "TRAMPOLINE" },
#endif
{}
};

3
arch/x86/kernel/head32.c
View file

@ -12,9 +12,12 @@
#include <asm/sections.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
#include <asm/trampoline.h>
void __init i386_start_kernel(void)
{
reserve_trampoline_memory();
reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
#ifdef CONFIG_BLK_DEV_INITRD

3
arch/x86/kernel/head64.c
View file

@ -24,6 +24,7 @@
#include <asm/kdebug.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>
#include <asm/trampoline.h>
/* boot cpu pda */
static struct x8664_pda _boot_cpu_pda __read_mostly;
@ -120,6 +121,8 @@ void __init x86_64_start_reservations(char *real_mode_data)
{
copy_bootdata(__va(real_mode_data));
reserve_trampoline_memory();
reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
#ifdef CONFIG_BLK_DEV_INITRD

19
arch/x86/kernel/trampoline.c
View file

@ -1,10 +1,26 @@
#include <linux/io.h>
#include <asm/trampoline.h>
#include <asm/e820.h>
/* ready for x86_64 and x86 */
unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
void __init reserve_trampoline_memory(void)
{
#ifdef CONFIG_X86_32
/*
* But first pinch a few for the stack/trampoline stuff
* FIXME: Don't need the extra page at 4K, but need to fix
* trampoline before removing it. (see the GDT stuff)
*/
reserve_early(PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE");
#endif
/* Has to be in very low memory so we can execute real-mode AP code. */
reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE,
"TRAMPOLINE");
}
/*
* Currently trivial. Write the real->protected mode
* bootstrap into the page concerned. The caller
@ -12,7 +28,6 @@ unsigned char *trampoline_base = __va(TRAMPOLINE_BASE);
*/
unsigned long setup_trampoline(void)
{
memcpy(trampoline_base, trampoline_data,
trampoline_end - trampoline_data);
memcpy(trampoline_base, trampoline_data, TRAMPOLINE_SIZE);
return virt_to_phys(trampoline_base);
}