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Commit 3e1e9002 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki Committed by Ingo Molnar
Browse files

x86: change static allocation of trampoline area 



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: default avatarRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 218d11a8

arch/x86/include/asm/trampoline.h

+7 −0
Original line number Diff line number Diff line
@@ -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__ */

arch/x86/kernel/e820.c

+0 −16
Original line number Diff line number Diff line
@@ -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

	{}

};

arch/x86/kernel/head32.c

+3 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/head64.c

+3 −0
Original line number Diff line number Diff line
@@ -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

arch/x86/kernel/trampoline.c

+17 −2
Original line number Diff line number Diff line 
#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);

}