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Commit 893f38d1 authored by Yinghai Lu's avatar Yinghai Lu Committed by Ingo Molnar
Browse files

x86: Use find_e820() instead of hard coded trampoline address 



Jens found the following crash/regression:

[    0.000000] found SMP MP-table at [ffff8800000fdd80] fdd80
[    0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 0-fff BIOS data page

and

[    0.000000] Kernel panic - not syncing: Overlapping early reservations 12-f011 MP-table mpc to 6000-7fff TRAMPOLINE

and bisected it to b24c2a92 ("x86: Move find_smp_config()
earlier and avoid bootmem usage").

It turns out the BIOS is using the first 64k for mptable,
without reserving it.

So try to find good range for the real-mode trampoline instead of
hard coding it, in case some bios tries to use that range for sth.

Reported-by: default avatarJens Axboe <jens.axboe@oracle.com>
Signed-off-by: default avatarYinghai Lu <yinghai@kernel.org>
Tested-by: default avatarJens Axboe <jens.axboe@oracle.com>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
LKML-Reference: <4B21630A.6000308@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent ebb682f5

arch/x86/include/asm/trampoline.h

+0 −1
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ extern unsigned long initial_code; 
extern unsigned long initial_gs;



#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);

arch/x86/kernel/e820.c

+10 −1
Original line number Diff line number Diff line
@@ -732,7 +732,16 @@ struct early_res { 
	char overlap_ok;

};

static struct early_res early_res[MAX_EARLY_RES] __initdata = {

	{ 0, PAGE_SIZE, "BIOS data page" },	/* BIOS data page */

	{ 0, PAGE_SIZE, "BIOS data page", 1 },	/* BIOS data page */

#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)

	 */

	{ PAGE_SIZE, PAGE_SIZE, "EX TRAMPOLINE", 1 },

#endif



	{}

};

arch/x86/kernel/head32.c

+0 −2
Original line number Diff line number Diff line
@@ -29,8 +29,6 @@ static void __init i386_default_early_setup(void) 


void __init i386_start_kernel(void)

{

	reserve_trampoline_memory();



	reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");



#ifdef CONFIG_BLK_DEV_INITRD

arch/x86/kernel/head64.c

+0 −2
Original line number Diff line number Diff line
@@ -98,8 +98,6 @@ 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(&__bss_stop), "TEXT DATA BSS");



#ifdef CONFIG_BLK_DEV_INITRD

arch/x86/kernel/mpparse.c

+0 −3
Original line number Diff line number Diff line
@@ -945,9 +945,6 @@ void __init early_reserve_e820_mpc_new(void) 
{

	if (enable_update_mptable && alloc_mptable) {

		u64 startt = 0;

#ifdef CONFIG_X86_TRAMPOLINE

		startt = TRAMPOLINE_BASE;

#endif

		mpc_new_phys = early_reserve_e820(startt, mpc_new_length, 4);

	}

}