From 893f38d144a4d96d2483cd7c3801d26e1b2c23e9 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Thu, 10 Dec 2009 13:07:22 -0800 Subject: 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 b24c2a9 ("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: Jens Axboe Signed-off-by: Yinghai Lu Tested-by: Jens Axboe Cc: Randy Dunlap LKML-Reference: <4B21630A.6000308@kernel.org> Signed-off-by: Ingo Molnar --- arch/x86/kernel/trampoline.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'arch/x86/kernel/trampoline.c') diff --git a/arch/x86/kernel/trampoline.c b/arch/x86/kernel/trampoline.c index cd022121cab6..c652ef62742d 100644 --- a/arch/x86/kernel/trampoline.c +++ b/arch/x86/kernel/trampoline.c @@ -12,21 +12,19 @@ #endif /* ready for x86_64 and x86 */ -unsigned char *__trampinitdata trampoline_base = __va(TRAMPOLINE_BASE); +unsigned char *__trampinitdata 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 + unsigned long mem; + /* Has to be in very low memory so we can execute real-mode AP code. */ - reserve_early(TRAMPOLINE_BASE, TRAMPOLINE_BASE + TRAMPOLINE_SIZE, - "TRAMPOLINE"); + mem = find_e820_area(0, 1<<20, TRAMPOLINE_SIZE, PAGE_SIZE); + if (mem == -1L) + panic("Cannot allocate trampoline\n"); + + trampoline_base = __va(mem); + reserve_early(mem, mem + TRAMPOLINE_SIZE, "TRAMPOLINE"); } /* -- cgit v1.2.1