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| author | Vivek Goyal <vgoyal@in.ibm.com> | 2006-01-12 03:35:20 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-11 19:09:58 -0800 |
| commit | 983d5dbdb2b38d024935f560a91cddcf704875f3 (patch) | |
| tree | 834cda0f26f3902aea74d1cd81a9202f78cc5f14 | |
| parent | 0d9cb75f2f41788a59bcd3dac30b264a4bebaf2e (diff) | |
| download | op-kernel-dev-983d5dbdb2b38d024935f560a91cddcf704875f3.zip op-kernel-dev-983d5dbdb2b38d024935f560a91cddcf704875f3.tar.gz | |
[PATCH] x86_64: Fix SMP bootup with CONFIG_KDUMP enabled
o This fix was posted for i386 long back. Posting it for x86_64.
http://marc.theaimsgroup.com/?l=linux-kernel&m=110380103229830&w=2
o This patch fixes the problem of secondary cpus boot up. This situation
is faced when kernel is built for default locations like 16MB and
onwards. In this configuration, only primary cpu (BP) comes and
secondary cpus don't boot.
o Problem occurs because in trampoline code, lgdt is not able to load the
GDT as it happens to be situated beyond 16MB. This is due to the fact
that cpu is still in real mode and default operand size is 16bit.
o This patch uses lgdtl instead of lgdt to force operand size to 32
instead of 16.
Signed-off-by: Vivek Goyal <vgoyal@in.ibm.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | arch/x86_64/kernel/trampoline.S | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/trampoline.S b/arch/x86_64/kernel/trampoline.S index 6d9c9a8..23a03eb9 100644 --- a/arch/x86_64/kernel/trampoline.S +++ b/arch/x86_64/kernel/trampoline.S @@ -42,8 +42,15 @@ r_base = . movl $0xA5A5A5A5, trampoline_data - r_base # write marker for master knows we're running - lidt idt_48 - r_base # load idt with 0, 0 - lgdt gdt_48 - r_base # load gdt with whatever is appropriate + /* + * GDT tables in non default location kernel can be beyond 16MB and + * lgdt will not be able to load the address as in real mode default + * operand size is 16bit. Use lgdtl instead to force operand size + * to 32 bit. + */ + + lidtl idt_48 - r_base # load idt with 0, 0 + lgdtl gdt_48 - r_base # load gdt with whatever is appropriate xor %ax, %ax inc %ax # protected mode (PE) bit |
