+++ /dev/null
-Subject: kexec: Move asm segment handling code to the assembly file (x86_64)
-From: http://xenbits.xensource.com/xen-unstable.hg (tip 13816)
-Patch-mainline: obsolete
-
-This patch moves the idt, gdt, and segment handling code from machine_kexec.c
-to relocate_kernel.S. The main reason behind this move is to avoid code
-duplication in the Xen hypervisor. With this patch all code required to kexec
-is put on the control page.
-
-On top of that this patch also counts as a cleanup - I think it is much
-nicer to write assembly directly in assembly files than wrap inline assembly
-in C functions for no apparent reason.
-
-Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
-Acked-by: jbeulich@novell.com
----
-
- Applies to 2.6.19-rc1.
-
- machine_kexec.c | 58 -----------------------------------------------------
- relocate_kernel.S | 50 +++++++++++++++++++++++++++++++++++++++++----
- 2 files changed, 45 insertions(+), 63 deletions(-)
-
-Index: head-2008-08-18/arch/x86/kernel/machine_kexec_64.c
-===================================================================
---- head-2008-08-18.orig/arch/x86/kernel/machine_kexec_64.c 2008-08-18 09:05:04.000000000 +0200
-+++ head-2008-08-18/arch/x86/kernel/machine_kexec_64.c 2008-08-18 10:13:08.000000000 +0200
-@@ -115,47 +115,6 @@ static int init_pgtable(struct kimage *i
- return init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
- }
-
--static void set_idt(void *newidt, u16 limit)
--{
-- struct desc_ptr curidt;
--
-- /* x86-64 supports unaliged loads & stores */
-- curidt.size = limit;
-- curidt.address = (unsigned long)newidt;
--
-- __asm__ __volatile__ (
-- "lidtq %0\n"
-- : : "m" (curidt)
-- );
--};
--
--
--static void set_gdt(void *newgdt, u16 limit)
--{
-- struct desc_ptr curgdt;
--
-- /* x86-64 supports unaligned loads & stores */
-- curgdt.size = limit;
-- curgdt.address = (unsigned long)newgdt;
--
-- __asm__ __volatile__ (
-- "lgdtq %0\n"
-- : : "m" (curgdt)
-- );
--};
--
--static void load_segments(void)
--{
-- __asm__ __volatile__ (
-- "\tmovl %0,%%ds\n"
-- "\tmovl %0,%%es\n"
-- "\tmovl %0,%%ss\n"
-- "\tmovl %0,%%fs\n"
-- "\tmovl %0,%%gs\n"
-- : : "a" (__KERNEL_DS) : "memory"
-- );
--}
--
- int machine_kexec_prepare(struct kimage *image)
- {
- unsigned long start_pgtable;
-@@ -214,23 +173,6 @@ void machine_kexec(struct kimage *image)
- page_list[PA_TABLE_PAGE] =
- (unsigned long)__pa(page_address(image->control_code_page));
-
-- /* The segment registers are funny things, they have both a
-- * visible and an invisible part. Whenever the visible part is
-- * set to a specific selector, the invisible part is loaded
-- * with from a table in memory. At no other time is the
-- * descriptor table in memory accessed.
-- *
-- * I take advantage of this here by force loading the
-- * segments, before I zap the gdt with an invalid value.
-- */
-- load_segments();
-- /* The gdt & idt are now invalid.
-- * If you want to load them you must set up your own idt & gdt.
-- */
-- set_gdt(phys_to_virt(0),0);
-- set_idt(phys_to_virt(0),0);
--
-- /* now call it */
- relocate_kernel((unsigned long)image->head, (unsigned long)page_list,
- image->start);
- }
-Index: head-2008-08-18/arch/x86/kernel/relocate_kernel_64.S
-===================================================================
---- head-2008-08-18.orig/arch/x86/kernel/relocate_kernel_64.S 2008-07-13 23:51:29.000000000 +0200
-+++ head-2008-08-18/arch/x86/kernel/relocate_kernel_64.S 2008-08-18 10:13:08.000000000 +0200
-@@ -160,13 +160,39 @@ relocate_new_kernel:
- movq PTR(PA_PGD)(%rsi), %r9
- movq %r9, %cr3
-
-+ /* setup idt */
-+ movq %r8, %rax
-+ addq $(idt_80 - relocate_kernel), %rax
-+ lidtq (%rax)
-+
-+ /* setup gdt */
-+ movq %r8, %rax
-+ addq $(gdt - relocate_kernel), %rax
-+ movq %r8, %r9
-+ addq $((gdt_80 - relocate_kernel) + 2), %r9
-+ movq %rax, (%r9)
-+
-+ movq %r8, %rax
-+ addq $(gdt_80 - relocate_kernel), %rax
-+ lgdtq (%rax)
-+
-+ /* setup data segment registers */
-+ xorl %eax, %eax
-+ movl %eax, %ds
-+ movl %eax, %es
-+ movl %eax, %fs
-+ movl %eax, %gs
-+ movl %eax, %ss
-+
- /* setup a new stack at the end of the physical control page */
- lea PAGE_SIZE(%r8), %rsp
-
-- /* jump to identity mapped page */
-- addq $(identity_mapped - relocate_kernel), %r8
-- pushq %r8
-- ret
-+ /* load new code segment and jump to identity mapped page */
-+ movq %r8, %rax
-+ addq $(identity_mapped - relocate_kernel), %rax
-+ pushq $(gdt_cs - gdt)
-+ pushq %rax
-+ lretq
-
- identity_mapped:
- /* store the start address on the stack */
-@@ -262,5 +288,19 @@ identity_mapped:
- xorq %r13, %r13
- xorq %r14, %r14
- xorq %r15, %r15
--
- ret
-+
-+ .align 16
-+gdt:
-+ .quad 0x0000000000000000 /* NULL descriptor */
-+gdt_cs:
-+ .quad 0x00af9a000000ffff
-+gdt_end:
-+
-+gdt_80:
-+ .word gdt_end - gdt - 1 /* limit */
-+ .quad 0 /* base - filled in by code above */
-+
-+idt_80:
-+ .word 0 /* limit */
-+ .quad 0 /* base */
projects / people / pmueller / ipfire-2.x.git / blobdiff