diff options
Diffstat (limited to 'patches/linux-2.6.16.33/linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch')
| -rw-r--r-- | patches/linux-2.6.16.33/linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch | 161 |
1 files changed, 161 insertions, 0 deletions
diff --git a/patches/linux-2.6.16.33/linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch b/patches/linux-2.6.16.33/linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch new file mode 100644 index 0000000000..1cf613284f --- /dev/null +++ b/patches/linux-2.6.16.33/linux-2.6.19-rc1-kexec-move_segment_code-x86_64.patch @@ -0,0 +1,161 @@ +kexec: Move asm segment handling code to the assembly file (x86_64) + +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> +--- + + Applies to 2.6.19-rc1. + + machine_kexec.c | 58 ----------------------------------------------------- + relocate_kernel.S | 50 +++++++++++++++++++++++++++++++++++++++++---- + 2 files changed, 45 insertions(+), 63 deletions(-) + +--- 0002/arch/x86_64/kernel/machine_kexec.c ++++ work/arch/x86_64/kernel/machine_kexec.c 2006-10-05 16:15:49.000000000 +0900 +@@ -112,47 +112,6 @@ static int init_pgtable(struct kimage *i + return init_level4_page(image, level4p, 0, end_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; +@@ -209,23 +168,6 @@ NORET_TYPE void machine_kexec(struct kim + 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); + } +--- 0002/arch/x86_64/kernel/relocate_kernel.S ++++ work/arch/x86_64/kernel/relocate_kernel.S 2006-10-05 16:18:07.000000000 +0900 +@@ -159,13 +159,39 @@ 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 4096(%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 */ +@@ -272,5 +298,19 @@ 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 */ |