From 36c4fd23cc06f81d68ee968c4c1bf1cebb3dcea5 Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Fri, 29 Jul 2005 13:02:09 -0600 Subject: [PATCH] [PATCH] x86_64 machine_kexec: Cleanup inline assembly. In an uncensored copy of code from i386 to x86_64 I wound up with inline assembly with the wrong constraints. Use input constraints instead of output constraints. So I know the assembler will do the right thing specify the size of the operand lidtq and lgdtq instead of just lidt and lgdt. Make load_segments use an input constraint, and delete the macro fun. Without having to reload %cs like I do on i386 this code is noticeably simpler. Signed-off-by: Eric W. Biederman Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/machine_kexec.c | 34 ++++++++++++++---------------- 1 file changed, 16 insertions(+), 18 deletions(-) diff --git a/arch/x86_64/kernel/machine_kexec.c b/arch/x86_64/kernel/machine_kexec.c index 60d1eff415..717f7db4b5 100644 --- a/arch/x86_64/kernel/machine_kexec.c +++ b/arch/x86_64/kernel/machine_kexec.c @@ -122,45 +122,43 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable) static void set_idt(void *newidt, u16 limit) { - unsigned char curidt[10]; + struct desc_ptr curidt; /* x86-64 supports unaliged loads & stores */ - (*(u16 *)(curidt)) = limit; - (*(u64 *)(curidt +2)) = (unsigned long)(newidt); + curidt.size = limit; + curidt.address = (unsigned long)newidt; __asm__ __volatile__ ( - "lidt %0\n" - : "=m" (curidt) + "lidtq %0\n" + : : "m" (curidt) ); }; static void set_gdt(void *newgdt, u16 limit) { - unsigned char curgdt[10]; + struct desc_ptr curgdt; /* x86-64 supports unaligned loads & stores */ - (*(u16 *)(curgdt)) = limit; - (*(u64 *)(curgdt +2)) = (unsigned long)(newgdt); + curgdt.size = limit; + curgdt.address = (unsigned long)newgdt; __asm__ __volatile__ ( - "lgdt %0\n" - : "=m" (curgdt) + "lgdtq %0\n" + : : "m" (curgdt) ); }; static void load_segments(void) { __asm__ __volatile__ ( - "\tmovl $"STR(__KERNEL_DS)",%eax\n" - "\tmovl %eax,%ds\n" - "\tmovl %eax,%es\n" - "\tmovl %eax,%ss\n" - "\tmovl %eax,%fs\n" - "\tmovl %eax,%gs\n" + "\tmovl %0,%%ds\n" + "\tmovl %0,%%es\n" + "\tmovl %0,%%ss\n" + "\tmovl %0,%%fs\n" + "\tmovl %0,%%gs\n" + : : "a" (__KERNEL_DS) ); -#undef STR -#undef __STR } typedef NORET_TYPE void (*relocate_new_kernel_t)(unsigned long indirection_page, -- 2.39.5