Messages in this thread Patch in this message | | | Date | Fri, 29 Jul 2005 21:04:16 -0700 | From | zach@vmware ... | Subject | [PATCH] 4/6 i386 better-descriptor-asm |
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GCC can generate better code around descriptor update and access functions when there is not an explicit "eax" register constraint.
Testing: You won't boot if this is messed up, since the TSS descriptor will be corrupted. Verified the assembler and booted.
Diffs-against: patch-2.6.13-rc4 + cpu-inline-cleanup + dt-inline-cleanup
Signed-off-by: Zachary Amsden <zach@vmware.com> Index: linux-2.6.13/include/asm-i386/desc.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/desc.h 2005-07-29 11:46:56.000000000 -0700 +++ linux-2.6.13/include/asm-i386/desc.h 2005-07-29 11:47:01.000000000 -0700 @@ -27,8 +27,8 @@ extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS]; -#define load_TR_desc() __asm__ __volatile__("ltr %%ax"::"a" (GDT_ENTRY_TSS*8)) -#define load_LDT_desc() __asm__ __volatile__("lldt %%ax"::"a" (GDT_ENTRY_LDT*8)) +#define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8)) +#define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8)) #define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr)) #define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr)) @@ -49,14 +49,14 @@ #define _set_tssldt_desc(n,addr,limit,type) \ __asm__ __volatile__ ("movw %w3,0(%2)\n\t" \ - "movw %%ax,2(%2)\n\t" \ - "rorl $16,%%eax\n\t" \ - "movb %%al,4(%2)\n\t" \ + "movw %w1,2(%2)\n\t" \ + "rorl $16,%1\n\t" \ + "movb %b1,4(%2)\n\t" \ "movb %4,5(%2)\n\t" \ "movb $0,6(%2)\n\t" \ - "movb %%ah,7(%2)\n\t" \ - "rorl $16,%%eax" \ - : "=m"(*(n)) : "a" (addr), "r"(n), "ir"(limit), "i"(type)) + "movb %h1,7(%2)\n\t" \ + "rorl $16,%1" \ + : "=m"(*(n)) : "q" (addr), "r"(n), "ir"(limit), "i"(type)) static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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