[PATCH] i386: inline assembler: cleanup and encapsulate descriptor and task register management
i386 inline assembler cleanup.
This change encapsulates descriptor and task register management. Also,
it is possible to improve assembler generation in two cases; savesegment
may store the value in a register instead of a memory location, which
allows GCC to optimize stack variables into registers, and MOV MEM, SEG
is always a 16-bit write to memory, making the casting in math-emu
unnecessary.
Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 361f2e7..46ce9b2 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -613,8 +613,8 @@
memcpy(thread->tls_array, &per_cpu(cpu_gdt_table, cpu),
GDT_ENTRY_TLS_ENTRIES * 8);
- __asm__ __volatile__("lgdt %0" : : "m" (cpu_gdt_descr[cpu]));
- __asm__ __volatile__("lidt %0" : : "m" (idt_descr));
+ load_gdt(&cpu_gdt_descr[cpu]);
+ load_idt(&idt_descr);
/*
* Delete NT
diff --git a/arch/i386/kernel/doublefault.c b/arch/i386/kernel/doublefault.c
index 789af3e..5edb1d3 100644
--- a/arch/i386/kernel/doublefault.c
+++ b/arch/i386/kernel/doublefault.c
@@ -20,7 +20,7 @@
struct Xgt_desc_struct gdt_desc = {0, 0};
unsigned long gdt, tss;
- __asm__ __volatile__("sgdt %0": "=m" (gdt_desc): :"memory");
+ store_gdt(&gdt_desc);
gdt = gdt_desc.address;
printk("double fault, gdt at %08lx [%d bytes]\n", gdt, gdt_desc.size);
diff --git a/arch/i386/kernel/efi.c b/arch/i386/kernel/efi.c
index 921fdb1..ecad519 100644
--- a/arch/i386/kernel/efi.c
+++ b/arch/i386/kernel/efi.c
@@ -104,8 +104,7 @@
local_flush_tlb();
cpu_gdt_descr[0].address = __pa(cpu_gdt_descr[0].address);
- __asm__ __volatile__("lgdt %0":"=m"
- (*(struct Xgt_desc_struct *) __pa(&cpu_gdt_descr[0])));
+ load_gdt((struct Xgt_desc_struct *) __pa(&cpu_gdt_descr[0]));
}
static void efi_call_phys_epilog(void)
@@ -114,7 +113,7 @@
cpu_gdt_descr[0].address =
(unsigned long) __va(cpu_gdt_descr[0].address);
- __asm__ __volatile__("lgdt %0":"=m"(cpu_gdt_descr));
+ load_gdt(&cpu_gdt_descr[0]);
cr4 = read_cr4();
if (cr4 & X86_CR4_PSE) {
diff --git a/arch/i386/kernel/reboot.c b/arch/i386/kernel/reboot.c
index c71fef3..1cbb9c0 100644
--- a/arch/i386/kernel/reboot.c
+++ b/arch/i386/kernel/reboot.c
@@ -13,6 +13,7 @@
#include <linux/dmi.h>
#include <asm/uaccess.h>
#include <asm/apic.h>
+#include <asm/desc.h>
#include "mach_reboot.h"
#include <linux/reboot_fixups.h>
@@ -242,13 +243,13 @@
/* Set up the IDT for real mode. */
- __asm__ __volatile__ ("lidt %0" : : "m" (real_mode_idt));
+ load_idt(&real_mode_idt);
/* Set up a GDT from which we can load segment descriptors for real
mode. The GDT is not used in real mode; it is just needed here to
prepare the descriptors. */
- __asm__ __volatile__ ("lgdt %0" : : "m" (real_mode_gdt));
+ load_gdt(&real_mode_gdt);
/* Load the data segment registers, and thus the descriptors ready for
real mode. The base address of each segment is 0x100, 16 times the
@@ -316,7 +317,7 @@
if (!reboot_thru_bios) {
if (efi_enabled) {
efi.reset_system(EFI_RESET_COLD, EFI_SUCCESS, 0, NULL);
- __asm__ __volatile__("lidt %0": :"m" (no_idt));
+ load_idt(&no_idt);
__asm__ __volatile__("int3");
}
/* rebooting needs to touch the page at absolute addr 0 */
@@ -325,7 +326,7 @@
mach_reboot_fixups(); /* for board specific fixups */
mach_reboot();
/* That didn't work - force a triple fault.. */
- __asm__ __volatile__("lidt %0": :"m" (no_idt));
+ load_idt(&no_idt);
__asm__ __volatile__("int3");
}
}
diff --git a/arch/i386/kernel/signal.c b/arch/i386/kernel/signal.c
index 140e340..7bcda6d 100644
--- a/arch/i386/kernel/signal.c
+++ b/arch/i386/kernel/signal.c
@@ -278,9 +278,9 @@
int tmp, err = 0;
tmp = 0;
- __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp));
+ savesegment(gs, tmp);
err |= __put_user(tmp, (unsigned int __user *)&sc->gs);
- __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp));
+ savesegment(fs, tmp);
err |= __put_user(tmp, (unsigned int __user *)&sc->fs);
err |= __put_user(regs->xes, (unsigned int __user *)&sc->es);
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index cd2d5d5..1144df0 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -1008,7 +1008,7 @@
* it uses the read-only mapped virtual address.
*/
idt_descr.address = fix_to_virt(FIX_F00F_IDT);
- __asm__ __volatile__("lidt %0" : : "m" (idt_descr));
+ load_idt(&idt_descr);
}
#endif
diff --git a/arch/i386/kernel/vm86.c b/arch/i386/kernel/vm86.c
index 2daa06f..16b4850 100644
--- a/arch/i386/kernel/vm86.c
+++ b/arch/i386/kernel/vm86.c
@@ -294,8 +294,8 @@
*/
info->regs32->eax = 0;
tsk->thread.saved_esp0 = tsk->thread.esp0;
- asm volatile("mov %%fs,%0":"=m" (tsk->thread.saved_fs));
- asm volatile("mov %%gs,%0":"=m" (tsk->thread.saved_gs));
+ savesegment(fs, tsk->thread.saved_fs);
+ savesegment(gs, tsk->thread.saved_gs);
tss = &per_cpu(init_tss, get_cpu());
tsk->thread.esp0 = (unsigned long) &info->VM86_TSS_ESP0;
diff --git a/arch/i386/math-emu/get_address.c b/arch/i386/math-emu/get_address.c
index 9117573..9819b70 100644
--- a/arch/i386/math-emu/get_address.c
+++ b/arch/i386/math-emu/get_address.c
@@ -155,7 +155,6 @@
{
struct desc_struct descriptor;
unsigned long base_address, limit, address, seg_top;
- unsigned short selector;
segment--;
@@ -173,17 +172,11 @@
/* fs and gs aren't used by the kernel, so they still have their
user-space values. */
case PREFIX_FS_-1:
- /* The cast is needed here to get gcc 2.8.0 to use a 16 bit register
- in the assembler statement. */
-
- __asm__("mov %%fs,%0":"=r" (selector));
- addr->selector = selector;
+ /* N.B. - movl %seg, mem is a 2 byte write regardless of prefix */
+ savesegment(fs, addr->selector);
break;
case PREFIX_GS_-1:
- /* The cast is needed here to get gcc 2.8.0 to use a 16 bit register
- in the assembler statement. */
- __asm__("mov %%gs,%0":"=r" (selector));
- addr->selector = selector;
+ savesegment(gs, addr->selector);
break;
default:
addr->selector = PM_REG_(segment);
diff --git a/arch/i386/power/cpu.c b/arch/i386/power/cpu.c
index 4e19c43..c7a6436 100644
--- a/arch/i386/power/cpu.c
+++ b/arch/i386/power/cpu.c
@@ -42,17 +42,17 @@
/*
* descriptor tables
*/
- asm volatile ("sgdt %0" : "=m" (ctxt->gdt_limit));
- asm volatile ("sidt %0" : "=m" (ctxt->idt_limit));
- asm volatile ("str %0" : "=m" (ctxt->tr));
+ store_gdt(&ctxt->gdt_limit);
+ store_idt(&ctxt->idt_limit);
+ store_tr(ctxt->tr);
/*
* segment registers
*/
- asm volatile ("movw %%es, %0" : "=m" (ctxt->es));
- asm volatile ("movw %%fs, %0" : "=m" (ctxt->fs));
- asm volatile ("movw %%gs, %0" : "=m" (ctxt->gs));
- asm volatile ("movw %%ss, %0" : "=m" (ctxt->ss));
+ savesegment(es, ctxt->es);
+ savesegment(fs, ctxt->fs);
+ savesegment(gs, ctxt->gs);
+ savesegment(ss, ctxt->ss);
/*
* control registers
@@ -118,16 +118,16 @@
* now restore the descriptor tables to their proper values
* ltr is done i fix_processor_context().
*/
- asm volatile ("lgdt %0" :: "m" (ctxt->gdt_limit));
- asm volatile ("lidt %0" :: "m" (ctxt->idt_limit));
+ load_gdt(&ctxt->gdt_limit);
+ load_idt(&ctxt->idt_limit);
/*
* segment registers
*/
- asm volatile ("movw %0, %%es" :: "r" (ctxt->es));
- asm volatile ("movw %0, %%fs" :: "r" (ctxt->fs));
- asm volatile ("movw %0, %%gs" :: "r" (ctxt->gs));
- asm volatile ("movw %0, %%ss" :: "r" (ctxt->ss));
+ loadsegment(es, ctxt->es);
+ loadsegment(fs, ctxt->fs);
+ loadsegment(gs, ctxt->gs);
+ loadsegment(ss, ctxt->ss);
/*
* sysenter MSRs