[PATCH] i386: inline asm cleanup

i386 Inline asm cleanup.  Use cr/dr accessor functions.

Also, a potential bugfix.  Also, some CR accessors really should be volatile.
Reads from CR0 (numeric state may change in an exception handler), writes to
CR4 (flipping CR4.TSD) and reads from CR2 (page fault) prevent instruction
re-ordering.  I did not add memory clobber to CR3 / CR4 / CR0 updates, as it
was not there to begin with, and in no case should kernel memory be clobbered,
except when doing a TLB flush, which already has memory clobber.

I noticed that page invalidation does not have a memory clobber.  I can't find
a bug as a result, but there is definitely a potential for a bug here:

#define __flush_tlb_single(addr) \
	__asm__ __volatile__("invlpg %0": :"m" (*(char *) addr))

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

7 files changed, 20 insertions, 40 deletions

diff --git a/arch/i386/kernel/cpu/common.c b/arch/i386/kernel/cpu/common.c
index 4553ffd94b1f..361f2e7ccb12 100644
--- a/arch/i386/kernel/cpu/common.c
+++ b/arch/i386/kernel/cpu/common.c
@@ -642,12 +642,12 @@ void __devinit cpu_init(void)
         asm volatile ("xorl %eax, %eax; movl %eax, %fs; movl %eax, %gs");
 
         /* Clear all 6 debug registers: */
-
-#define CD(register) set_debugreg(0, register)
-
-        CD(0); CD(1); CD(2); CD(3); /* no db4 and db5 */; CD(6); CD(7);
-
-#undef CD
+        set_debugreg(0, 0);
+        set_debugreg(0, 1);
+        set_debugreg(0, 2);
+        set_debugreg(0, 3);
+        set_debugreg(0, 6);
+        set_debugreg(0, 7);
 
         /*
          * Force FPU initialization:
diff --git a/arch/i386/kernel/cpu/cpufreq/longhaul.c b/arch/i386/kernel/cpu/cpufreq/longhaul.c
index 04e3563da4fe..bf02b5026e62 100644
--- a/arch/i386/kernel/cpu/cpufreq/longhaul.c
+++ b/arch/i386/kernel/cpu/cpufreq/longhaul.c
@@ -64,8 +64,6 @@ static int dont_scale_voltage;
 #define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "longhaul", msg)
 
 
-#define __hlt()     __asm__ __volatile__("hlt": : :"memory")
-
 /* Clock ratios multiplied by 10 */
 static int clock_ratio[32];
 static int eblcr_table[32];
@@ -168,11 +166,9 @@ static void do_powersaver(union msr_longhaul *longhaul,
         outb(0xFE,0x21);        /* TMR0 only */
         outb(0xFF,0x80);        /* delay */
 
-        local_irq_enable();
-
-        __hlt();
+        safe_halt();
         wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
-        __hlt();
+        halt();
 
         local_irq_disable();
 
@@ -251,9 +247,7 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
                 bcr2.bits.CLOCKMUL = clock_ratio_index;
                 local_irq_disable();
                 wrmsrl (MSR_VIA_BCR2, bcr2.val);
-                local_irq_enable();
-
-                __hlt();
+                safe_halt();
 
                 /* Disable software clock multiplier */
                 rdmsrl (MSR_VIA_BCR2, bcr2.val);
diff --git a/arch/i386/kernel/cpu/cyrix.c b/arch/i386/kernel/cpu/cyrix.c
index ba4b01138c8f..ff87cc22b323 100644
--- a/arch/i386/kernel/cpu/cyrix.c
+++ b/arch/i386/kernel/cpu/cyrix.c
@@ -132,11 +132,7 @@ static void __init set_cx86_memwb(void)
         setCx86(CX86_CCR2, getCx86(CX86_CCR2) & ~0x04);
         /* set 'Not Write-through' */
         cr0 = 0x20000000;
-        __asm__("movl %%cr0,%%eax\n\t"
-                "orl %0,%%eax\n\t"
-                "movl %%eax,%%cr0\n"
-                : : "r" (cr0)
-                :"ax");
+        write_cr0(read_cr0() | cr0);
         /* CCR2 bit 2: lock NW bit and set WT1 */
         setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x14 );
 }
diff --git a/arch/i386/kernel/efi.c b/arch/i386/kernel/efi.c
index 850648ae8305..921fdb15fc9b 100644
--- a/arch/i386/kernel/efi.c
+++ b/arch/i386/kernel/efi.c
@@ -79,7 +79,7 @@ static void efi_call_phys_prelog(void)
          * directory. If I have PSE, I just need to duplicate one entry in
          * page directory.
          */
-        __asm__ __volatile__("movl %%cr4, %0":"=r"(cr4));
+        cr4 = read_cr4();
 
         if (cr4 & X86_CR4_PSE) {
                 efi_bak_pg_dir_pointer[0].pgd =
@@ -115,7 +115,7 @@ static void efi_call_phys_epilog(void)
         cpu_gdt_descr[0].address =
                 (unsigned long) __va(cpu_gdt_descr[0].address);
         __asm__ __volatile__("lgdt %0":"=m"(cpu_gdt_descr));
-        __asm__ __volatile__("movl %%cr4, %0":"=r"(cr4));
+        cr4 = read_cr4();
 
         if (cr4 & X86_CR4_PSE) {
                 swapper_pg_dir[pgd_index(0)].pgd =
diff --git a/arch/i386/kernel/machine_kexec.c b/arch/i386/kernel/machine_kexec.c
index cb699a2aa1f8..f19f6d34bcbf 100644
--- a/arch/i386/kernel/machine_kexec.c
+++ b/arch/i386/kernel/machine_kexec.c
@@ -17,13 +17,7 @@
 #include <asm/apic.h>
 #include <asm/cpufeature.h>
 #include <asm/desc.h>
-
-static inline unsigned long read_cr3(void)
-{
-        unsigned long cr3;
-        asm volatile("movl %%cr3,%0": "=r"(cr3));
-        return cr3;
-}
+#include <asm/system.h>
 
 #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
 
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index e3f362e8af5b..761d4ed47ef3 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -313,16 +313,12 @@ void show_regs(struct pt_regs * regs)
         printk(" DS: %04x ES: %04x\n",
                 0xffff & regs->xds,0xffff & regs->xes);
 
-        __asm__("movl %%cr0, %0": "=r" (cr0));
-        __asm__("movl %%cr2, %0": "=r" (cr2));
-        __asm__("movl %%cr3, %0": "=r" (cr3));
-        /* This could fault if %cr4 does not exist */
-        __asm__("1: movl %%cr4, %0              \n"
-                "2:                             \n"
-                ".section __ex_table,\"a\"      \n"
-                ".long 1b,2b                    \n"
-                ".previous                      \n"
-                : "=r" (cr4): "0" (0));
+        cr0 = read_cr0();
+        cr2 = read_cr2();
+        cr3 = read_cr3();
+        if (current_cpu_data.x86 > 4) {
+                cr4 = read_cr4();
+        }
         printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
         show_trace(NULL, &regs->esp);
 }
diff --git a/arch/i386/kernel/smp.c b/arch/i386/kernel/smp.c
index cec4bde67161..48b55db3680f 100644
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -576,7 +576,7 @@ static void stop_this_cpu (void * dummy)
         local_irq_disable();
         disable_local_APIC();
         if (cpu_data[smp_processor_id()].hlt_works_ok)
-                for(;;) __asm__("hlt");
+                for(;;) halt();
         for (;;);
 }