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SubjectRe: [PATCH] 1/5 more-asm-cleanup
H. Peter Anvin wrote:

>
> Reject! This is a bogus patch; Intel's CPUID level 4 has a
> nonstandard dependency on ECX (idiots...) and therefore this needs
> special handling.
>
> -hpa


Here's a better idea. Let's comment that unusual dependency and make it
explicit in the macro.

Some more assembler cleanups I noticed along the way.

Diffs against: 2.6.13-rc4-mm1

Signed-off-by: Zachary Amsden <zach@vmware.com)
Index: linux-2.6.13/arch/i386/kernel/crash.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/crash.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/crash.c 2005-08-03 15:19:39.000000000 -0700
@@ -153,7 +153,7 @@
disable_local_APIC();
atomic_dec(&waiting_for_crash_ipi);
/* Assume hlt works */
- __asm__("hlt");
+ halt();
for(;;);

return 1;
Index: linux-2.6.13/arch/i386/kernel/machine_kexec.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/machine_kexec.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/machine_kexec.c 2005-08-03 15:19:39.000000000 -0700
@@ -93,10 +93,7 @@
curidt.size = limit;
curidt.address = (unsigned long)newidt;

- __asm__ __volatile__ (
- "lidtl %0\n"
- : : "m" (curidt)
- );
+ load_idt(&curidt);
};


@@ -108,10 +105,7 @@
curgdt.size = limit;
curgdt.address = (unsigned long)newgdt;

- __asm__ __volatile__ (
- "lgdtl %0\n"
- : : "m" (curgdt)
- );
+ load_gdt(&curgdt);
};

static void load_segments(void)
Index: linux-2.6.13/arch/i386/kernel/process.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/process.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/process.c 2005-08-03 17:27:48.000000000 -0700
@@ -165,7 +165,7 @@
*/
local_irq_disable();
while (1)
- __asm__ __volatile__("hlt":::"memory");
+ halt();
}
#else
static inline void play_dead(void)
Index: linux-2.6.13/arch/i386/kernel/msr.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/msr.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/msr.c 2005-08-03 15:19:39.000000000 -0700
@@ -46,23 +46,13 @@

static struct class *msr_class;

-/* Note: "err" is handled in a funny way below. Otherwise one version
- of gcc or another breaks. */
-
static inline int wrmsr_eio(u32 reg, u32 eax, u32 edx)
{
int err;

- asm volatile ("1: wrmsr\n"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl %4,%0\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- " .align 4\n" " .long 1b,3b\n" ".previous":"=&bDS" (err)
- :"a"(eax), "d"(edx), "c"(reg), "i"(-EIO), "0"(0));
-
+ err = wrmsr_safe(reg, eax, edx);
+ if (err)
+ err = -EIO;
return err;
}

@@ -70,18 +60,9 @@
{
int err;

- asm volatile ("1: rdmsr\n"
- "2:\n"
- ".section .fixup,\"ax\"\n"
- "3: movl %4,%0\n"
- " jmp 2b\n"
- ".previous\n"
- ".section __ex_table,\"a\"\n"
- " .align 4\n"
- " .long 1b,3b\n"
- ".previous":"=&bDS" (err), "=a"(*eax), "=d"(*edx)
- :"c"(reg), "i"(-EIO), "0"(0));
-
+ err = rdmsr_safe(reg, eax, edx);
+ if (err)
+ err = -EIO;
return err;
}

Index: linux-2.6.13/arch/i386/kernel/cpu/intel.c
===================================================================
--- linux-2.6.13.orig/arch/i386/kernel/cpu/intel.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/kernel/cpu/intel.c 2005-08-03 20:22:55.000000000 -0700
@@ -82,16 +82,13 @@
*/
static int __devinit num_cpu_cores(struct cpuinfo_x86 *c)
{
- unsigned int eax;
+ unsigned int eax, ebx, ecx, edx;

if (c->cpuid_level < 4)
return 1;

- __asm__("cpuid"
- : "=a" (eax)
- : "0" (4), "c" (0)
- : "bx", "dx");
-
+ /* Intel has a non-standard dependency on %ecx for this CPUID level. */
+ cpuid_count(4, 0, &eax, &ebx, &ecx, &edx);
if (eax & 0x1f)
return ((eax >> 26) + 1);
else
Index: linux-2.6.13/arch/i386/mach-voyager/voyager_basic.c
===================================================================
--- linux-2.6.13.orig/arch/i386/mach-voyager/voyager_basic.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/mach-voyager/voyager_basic.c 2005-08-03 15:19:39.000000000 -0700
@@ -234,10 +234,9 @@
#endif
}
/* and wait for it to happen */
- for(;;) {
- __asm("cli");
- __asm("hlt");
- }
+ local_irq_disable();
+ for(;;)
+ halt();
}

/* copied from process.c */
@@ -272,10 +271,9 @@
outb(basebd | 0x08, VOYAGER_MC_SETUP);
outb(0x02, catbase + 0x21);
}
- for(;;) {
- asm("cli");
- asm("hlt");
- }
+ local_irq_disable();
+ for(;;)
+ halt();
}

void
Index: linux-2.6.13/arch/i386/mach-voyager/voyager_smp.c
===================================================================
--- linux-2.6.13.orig/arch/i386/mach-voyager/voyager_smp.c 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/arch/i386/mach-voyager/voyager_smp.c 2005-08-03 15:19:39.000000000 -0700
@@ -1015,7 +1015,7 @@
cpu_clear(smp_processor_id(), cpu_online_map);
local_irq_disable();
for(;;)
- __asm__("hlt");
+ halt();
}

static DEFINE_SPINLOCK(call_lock);
Index: linux-2.6.13/include/asm-i386/msr.h
===================================================================
--- linux-2.6.13.orig/include/asm-i386/msr.h 2005-08-03 15:18:18.000000000 -0700
+++ linux-2.6.13/include/asm-i386/msr.h 2005-08-03 17:16:07.000000000 -0700
@@ -47,6 +47,21 @@
: "c" (msr), "0" (a), "d" (b), "i" (-EFAULT));\
ret__; })

+/* rdmsr with exception handling */
+#define rdmsr_safe(msr,a,b) ({ int ret__; \
+ asm volatile("2: rdmsr ; xorl %0,%0\n" \
+ "1:\n\t" \
+ ".section .fixup,\"ax\"\n\t" \
+ "3: movl %4,%0 ; jmp 1b\n\t" \
+ ".previous\n\t" \
+ ".section __ex_table,\"a\"\n" \
+ " .align 4\n\t" \
+ " .long 2b,3b\n\t" \
+ ".previous" \
+ : "=r" (ret__), "=a" (*(a)), "=d" (*(b)) \
+ : "c" (msr), "i" (-EFAULT));\
+ ret__; })
+
#define rdtsc(low,high) \
__asm__ __volatile__("rdtsc" : "=a" (low), "=d" (high))
\
 
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