[PATCH] [4/7] Convert TSC disabling to generic cpuid disable bitmap

From: Andi Kleen
Date: Fri Jan 18 2008 - 12:28:44 EST



This cleans up quite a lot of code.

I think I test compiled all the affected variants (voyager, numaq),
but didn't test them, but the change is pretty straight forward for
them.

This means NUMAQ didn't compile, but I don't think it was related
to my patches.

Signed-off-by: Andi Kleen <ak@xxxxxxx>

---
arch/x86/kernel/cpu/bugs.c | 2 +-
arch/x86/kernel/cpu/common.c | 9 ---------
arch/x86/kernel/numaq_32.c | 2 +-
arch/x86/kernel/tsc_32.c | 14 +++-----------
arch/x86/mach-voyager/setup.c | 2 +-
arch/x86/xen/time.c | 2 +-
include/asm-x86/tsc.h | 2 --
7 files changed, 7 insertions(+), 26 deletions(-)

Index: linux/arch/x86/kernel/cpu/bugs.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/bugs.c
+++ linux/arch/x86/kernel/cpu/bugs.c
@@ -154,7 +154,7 @@ static void __init check_config(void)
* If we configured ourselves for a TSC, we'd better have one!
*/
#ifdef CONFIG_X86_TSC
- if (!cpu_has_tsc && !tsc_disable)
+ if (!cpu_has_tsc)
panic("Kernel compiled for Pentium+, requires TSC feature!");
#endif

Index: linux/arch/x86/kernel/cpu/common.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/common.c
+++ linux/arch/x86/kernel/cpu/common.c
@@ -446,10 +446,6 @@ void __cpuinit identify_cpu(struct cpuin
* we do "generic changes."
*/

- /* TSC disabled? */
- if ( tsc_disable )
- clear_bit(X86_FEATURE_TSC, c->x86_capability);
-
/* If the model name is still unset, do table lookup. */
if ( !c->x86_model_id[0] ) {
char *p;
@@ -650,11 +646,6 @@ void __cpuinit cpu_init(void)

if (cpu_has_vme || cpu_has_tsc || cpu_has_de)
clear_in_cr4(X86_CR4_VME|X86_CR4_PVI|X86_CR4_TSD|X86_CR4_DE);
- if (tsc_disable && cpu_has_tsc) {
- printk(KERN_NOTICE "Disabling TSC...\n");
- /**** FIX-HPA: DOES THIS REALLY BELONG HERE? ****/
- clear_bit(X86_FEATURE_TSC, boot_cpu_data.x86_capability);
- }

load_idt(&idt_descr);
switch_to_new_gdt();
Index: linux/arch/x86/kernel/numaq_32.c
===================================================================
--- linux.orig/arch/x86/kernel/numaq_32.c
+++ linux/arch/x86/kernel/numaq_32.c
@@ -82,7 +82,7 @@ static int __init numaq_tsc_disable(void
{
if (num_online_nodes() > 1) {
printk(KERN_DEBUG "NUMAQ: disabling TSC\n");
- tsc_disable = 1;
+ setup_clear_cpu_cap(X86_FEATURE_TSC);
}
return 0;
}
Index: linux/arch/x86/kernel/tsc_32.c
===================================================================
--- linux.orig/arch/x86/kernel/tsc_32.c
+++ linux/arch/x86/kernel/tsc_32.c
@@ -24,8 +24,6 @@ static int tsc_enabled;
unsigned int tsc_khz;
EXPORT_SYMBOL_GPL(tsc_khz);

-int tsc_disable;
-
#ifdef CONFIG_X86_TSC
static int __init tsc_setup(char *str)
{
@@ -40,8 +38,7 @@ static int __init tsc_setup(char *str)
*/
static int __init tsc_setup(char *str)
{
- tsc_disable = 1;
-
+ setup_clear_cpu_cap(X86_FEATURE_TSC);
return 1;
}
#endif
@@ -395,7 +392,7 @@ void __init tsc_init(void)
{
int cpu;

- if (!cpu_has_tsc || tsc_disable)
+ if (!cpu_has_tsc)
goto out_no_tsc;

cpu_khz = calculate_cpu_khz();
@@ -439,10 +436,5 @@ void __init tsc_init(void)
return;

out_no_tsc:
- /*
- * Set the tsc_disable flag if there's no TSC support, this
- * makes it a fast flag for the kernel to see whether it
- * should be using the TSC.
- */
- tsc_disable = 1;
+ setup_clear_cpu_cap(X86_FEATURE_TSC);
}
Index: linux/arch/x86/mach-voyager/setup.c
===================================================================
--- linux.orig/arch/x86/mach-voyager/setup.c
+++ linux/arch/x86/mach-voyager/setup.c
@@ -37,7 +37,7 @@ void __init pre_setup_arch_hook(void)
{
/* Voyagers run their CPUs from independent clocks, so disable
* the TSC code because we can't sync them */
- tsc_disable = 1;
+ setup_clear_cpu_cap(X86_FEATURE_TSC);
}

void __init trap_init_hook(void)
Index: linux/arch/x86/xen/time.c
===================================================================
--- linux.orig/arch/x86/xen/time.c
+++ linux/arch/x86/xen/time.c
@@ -592,7 +592,7 @@ __init void xen_time_init(void)
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);

- tsc_disable = 0;
+ setup_clear_cpu_cap(X86_FEATURE_TSC);

xen_setup_timer(cpu);
xen_setup_cpu_clockevents();
Index: linux/include/asm-x86/tsc.h
===================================================================
--- linux.orig/include/asm-x86/tsc.h
+++ linux/include/asm-x86/tsc.h
@@ -16,8 +16,6 @@ typedef unsigned long long cycles_t;

extern unsigned int cpu_khz;
extern unsigned int tsc_khz;
-/* flag for disabling the tsc */
-extern int tsc_disable;

extern void disable_TSC(void);

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