From: Andi Kleen <ak@suse.de>
Date: Wed, 30 Jan 2008 12:33:20 +0000 (+0100)
Subject: x86: add framework to disable CPUID bits on the command line
X-Git-Tag: v2.6.25-rc1~1143^2~233
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7d851c8d3db0f79b92c8b14361779ede8acd2488;p=linux-2.6

x86: add framework to disable CPUID bits on the command line

There are already various options to disable specific cpuid bits
on the command line. They all use their own variable. Add a generic
mask to make this easier in the future.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 4bd326d032..f0f29ddf33 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -57,6 +57,8 @@ DEFINE_PER_CPU(struct gdt_page, gdt_page) = { .gdt = {
 } };
 EXPORT_PER_CPU_SYMBOL_GPL(gdt_page);
 
+__u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
+
 static int cachesize_override __cpuinitdata = -1;
 static int disable_x86_fxsr __cpuinitdata;
 static int disable_x86_serial_nr __cpuinitdata = 1;
@@ -497,6 +499,10 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
 			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
 	}
 
+	/* Clear all flags overriden by options */
+	for (i = 0; i < NCAPINTS; i++)
+		c->x86_capability[i] ^= cleared_cpu_caps[i];
+
 	/* Init Machine Check Exception if available. */
 	mcheck_init(c);
 
diff --git a/arch/x86/kernel/setup_64.c b/arch/x86/kernel/setup_64.c
index 7edb43f0b2..df159520bb 100644
--- a/arch/x86/kernel/setup_64.c
+++ b/arch/x86/kernel/setup_64.c
@@ -80,6 +80,8 @@
 struct cpuinfo_x86 boot_cpu_data __read_mostly;
 EXPORT_SYMBOL(boot_cpu_data);
 
+__u32 cleared_cpu_caps[NCAPINTS] __cpuinitdata;
+
 unsigned long mmu_cr4_features;
 
 /* Boot loader ID as an integer, for the benefit of proc_dointvec */
@@ -1013,6 +1015,10 @@ void __cpuinit identify_cpu(struct cpuinfo_x86 *c)
 			boot_cpu_data.x86_capability[i] &= c->x86_capability[i];
 	}
 
+	/* Clear all flags overriden by options */
+	for (i = 0; i < NCAPINTS; i++)
+		c->x86_capability[i] ^= cleared_cpu_caps[i];
+
 #ifdef CONFIG_X86_MCE
 	mcheck_init(c);
 #endif
diff --git a/include/asm-x86/cpufeature.h b/include/asm-x86/cpufeature.h
index 29727bf0e1..b8f53f869e 100644
--- a/include/asm-x86/cpufeature.h
+++ b/include/asm-x86/cpufeature.h
@@ -131,6 +131,10 @@
 
 #define set_cpu_cap(c, bit)	set_bit(bit, (unsigned long *)((c)->x86_capability))
 #define clear_cpu_cap(c, bit)	clear_bit(bit, (unsigned long *)((c)->x86_capability))
+#define setup_clear_cpu_cap(bit) do { \
+	clear_cpu_cap(&boot_cpu_data, bit);	\
+	set_bit(bit, cleared_cpu_caps); 	\
+} while (0)
 
 #define cpu_has_fpu		boot_cpu_has(X86_FEATURE_FPU)
 #define cpu_has_vme		boot_cpu_has(X86_FEATURE_VME)
diff --git a/include/asm-x86/processor.h b/include/asm-x86/processor.h
index 81ecfed83e..ab4d0c2a3f 100644
--- a/include/asm-x86/processor.h
+++ b/include/asm-x86/processor.h
@@ -118,6 +118,7 @@ struct cpuinfo_x86 {
 extern struct cpuinfo_x86 boot_cpu_data;
 extern struct cpuinfo_x86 new_cpu_data;
 extern struct tss_struct doublefault_tss;
+extern __u32 cleared_cpu_caps[NCAPINTS];
 
 #ifdef CONFIG_SMP
 DECLARE_PER_CPU(struct cpuinfo_x86, cpu_info);