To disable CLFLUSH usage, especially in change_page_attr().

Ingo asked for this.

Signed-off-by: Andi Kleen <[EMAIL PROTECTED]>

---
 Documentation/kernel-parameters.txt |    2 ++
 arch/x86/kernel/cpu/common.c        |    7 +++++++
 arch/x86/kernel/setup_64.c          |    7 +++++++
 3 files changed, 16 insertions(+)

Index: linux/arch/x86/kernel/cpu/common.c
===================================================================
--- linux.orig/arch/x86/kernel/cpu/common.c
+++ linux/arch/x86/kernel/cpu/common.c
@@ -542,6 +542,13 @@ void __cpuinit detect_ht(struct cpuinfo_
 }
 #endif
 
+static __init int setup_noclflush(char *arg)
+{
+       setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
+       return 1;
+}
+__setup("noclflush", setup_noclflush);
+
 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
 {
        char *vendor = NULL;
Index: linux/arch/x86/kernel/setup_64.c
===================================================================
--- linux.orig/arch/x86/kernel/setup_64.c
+++ linux/arch/x86/kernel/setup_64.c
@@ -1042,6 +1042,13 @@ void __cpuinit identify_cpu(struct cpuin
        }
 }
 
+static __init int setup_noclflush(char *arg)
+{
+       setup_clear_cpu_cap(X86_FEATURE_CLFLSH);
+       return 1;
+}
+__setup("noclflush", setup_noclflush);
+
 void __cpuinit print_cpu_info(struct cpuinfo_x86 *c)
 {
        if (c->x86_model_id[0])
Index: linux/Documentation/kernel-parameters.txt
===================================================================
--- linux.orig/Documentation/kernel-parameters.txt
+++ linux/Documentation/kernel-parameters.txt
@@ -1173,6 +1173,8 @@ and is between 256 and 4096 characters. 
                        register save and restore. The kernel will only save
                        legacy floating-point registers on task switch.
 
+       noclflush       [BUGS=X86] Don't use the CLFLUSH instruction
+
        nohlt           [BUGS=ARM]
 
        no-hlt          [BUGS=X86-32] Tells the kernel that the hlt
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