2.5.24-dj2: oops in finalize_mtrr_state with bochs

2.5.24-dj2: oops in finalize_mtrr_state with bochs

[Manfred Spraul]

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The bochs cpu emulator (tries to emulate Pentium cpus) oopses in 
finalize_mtrr_state():

mtrr_if is NULL, and thus use_intel() crashes.

Patch attached. I've modified is_cpu() as well, without checking if this 
macro could be used if mtrr_if is not initialized.

Partially tested - bochs now hangs at the first access to the ide 
interface :-(
--
	Manfred

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diff -u 2.5/arch/i386/kernel/cpu/mtrr/mtrr.h build-2.5/arch/i386/kernel/cpu/mtrr/mtrr.h
--- 2.5/arch/i386/kernel/cpu/mtrr/mtrr.h	Tue Jun 25 20:27:47 2002
+++ build-2.5/arch/i386/kernel/cpu/mtrr/mtrr.h	Tue Jun 25 21:22:15 2002
@@ -88,8 +88,8 @@
 extern u32 size_or_mask, size_and_mask;
 extern struct mtrr_ops * mtrr_if;
 
-#define is_cpu(vnd)	(mtrr_if->vendor == X86_VENDOR_##vnd)
-#define use_intel()	(mtrr_if->use_intel_if == 1)
+#define is_cpu(vnd)	(mtrr_if && mtrr_if->vendor == X86_VENDOR_##vnd)
+#define use_intel()	(mtrr_if && mtrr_if->use_intel_if == 1)
 
 extern unsigned int num_var_ranges;