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authorAndi Kleen <ak@suse.de>2005-04-16 15:25:10 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:25:10 -0700
commit1f2c958ad51fed18b23558e2047b98dfa752e689 (patch)
treea82d8c45c10498dad5b7e2187b842c0e76d4490a /arch/i386
parentf0de53bbc2118c754ee923516122d91add288582 (diff)
downloadop-kernel-dev-1f2c958ad51fed18b23558e2047b98dfa752e689.zip
op-kernel-dev-1f2c958ad51fed18b23558e2047b98dfa752e689.tar.gz
[PATCH] x86_64: Always use CPUID 80000008 to figure out MTRR address space size
It doesn't make sense to only do this only for AMD K8. This would support future CPUs with extended address spaces properly. For i386 and x86-64 Cc: <davej@redhat.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386')
-rw-r--r--arch/i386/kernel/cpu/mtrr/main.c49
1 files changed, 15 insertions, 34 deletions
diff --git a/arch/i386/kernel/cpu/mtrr/main.c b/arch/i386/kernel/cpu/mtrr/main.c
index 8f67b49..54999e4 100644
--- a/arch/i386/kernel/cpu/mtrr/main.c
+++ b/arch/i386/kernel/cpu/mtrr/main.c
@@ -614,40 +614,21 @@ static int __init mtrr_init(void)
mtrr_if = &generic_mtrr_ops;
size_or_mask = 0xff000000; /* 36 bits */
size_and_mask = 0x00f00000;
-
- switch (boot_cpu_data.x86_vendor) {
- case X86_VENDOR_AMD:
- /* The original Athlon docs said that
- total addressable memory is 44 bits wide.
- It was not really clear whether its MTRRs
- follow this or not. (Read: 44 or 36 bits).
- However, "x86-64_overview.pdf" explicitly
- states that "previous implementations support
- 36 bit MTRRs" and also provides a way to
- query the width (in bits) of the physical
- addressable memory on the Hammer family.
- */
- if (boot_cpu_data.x86 == 15
- && (cpuid_eax(0x80000000) >= 0x80000008)) {
- u32 phys_addr;
- phys_addr = cpuid_eax(0x80000008) & 0xff;
- size_or_mask =
- ~((1 << (phys_addr - PAGE_SHIFT)) - 1);
- size_and_mask = ~size_or_mask & 0xfff00000;
- }
- /* Athlon MTRRs use an Intel-compatible interface for
- * getting and setting */
- break;
- case X86_VENDOR_CENTAUR:
- if (boot_cpu_data.x86 == 6) {
- /* VIA Cyrix family have Intel style MTRRs, but don't support PAE */
- size_or_mask = 0xfff00000; /* 32 bits */
- size_and_mask = 0;
- }
- break;
-
- default:
- break;
+
+ /* This is an AMD specific MSR, but we assume(hope?) that
+ Intel will implement it to when they extend the address
+ bus of the Xeon. */
+ if (cpuid_eax(0x80000000) >= 0x80000008) {
+ u32 phys_addr;
+ phys_addr = cpuid_eax(0x80000008) & 0xff;
+ size_or_mask = ~((1 << (phys_addr - PAGE_SHIFT)) - 1);
+ size_and_mask = ~size_or_mask & 0xfff00000;
+ } else if (boot_cpu_data.x86_vendor == X86_VENDOR_CENTAUR &&
+ boot_cpu_data.x86 == 6) {
+ /* VIA C* family have Intel style MTRRs, but
+ don't support PAE */
+ size_or_mask = 0xfff00000; /* 32 bits */
+ size_and_mask = 0;
}
} else {
switch (boot_cpu_data.x86_vendor) {
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