diff options
Diffstat (limited to 'arch/i386/kernel/cpu/mtrr')
| -rw-r--r-- | arch/i386/kernel/cpu/mtrr/main.c | 49 |
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 8f67b490a7f..54999e4c55f 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) { |