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author | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 09:16:28 (GMT) |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2007-10-11 09:16:28 (GMT) |
commit | 2ec1df4130c60d1eb49dc0fa0ed15858fede6b05 (patch) | |
tree | 97e578ba1546770eadbe84cff2dc44256f97b9d7 /arch/x86/kernel/cpu/mtrr/amd.c | |
parent | ee580dc91efd83e6b55955e7261e8ad2a0e08d1a (diff) | |
download | linux-2ec1df4130c60d1eb49dc0fa0ed15858fede6b05.tar.xz |
i386: move kernel/cpu/mtrr
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr/amd.c')
-rw-r--r-- | arch/x86/kernel/cpu/mtrr/amd.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/amd.c b/arch/x86/kernel/cpu/mtrr/amd.c new file mode 100644 index 0000000..0949cdb --- /dev/null +++ b/arch/x86/kernel/cpu/mtrr/amd.c @@ -0,0 +1,121 @@ +#include <linux/init.h> +#include <linux/mm.h> +#include <asm/mtrr.h> +#include <asm/msr.h> + +#include "mtrr.h" + +static void +amd_get_mtrr(unsigned int reg, unsigned long *base, + unsigned long *size, mtrr_type * type) +{ + unsigned long low, high; + + rdmsr(MSR_K6_UWCCR, low, high); + /* Upper dword is region 1, lower is region 0 */ + if (reg == 1) + low = high; + /* The base masks off on the right alignment */ + *base = (low & 0xFFFE0000) >> PAGE_SHIFT; + *type = 0; + if (low & 1) + *type = MTRR_TYPE_UNCACHABLE; + if (low & 2) + *type = MTRR_TYPE_WRCOMB; + if (!(low & 3)) { + *size = 0; + return; + } + /* + * This needs a little explaining. The size is stored as an + * inverted mask of bits of 128K granularity 15 bits long offset + * 2 bits + * + * So to get a size we do invert the mask and add 1 to the lowest + * mask bit (4 as its 2 bits in). This gives us a size we then shift + * to turn into 128K blocks + * + * eg 111 1111 1111 1100 is 512K + * + * invert 000 0000 0000 0011 + * +1 000 0000 0000 0100 + * *128K ... + */ + low = (~low) & 0x1FFFC; + *size = (low + 4) << (15 - PAGE_SHIFT); + return; +} + +static void amd_set_mtrr(unsigned int reg, unsigned long base, + unsigned long size, mtrr_type type) +/* [SUMMARY] Set variable MTRR register on the local CPU. + <reg> The register to set. + <base> The base address of the region. + <size> The size of the region. If this is 0 the region is disabled. + <type> The type of the region. + <do_safe> If TRUE, do the change safely. If FALSE, safety measures should + be done externally. + [RETURNS] Nothing. +*/ +{ + u32 regs[2]; + + /* + * Low is MTRR0 , High MTRR 1 + */ + rdmsr(MSR_K6_UWCCR, regs[0], regs[1]); + /* + * Blank to disable + */ + if (size == 0) + regs[reg] = 0; + else + /* Set the register to the base, the type (off by one) and an + inverted bitmask of the size The size is the only odd + bit. We are fed say 512K We invert this and we get 111 1111 + 1111 1011 but if you subtract one and invert you get the + desired 111 1111 1111 1100 mask + + But ~(x - 1) == ~x + 1 == -x. Two's complement rocks! */ + regs[reg] = (-size >> (15 - PAGE_SHIFT) & 0x0001FFFC) + | (base << PAGE_SHIFT) | (type + 1); + + /* + * The writeback rule is quite specific. See the manual. Its + * disable local interrupts, write back the cache, set the mtrr + */ + wbinvd(); + wrmsr(MSR_K6_UWCCR, regs[0], regs[1]); +} + +static int amd_validate_add_page(unsigned long base, unsigned long size, unsigned int type) +{ + /* Apply the K6 block alignment and size rules + In order + o Uncached or gathering only + o 128K or bigger block + o Power of 2 block + o base suitably aligned to the power + */ + if (type > MTRR_TYPE_WRCOMB || size < (1 << (17 - PAGE_SHIFT)) + || (size & ~(size - 1)) - size || (base & (size - 1))) + return -EINVAL; + return 0; +} + +static struct mtrr_ops amd_mtrr_ops = { + .vendor = X86_VENDOR_AMD, + .set = amd_set_mtrr, + .get = amd_get_mtrr, + .get_free_region = generic_get_free_region, + .validate_add_page = amd_validate_add_page, + .have_wrcomb = positive_have_wrcomb, +}; + +int __init amd_init_mtrr(void) +{ + set_mtrr_ops(&amd_mtrr_ops); + return 0; +} + +//arch_initcall(amd_mtrr_init); |