diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/amd.c | 97 |
1 files changed, 51 insertions, 46 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/amd.c b/arch/x86/kernel/cpu/mtrr/amd.c index ee2331b0e58..33af14110df 100644 --- a/arch/x86/kernel/cpu/mtrr/amd.c +++ b/arch/x86/kernel/cpu/mtrr/amd.c @@ -7,15 +7,15 @@ static void amd_get_mtrr(unsigned int reg, unsigned long *base, - unsigned long *size, mtrr_type * type) + 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 */ + /* Upper dword is region 1, lower is region 0 */ if (reg == 1) low = high; - /* The base masks off on the right alignment */ + /* The base masks off on the right alignment */ *base = (low & 0xFFFE0000) >> PAGE_SHIFT; *type = 0; if (low & 1) @@ -27,74 +27,81 @@ amd_get_mtrr(unsigned int reg, unsigned long *base, 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 + * 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 + * 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 + * eg 111 1111 1111 1100 is 512K * - * invert 000 0000 0000 0011 - * +1 000 0000 0000 0100 - * *128K ... + * 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. - [RETURNS] Nothing. -*/ +/** + * amd_set_mtrr - 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. + * + * Returns nothing. + */ +static void +amd_set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type) { u32 regs[2]; /* - * Low is MTRR0 , High MTRR 1 + * Low is MTRR0, High MTRR 1 */ rdmsr(MSR_K6_UWCCR, regs[0], regs[1]); /* - * Blank to disable + * Blank to disable */ - if (size == 0) + 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! */ + } 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 + * 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) +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 - */ + /* + * 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; @@ -115,5 +122,3 @@ int __init amd_init_mtrr(void) set_mtrr_ops(&amd_mtrr_ops); return 0; } - -//arch_initcall(amd_mtrr_init); |