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r: 158666
b: refs/heads/master
c: 4220445
h: refs/heads/master
v: v3
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Jaswinder Singh Rajput authored and Ingo Molnar committed Jul 4, 2009
1 parent 46e8eee commit bf891be
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2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: d7e57676e3ed7ab9b2c7c4bcb7873e51eacbdb84
refs/heads/master: 42204455f160dab0c47f19e1be23f5c927af2d17
97 changes: 51 additions & 46 deletions trunk/arch/x86/kernel/cpu/mtrr/amd.c
Original file line number Diff line number Diff line change
Expand Up @@ -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)
Expand All @@ -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;
Expand All @@ -115,5 +122,3 @@ int __init amd_init_mtrr(void)
set_mtrr_ops(&amd_mtrr_ops);
return 0;
}

//arch_initcall(amd_mtrr_init);

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