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algorithm to find best suited mtrr values to match a memory region. tested ok with 3071MB.

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git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@24424 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Jérôme Duval 2008-03-17 19:50:46 +00:00
parent e30b6f2693
commit 4f893e39ab
1 changed files with 104 additions and 25 deletions
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129
src/system/kernel/arch/x86/arch_vm.cpp
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@ -31,6 +31,13 @@
# define TRACE(x) ;
#endif
#define TRACE_MTRR_ARCH_VM
#ifdef TRACE_MTRR_ARCH_VM
# define TRACE_MTRR(x...) dprintf(x)
#else
# define TRACE_MTRR(x...)
#endif
#define kMaxMemoryTypeRegisters 32
@ -83,6 +90,22 @@ nearest_power(addr_t value)
}
static void
nearest_powers(uint64 value, uint64 *lower, uint64 *upper)
{
uint64 power = 1UL << 12;
*lower = power;
// 12 bits is the smallest supported alignment/length
while (value >= power) {
*lower = power;
power <<= 1;
}
*upper = power;
}
static status_t
set_memory_type(int32 id, uint64 base, uint64 length, uint32 type)
{
@ -91,23 +114,21 @@ set_memory_type(int32 id, uint64 base, uint64 length, uint32 type)
if (type == 0)
return B_OK;
uint32 newType;
switch (type) {
case B_MTR_UC:
newType = IA32_MTR_UNCACHED;
type = IA32_MTR_UNCACHED;
break;
case B_MTR_WC:
newType = IA32_MTR_WRITE_COMBINING;
type = IA32_MTR_WRITE_COMBINING;
break;
case B_MTR_WT:
newType = IA32_MTR_WRITE_THROUGH;
type = IA32_MTR_WRITE_THROUGH;
break;
case B_MTR_WP:
newType = IA32_MTR_WRITE_PROTECTED;
type = IA32_MTR_WRITE_PROTECTED;
break;
case B_MTR_WB:
newType = IA32_MTR_WRITE_BACK;
type = IA32_MTR_WRITE_BACK;
break;
default:
@ -118,41 +139,99 @@ set_memory_type(int32 id, uint64 base, uint64 length, uint32 type)
return B_NOT_SUPPORTED;
// length must be a power of 2; just round it up to the next value
uint64 newLength = nearest_power(length);
length = nearest_power(length);
// avoids more than 2GB slots
if (newLength > 0x80000000)
newLength = 0x80000000;
if (newLength + base <= base) {
if (length + base <= base) {
// 4GB overflow
return B_BAD_VALUE;
}
// base must be aligned to the length
if (base & (newLength - 1))
if (base & (length - 1))
return B_BAD_VALUE;
index = allocate_mtrr();
if (index < 0)
return B_ERROR;
TRACE(("allocate MTRR slot %ld, base = %Lx, length = %Lx\n", index,
base, newLength));
TRACE_MTRR("allocate MTRR slot %ld, base = %Lx, length = %Lx\n", index, base, length);
sMemoryTypeIDs[index] = id;
x86_set_mtrr(index, base, newLength, newType);
// now handle remaining memory
if (length > newLength) {
// TODO iterate over smaller lengths to avoid the PCI hole after the physical memory.
set_memory_type(id, base + newLength, length - newLength, type);
}
x86_set_mtrr(index, base, length, type);
return B_OK;
}
static int64 sols[5];
static int solCount;
static int64 props[5];
static void
find_nearest(uint64 value, int iteration)
{
TRACE_MTRR("find_nearest %Lx %d\n", value, iteration);
if (iteration > 4 || (iteration + 1) >= solCount)
return;
uint64 down, up;
int i;
nearest_powers(value, &down, &up);
props[iteration] = down;
if (value - down < 0x100000) {
for (i=0; i<=iteration; i++)
sols[i] = props[i];
solCount = iteration + 1;
return;
}
find_nearest(value - down, iteration + 1);
props[iteration] = -up;
if (up - value < 0x100000) {
for (i=0; i<=iteration; i++)
sols[i] = props[i];
solCount = iteration + 1;
return;
}
find_nearest(up - value, iteration + 1);
}
static status_t
set_memory_write_back(int32 id, uint64 base, uint64 length)
{
int i;
TRACE_MTRR("set_memory_write_back base %Lx length %Lx\n", base, length);
solCount = 5;
find_nearest(length, 0);
#ifdef TRACE_MTRR
dprintf("sols: ");
for (i=0; i<solCount; i++) {
dprintf("0x%Lx ", sols[i]);
}
dprintf("\n");
#endif
bool nextDown = false;
for (int i = 0; i < solCount; i++) {
if (sols[i] < 0) {
if (nextDown)
base += sols[i];
set_memory_type(id, base, -sols[i], nextDown ? B_MTR_UC : B_MTR_WB);
if (!nextDown)
base -= sols[i];
nextDown = !nextDown;
} else {
if (nextDown)
base -= sols[i];
set_memory_type(id, base, sols[i], nextDown ? B_MTR_UC : B_MTR_WB);
if (!nextDown)
base += sols[i];
}
}
}
// #pragma mark -
@ -226,8 +305,8 @@ arch_vm_init_post_modules(kernel_args *args)
// set the physical memory ranges to write-back mode
for (uint32 i = 0; i < args->num_physical_memory_ranges; i++) {
set_memory_type(-1, args->physical_memory_range[i].start,
args->physical_memory_range[i].size, B_MTR_WB);
set_memory_write_back(-1, args->physical_memory_range[i].start,
args->physical_memory_range[i].size);
}
return B_OK;