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sortix--sortix/kernel/x86-family/pat.cpp

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Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
/*******************************************************************************
Refactor kernel PAT, MTRR, and MSR usage.
2013-09-14 11:10:14 -04:00
Copyright(C) Jonas 'Sortie' Termansen 2012, 2013.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
Update copyright headers of old files to the current format.
2013-07-10 09:26:01 -04:00
This file is part of Sortix.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
Update copyright headers of old files to the current format.
2013-07-10 09:26:01 -04:00
Sortix is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later
version.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
Update copyright headers of old files to the current format.
2013-07-10 09:26:01 -04:00
Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
details.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
Update copyright headers of old files to the current format.
2013-07-10 09:26:01 -04:00
You should have received a copy of the GNU General Public License along with
Sortix. If not, see <http://www.gnu.org/licenses/>.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
Refactor kernel PAT, MTRR, and MSR usage.
2013-09-14 11:10:14 -04:00
x86-family/pat.cpp
Tests whether PAT is available and initializes it.
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
*******************************************************************************/
Refactor kernel PAT, MTRR, and MSR usage.
2013-09-14 11:10:14 -04:00
#include <msr.h>
#include <stdint.h>
#include <sortix/kernel/cpuid.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/pat.h>
#include "memorymanagement.h"
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
namespace Sortix {
Refactor kernel PAT, MTRR, and MSR usage.
2013-09-14 11:10:14 -04:00
static const uint32_t bit_PAT = 0x00010000U;
bool IsPATSupported()
{
if ( !IsCPUIdSupported() )
return false;
uint32_t eax, ebx, ecx, edx;
cpuid(1, eax, ebx, ecx, edx);
uint32_t features = edx;
return features & bit_PAT;
}
void InitializePAT()
{
using namespace Sortix::Memory;
const uint32_t LOW = PA[0] << 0 | PA[1] << 8 | PA[2] << 16 | PA[3] << 24;
const uint32_t HIGH = PA[4] << 0 | PA[5] << 8 | PA[6] << 16 | PA[7] << 24;
const int PAT_REG = 0x0277;
wrmsr(PAT_REG, (uint64_t) LOW << 0 | (uint64_t) HIGH << 32);
}
Added support for MSRs, PAT and MTRRs. This provides control over the caching of memory, which makes write-combined IO possible. Graphics drivers can use this to transfer data at a much higher rate to the video memory. The implementation is a bit hacky but it'll do for now. It provides enough support for the experimental VBE driver to work on the real computers I tested it on, even if the BIOS uses screwed up default MTRRs. The virtual memory layer now automatically uses the PAT feature if available but in a backwards compatible manner and otherwise just tries to approximate PAT features if they are asked for.
2012-06-30 18:50:27 -04:00
} // namespace Sortix
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