Initial commit

Signed-off-by: Park Ju Hyung <[email protected]>

.gitignore

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+*.so 
+*.o
+*.efi

DisablePROCHOT.c

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+// Copyright (c) 2018 Park Ju Hyung
+
+#include <efibind.h>
+#include <efidef.h>
+#include <efidevp.h>
+#include <eficon.h>
+#include <efiprot.h>
+#include <efiapi.h>
+#include <efierr.h>
+
+static uint64_t AsmWriteMsr64(uint32_t index, uint64_t val)
+{
+	uint32_t low;
+	uint32_t high;
+
+	low  = (uint32_t)(val);
+	high = (uint32_t)(val >> 32);
+
+	__asm__ __volatile__ (
+		"wrmsr"
+		:
+		: "c" (index),
+		  "a" (low),
+		  "d" (high)
+	);
+
+	return val;
+}
+
+EFI_STATUS
+efi_main(EFI_HANDLE image, EFI_SYSTEM_TABLE *systemTable)
+{
+	SIMPLE_TEXT_OUTPUT_INTERFACE *conOut = systemTable->ConOut;
+	conOut->OutputString(conOut, L"Disabling BD PROCHOT\r\n");
+
+	AsmWriteMsr64(0x1FC, 0);
+
+	conOut->OutputString(conOut, L"BD PROCHOT disabled\r\n");
+
+	return EFI_SUCCESS;
+}

README.md

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+# Disable BD PROCHOT UEFI extension
+A small EFI executable for disabling BD(Bi-directional) PROCHOT upon boot.
+
+BD PROCHOT causes CPU to lock on the lowest clock speed, if motherboard deems
+certain parts are overheated(hence bi-directional).
+
+If a thermal sensor on the motherboard is broken, BD PROCHOT can always be tripped.
+If your motherboard is out of warranty, feel free to use this instead.
+
+While modern PC setups are very safe from components overheating so extremely
+to cause BD PROCHOT(it's mostly for extremely poorly maintained PCs),
+I still hold no responsibilities from possible damages being caused to your PC.
+
+## Why use this instead of ThrottleStop?
+ThrottleStop is loaded after the OS has finished booting,
+which means your entire OS loading is still done extremely slowly.
+
+This doesn't mean ThrottleStop is no longer needed.
+Please read below.
+
+## Usage
+This EFI executable must be loaded at the bootloader level.
+Please use rEFInd or Clover.
+
+Copying DisablePROCHOT.efi to drivers64UEFI directory is enough for Clover.
+
+## Warning
+Entering ACPI S3 state(suspend) causes the BD PROCHOT MSR bit getting re-enabled.
+You need to use some userspace tool for disabling BD PROCHOT for such cases.
+
+In case of Windows, use ThrottleStop.

build.sh

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+#!/bin/bash
+
+gcc -I/usr/include/efi -I/usr/include/efi/x86_64 \
+    -DGNU_EFI_USE_MS_ABI -Dx86_64 \
+    -fPIC -fshort-wchar -ffreestanding -fno-stack-protector -maccumulate-outgoing-args \
+    -Wall -Werror \
+    -m64 -mno-red-zone \
+    -c -o DisablePROCHOT.o DisablePROCHOT.c
+
+ld -T /usr/lib/elf_x86_64_efi.lds -Bsymbolic -shared -nostdlib -znocombreloc \
+    /usr/lib/crt0-efi-x86_64.o \
+    -o DisablePROCHOT.so DisablePROCHOT.o \
+    $(gcc -print-libgcc-file-name) /usr/lib/libgnuefi.a
+
+objcopy -j .text -j .sdata -j .data -j .dynamic -j .dynsym -j .rel \
+        -j .rela -j .reloc -S --target=efi-app-x86_64 DisablePROCHOT.so DisablePROCHOT.efi
+
+ls -l DisablePROCHOT.efi
+md5sum DisablePROCHOT.efi