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authorRegia König2022-08-09 11:00:00 +0200
committerRegia König2022-08-09 11:00:00 +0200
commit9814d8cb459f2c9dc3b6d6b131fa7b4461744256 (patch)
tree9f684a2908770f90fb84c285f9f9e3d528abf1d6 /documentation
parentstart documentation (diff)
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memtest86-9814d8cb459f2c9dc3b6d6b131fa7b4461744256.tar.xz
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Move all documentation into directory -documentation-
Diffstat (limited to 'documentation')
-rw-r--r--documentation/README17
-rw-r--r--documentation/gdb with efi application0
-rw-r--r--documentation/how to run OVMF17
-rw-r--r--documentation/ovmf_with_gdb_16_5_2022.txt171
4 files changed, 205 insertions, 0 deletions
diff --git a/documentation/README b/documentation/README
new file mode 100644
index 0000000..048c893
--- /dev/null
+++ b/documentation/README
@@ -0,0 +1,17 @@
+https://retrage.github.io/2019/12/05/debugging-ovmf-en.html
+
+How to debug with gdb:
+
+1. make run
+
+2. ./gen_symbol_offets.sh > gdbscript
+
+3. make debug
+
+4. open second terminal. Type gdb
+
+5. In second terminal:
+ (gdb) source gdbscript
+ (gdb) b CoreHandleProtocol
+ (gdb) target remote localhost:1234
+ (gdb) c
diff --git a/documentation/gdb with efi application b/documentation/gdb with efi application
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/documentation/gdb with efi application
diff --git a/documentation/how to run OVMF b/documentation/how to run OVMF
new file mode 100644
index 0000000..9776c9e
--- /dev/null
+++ b/documentation/how to run OVMF
@@ -0,0 +1,17 @@
+- Create a directory for the *.efi applications. The name is "hda-contents"
+
+1. With qemu-system-x86_64 command:
+
+- Create OVMF.fd -> rename it to bios.bin
+
+- Either place it into the same directory from where the command is executed
+ or specify the path to bios.bin as argument to -L
+
+run qemu-system-x86_64 -L . -hda fat:hda-contents -net none // TODO not possible to boot into EFI shell
+
+
+
+2. With kvm command:
+
+run sudo kvm -bios OVMF.fd -hda fat:hda-contents -net none // boots into UEFI Shell
+
diff --git a/documentation/ovmf_with_gdb_16_5_2022.txt b/documentation/ovmf_with_gdb_16_5_2022.txt
new file mode 100644
index 0000000..c5b8b7a
--- /dev/null
+++ b/documentation/ovmf_with_gdb_16_5_2022.txt
@@ -0,0 +1,171 @@
+https://retrage.github.io/2019/12/05/debugging-ovmf-en.html
+
+
+Building EDK2
+Build EDK2 using gcc as usual.
+
+$ git clone git@github.com:tianocore/edk2.git
+$ cd edk2
+$ git submodule update --init --recursive
+$ make -C BaseTools
+$ source ./edksetup.sh
+$ build -p OvmfPkg/OvmfPkgX64.dsc -b DEBUG -a X64 -t GCC5
+To make debugging easy, create a Makefile as follow. Note that we have to connect debugcon at 0x402 to dump debug information (debug.log) from OVMF[4].
+
+#!/usr/bin/env make
+
+SHELL=/bin/bash
+
+LOG=debug.log
+OVMFBASE=edk2/Build/OvmfX64/DEBUG_GCC5/
+OVMFCODE=$(OVMFBASE)/FV/OVMF_CODE.fd
+OVMFVARS=$(OVMFBASE)/FV/OVMF_VARS.fd
+QEMU=qemu-system-x86_64
+QEMUFLAGS=-drive format=raw,file=fat:rw:image \
+ -drive if=pflash,format=raw,readonly,file=$(OVMFCODE) \
+ -drive if=pflash,format=raw,file=$(OVMFVARS) \
+ -debugcon file:$(LOG) -global isa-debugcon.iobase=0x402 \
+ -serial stdio \
+ -nographic \
+ -nodefaults
+
+run:
+ $(QEMU) $(QEMUFLAGS)
+
+debug:
+ $(QEMU) $(QEMUFLAGS) -s -S
+
+.PHONY: run debug
+Before debugging, run the firmware to get debug.log. It may be better to provide startup.nsh script.
+
+$ make run
+Now, we have debug.log. It includes the addresses of loaded UEFI images like this:
+
+Loading PEIM at 0x00007EA8000 EntryPoint=0x00007EAB0BC DxeCore.efi
+Next, extract text section (.text) RVA from *.efi PE binaries. This can be done by readelf if it is ELF, but the images are PE format. Here we use retrage/peinfo[3].
+
+$ git clone git@github.com:retrage/peinfo.git
+$ cd peinfo
+$ make
+peinfo extracts section information from a binary. This time we want to know VirtualAddress in RVA.
+
+Name: .text
+VirtualSize: 0x000204c0
+VirtualAddress: 0x00000240
+SizeOfRawData: 0x000204c0
+PointerToRawData: 0x00000240
+PointerToRelocations: 0x00000000
+PointerToLinenumbers: 0x00000000
+NumberOfRelocations: 0x0000
+NumberOfLinenumbers: 0x0000
+Characteristics: 0x60000020
+Run following bash script with debug.log and peinfo. This outputs a snippet of GDB script that adds symbol information (add-symbol-file). It calculates the address of UEFI image text section from base address and VirtualAddress.
+
+#!/bin/bash
+
+LOG="debug.log"
+BUILD="edk2/Build/OvmfX64/DEBUG_GCC5/X64"
+PEINFO="peinfo/peinfo"
+
+cat ${LOG} | grep Loading | grep -i efi | while read LINE; do
+ BASE="`echo ${LINE} | cut -d " " -f4`"
+ NAME="`echo ${LINE} | cut -d " " -f6 | tr -d "[:cntrl:]"`"
+ ADDR="`${PEINFO} ${BUILD}/${NAME} \
+ | grep -A 5 text | grep VirtualAddress | cut -d " " -f2`"
+ TEXT="`python -c "print(hex(${BASE} + ${ADDR}))"`"
+ SYMS="`echo ${NAME} | sed -e "s/\.efi/\.debug/g"`"
+ echo "add-symbol-file ${BUILD}/${SYMS} ${TEXT}"
+done
+$ bash gen_symbol_offsets.sh > gdbscript
+cat gdb
+The generated GDB script is like this:
+
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/PcdPeim.debug 0x82c380
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/ReportStatusCodeRouterPei.debug 0x831080
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/StatusCodeHandlerPei.debug 0x833100
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/PlatformPei.debug 0x835100
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/PeiCore.debug 0x7ee8240
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/DxeIpl.debug 0x7ee3240
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/S3Resume2Pei.debug 0x7edf240
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/CpuMpPei.debug 0x7ed6240
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/DxeCore.debug 0x7ea8240
+add-symbol-file edk2/Build/OvmfX64/DEBUG_GCC5/X64/DevicePathDxe.debug 0x7b8f240
+Now we are ready.
+
+$ less debug.log
+...
+The 0th FV start address is 0x0000082000
+...
+Loading PEIM at 0x0000082BFC0
+ Entry Point = 0x0000082F40A PcdPeim.efi
+...
+
+$ make debug
+
+Let’s place a breakpoint at BootServices->HandleProtocol().
+
+(gdb) source gdbscript
+.
+.
+.
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/UsbBusDxe.debug" at
+ .text_addr = 0x6c85240
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/UsbKbDxe.debug" at
+ .text_addr = 0x6cb3240
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/UsbMassStorageDxe.debug" at
+ .text_addr = 0x6c6d240
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/QemuVideoDxe.debug" at
+ .text_addr = 0x6c66240
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/VirtioGpuDxe.debug" at
+ .text_addr = 0x6c60240
+add symbol table from file "/home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/Shell.debug" at
+ .text_addr = 0x64f5240
+
+(gdb) info functions CoreHandleProtocol
+All functions matching regular expression "CoreHandleProtocol":
+File /.../edk2/MdeModulePkg/Core/Dxe/Hand/Handle.c:
+EFI_STATUS CoreHandleProtocol(EFI_HANDLE, EFI_GUID *, void **);
+
+(gdb) info address CoreHandleProtocol
+Symbol "CoreHandleProtocol" is a function at address 0x7ea4aa9.
+
+(gdb) b CoreHandleProtocol
+
+(gdb) info symbol 0x82F40A
+_ModuleEntryPoint in section .text of /home/koenigr/Memtest/git/edk2/Build/OvmfX64/DEBUG_GCC5/X64/PcdPeim.debug
+
+(gdb) b *0x82F40A
+Breakpoint 2 at 0x82f40a: file /home/koenigr/Memtest/git/edk2/MdePkg/Library/PeimEntryPoint/PeimEntryPoint.c, line 33.
+
+(gdb) target remote localhost:1234
+Remote debugging using localhost:1234
+warning: No executable has been specified and target does not support
+determining executable automatically. Try using the "file" command.
+0x000000000000fff0 in ?? ()
+
+(gdb) c
+
+The debugger stops, and we can do source code level debug.
+
+!!!!!!!!!!!!!!!!!!!!!!!!!!! DOES NOT WORK !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+
+ ┌──/home/akira/src/ovmf-debug/edk2/MdeModulePkg/Core/Dxe/Hand/Handle.c──────┐
+ │933 CoreHandleProtocol ( │
+ │934 IN EFI_HANDLE UserHandle, │
+ │935 IN EFI_GUID *Protocol, │
+ │936 OUT VOID **Interface │
+ │937 ) │
+B+>│938 { │
+ │939 return CoreOpenProtocol ( │
+ │940 UserHandle, │
+ │941 Protocol, │
+ │942 Interface, │
+ │943 gDxeCoreImageHandle, │
+ │944 NULL, │
+ │945 EFI_OPEN_PROTOCOL_BY_HANDLE_PROTOCOL │
+ └───────────────────────────────────────────────────────────────────────────┘
+remote Thread 1 In: CoreHandleProtocol L938 PC: 0x7eb6ad4
+
+
+
+(gdb)