[PATCH] efi_loader: Expose relocated address for gdb debugging purposes
* If users want to debug EFI applications via qemu + GDB, they need to know the relocated address of the application to align their symbols to in GDB via add-symbol-file. * This exposes where EFI applications are relocated to enable debugging EFI applications via qemu + gdb * Usage is generally determining the address, then add-symbol-file (efi loader) (address) * The address can change, but is generally consistent with the same qemu version and u-boot binary. (allowing you to boot once, find the address, then reboot with qemu -s -S --- lib/efi_loader/efi_image_loader.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index 773bd0677c..2b8c1ef464 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -906,6 +906,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, ret = EFI_OUT_OF_RESOURCES; goto err; } + log_info("64-bit EFI image loaded at relocated address %p\n", efi_reloc); + handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size; rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress; @@ -922,6 +924,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, ret = EFI_OUT_OF_RESOURCES; goto err; } + log_info("32-bit EFI image loaded at relocated address %p\n", efi_reloc); + handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size; rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
On 3/24/22 17:22, Alexander von Gluck IV wrote:
- If users want to debug EFI applications via qemu + GDB, they need to know the relocated address of the application to align their symbols to in GDB via add-symbol-file.
- This exposes where EFI applications are relocated to enable debugging EFI applications via qemu + gdb
- Usage is generally determining the address, then add-symbol-file (efi loader) (address)
- The address can change, but is generally consistent with the same qemu version and u-boot binary. (allowing you to boot once, find the address, then reboot with qemu -s -S
lib/efi_loader/efi_image_loader.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c index 773bd0677c..2b8c1ef464 100644 --- a/lib/efi_loader/efi_image_loader.c +++ b/lib/efi_loader/efi_image_loader.c @@ -906,6 +906,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, ret = EFI_OUT_OF_RESOURCES; goto err; }
log_info("64-bit EFI image loaded at relocated address %p\n", efi_reloc);- handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size; rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
@@ -922,6 +924,8 @@ efi_status_t efi_load_pe(struct efi_loaded_image_obj *handle, ret = EFI_OUT_OF_RESOURCES; goto err; }
log_info("32-bit EFI image loaded at relocated address %p\n", efi_reloc);- handle->entry = efi_reloc + opt->AddressOfEntryPoint; rel_size = opt->DataDirectory[rel_idx].Size; rel = efi_reloc + opt->DataDirectory[rel_idx].VirtualAddress;
Do we really always need this output for every invokation of LoadImage()?
Writing test messages during the runtime of a menu driven program like the UEFI SCT can be very disturbing.
Isn't it sufficient to show this output for binaries directly launched by U-Boot?
Best regards
Heinrich
March 24, 2022 12:06 PM, "Heinrich Schuchardt" xypron.glpk@gmx.de wrote:
On 3/24/22 17:22, Alexander von Gluck IV wrote: Do we really always need this output for every invokation of LoadImage()?
Writing test messages during the runtime of a menu driven program like the UEFI SCT can be very disturbing.
Isn't it sufficient to show this output for binaries directly launched by U-Boot?
Ideally this would be exposed strictly for the binaries directly launched, however the bare relocated address isn't exposed outside of the brief usage by LoadImage.
I figured that adding a required pointer arg to expose the relocated address might be overkill.
using log_debug over log_info was brought up as a good change, but that still suffers the same potential impact.
Maybe adding reloc_addr storage to efi_loaded_image_obj would be cleaner? (then digging it up during the efi launch for a quick log_info?)
-- Alex
March 24, 2022 1:25 PM, "Alexander von Gluck IV" kallisti5@unixzen.com wrote:
March 24, 2022 12:06 PM, "Heinrich Schuchardt" xypron.glpk@gmx.de wrote:
On 3/24/22 17:22, Alexander von Gluck IV wrote: Do we really always need this output for every invokation of LoadImage()?
Writing test messages during the runtime of a menu driven program like the UEFI SCT can be very disturbing.
Isn't it sufficient to show this output for binaries directly launched by U-Boot?
Ideally this would be exposed strictly for the binaries directly launched, however the bare relocated address isn't exposed outside of the brief usage by LoadImage.
I figured that adding a required pointer arg to expose the relocated address might be overkill.
using log_debug over log_info was brought up as a good change, but that still suffers the same potential impact.
Maybe adding reloc_addr storage to efi_loaded_image_obj would be cleaner? (then digging it up during the efi launch for a quick log_info?)
"PATCH] efi_loader (v2): Expose relocated address for gdb debugging purposes" has been submitted. Instead of printing the relocated address out immediately, v2 stores it in the efi_loaded_image_obj and references it later during the initial EFI boot.
The output of v2 can be seen below.
54 bytes read in 0 ms uEnv.txt says to look for efi bootloader named EFI/BOOT/BOOTRISCV64.EFI on virtio 0! Found EFI/BOOT/BOOTRISCV64.EFI on virtio 0! Loading bootloader... 800283 bytes read in 1 ms (763.2 MiB/s) Using internal DTB... Launching EFI loader... Scanning disk virtio-blk#8... Found 3 disks ** Unable to read file ubootefi.var ** Failed to load EFI variables Booting /EFI\BOOT\BOOTRISCV64.EFI EFI image relocated to 0xbe68e000
participants (3)
-
Alex -
Alexander von Gluck IV
-
Heinrich Schuchardt