Re: [PATCH 1/1] doc: add more details for crash dump analysis

On 8/2/22 9:29 AM, Heinrich Schuchardt wrote:

• describe crashs in UEFI binaries
• provide architechture specific information for the sandbox and RISC-V

Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

doc/develop/crash_dumps.rst | 52 +++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+)

diff --git a/doc/develop/crash_dumps.rst b/doc/develop/crash_dumps.rst index 85030b4e36..9e7ae3d751 100644 --- a/doc/develop/crash_dumps.rst +++ b/doc/develop/crash_dumps.rst @@ -122,3 +122,55 @@ If we want to dive deeper, we can disassemble the U-Boot binary::

This example is based on the ARMv8 architecture but the same procedures can be used on other architectures as well.

+Crashs in UEFI binaries +-----------------------

+If UEFI images are loaded when a crash occurs, their load addresses are +displayed. If the process counter points to an address in a loaded UEFI +binary, the relative process counter position is indicated. Here is an +example executed on the U-Boot sandbox::

• => load host 0:1 $kernel_addr_r buggy.efi
• 5632 bytes read in 0 ms
• => bootefi $kernel_addr_r
• Booting /buggy.efi
• Buggy world!
• Segmentation violation
• pc = 0x19fc264c, pc_reloc = 0xffffaa4688b1664c
• UEFI image [0x0000000019fc0000:0x0000000019fc6137] pc=0x264c '/buggy.efi'

+The crash occured in UEFI binary buggy.efi at relative position 0x264c. +Disassembly may be used to find the actual source code location::

• $ x86_64-linux-gnu-objdump -S -D buggy_efi.so
• 0000000000002640 <memset>:

•    2640:       f3 0f 1e fa             endbr64
  

•    2644:       48 89 f8                mov    %rdi,%rax
  

•    2647:       48 89 f9                mov    %rdi,%rcx
  

•    264a:       eb 0b                   jmp    2657 <memset+0x17>
  

•    264c:       40 88 31                mov    %sil,(%rcx)
  

+Architecture specific details +-----------------------------

+RISC-V +~~~~~~

+On the RISC-V architecture CONFIG_SHOW_REGS=y has to be specified to show +all registers in crash dumps.

See also: CONFIG_ARMV8_SPL_EXCEPTION_VECTORS

+Sandbox +~~~~~~~

+The sandbox U-Boot binary must be invoked with parameter *-S* to display crash +dumps:

+.. code-block:: bash

• ./u-boot -S -T

+Only with CONFIG_SANDBOX_CRASH_RESET=y the sandbox reboots after a crash.