Alexandru Gagniuc (mr.nuke.me@gmail.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/1454
-gerrit
commit 8455ac802e133d0fc7bfec98b1e72300ffb15d36 Author: Alexandru Gagniuc mr.nuke.me@gmail.com Date: Wed Aug 15 06:45:18 2012 -0500
coreboot: Dump memory around problem area when encountering exception
When we encounter an x86 exception, we print the problem address, dump the registers and die. This may not be sufficient information for debug. Also dump the memory around the problem instruction. This has proven useful in identifying memory issues, and DRAM burst reordering problems.
Change-Id: I6411344e89f946e16d11217d7dbd73812c45d54c Signed-off-by: Alexandru Gagniuc mr.nuke.me@gmail.com --- src/arch/x86/lib/exception.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
diff --git a/src/arch/x86/lib/exception.c b/src/arch/x86/lib/exception.c index 4721bc8..d9a6776 100644 --- a/src/arch/x86/lib/exception.c +++ b/src/arch/x86/lib/exception.c @@ -475,6 +475,7 @@ void x86_exception(struct eregs *info) put_packet(out_buffer); } #else /* !CONFIG_GDB_STUB */ +#define MDUMP_SIZE 0x80 printk(BIOS_EMERG, "Unexpected Exception: %d @ %02x:%08x - Halting\n" "Code: %d eflags: %08x\n" @@ -484,6 +485,18 @@ void x86_exception(struct eregs *info) info->error_code, info->eflags, info->eax, info->ebx, info->ecx, info->edx, info->edi, info->esi, info->ebp, info->esp); + u8 *code = (u8*)((u32)info->eip - (MDUMP_SIZE >>1)); + /* Align to 8-byte boundary please, and print eight bytes per row. + * This is done to make DRAM burst timing/reordering errors more + * evident from the looking at the dump */ + code = (u8*)((u32)code & ~(0x7)); + int i; + for(i = 0; i < MDUMP_SIZE; i++) + { + if( (i&0x07) == 0 ) + printk(BIOS_EMERG, "\n%.8x:\t", (int)code + i ); + printk(BIOS_EMERG, "%.2x ", code[i]); + } die(""); #endif }