From fdc8c8b5fa88494ee5f62572830de10d4187dcce Mon Sep 17 00:00:00 2001 From: Lee Leahy Date: Tue, 7 Jun 2016 08:45:17 -0700 Subject: arch/x86: Add debug spinloop Conditionally add a debug spinloop to enable easy connection of JTAG debuggers. TEST=Build and run on Galileo Gen2 with a JTAG debugger. Change-Id: I7a21f9e6bfb10912d06ce48447c61202553630d0 Signed-off-by: Lee Leahy Reviewed-on: https://review.coreboot.org/15127 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin --- src/arch/x86/Kconfig | 7 +++++++ src/arch/x86/bootblock_crt0.S | 9 +++++++++ 2 files changed, 16 insertions(+) (limited to 'src/arch/x86') diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig index 724c4dba61..8609e20136 100644 --- a/src/arch/x86/Kconfig +++ b/src/arch/x86/Kconfig @@ -117,6 +117,13 @@ config PC80_SYSTEM bool default y if ARCH_X86 +config BOOTBLOCK_DEBUG_SPINLOOP + bool + default n + help + Add a spin (JMP .) in bootblock_crt0.S during early bootblock to wait + for a JTAG debugger to break into the execution sequence. + config BOOTBLOCK_MAINBOARD_INIT string diff --git a/src/arch/x86/bootblock_crt0.S b/src/arch/x86/bootblock_crt0.S index 9fbce5dbb5..8ae82b4368 100644 --- a/src/arch/x86/bootblock_crt0.S +++ b/src/arch/x86/bootblock_crt0.S @@ -32,6 +32,15 @@ #include #include +#if IS_ENABLED(CONFIG_BOOTBLOCK_DEBUG_SPINLOOP) + + /* Wait for a JTAG debugger to break in and set EBX non-zero */ + xor %ebx, %ebx + +debug_spinloop: + cmp $0, %ebx + jz debug_spinloop +#endif bootblock_protected_mode_entry: /* Save BIST result */ -- cgit v1.2.3