From d131ea30785d0d862e169135a9d4c24afaeaa8c0 Mon Sep 17 00:00:00 2001 From: Lee Leahy Date: Wed, 8 Jun 2016 13:40:08 -0700 Subject: arch/x86: Add debug spinloops in assembly_entry.S Use Kconfig values to enable debug spinloops in assembly_entry.S. This makes it easy to debug the assembly code. TEST=Build and run on Galileo Gen2 Change-Id: Ic56bf2260b8e3181403623961874c9289f3ca945 Signed-off-by: Lee Leahy Reviewed-on: https://review.coreboot.org/15135 Tested-by: build bot (Jenkins) Reviewed-by: Paul Menzel Reviewed-by: Aaron Durbin --- src/arch/x86/Kconfig | 14 ++++++++++++++ src/arch/x86/assembly_entry.S | 11 +++++++++++ 2 files changed, 25 insertions(+) (limited to 'src/arch/x86') diff --git a/src/arch/x86/Kconfig b/src/arch/x86/Kconfig index 8609e20136..1fea99ac3b 100644 --- a/src/arch/x86/Kconfig +++ b/src/arch/x86/Kconfig @@ -179,3 +179,17 @@ config VERSTAGE_ADDR # from a program loaded in ram and subsequently loading ramstage. config POSTCAR_STAGE def_bool n + +config VERSTAGE_DEBUG_SPINLOOP + bool + default n + help + Add a spin (JMP .) in assembly_entry.S during early verstage to wait + for a JTAG debugger to break into the execution sequence. + +config ROMSTAGE_DEBUG_SPINLOOP + bool + default n + help + Add a spin (JMP .) in assembly_entry.S during early romstage to wait + for a JTAG debugger to break into the execution sequence. diff --git a/src/arch/x86/assembly_entry.S b/src/arch/x86/assembly_entry.S index 86dbba4668..d1f5d61ce7 100644 --- a/src/arch/x86/assembly_entry.S +++ b/src/arch/x86/assembly_entry.S @@ -52,6 +52,17 @@ _start: sub %edi, %ecx rep stosl +#if ((ENV_VERSTAGE && IS_ENABLED(CONFIG_VERSTAGE_DEBUG_SPINLOOP)) \ + || (ENV_ROMSTAGE && IS_ENABLED(CONFIG_ROMSTAGE_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 + jmp car_stage_entry /* This is here for linking purposes. */ -- cgit v1.2.3