From 72548e836b0c4abbb652e791dee9c91203a9a4c6 Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Fri, 4 Oct 2013 09:36:56 +0100 Subject: x86/efi: Add EFI framebuffer earlyprintk support It's incredibly difficult to diagnose early EFI boot issues without special hardware because earlyprintk=vga doesn't work on EFI systems. Add support for writing to the EFI framebuffer, via earlyprintk=efi, which will actually give users a chance of providing debug output. Cc: H. Peter Anvin Acked-by: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Jones Signed-off-by: Matt Fleming --- arch/x86/Kconfig.debug | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86/Kconfig.debug') diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug index 78d91afb8e50..0f3621ed1db6 100644 --- a/arch/x86/Kconfig.debug +++ b/arch/x86/Kconfig.debug @@ -59,6 +59,16 @@ config EARLY_PRINTK_DBGP with klogd/syslogd or the X server. You should normally N here, unless you want to debug such a crash. You need usb debug device. +config EARLY_PRINTK_EFI + bool "Early printk via the EFI framebuffer" + depends on EFI && EARLY_PRINTK + select FONT_SUPPORT + ---help--- + Write kernel log output directly into the EFI framebuffer. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. + config X86_PTDUMP bool "Export kernel pagetable layout to userspace via debugfs" depends on DEBUG_KERNEL -- cgit v1.2.3