x86/kexec: Add CONFIG_KEXEC_DEBUG option

This does nothing yet. Support for x86_64 will follow in subsequent
commits, and an Arm64 version is also being worked on.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 74777a97e394aacfe11b824225df77bedf734734..c54cbd36c71027b8316a25a6d184378e24fb2192 100644 (file)
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -13,6 +13,7 @@ config X86_VERBOSE_BOOTUP
 
 config EARLY_PRINTK
        bool "Early printk" if EXPERT
+       select HAVE_KEXEC_DEBUG if X86_64
        default y
        help
          Write kernel log output directly into the VGA buffer or to a serial

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 4d111f871951676544ed248b394c22b157b9536a..a65b49c083c906683573869da1500f3c88ba82a6 100644 (file)
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -17,6 +17,9 @@ config KEXEC_ELF
 config HAVE_IMA_KEXEC
        bool
 
+config HAVE_KEXEC_DEBUG
+       bool
+
 config KEXEC
        bool "Enable kexec system call"
        depends on ARCH_SUPPORTS_KEXEC
@@ -95,6 +98,14 @@ config KEXEC_JUMP
          Jump between original kernel and kexeced kernel and invoke
          code in physical address mode via KEXEC
 
+config KEXEC_DEBUG
+       bool "Debug kexec transition"
+       depends on HAVE_KEXEC_DEBUG
+       help
+         Faults during kexec can be difficult to debug. This installs exception
+         handlers and attempts to report faults. On x86_64 this would use the
+         serial port configured for earlyprintk.
+
 config CRASH_DUMP
        bool "kernel crash dumps"
        default ARCH_DEFAULT_CRASH_DUMP