[PATCH v17 10/13] arm64: kdump: add VMCOREINFO for user-space coredump tools

[Geoff Levand]

From: AKASHI Takahiro <takahiro.akashi at linaro.org>

For the current crash utility, we need to know, at least, a value of
"kimage_voffset" to handle the contents of core dump file (/proc/vmcore)
correctly due to the introduction of KASLR (CONFIG_RANDOMIZE_BASE) in v4.6.

More VMCOREINFO may be added later for makedumpfile command.
---
 arch/arm64/kernel/machine_kexec.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c
index 92e8a92..ac3655f 100644
--- a/arch/arm64/kernel/machine_kexec.c
+++ b/arch/arm64/kernel/machine_kexec.c
@@ -22,6 +22,7 @@
 
 #include <asm/cacheflush.h>
 #include <asm/cpu_ops.h>
+#include <asm/memory.h>
 #include <asm/mmu_context.h>
 #include <asm/system_misc.h>
 
@@ -299,3 +300,10 @@ void machine_crash_shutdown(struct pt_regs *regs)
 
 	pr_info("Starting crashdump kernel...\n");
 }
+
+void arch_crash_save_vmcoreinfo(void)
+{
+	/* Please note VMCOREINFO_NUMBER() uses "%d", not "%x" */
+	vmcoreinfo_append_str("NUMBER(kimage_voffset)=0x%llx\n",
+						kimage_voffset);
+}
-- 
2.5.0