[RFC,8/8] riscv/kaslr: dump out kernel offset information on panic

Commit Message

Zong Li March 24, 2020, 7:30 a.m. UTC

Dump out the kernel offset when panic to help debug kernel.

Signed-off-by: Zong Li <[e-mail]>
---
 arch/riscv/kernel/setup.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Patch

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 913d25e4b9fa..3ce50bf628ba 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -85,3 +85,26 @@  void __init setup_arch(char **cmdline_p)
 
 	riscv_fill_hwcap();
 }
+
+static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
+			      void *p)
+{
+	pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
+		 get_kaslr_offset(), PAGE_OFFSET);
+
+	return 0;
+}
+
+static struct notifier_block kernel_offset_notifier = {
+	.notifier_call = dump_kernel_offset
+};
+
+static int __init register_kernel_offset_dumper(void)
+{
+	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && get_kaslr_offset() > 0)
+		atomic_notifier_chain_register(&panic_notifier_list,
+					       &kernel_offset_notifier);
+
+	return 0;
+}
+__initcall(register_kernel_offset_dumper);