[PATCH v3] arm64: add the printing of tpidr_elx in __show_regs()

[Zhen Lei]

Commit 7158627686f0 ("arm64: percpu: implement optimised pcpu access
using tpidr_el1") and commit 6d99b68933fb ("arm64: alternatives: use
tpidr_el2 on VHE hosts") use tpidr_elx to cache my_cpu_offset to optimize
pcpu access. However, when performing reverse execution based on the
registers and the memory contents in kdump, this information is sometimes
required if there is a pcpu access.

Signed-off-by: Zhen Lei <thunder.leizhen@xxxxxxxxxx>
---
 arch/arm64/kernel/process.c | 5 +++++
 1 file changed, 5 insertions(+)

v2 --> v3:
1) Relace "switch (read_sysreg(CurrentEL))" statement with
   "if (is_kernel_in_hyp_mode())" statement.
2) Change the register name to lowercase.

v1 --> v2:
Directly print the tpidr_elx register of the current exception level.
Avoid coupling with the implementation of 'my_cpu_offset'.

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 7fa97df55e3ad3f..7b6bccce9721c36 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -216,6 +216,11 @@ void __show_regs(struct pt_regs *regs)
 	show_regs_print_info(KERN_DEFAULT);
 	print_pstate(regs);
 
+	if (is_kernel_in_hyp_mode())
+		printk("tpidr_el2 : %016llx\n", read_sysreg(tpidr_el2));
+	else
+		printk("tpidr_el1 : %016llx\n", read_sysreg(tpidr_el1));
+
 	if (!user_mode(regs)) {
 		printk("pc : %pS\n", (void *)regs->pc);
 		printk("lr : %pS\n", (void *)ptrauth_strip_insn_pac(lr));
-- 
2.25.1