arm64: Correctly report LR and SP for compat tasks

When a task crashes and we print debugging information, ensure that
compat tasks show the actual AArch32 LR and SP registers rather than the
AArch64 ones.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 57fb55c44c901c19c7264f02ff44d6c481fadc56..7ae8a1f00c3c82bf256f716aee79aaf24fac8f1b 100644 (file)
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -143,15 +143,26 @@ void machine_restart(char *cmd)
 
 void __show_regs(struct pt_regs *regs)
 {
-       int i;
+       int i, top_reg;
+       u64 lr, sp;
+
+       if (compat_user_mode(regs)) {
+               lr = regs->compat_lr;
+               sp = regs->compat_sp;
+               top_reg = 12;
+       } else {
+               lr = regs->regs[30];
+               sp = regs->sp;
+               top_reg = 29;
+       }
 
        show_regs_print_info(KERN_DEFAULT);
        print_symbol("PC is at %s\n", instruction_pointer(regs));
-       print_symbol("LR is at %s\n", regs->regs[30]);
+       print_symbol("LR is at %s\n", lr);
        printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
-              regs->pc, regs->regs[30], regs->pstate);
-       printk("sp : %016llx\n", regs->sp);
-       for (i = 29; i >= 0; i--) {
+              regs->pc, lr, regs->pstate);
+       printk("sp : %016llx\n", sp);
+       for (i = top_reg; i >= 0; i--) {
                printk("x%-2d: %016llx ", i, regs->regs[i]);
                if (i % 2 == 0)
                        printk("\n");