arm64: unwind: reference pt_regs via embedded stack frame

[sfrench/cifs-2.6.git] / arch / arm64 / kernel / entry.S

diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 9e126d3d8b531ee5fb439a3d3b8ecba175bf572d..612a077ba109d533bb9f1406e7ea54ad947cd01d 100644 (file)
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -111,6 +111,18 @@
        mrs     x23, spsr_el1
        stp     lr, x21, [sp, #S_LR]
 
+       /*
+        * In order to be able to dump the contents of struct pt_regs at the
+        * time the exception was taken (in case we attempt to walk the call
+        * stack later), chain it together with the stack frames.
+        */
+       .if \el == 0
+       stp     xzr, xzr, [sp, #S_STACKFRAME]
+       .else
+       stp     x29, x22, [sp, #S_STACKFRAME]
+       .endif
+       add     x29, sp, #S_STACKFRAME
+
 #ifdef CONFIG_ARM64_SW_TTBR0_PAN
        /*
         * Set the TTBR0 PAN bit in SPSR. When the exception is taken from
@@ -265,14 +277,6 @@ alternative_else_nop_endif
 
        /* switch to the irq stack */
        mov     sp, x26
-
-       /*
-        * Add a dummy stack frame, this non-standard format is fixed up
-        * by unwind_frame()
-        */
-       stp     x29, x19, [sp, #-16]!
-       mov     x29, sp
-
 9998:
        .endm