arm64: Fix compat register mappings

commit 5accd17 upstream.

For reasons not entirely apparent, but now enshrined in history, the
architectural mapping of AArch32 banked registers to AArch64 registers
actually orders SP_<mode> and LR_<mode> backwards compared to the
intuitive r13/r14 order, for all modes except FIQ.

Fix the compat_<reg>_<mode> macros accordingly, in the hope of avoiding
subtle bugs with KVM and AArch32 guests.

Signed-off-by: Robin Murphy <[email protected]>
Acked-by: Will Deacon <[email protected]>
Signed-off-by: Catalin Marinas <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

arch/arm64/include/asm/ptrace.h

@@ -71,14 +71,14 @@
 #define compat_sp	regs[13]
 #define compat_lr	regs[14]
 #define compat_sp_hyp	regs[15]
-#define compat_sp_irq	regs[16]
-#define compat_lr_irq	regs[17]
-#define compat_sp_svc	regs[18]
-#define compat_lr_svc	regs[19]
-#define compat_sp_abt	regs[20]
-#define compat_lr_abt	regs[21]
-#define compat_sp_und	regs[22]
-#define compat_lr_und	regs[23]
+#define compat_lr_irq	regs[16]
+#define compat_sp_irq	regs[17]
+#define compat_lr_svc	regs[18]
+#define compat_sp_svc	regs[19]
+#define compat_lr_abt	regs[20]
+#define compat_sp_abt	regs[21]
+#define compat_lr_und	regs[22]
+#define compat_sp_und	regs[23]
 #define compat_r8_fiq	regs[24]
 #define compat_r9_fiq	regs[25]
 #define compat_r10_fiq	regs[26]