arm64: expand register mapping between AArch32 and AArch64

The general purpose registers in AArch32 are mapped in an
architecturally defined manner into the AArch64 registers.

It allows the AArch32 registers of an application or a virtual
machine to be inspected by the OS or an hypervisor.
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm64/include/asm/ptrace.h

@@ -44,10 +44,27 @@
 
 /* sizeof(struct user) for AArch32 */
 #define COMPAT_USER_SZ	296
-/* AArch32 uses x13 as the stack pointer... */
+
+/* Architecturally defined mapping between AArch32 and AArch64 registers */
+#define compat_usr(x)	regs[(x)]
 #define compat_sp	regs[13]
-/* ... and x14 as the link register. */
 #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_r8_fiq	regs[24]
+#define compat_r9_fiq	regs[25]
+#define compat_r10_fiq	regs[26]
+#define compat_r11_fiq	regs[27]
+#define compat_r12_fiq	regs[28]
+#define compat_sp_fiq	regs[29]
+#define compat_lr_fiq	regs[30]
 
 /*
  * This struct defines the way the registers are stored on the stack during an