From 1f38c6603c7160a2ee6b714293bf936f4f371b73 Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Fri, 11 Dec 2015 15:28:21 +0000 Subject: [PATCH] xen/arm64: Document the register mapping aarch64 <-> aarch32 The mapping between aarch64 and aarch32 has not been chosen in random. It's based on D1.20.1 in ARM DDI 0487A.d. The section is not obvious to find in the spec, so make it clear for the anyone else. Signed-off-by: Julien Grall Acked-by: Ian Campbell --- xen/include/asm-arm/arm64/processor.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/xen/include/asm-arm/arm64/processor.h b/xen/include/asm-arm/arm64/processor.h index 3a9c0cde0f..fef35a5aef 100644 --- a/xen/include/asm-arm/arm64/processor.h +++ b/xen/include/asm-arm/arm64/processor.h @@ -15,7 +15,12 @@ /* On stack VCPU state */ struct cpu_user_regs { - /* Aarch64 Aarch32 */ + /* + * The mapping AArch64 <-> AArch32 is based on D1.20.1 in ARM DDI + * 0487A.d. + * + * AArch64 AArch32 + */ __DECL_REG(x0, r0/*_usr*/); __DECL_REG(x1, r1/*_usr*/); __DECL_REG(x2, r2/*_usr*/); -- 2.30.2