[PATCH 1/4] arm64/sysreg: Allow a 'Mapping' descriptor for system registers

[Marc Zyngier <maz@kernel.org>]

*EL02 and *_EL12 system registers are actually only accessors for
EL0 and EL1 registers accessed from EL2 when HCR_EL2.E2H==1. They
do not have fields of their own.

To that effect, introduce a 'Mapping' entry, describing which
system register an _EL12 register maps to.

Implementation wise, this is handled the same was as Fields,
which ls only a comment.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/tools/gen-sysreg.awk | 2 +-
 arch/arm64/tools/sysreg         | 7 +++++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/tools/gen-sysreg.awk b/arch/arm64/tools/gen-sysreg.awk
index d1254a056114e..1a2afc9fdd42e 100755
--- a/arch/arm64/tools/gen-sysreg.awk
+++ b/arch/arm64/tools/gen-sysreg.awk
@@ -206,7 +206,7 @@ END {
 
 # Currently this is effectivey a comment, in future we may want to emit
 # defines for the fields.
-/^Fields/ && block_current() == "Sysreg" {
+(/^Fields/ || /^Mapping/) && block_current() == "Sysreg" {
 	expect_fields(2)
 
 	if (next_bit != 63)
diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index b081b54d6d227..b6846c601df6c 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -38,6 +38,13 @@
 # Fields	<fieldsname>
 # EndSysreg
 
+# For register names indicating a cross-EL access (*_EL12, *EL02),
+# a Mapping entry describes the register it actually accesses:
+
+# Sysreg 	<name_EL12>	<op0> 	<op1>	<crn>	<crm>	<op2>
+# Mapping	<name_EL1>
+# EndSysreg
+
 # For ID registers we adopt a few conventions for translating the
 # language in the ARM into defines:
 #
-- 
2.39.2