[PATCH v2 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.

Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/tools/gen-sysreg.awk |  2 +-
 arch/arm64/tools/sysreg         | 12 ++++++++++--
 2 files changed, 11 insertions(+), 3 deletions(-)

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..da3f02cdf1052 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -24,8 +24,16 @@
 #	...
 # EndEnum
 
-# Alternatively if multiple registers share the same layout then
-# a SysregFields block can be used to describe the shared layout
+# For VHE aliases (*_EL12, *_EL02) of system registers, a Mapping
+# entry describes the register the alias actually accesses:
+
+# Sysreg 	<name_EL12>	<op0> 	<op1>	<crn>	<crm>	<op2>
+# Mapping	<name_EL1>
+# EndSysreg
+
+# Where multiple system regsiters are not VHE aliases but share a
+# common layout, a SysregFields block can be used to describe the
+# shared layout:
 
 # SysregFields	<fieldsname>
 # <field>
-- 
2.39.2