[PATCH v4 28/61] arm64: idreg-override: Create a pseudo feature for rodata=off

[Ard Biesheuvel]

From: Ard Biesheuvel <ardb at kernel.org>

Add rodata=off to the set of kernel command line options that is parsed
early using the CPU feature override detection code, so we can easily
refer to it when creating the kernel mapping.

Signed-off-by: Ard Biesheuvel <ardb at kernel.org>
---
 arch/arm64/include/asm/cpufeature.h   | 1 +
 arch/arm64/kernel/pi/idreg-override.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
index 6c0e2cb710d0..54f3dbeb9e80 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -17,6 +17,7 @@
 
 #define ARM64_SW_FEATURE_OVERRIDE_NOKASLR	0
 #define ARM64_SW_FEATURE_OVERRIDE_HVHE		4
+#define ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF	8
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c
index 26961e0f94b7..1aa59c01ab33 100644
--- a/arch/arm64/kernel/pi/idreg-override.c
+++ b/arch/arm64/kernel/pi/idreg-override.c
@@ -163,6 +163,7 @@ static const struct ftr_set_desc sw_features __prel64_initconst = {
 	.fields		= {
 		FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR, NULL),
 		FIELD("hvhe", ARM64_SW_FEATURE_OVERRIDE_HVHE, hvhe_filter),
+		FIELD("rodataoff", ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF, NULL),
 		{}
 	},
 };
@@ -196,6 +197,7 @@ static const struct {
 	{ "arm64.nomops",		"id_aa64isar2.mops=0" },
 	{ "arm64.nomte",		"id_aa64pfr1.mte=0" },
 	{ "nokaslr",			"arm64_sw.nokaslr=1" },
+	{ "rodata=off",			"arm64_sw.rodataoff=1" },
 };
 
 static int __init parse_hexdigit(const char *p, u64 *v)
-- 
2.42.0.283.g2d96d420d3-goog