[PATCH v7 24/33] arm64: idreg-override: Create a pseudo feature for rodata=off

[Ard Biesheuvel]

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 f44a7860636fd411..b8c7a2d13bbe44e2 100644
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -16,6 +16,7 @@
 #define cpu_feature(x)		KERNEL_HWCAP_ ## x
 
 #define ARM64_SW_FEATURE_OVERRIDE_NOKASLR	0
+#define ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF	4
 
 #ifndef __ASSEMBLY__
 
diff --git a/arch/arm64/kernel/pi/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c
index c21d1e9f43a11ba7..e524d36d8fc1526f 100644
--- a/arch/arm64/kernel/pi/idreg-override.c
+++ b/arch/arm64/kernel/pi/idreg-override.c
@@ -133,6 +133,7 @@ DEFINE_OVERRIDE(5, smfr0, "id_aa64smfr0", id_aa64smfr0_override,
 
 DEFINE_OVERRIDE(6, sw_features, "arm64_sw", arm64_sw_feature_override,
 		FIELD("nokaslr", ARM64_SW_FEATURE_OVERRIDE_NOKASLR),
+		FIELD("rodataoff", ARM64_SW_FEATURE_OVERRIDE_RODATA_OFF),
 		{});
 
 /*
@@ -164,6 +165,7 @@ static const struct {
 	  "id_aa64isar2.gpa3=0 id_aa64isar2.apa3=0"	   },
 	{ "arm64.nomte",		"id_aa64pfr1.mte=0" },
 	{ "nokaslr",			"arm64_sw.nokaslr=1" },
+	{ "rodata=off",			"arm64_sw.rodataoff=1" },
 };
 
 static int __init find_field(const char *cmdline, char *opt, int len,
-- 
2.35.1