arm64: idreg-override: Move to early mini C runtime

We will want to parse the ID register overrides even earlier, so that we
can take them into account before creating the kernel mapping. So
migrate the code and make it work in the context of the early C runtime.
We will move the invocation to an earlier stage in a subsequent patch.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20240214122845.2033971-49-ardb+git@google.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

5 files changed, 30 insertions, 28 deletions

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 78f14084f6d7..4236f1e0fffa 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile
@@ -33,8 +33,7 @@ obj-y			:= debug-monitors.o entry.o irq.o fpsimd.o		\
 			   return_address.o cpuinfo.o cpu_errata.o		\
 			   cpufeature.o alternative.o cacheinfo.o		\
 			   smp.o smp_spin_table.o topology.o smccc-call.o	\
-			   syscall.o proton-pack.o idreg-override.o idle.o	\
-			   patching.o
+			   syscall.o proton-pack.o idle.o patching.o pi/
 
 obj-$(CONFIG_COMPAT)			+= sys32.o signal32.o			\
 					   sys_compat.o
@@ -57,7 +56,6 @@ obj-$(CONFIG_ACPI)			+= acpi.o
 obj-$(CONFIG_ACPI_NUMA)			+= acpi_numa.o
 obj-$(CONFIG_ARM64_ACPI_PARKING_PROTOCOL)	+= acpi_parking_protocol.o
 obj-$(CONFIG_PARAVIRT)			+= paravirt.o
-obj-$(CONFIG_RELOCATABLE)		+= pi/
 obj-$(CONFIG_RANDOMIZE_BASE)		+= kaslr.o
 obj-$(CONFIG_HIBERNATION)		+= hibernate.o hibernate-asm.o
 obj-$(CONFIG_ELF_CORE)			+= elfcore.o
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index a8fa64fc30d7..ca5e5fbefcd3 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -510,10 +510,9 @@ SYM_FUNC_START_LOCAL(__primary_switched)
 #if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
 	bl	kasan_early_init
 #endif
-	mov	x0, x21				// pass FDT address in x0
-	bl	early_fdt_map			// Try mapping the FDT early
 	mov	x0, x20				// pass the full boot status
-	bl	init_feature_override		// Parse cpu feature overrides
+	mov	x1, x22				// pass the low FDT mapping
+	bl	__pi_init_feature_override	// Parse cpu feature overrides
 #ifdef CONFIG_UNWIND_PATCH_PAC_INTO_SCS
 	bl	scs_patch_vmlinux
 #endif
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index e931ce078a00..eacc3d167733 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -37,6 +37,15 @@ PROVIDE(__pi___memmove			= __pi_memmove);
 PROVIDE(__pi___memset			= __pi_memset);
 
 PROVIDE(__pi_vabits_actual		= vabits_actual);
+PROVIDE(__pi_id_aa64isar1_override	= id_aa64isar1_override);
+PROVIDE(__pi_id_aa64isar2_override	= id_aa64isar2_override);
+PROVIDE(__pi_id_aa64mmfr1_override	= id_aa64mmfr1_override);
+PROVIDE(__pi_id_aa64pfr0_override	= id_aa64pfr0_override);
+PROVIDE(__pi_id_aa64pfr1_override	= id_aa64pfr1_override);
+PROVIDE(__pi_id_aa64smfr0_override	= id_aa64smfr0_override);
+PROVIDE(__pi_id_aa64zfr0_override	= id_aa64zfr0_override);
+PROVIDE(__pi_arm64_sw_feature_override	= arm64_sw_feature_override);
+PROVIDE(__pi__ctype			= _ctype);
 
 #ifdef CONFIG_KVM
 
diff --git a/arch/arm64/kernel/pi/Makefile b/arch/arm64/kernel/pi/Makefile
index d084c1dcf416..7f6dfce893c3 100644
--- a/arch/arm64/kernel/pi/Makefile
+++ b/arch/arm64/kernel/pi/Makefile
@@ -38,6 +38,7 @@ $(obj)/lib-%.pi.o: OBJCOPYFLAGS += --prefix-alloc-sections=.init
 $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
 	$(call if_changed_rule,cc_o_c)
 
-obj-y				:= relocate.pi.o
-obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr_early.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o
+obj-y				:= idreg-override.pi.o lib-fdt.pi.o lib-fdt_ro.pi.o
+obj-$(CONFIG_RELOCATABLE)	+= relocate.pi.o
+obj-$(CONFIG_RANDOMIZE_BASE)	+= kaslr_early.pi.o
 extra-y				:= $(patsubst %.pi.o,%.o,$(obj-y))
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/pi/idreg-override.c
index e30fd9e32ef3..f9e05c10faab 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/pi/idreg-override.c
@@ -14,6 +14,8 @@
 #include <asm/cpufeature.h>
 #include <asm/setup.h>
 
+#include "pi.h"
+
 #define FTR_DESC_NAME_LEN	20
 #define FTR_DESC_FIELD_LEN	10
 #define FTR_ALIAS_NAME_LEN	30
@@ -21,15 +23,6 @@
 
 static u64 __boot_status __initdata;
 
-// temporary __prel64 related definitions
-// to be removed when this code is moved under pi/
-
-#define __prel64_initconst	__initconst
-
-#define PREL64(type, name)	union { type *name; }
-
-#define prel64_pointer(__d)	(__d)
-
 typedef bool filter_t(u64 val);
 
 struct ftr_set_desc {
@@ -313,16 +306,11 @@ static __init void __parse_cmdline(const char *cmdline, bool parse_aliases)
 	} while (1);
 }
 
-static __init const u8 *get_bootargs_cmdline(void)
+static __init const u8 *get_bootargs_cmdline(const void *fdt)
 {
 	const u8 *prop;
-	void *fdt;
 	int node;
 
-	fdt = get_early_fdt_ptr();
-	if (!fdt)
-		return NULL;
-
 	node = fdt_path_offset(fdt, "/chosen");
 	if (node < 0)
 		return NULL;
@@ -334,9 +322,9 @@ static __init const u8 *get_bootargs_cmdline(void)
 	return strlen(prop) ? prop : NULL;
 }
 
-static __init void parse_cmdline(void)
+static __init void parse_cmdline(const void *fdt)
 {
-	const u8 *prop = get_bootargs_cmdline();
+	const u8 *prop = get_bootargs_cmdline(fdt);
 
 	if (IS_ENABLED(CONFIG_CMDLINE_FORCE) || !prop)
 		__parse_cmdline(CONFIG_CMDLINE, true);
@@ -346,9 +334,9 @@ static __init void parse_cmdline(void)
 }
 
 /* Keep checkers quiet */
-void init_feature_override(u64 boot_status);
+void init_feature_override(u64 boot_status, const void *fdt);
 
-asmlinkage void __init init_feature_override(u64 boot_status)
+asmlinkage void __init init_feature_override(u64 boot_status, const void *fdt)
 {
 	struct arm64_ftr_override *override;
 	const struct ftr_set_desc *reg;
@@ -364,7 +352,7 @@ asmlinkage void __init init_feature_override(u64 boot_status)
 
 	__boot_status = boot_status;
 
-	parse_cmdline();
+	parse_cmdline(fdt);
 
 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
 		reg = prel64_pointer(regs[i].reg);
@@ -373,3 +361,10 @@ asmlinkage void __init init_feature_override(u64 boot_status)
 				       (unsigned long)(override + 1));
 	}
 }
+
+char * __init skip_spaces(const char *str)
+{
+	while (isspace(*str))
+		++str;
+	return (char *)str;
+}