diff mbox series

[v3,15/30] arm64: idreg-override: use early FDT mapping in ID map

Message ID 20220411094824.4176877-16-ardb@kernel.org
State Accepted
Commit a004393f45d9a55e55d76f252914bdddffdde204
Headers show
Series arm64: support WXN and entry with MMU enabled | expand

Commit Message

Ard Biesheuvel April 11, 2022, 9:48 a.m. UTC 
Instead of calling into the kernel to map the FDT into the kernel page
tables before even calling start_kernel(), let's switch to the initial,
temporary mapping of the device tree that has been added to the ID map.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/kernel/head.S           |  3 +--
 arch/arm64/kernel/idreg-override.c | 17 ++++++-----------
 2 files changed, 7 insertions(+), 13 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index bec3805c941c..eae147fabbee 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -468,8 +468,7 @@  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, x19				// pass FDT address in x0
 	bl	init_feature_override		// Parse cpu feature overrides
 #ifdef CONFIG_RANDOMIZE_BASE
 	tst	x23, ~(MIN_KIMG_ALIGN - 1)	// already running randomized?
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 8a2ceb591686..f92836e196e5 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -201,16 +201,11 @@  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;
@@ -222,9 +217,9 @@  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);
@@ -234,9 +229,9 @@  static __init void parse_cmdline(void)
 }
 
 /* Keep checkers quiet */
-void init_feature_override(void);
+void init_feature_override(const void *fdt);
 
-asmlinkage void __init init_feature_override(void)
+asmlinkage void __init init_feature_override(const void *fdt)
 {
 	int i;
 
@@ -247,7 +242,7 @@  asmlinkage void __init init_feature_override(void)
 		}
 	}
 
-	parse_cmdline();
+	parse_cmdline(fdt);
 
 	for (i = 0; i < ARRAY_SIZE(regs); i++) {
 		if (regs[i]->override)