linux-hardening - [PATCH v4 21/26] arm64: setup: drop early FDT pointer helpers

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Date:   Mon, 13 Jun 2022 16:45:45 +0200
From:   Ard Biesheuvel <ardb@...nel.org>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     linux-hardening@...r.kernel.org, Ard Biesheuvel <ardb@...nel.org>,
        Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Kees Cook <keescook@...omium.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Mark Brown <broonie@...nel.org>,
        Anshuman Khandual <anshuman.khandual@....com>
Subject: [PATCH v4 21/26] arm64: setup: drop early FDT pointer helpers

We no longer need to call into the kernel to map the FDT before calling
into the kernel so let's drop the helpers we added for this.

Signed-off-by: Ard Biesheuvel <ardb@...nel.org>
---
 arch/arm64/include/asm/setup.h |  3 ---
 arch/arm64/kernel/head.S       |  2 --
 arch/arm64/kernel/setup.c      | 15 ---------------
 3 files changed, 20 deletions(-)

diff --git a/arch/arm64/include/asm/setup.h b/arch/arm64/include/asm/setup.h
index 6437df661700..5f147a418281 100644
--- a/arch/arm64/include/asm/setup.h
+++ b/arch/arm64/include/asm/setup.h
@@ -5,9 +5,6 @@
 
 #include <uapi/asm/setup.h>
 
-void *get_early_fdt_ptr(void);
-void early_fdt_map(u64 dt_phys);
-
 /*
  * These two variables are used in the head.S file.
  */
diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 5a2ff6466b6b..6bf685f988f1 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -446,8 +446,6 @@ 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, x22				// pass FDT address in x0
 	bl	init_feature_override		// Parse cpu feature overrides
 	mov	x0, x20
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index cf3a759f10d4..6c2120afe542 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -163,21 +163,6 @@ static void __init smp_build_mpidr_hash(void)
 		pr_warn("Large number of MPIDR hash buckets detected\n");
 }
 
-static void *early_fdt_ptr __initdata;
-
-void __init *get_early_fdt_ptr(void)
-{
-	return early_fdt_ptr;
-}
-
-asmlinkage void __init early_fdt_map(u64 dt_phys)
-{
-	int fdt_size;
-
-	early_fixmap_init();
-	early_fdt_ptr = fixmap_remap_fdt(dt_phys, &fdt_size, PAGE_KERNEL);
-}
-
 static void __init setup_machine_fdt(phys_addr_t dt_phys)
 {
 	int size;
-- 
2.30.2