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From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: will@kernel.org, catalin.marinas@arm.com, maz@kernel.org,
	mark.rutland@arm.com, linux-efi@vger.kernel.org,
	keescook@chromium.org, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH v3 2/7] arm64: kernel: move ID map out of .text mapping
Date: Sat, 27 Aug 2022 17:58:47 +0200	[thread overview]
Message-ID: <20220827155852.3338551-3-ardb@kernel.org> (raw)
In-Reply-To: <20220827155852.3338551-1-ardb@kernel.org>

Reorganize the ID map slightly so that only code that is executed via
the 1:1 mapping remains. This allows us to move the ID map out of the
.text segment, as it will no longer need executable permissions via the
kernel mapping.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 arch/arm64/kernel/head.S        | 5 ++++-
 arch/arm64/kernel/vmlinux.lds.S | 2 +-
 arch/arm64/mm/proc.S            | 2 --
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index bd7c04f1f993..cfc7ba25bf87 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -474,7 +474,7 @@ SYM_FUNC_END(__primary_switched)
  * end early head section, begin head code that is also used for
  * hotplug and needs to have the same protections as the text region
  */
-	.section ".idmap.text","awx"
+	.text
 
 /*
  * Starting from EL2 or EL1, configure the CPU to execute at the highest
@@ -554,6 +554,7 @@ SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)
 	ret
 SYM_FUNC_END(set_cpu_boot_mode_flag)
 
+	.section ".idmap.text","awx"
 	/*
 	 * This provides a "holding pen" for platforms to hold all secondary
 	 * cores are held until we're ready for them to initialise.
@@ -598,6 +599,7 @@ SYM_FUNC_START_LOCAL(secondary_startup)
 	br	x8
 SYM_FUNC_END(secondary_startup)
 
+	.text
 SYM_FUNC_START_LOCAL(__secondary_switched)
 	mov	x0, x20
 	bl	set_cpu_boot_mode_flag
@@ -657,6 +659,7 @@ SYM_FUNC_END(__secondary_too_slow)
  * Checks if the selected granule size is supported by the CPU.
  * If it isn't, park the CPU
  */
+	.section ".idmap.text","awx"
 SYM_FUNC_START(__enable_mmu)
 	mrs	x3, ID_AA64MMFR0_EL1
 	ubfx	x3, x3, #ID_AA64MMFR0_TGRAN_SHIFT, 4
diff --git a/arch/arm64/kernel/vmlinux.lds.S b/arch/arm64/kernel/vmlinux.lds.S
index 0efccdf52be2..5002d869fa7f 100644
--- a/arch/arm64/kernel/vmlinux.lds.S
+++ b/arch/arm64/kernel/vmlinux.lds.S
@@ -168,7 +168,6 @@ SECTIONS
 			LOCK_TEXT
 			KPROBES_TEXT
 			HYPERVISOR_TEXT
-			IDMAP_TEXT
 			*(.gnu.warning)
 		. = ALIGN(16);
 		*(.got)			/* Global offset table		*/
@@ -195,6 +194,7 @@ SECTIONS
 		TRAMP_TEXT
 		HIBERNATE_TEXT
 		KEXEC_TEXT
+		IDMAP_TEXT
 		. = ALIGN(PAGE_SIZE);
 	}
 
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index 7837a69524c5..113a4fedf5b8 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -107,7 +107,6 @@ SYM_FUNC_END(cpu_do_suspend)
  *
  * x0: Address of context pointer
  */
-	.pushsection ".idmap.text", "awx"
 SYM_FUNC_START(cpu_do_resume)
 	ldp	x2, x3, [x0]
 	ldp	x4, x5, [x0, #16]
@@ -163,7 +162,6 @@ alternative_else_nop_endif
 	isb
 	ret
 SYM_FUNC_END(cpu_do_resume)
-	.popsection
 #endif
 
 	.pushsection ".idmap.text", "awx"
-- 
2.35.1


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  parent reply	other threads:[~2022-08-27 16:00 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-27 15:58 [PATCH v3 0/7] arm64: efi: leave MMU and caches on at boot Ard Biesheuvel
2022-08-27 15:58 ` [PATCH v3 1/7] arm64: lds: reduce effective minimum image alignment to 64k Ard Biesheuvel
2022-08-27 15:58 ` Ard Biesheuvel [this message]
2022-08-27 15:58 ` [PATCH v3 3/7] arm64: head: record the MMU state at primary entry Ard Biesheuvel
2022-08-27 15:58 ` [PATCH v3 4/7] arm64: head: avoid cache invalidation when entering with the MMU on Ard Biesheuvel
2022-08-27 15:58 ` [PATCH v3 5/7] arm64: head: clean the ID map page to the PoC Ard Biesheuvel
2022-08-27 15:58 ` [PATCH v3 6/7] arm64: efi/libstub: use EFI_LOADER_CODE region when moving the kernel in memory Ard Biesheuvel
2022-08-27 15:58 ` [PATCH v3 7/7] arm64: efi/libstub: enter with the MMU on Ard Biesheuvel

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