All of lore.kernel.org
 help / color / mirror / Atom feed
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org, keescook@chromium.org,
	Ard Biesheuvel <ardb@kernel.org>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH v4 2/6] arm64: kernel: move identity map out of .text mapping
Date: Tue, 18 Oct 2022 13:04:37 +0200	[thread overview]
Message-ID: <20221018110441.3855148-3-ardb@kernel.org> (raw)
In-Reply-To: <20221018110441.3855148-1-ardb@kernel.org>

Reorganize the ID map slightly so that only code that is executed with
the MMU off or via the 1:1 mapping remains. This allows us to move the
identity 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        | 28 +++++++++++---------
 arch/arm64/kernel/vmlinux.lds.S |  2 +-
 arch/arm64/mm/proc.S            |  2 --
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index f168e3309704..25a84ce1700c 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -543,19 +543,6 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
 	eret
 SYM_FUNC_END(init_kernel_el)
 
-/*
- * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
- * in w0. See arch/arm64/include/asm/virt.h for more info.
- */
-SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)
-	adr_l	x1, __boot_cpu_mode
-	cmp	w0, #BOOT_CPU_MODE_EL2
-	b.ne	1f
-	add	x1, x1, #4
-1:	str	w0, [x1]			// Save CPU boot mode
-	ret
-SYM_FUNC_END(set_cpu_boot_mode_flag)
-
 	/*
 	 * This provides a "holding pen" for platforms to hold all secondary
 	 * cores are held until we're ready for them to initialise.
@@ -600,6 +587,7 @@ 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
@@ -628,6 +616,19 @@ SYM_FUNC_START_LOCAL(__secondary_too_slow)
 	b	__secondary_too_slow
 SYM_FUNC_END(__secondary_too_slow)
 
+/*
+ * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
+ * in w0. See arch/arm64/include/asm/virt.h for more info.
+ */
+SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)
+	adr_l	x1, __boot_cpu_mode
+	cmp	w0, #BOOT_CPU_MODE_EL2
+	b.ne	1f
+	add	x1, x1, #4
+1:	str	w0, [x1]			// Save CPU boot mode
+	ret
+SYM_FUNC_END(set_cpu_boot_mode_flag)
+
 /*
  * The booting CPU updates the failed status @__early_cpu_boot_status,
  * with MMU turned off.
@@ -659,6 +660,7 @@ 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_EL1_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 b9ecbbae1e1a..d7ca6f23fb0d 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -110,7 +110,6 @@ 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]
@@ -166,7 +165,6 @@ alternative_else_nop_endif
 	isb
 	ret
 SYM_FUNC_END(cpu_do_resume)
-	.popsection
 #endif
 
 	.pushsection ".idmap.text", "awx"
-- 
2.35.1


WARNING: multiple messages have this Message-ID (diff)
From: Ard Biesheuvel <ardb@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org, keescook@chromium.org,
	Ard Biesheuvel <ardb@kernel.org>, Will Deacon <will@kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Marc Zyngier <maz@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: [PATCH v4 2/6] arm64: kernel: move identity map out of .text mapping
Date: Tue, 18 Oct 2022 13:04:37 +0200	[thread overview]
Message-ID: <20221018110441.3855148-3-ardb@kernel.org> (raw)
In-Reply-To: <20221018110441.3855148-1-ardb@kernel.org>

Reorganize the ID map slightly so that only code that is executed with
the MMU off or via the 1:1 mapping remains. This allows us to move the
identity 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        | 28 +++++++++++---------
 arch/arm64/kernel/vmlinux.lds.S |  2 +-
 arch/arm64/mm/proc.S            |  2 --
 3 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index f168e3309704..25a84ce1700c 100644
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -543,19 +543,6 @@ SYM_INNER_LABEL(init_el2, SYM_L_LOCAL)
 	eret
 SYM_FUNC_END(init_kernel_el)
 
-/*
- * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
- * in w0. See arch/arm64/include/asm/virt.h for more info.
- */
-SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)
-	adr_l	x1, __boot_cpu_mode
-	cmp	w0, #BOOT_CPU_MODE_EL2
-	b.ne	1f
-	add	x1, x1, #4
-1:	str	w0, [x1]			// Save CPU boot mode
-	ret
-SYM_FUNC_END(set_cpu_boot_mode_flag)
-
 	/*
 	 * This provides a "holding pen" for platforms to hold all secondary
 	 * cores are held until we're ready for them to initialise.
@@ -600,6 +587,7 @@ 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
@@ -628,6 +616,19 @@ SYM_FUNC_START_LOCAL(__secondary_too_slow)
 	b	__secondary_too_slow
 SYM_FUNC_END(__secondary_too_slow)
 
+/*
+ * Sets the __boot_cpu_mode flag depending on the CPU boot mode passed
+ * in w0. See arch/arm64/include/asm/virt.h for more info.
+ */
+SYM_FUNC_START_LOCAL(set_cpu_boot_mode_flag)
+	adr_l	x1, __boot_cpu_mode
+	cmp	w0, #BOOT_CPU_MODE_EL2
+	b.ne	1f
+	add	x1, x1, #4
+1:	str	w0, [x1]			// Save CPU boot mode
+	ret
+SYM_FUNC_END(set_cpu_boot_mode_flag)
+
 /*
  * The booting CPU updates the failed status @__early_cpu_boot_status,
  * with MMU turned off.
@@ -659,6 +660,7 @@ 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_EL1_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 b9ecbbae1e1a..d7ca6f23fb0d 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -110,7 +110,6 @@ 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]
@@ -166,7 +165,6 @@ alternative_else_nop_endif
 	isb
 	ret
 SYM_FUNC_END(cpu_do_resume)
-	.popsection
 #endif
 
 	.pushsection ".idmap.text", "awx"
-- 
2.35.1


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2022-10-18 11:05 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18 11:04 [PATCH v4 0/6] arm64: efi: leave MMU and caches on at boot Ard Biesheuvel
2022-10-18 11:04 ` Ard Biesheuvel
2022-10-18 11:04 ` [PATCH v4 1/6] arm64: lds: reduce effective minimum image alignment to 64k Ard Biesheuvel
2022-10-18 11:04   ` Ard Biesheuvel
2022-10-18 11:04 ` Ard Biesheuvel [this message]
2022-10-18 11:04   ` [PATCH v4 2/6] arm64: kernel: move identity map out of .text mapping Ard Biesheuvel
2022-10-18 11:04 ` [PATCH v4 3/6] arm64: head: record the MMU state at primary entry Ard Biesheuvel
2022-10-18 11:04   ` Ard Biesheuvel
2022-10-18 11:04 ` [PATCH v4 4/6] arm64: head: avoid cache invalidation when entering with the MMU on Ard Biesheuvel
2022-10-18 11:04   ` Ard Biesheuvel
2022-10-18 11:04 ` [PATCH v4 5/6] arm64: head: clean the ID map page to the PoC Ard Biesheuvel
2022-10-18 11:04   ` Ard Biesheuvel
2022-10-18 11:04 ` [PATCH v4 6/6] arm64: efi/libstub: enter with the MMU on Ard Biesheuvel
2022-10-18 11:04   ` Ard Biesheuvel
2022-11-07 16:12 ` [PATCH v4 0/6] arm64: efi: leave MMU and caches on at boot Will Deacon
2022-11-07 16:12   ` Will Deacon
2022-11-07 16:26   ` Ard Biesheuvel
2022-11-07 16:26     ` Ard Biesheuvel

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20221018110441.3855148-3-ardb@kernel.org \
    --to=ardb@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=keescook@chromium.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-efi@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=maz@kernel.org \
    --cc=will@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.