linux-kernel - [PATCH 4.15 047/202] [Variant 3/Meltdown] arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

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Message-Id: <20180215151715.665160566@linuxfoundation.org>
Date:   Thu, 15 Feb 2018 16:15:47 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Marc Zyngier <marc.zyngier@....com>,
        Will Deacon <will.deacon@....com>,
        Catalin Marinas <catalin.marinas@....com>
Subject: [PATCH 4.15 047/202] [Variant 3/Meltdown] arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

4.15-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Will Deacon <will.deacon@....com>


Commit 439e70e27a51 upstream.

The identity map is mapped as both writeable and executable by the
SWAPPER_MM_MMUFLAGS and this is relied upon by the kpti code to manage
a synchronisation flag. Update the .pushsection flags to reflect the
actual mapping attributes.

Reported-by: Marc Zyngier <marc.zyngier@....com>
Signed-off-by: Will Deacon <will.deacon@....com>
Signed-off-by: Catalin Marinas <catalin.marinas@....com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/arm64/kernel/cpu-reset.S |    2 +-
 arch/arm64/kernel/head.S      |    2 +-
 arch/arm64/kernel/sleep.S     |    2 +-
 arch/arm64/mm/proc.S          |    8 ++++----
 4 files changed, 7 insertions(+), 7 deletions(-)

--- a/arch/arm64/kernel/cpu-reset.S
+++ b/arch/arm64/kernel/cpu-reset.S
@@ -16,7 +16,7 @@
 #include <asm/virt.h>
 
 .text
-.pushsection    .idmap.text, "ax"
+.pushsection    .idmap.text, "awx"
 
 /*
  * __cpu_soft_restart(el2_switch, entry, arg0, arg1, arg2) - Helper for
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -371,7 +371,7 @@ ENDPROC(__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","ax"
+	.section ".idmap.text","awx"
 
 ENTRY(kimage_vaddr)
 	.quad		_text - TEXT_OFFSET
--- a/arch/arm64/kernel/sleep.S
+++ b/arch/arm64/kernel/sleep.S
@@ -96,7 +96,7 @@ ENTRY(__cpu_suspend_enter)
 	ret
 ENDPROC(__cpu_suspend_enter)
 
-	.pushsection ".idmap.text", "ax"
+	.pushsection ".idmap.text", "awx"
 ENTRY(cpu_resume)
 	bl	el2_setup		// if in EL2 drop to EL1 cleanly
 	bl	__cpu_setup
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -86,7 +86,7 @@ ENDPROC(cpu_do_suspend)
  *
  * x0: Address of context pointer
  */
-	.pushsection ".idmap.text", "ax"
+	.pushsection ".idmap.text", "awx"
 ENTRY(cpu_do_resume)
 	ldp	x2, x3, [x0]
 	ldp	x4, x5, [x0, #16]
@@ -152,7 +152,7 @@ ENTRY(cpu_do_switch_mm)
 	ret
 ENDPROC(cpu_do_switch_mm)
 
-	.pushsection ".idmap.text", "ax"
+	.pushsection ".idmap.text", "awx"
 
 .macro	__idmap_cpu_set_reserved_ttbr1, tmp1, tmp2
 	adrp	\tmp1, empty_zero_page
@@ -184,7 +184,7 @@ ENDPROC(idmap_cpu_replace_ttbr1)
 	.popsection
 
 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
-	.pushsection ".idmap.text", "ax"
+	.pushsection ".idmap.text", "awx"
 
 	.macro	__idmap_kpti_get_pgtable_ent, type
 	dc	cvac, cur_\()\type\()p		// Ensure any existing dirty
@@ -373,7 +373,7 @@ ENDPROC(idmap_kpti_install_ng_mappings)
  *	Initialise the processor for turning the MMU on.  Return in x0 the
  *	value of the SCTLR_EL1 register.
  */
-	.pushsection ".idmap.text", "ax"
+	.pushsection ".idmap.text", "awx"
 ENTRY(__cpu_setup)
 	tlbi	vmalle1				// Invalidate local TLB
 	dsb	nsh