[PATCH 4.9 076/102] arm64: idmap: Use "awx" flags for .idmap.text .pushsection directives

From: Greg Kroah-Hartman
Date: Fri Apr 06 2018 - 10:35:38 EST


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

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

From: Will Deacon <will.deacon@xxxxxxx>

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@xxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxx> [v4.9 backport]
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> [v4.9 backport]
Tested-by: Will Deacon <will.deacon@xxxxxxx>
Tested-by: Greg Hackmann <ghackmann@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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
@@ -473,7 +473,7 @@ 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
@@ -95,7 +95,7 @@ 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
@@ -83,7 +83,7 @@ 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]
@@ -147,7 +147,7 @@ alternative_else_nop_endif
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
@@ -180,7 +180,7 @@ 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
@@ -368,7 +368,7 @@ 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