[PATCH] arm64: Fix TTBR + PAN + 52-bit PA logic in cpu_do_switch_mm
Steve Capper
steve.capper at arm.com
Wed Jan 24 00:27:08 PST 2018
In cpu_do_switch_mm(.) with ARM64_SW_TTBR0_PAN=y we apply phys_to_ttbr
to a value that already has an ASID inserted into the upper bits. For
52-bit PA configurations this then can give us TTBR0_EL1 registers that
cause translation table walks to attempt to access non-zero PA[51:48]
spuriously. Ultimately leading to a Synchronous External Abort on level
1 translation.
This patch re-arranges the logic in cpu_do_switch_mm(.) such that
phys_to_ttbr is called before the ASID is inserted into the TTBR0 value.
Signed-off-by: Steve Capper <steve.capper at arm.com>
---
This applies to the arm64 for-next/core branch.
---
arch/arm64/mm/proc.S | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
index c6a12073ef46..9f177aac6390 100644
--- a/arch/arm64/mm/proc.S
+++ b/arch/arm64/mm/proc.S
@@ -153,14 +153,14 @@ ENDPROC(cpu_do_resume)
ENTRY(cpu_do_switch_mm)
mrs x2, ttbr1_el1
mmid x1, x1 // get mm->context.id
+ phys_to_ttbr x0, x3
#ifdef CONFIG_ARM64_SW_TTBR0_PAN
- bfi x0, x1, #48, #16 // set the ASID field in TTBR0
+ bfi x3, x1, #48, #16 // set the ASID field in TTBR0
#endif
bfi x2, x1, #48, #16 // set the ASID
msr ttbr1_el1, x2 // in TTBR1 (since TCR.A1 is set)
isb
- phys_to_ttbr x0, x2
- msr ttbr0_el1, x2 // now update TTBR0
+ msr ttbr0_el1, x3 // now update TTBR0
isb
b post_ttbr_update_workaround // Back to C code...
ENDPROC(cpu_do_switch_mm)
--
2.11.0
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