From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 3/7] arm64: mm: Permit transitioning from Global to Non-Global without BBM
Date: Fri, 26 Jan 2018 12:03:13 +0000 [thread overview]
Message-ID: <1516968197-23206-4-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1516968197-23206-1-git-send-email-will.deacon@arm.com>
Break-before-make is not needed when transitioning from Global to
Non-Global mappings, provided that the contiguous hint is not being used.
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/mm/mmu.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index b44992ec9643..fc7902bda02b 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -118,6 +118,10 @@ static bool pgattr_change_is_safe(u64 old, u64 new)
if ((old | new) & PTE_CONT)
return false;
+ /* Transitioning from Global to Non-Global is safe */
+ if (((old ^ new) == PTE_NG) && (new & PTE_NG))
+ return true;
+
return ((old ^ new) & ~mask) == 0;
}
--
2.1.4
next prev parent reply other threads:[~2018-01-26 12:03 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-26 12:03 [PATCH 0/7] Fix kpti-enabled kernels for Cavium ThunderX Will Deacon
2018-01-26 12:03 ` [PATCH 1/7] arm64: Add software workaround for Falkor erratum 1041 Will Deacon
2018-01-26 12:03 ` [PATCH 2/7] arm64: kpti: Make use of nG dependent on arm64_kernel_unmapped_at_el0() Will Deacon
2018-01-26 12:03 ` Will Deacon [this message]
2018-01-26 12:03 ` [PATCH 4/7] arm64: kpti: Add ->enable callback to remap swapper using nG mappings Will Deacon
2018-01-26 13:40 ` Marc Zyngier
2018-01-26 14:05 ` Will Deacon
2018-01-26 14:23 ` Marc Zyngier
2018-01-26 12:03 ` [PATCH 5/7] arm64: Force KPTI to be disabled on Cavium ThunderX Will Deacon
2018-01-26 12:03 ` [PATCH 6/7] arm64: assembler: Change order of macro arguments in phys_to_ttbr Will Deacon
2018-01-26 14:17 ` Robin Murphy
2018-01-26 12:03 ` [PATCH 7/7] arm64: entry: Reword comment about post_ttbr_update_workaround Will Deacon
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