From: Reiji Watanabe <reijiw@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will@kernel.org>
Cc: Marc Zyngier <maz@kernel.org>,
Robin Murphy <robin.murphy@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Peter Collingbourne <pcc@google.com>,
Evgenii Stepanov <eugenis@google.com>,
guanghuifeng@linux.alibaba.com,
linux-arm-kernel@lists.infradead.org,
Peter Shier <pshier@google.com>,
Ricardo Koller <ricarkol@google.com>,
Oliver Upton <oupton@google.com>,
Jing Zhang <jingzhangos@google.com>,
Raghavendra Rao Anata <rananta@google.com>,
Reiji Watanabe <reijiw@google.com>
Subject: [PATCH v4 1/2] arm64: clear_page() shouldn't use DC ZVA when DCZID_EL0.DZP == 1
Date: Sun, 5 Dec 2021 16:47:35 -0800 [thread overview]
Message-ID: <20211206004736.1520989-2-reijiw@google.com> (raw)
In-Reply-To: <20211206004736.1520989-1-reijiw@google.com>
Currently, clear_page() uses DC ZVA instruction unconditionally. But it
should make sure that DCZID_EL0.DZP, which indicates whether or not use
of DC ZVA instruction is prohibited, is zero when using the instruction.
Use STNP instead when DCZID_EL0.DZP == 1.
Fixes: f27bb139c387 ("arm64: Miscellaneous library functions")
Signed-off-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
arch/arm64/lib/clear_page.S | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/arm64/lib/clear_page.S b/arch/arm64/lib/clear_page.S
index b84b179edba3..1fd5d790ab80 100644
--- a/arch/arm64/lib/clear_page.S
+++ b/arch/arm64/lib/clear_page.S
@@ -16,6 +16,7 @@
*/
SYM_FUNC_START_PI(clear_page)
mrs x1, dczid_el0
+ tbnz x1, #4, 2f /* Branch if DC ZVA is prohibited */
and w1, w1, #0xf
mov x2, #4
lsl x1, x2, x1
@@ -25,5 +26,14 @@ SYM_FUNC_START_PI(clear_page)
tst x0, #(PAGE_SIZE - 1)
b.ne 1b
ret
+
+2: stnp xzr, xzr, [x0]
+ stnp xzr, xzr, [x0, #16]
+ stnp xzr, xzr, [x0, #32]
+ stnp xzr, xzr, [x0, #48]
+ add x0, x0, #64
+ tst x0, #(PAGE_SIZE - 1)
+ b.ne 2b
+ ret
SYM_FUNC_END_PI(clear_page)
EXPORT_SYMBOL(clear_page)
--
2.34.1.400.ga245620fadb-goog
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next prev parent reply other threads:[~2021-12-06 0:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-06 0:47 [PATCH v4 0/2] arm64: DC {ZVA,GVA,GZVA} shouldn't be used when DCZID_EL0.DZP == 1 Reiji Watanabe
2021-12-06 0:47 ` Reiji Watanabe [this message]
2021-12-06 0:47 ` [PATCH v4 2/2] arm64: mte: DC {GVA,GZVA} " Reiji Watanabe
2021-12-06 17:27 ` [PATCH v4 0/2] arm64: DC {ZVA, GVA, GZVA} " Catalin Marinas
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