* [PATCH v2 0/1] Add option to disable mte support
@ 2021-07-29 2:07 yee.lee
2021-07-29 2:07 ` [PATCH v2 1/1] arm64/cpufeature: Add arm64.nomte to override id-reg yee.lee
0 siblings, 1 reply; 2+ messages in thread
From: yee.lee @ 2021-07-29 2:07 UTC (permalink / raw)
To: linux-kernel
Cc: nicholas.Tang, Kuan-Ying.lee, chinwen.chang, Yee Lee,
Matthias Brugger, moderated list:ARM/Mediatek SoC support,
moderated list:ARM/Mediatek SoC support
From: Yee Lee <yee.lee@mediatek.com>
For some case of low-end devices with limited resources,
an option to disable mte support is necessary.
This patch Adds an alias in id-reg override mechanism
to suppress the mte feature via passing a param.
=== Test ===
QEMU5.2 + mte
passed "arm64.nomte" in cmdline
boot log:
..(skip)
[ 0.000000] CPU features: SYS_ID_AA64PFR1_EL1[11:8]: forced to 0
Changed since v2:
- Use id-reg override machanism to suppress feature.
Yee Lee (1):
arm64/cpufeature: Add arm64.nomte to override id-reg
arch/arm64/kernel/idreg-override.c | 2 ++
1 file changed, 2 insertions(+)
--
2.18.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* [PATCH v2 1/1] arm64/cpufeature: Add arm64.nomte to override id-reg
2021-07-29 2:07 [PATCH v2 0/1] Add option to disable mte support yee.lee
@ 2021-07-29 2:07 ` yee.lee
0 siblings, 0 replies; 2+ messages in thread
From: yee.lee @ 2021-07-29 2:07 UTC (permalink / raw)
To: linux-kernel
Cc: nicholas.Tang, Kuan-Ying.lee, chinwen.chang, Yee Lee,
Catalin Marinas, Will Deacon, Matthias Brugger, Marc Zyngier,
David Brazdil, Ard Biesheuvel, Fuad Tabba,
moderated list:ARM64 PORT (AARCH64 ARCHITECTURE),
moderated list:ARM/Mediatek SoC support
From: Yee Lee <yee.lee@mediatek.com>
Add an alias, "arm64.nomte", to override id-reg and
suppress mte feature.
Suggested-by: Marc Zyngier <maz@kernel.org>
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Yee Lee <yee.lee@mediatek.com>
---
arch/arm64/kernel/idreg-override.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c
index 53a381a7f65d..d8e606fe3c21 100644
--- a/arch/arm64/kernel/idreg-override.c
+++ b/arch/arm64/kernel/idreg-override.c
@@ -54,6 +54,7 @@ static const struct ftr_set_desc pfr1 __initconst = {
.override = &id_aa64pfr1_override,
.fields = {
{ "bt", ID_AA64PFR1_BT_SHIFT },
+ { "mte", ID_AA64PFR1_MTE_SHIFT},
{}
},
};
@@ -100,6 +101,7 @@ static const struct {
{ "arm64.nopauth",
"id_aa64isar1.gpi=0 id_aa64isar1.gpa=0 "
"id_aa64isar1.api=0 id_aa64isar1.apa=0" },
+ { "arm64.nomte", "id_aa64pfr1.mte=0" },
{ "nokaslr", "kaslr.disabled=1" },
};
--
2.18.0
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