From 58f1839adc9a6011266049cb2ff98b1e26325fa0 Mon Sep 17 00:00:00 2001 From: Yee Lee Date: Wed, 28 Jul 2021 21:31:57 +0800 Subject: [PATCH] FROMGIT: arm64/cpufeature: Optionally disable MTE via command-line MTE support needs to be optionally disabled in runtime for HW issue workaround, FW development and some evaluation works on system resource and performance. This patch makes two changes: (1) moves init of tag-allocation bits(ATA/ATA0) to cpu_enable_mte() as not cached in TLB. (2) allows ID_AA64PFR1_EL1.MTE to be overridden on its shadow value by giving "arm64.nomte" on cmdline. When the feature value is off, ATA and TCF will not set and the related functionalities are accordingly suppressed. Change-Id: Ic9cf6d3a12a33b312643d96101c72a657cb714af Link: https://lore.kernel.org/lkml/20210803070824.7586-2-yee.lee@mediatek.com/ (cherry picked from commit 7a062ce31807eb402c38edbec50c1b848b4298f3 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git next) Bug: 195507092 Suggested-by: Catalin Marinas Suggested-by: Marc Zyngier Suggested-by: Suzuki K Poulose Signed-off-by: Yee Lee --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ arch/arm64/include/asm/sysreg.h | 3 +-- arch/arm64/kernel/cpufeature.c | 3 +++ arch/arm64/kernel/idreg-override.c | 2 ++ 4 files changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 29c5f46bee20..093524d70372 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -393,6 +393,9 @@ arm64.nopauth [ARM64] Unconditionally disable Pointer Authentication support + arm64.nomte [ARM64] Unconditionally disable Memory Tagging Extension + support + ataflop= [HW,M68k] atarimouse= [HW,MOUSE] Atari Mouse diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 6201de6fdaac..2f09c856b6bc 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -684,8 +684,7 @@ (SCTLR_ELx_M | SCTLR_ELx_C | SCTLR_ELx_SA | SCTLR_EL1_SA0 | \ SCTLR_EL1_SED | SCTLR_ELx_I | SCTLR_EL1_DZE | SCTLR_EL1_UCT | \ SCTLR_EL1_NTWE | SCTLR_ELx_IESB | SCTLR_EL1_SPAN | SCTLR_ELx_ITFSB | \ - SCTLR_ELx_ATA | SCTLR_EL1_ATA0 | ENDIAN_SET_EL1 | SCTLR_EL1_UCI | \ - SCTLR_EL1_RES1) + ENDIAN_SET_EL1 | SCTLR_EL1_UCI | SCTLR_EL1_RES1) /* MAIR_ELx memory attributes (used by Linux) */ #define MAIR_ATTR_DEVICE_nGnRnE UL(0x00) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index c9711b504e8f..d9e5c16f2037 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1835,6 +1835,9 @@ static void bti_enable(const struct arm64_cpu_capabilities *__unused) #ifdef CONFIG_ARM64_MTE static void cpu_enable_mte(struct arm64_cpu_capabilities const *cap) { + sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ATA | SCTLR_EL1_ATA0); + isb(); + /* * Clear the tags in the zero page. This needs to be done via the * linear map which has the Tagged attribute. diff --git a/arch/arm64/kernel/idreg-override.c b/arch/arm64/kernel/idreg-override.c index cc071712c6f9..81b7ecb69cd1 100644 --- a/arch/arm64/kernel/idreg-override.c +++ b/arch/arm64/kernel/idreg-override.c @@ -42,6 +42,7 @@ static const struct ftr_set_desc pfr1 __initconst = { .override = &id_aa64pfr1_override, .fields = { { "bt", ID_AA64PFR1_BT_SHIFT }, + { "mte", ID_AA64PFR1_MTE_SHIFT}, {} }, }; @@ -88,6 +89,7 @@ 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" }, };