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bh=LjiJ694sqeXItqprsgR0LHqp1yHVdqalRgKn46ETCXI=; b=sKNwfV7RHFnF9Z9jHCEKUpRJ8F2aV7+n/lE/4FpzWTiP3dpQUCtb3temePnWKWOkB7 H+xuUktrNoxCzn4ni7oqFLU2BRxbdROtSyHRL2FgLO5CpzZeB2TIMQnMb1uncxXMOoMj 7d/XelM09YzjY74yII4vwxmHuvzsPiE6a8VOtPHySafRPVIpc2g76ZR9k5TNzmOVIO7I XRUJn7GSoS0mIy6SPs+192g/1FUT8ruFco5+usYFdGEl4JEBlr7rDrowBnGGD3WWWmn1 UEVl+O+qRQNbJxaaZEVi7PqrerobpChDgpcPC+MR3A7i7jk22s2wvaiCQvqUdpIs4Zh4 fZ1g== X-Gm-Message-State: AOAM531ZY6+abyTzF9U+SX6NHJllpbi9jKiCGzVAcvLa4ALL55+wpTWs j233Db7AHwRGgUaeqHXv3ng= X-Google-Smtp-Source: ABdhPJypqXhC+H+i7sFrclH+4nyn6OjMkGbUc6dyjcw1DvG2o19T/GcO6p9Dk2IoWsly2r9aOkk+SQ== X-Received: by 2002:a17:902:a703:: with SMTP id w3mr4876394plq.259.1598294162686; Mon, 24 Aug 2020 11:36:02 -0700 (PDT) Received: from stbirv-lnx-3.igp.broadcom.net ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id j10sm12167900pff.171.2020.08.24.11.36.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 24 Aug 2020 11:36:02 -0700 (PDT) From: Florian Fainelli To: linux-arm-kernel@lists.infradead.org Subject: [PATCH stable 4.19 v2 1/2] arm64: Add support for SB barrier and patch in over DSB; ISB sequences Date: Mon, 24 Aug 2020 11:35:11 -0700 Message-Id: <1598294112-19197-2-git-send-email-f.fainelli@gmail.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1598294112-19197-1-git-send-email-f.fainelli@gmail.com> References: <1598294112-19197-1-git-send-email-f.fainelli@gmail.com> Cc: Marc Zyngier , Florian Fainelli , Fangrui Song , Nick Desaulniers , Greg KH , Will Deacon , open list , stable@vger.kernel.org, "open list:KERNEL VIRTUAL MACHINE FOR ARM64 \(KVM/arm64\)" , Mark Brown , Kristina Martsenko , Sami Tolvanen , Catalin Marinas , Will Deacon , Ard Biesheuvel X-BeenThere: kvmarm@lists.cs.columbia.edu X-Mailman-Version: 2.1.14 Precedence: list List-Id: Where KVM/ARM decisions are made List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu From: Will Deacon commit bd4fb6d270bc423a9a4098108784f7f9254c4e6d upstream We currently use a DSB; ISB sequence to inhibit speculation in set_fs(). Whilst this works for current CPUs, future CPUs may implement a new SB barrier instruction which acts as an architected speculation barrier. On CPUs that support it, patch in an SB; NOP sequence over the DSB; ISB sequence and advertise the presence of the new instruction to userspace. Signed-off-by: Will Deacon [florian: adjust conflicts in cpucaps.h and cpufeature.c] Signed-off-by: Florian Fainelli --- arch/arm64/include/asm/assembler.h | 13 +++++++++++++ arch/arm64/include/asm/barrier.h | 4 ++++ arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/include/asm/sysreg.h | 6 ++++++ arch/arm64/include/asm/uaccess.h | 3 +-- arch/arm64/include/uapi/asm/hwcap.h | 1 + arch/arm64/kernel/cpufeature.c | 12 ++++++++++++ arch/arm64/kernel/cpuinfo.c | 1 + 8 files changed, 40 insertions(+), 3 deletions(-) diff --git a/arch/arm64/include/asm/assembler.h b/arch/arm64/include/asm/assembler.h index 5a97ac853168..45ca06f3ddcb 100644 --- a/arch/arm64/include/asm/assembler.h +++ b/arch/arm64/include/asm/assembler.h @@ -127,6 +127,19 @@ .endm /* + * Speculation barrier + */ + .macro sb +alternative_if_not ARM64_HAS_SB + dsb nsh + isb +alternative_else + SB_BARRIER_INSN + nop +alternative_endif + .endm + +/* * Sanitise a 64-bit bounded index wrt speculation, returning zero if out * of bounds. */ diff --git a/arch/arm64/include/asm/barrier.h b/arch/arm64/include/asm/barrier.h index 822a9192c551..f66bb04fdf2d 100644 --- a/arch/arm64/include/asm/barrier.h +++ b/arch/arm64/include/asm/barrier.h @@ -34,6 +34,10 @@ #define psb_csync() asm volatile("hint #17" : : : "memory") #define csdb() asm volatile("hint #20" : : : "memory") +#define spec_bar() asm volatile(ALTERNATIVE("dsb nsh\nisb\n", \ + SB_BARRIER_INSN"nop\n", \ + ARM64_HAS_SB)) + #define mb() dsb(sy) #define rmb() dsb(ld) #define wmb() dsb(st) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index df8fe8ecc37e..383451eca5c6 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -54,7 +54,8 @@ #define ARM64_WORKAROUND_1463225 33 #define ARM64_SSBS 34 #define ARM64_WORKAROUND_1542419 35 +#define ARM64_HAS_SB 36 -#define ARM64_NCAPS 36 +#define ARM64_NCAPS 37 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index ed99d941c462..582075fad6c5 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -97,6 +97,11 @@ #define SET_PSTATE_SSBS(x) __emit_inst(0xd5000000 | REG_PSTATE_SSBS_IMM | \ (!!x)<<8 | 0x1f) +#define __SYS_BARRIER_INSN(CRm, op2, Rt) \ + __emit_inst(0xd5000000 | sys_insn(0, 3, 3, (CRm), (op2)) | ((Rt) & 0x1f)) + +#define SB_BARRIER_INSN __SYS_BARRIER_INSN(0, 7, 31) + #define SYS_DC_ISW sys_insn(1, 0, 7, 6, 2) #define SYS_DC_CSW sys_insn(1, 0, 7, 10, 2) #define SYS_DC_CISW sys_insn(1, 0, 7, 14, 2) @@ -521,6 +526,7 @@ #define ID_AA64ISAR0_AES_SHIFT 4 /* id_aa64isar1 */ +#define ID_AA64ISAR1_SB_SHIFT 36 #define ID_AA64ISAR1_LRCPC_SHIFT 20 #define ID_AA64ISAR1_FCMA_SHIFT 16 #define ID_AA64ISAR1_JSCVT_SHIFT 12 diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index e66b0fca99c2..3c3bf4171f3b 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -46,8 +46,7 @@ static inline void set_fs(mm_segment_t fs) * Prevent a mispredicted conditional call to set_fs from forwarding * the wrong address limit to access_ok under speculation. */ - dsb(nsh); - isb(); + spec_bar(); /* On user-mode return, check fs is correct */ set_thread_flag(TIF_FSCHECK); diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 2bcd6e4f3474..7784f7cba16c 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -49,5 +49,6 @@ #define HWCAP_ILRCPC (1 << 26) #define HWCAP_FLAGM (1 << 27) #define HWCAP_SSBS (1 << 28) +#define HWCAP_SB (1 << 29) #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index ac3126aba036..9cc917277a82 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -138,6 +138,7 @@ static const struct arm64_ftr_bits ftr_id_aa64isar0[] = { }; static const struct arm64_ftr_bits ftr_id_aa64isar1[] = { + ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_SB_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_LRCPC_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_FCMA_SHIFT, 4, 0), ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64ISAR1_JSCVT_SHIFT, 4, 0), @@ -1336,6 +1337,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_enable_ssbs, }, #endif + { + .desc = "Speculation barrier (SB)", + .capability = ARM64_HAS_SB, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_cpuid_feature, + .sys_reg = SYS_ID_AA64ISAR1_EL1, + .field_pos = ID_AA64ISAR1_SB_SHIFT, + .sign = FTR_UNSIGNED, + .min_field_value = 1, + }, {}, }; @@ -1390,6 +1401,7 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_FCMA_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_FCMA), HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_LRCPC), HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_LRCPC_SHIFT, FTR_UNSIGNED, 2, CAP_HWCAP, HWCAP_ILRCPC), + HWCAP_CAP(SYS_ID_AA64ISAR1_EL1, ID_AA64ISAR1_SB_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_SB), HWCAP_CAP(SYS_ID_AA64MMFR2_EL1, ID_AA64MMFR2_AT_SHIFT, FTR_UNSIGNED, 1, CAP_HWCAP, HWCAP_USCAT), #ifdef CONFIG_ARM64_SVE HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE), diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index dce971f2c167..63a49a66a28c 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -82,6 +82,7 @@ static const char *const hwcap_str[] = { "ilrcpc", "flagm", "ssbs", + "sb", NULL }; -- 2.7.4 _______________________________________________ kvmarm mailing list kvmarm@lists.cs.columbia.edu https://lists.cs.columbia.edu/mailman/listinfo/kvmarm