From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 66D5A1A00D5 for ; Thu, 20 Jun 2024 09:26:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718875594; cv=none; b=W5nGsdDxCxCB/tATv0i/W6MLV3r+21cpAX4PYgOuNDrKSkMFXmmsaIUC5ccyALs39rh/wNOfbdiUhJu4PQgju1vwYBaUciPRoShNdSn+l0G1jiLzM7OOZJaLspNZhVxU15aVikzy9CQ3lXqyPDuiM6VVrSe1CKB26HgSF+1rcKk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718875594; c=relaxed/simple; bh=uEQgTpeI2KiK3xwmyb+NOVfGvR3oCgMSDiaJro7gRYM=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=c2hiF7VhPwqiAHtYAzNTCM9ZvQFFiHBpBEvDXTS0Z1pXO2Cd1GqLDlRPecKVUzaKIilFdulRK9mGGo4+KlAz+0Bb6rKh9opjaGYZ8V12ig6UerZF409DK40TREllLbihbBHMdoKoWRUQFEM1MKQ6ZLpun2CEwRckc/j0zTHaDHQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id A29C6DA7; Thu, 20 Jun 2024 02:26:56 -0700 (PDT) Received: from a077893.arm.com (unknown [10.163.46.59]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 607863F6A8; Thu, 20 Jun 2024 02:26:27 -0700 (PDT) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Jonathan Corbet , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Catalin Marinas , Will Deacon , Mark Brown , Mark Rutland , kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [RFC V2 3/3] arm64/hw_breakpoint: Enable FEAT_Debugv8p9 Date: Thu, 20 Jun 2024 14:56:07 +0530 Message-Id: <20240620092607.267132-4-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240620092607.267132-1-anshuman.khandual@arm.com> References: <20240620092607.267132-1-anshuman.khandual@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Currently there can be maximum 16 breakpoints, and 16 watchpoints available on a given platform - as detected from ID_AA64DFR0_EL1.[BRPs|WRPs] register fields. But these breakpoint, and watchpoints can be extended further up to 64 via a new arch feature FEAT_Debugv8p9. This first enables banked access for the breakpoint and watchpoint register set via MDSELR_EL1, extended exceptions via MDSCR_EL1.EMBWE and determining available breakpoints and watchpoints in the platform from ID_AA64DFR1_EL1, when FEAT_Debugv8p9 is enabled. Cc: Catalin Marinas Cc: Will Deacon Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- arch/arm64/include/asm/debug-monitors.h | 1 + arch/arm64/include/asm/hw_breakpoint.h | 50 ++++++++++++++++++++----- arch/arm64/kernel/debug-monitors.c | 16 ++++++-- arch/arm64/kernel/hw_breakpoint.c | 33 ++++++++++++++++ 4 files changed, 86 insertions(+), 14 deletions(-) diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h index 13d437bcbf58..a14097673ae0 100644 --- a/arch/arm64/include/asm/debug-monitors.h +++ b/arch/arm64/include/asm/debug-monitors.h @@ -20,6 +20,7 @@ #define DBG_MDSCR_KDE (1 << 13) #define DBG_MDSCR_MDE (1 << 15) #define DBG_MDSCR_MASK ~(DBG_MDSCR_KDE | DBG_MDSCR_MDE) +#define DBG_MDSCR_EMBWE (1UL << 32) #define DBG_ESR_EVT(x) (((x) >> 27) & 0x7) diff --git a/arch/arm64/include/asm/hw_breakpoint.h b/arch/arm64/include/asm/hw_breakpoint.h index bd81cf17744a..362c4d4a64ac 100644 --- a/arch/arm64/include/asm/hw_breakpoint.h +++ b/arch/arm64/include/asm/hw_breakpoint.h @@ -79,8 +79,8 @@ static inline void decode_ctrl_reg(u32 reg, * Limits. * Changing these will require modifications to the register accessors. */ -#define ARM_MAX_BRP 16 -#define ARM_MAX_WRP 16 +#define ARM_MAX_BRP 64 +#define ARM_MAX_WRP 64 /* Virtual debug register bases. */ #define AARCH64_DBG_REG_BVR 0 @@ -94,13 +94,25 @@ static inline void decode_ctrl_reg(u32 reg, #define AARCH64_DBG_REG_NAME_WVR wvr #define AARCH64_DBG_REG_NAME_WCR wcr +static inline bool is_debug_v8p9_enabled(void) +{ + u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); + int dver = cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_DebugVer_SHIFT); + + return dver == ID_AA64DFR0_EL1_DebugVer_V8P9; +} + /* Accessor macros for the debug registers. */ #define AARCH64_DBG_READ(N, REG, VAL) do {\ VAL = read_sysreg(dbg##REG##N##_el1);\ + if (is_debug_v8p9_enabled()) \ + preempt_enable(); \ } while (0) #define AARCH64_DBG_WRITE(N, REG, VAL) do {\ write_sysreg(VAL, dbg##REG##N##_el1);\ + if (is_debug_v8p9_enabled()) \ + preempt_enable(); \ } while (0) struct task_struct; @@ -138,19 +150,37 @@ static inline void ptrace_hw_copy_thread(struct task_struct *task) /* Determine number of BRP registers available. */ static inline int get_num_brps(void) { - u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); - return 1 + - cpuid_feature_extract_unsigned_field(dfr0, - ID_AA64DFR0_EL1_BRPs_SHIFT); + u64 dfr0, dfr1; + int dver, brps; + + dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); + dver = cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_DebugVer_SHIFT); + if (dver == ID_AA64DFR0_EL1_DebugVer_V8P9) { + dfr1 = read_sanitised_ftr_reg(SYS_ID_AA64DFR1_EL1); + brps = cpuid_feature_extract_unsigned_field_width(dfr1, + ID_AA64DFR1_EL1_BRPs_SHIFT, 8); + } else { + brps = cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_BRPs_SHIFT); + } + return 1 + brps; } /* Determine number of WRP registers available. */ static inline int get_num_wrps(void) { - u64 dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); - return 1 + - cpuid_feature_extract_unsigned_field(dfr0, - ID_AA64DFR0_EL1_WRPs_SHIFT); + u64 dfr0, dfr1; + int dver, wrps; + + dfr0 = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1); + dver = cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_DebugVer_SHIFT); + if (dver == ID_AA64DFR0_EL1_DebugVer_V8P9) { + dfr1 = read_sanitised_ftr_reg(SYS_ID_AA64DFR1_EL1); + wrps = cpuid_feature_extract_unsigned_field_width(dfr1, + ID_AA64DFR1_EL1_WRPs_SHIFT, 8); + } else { + wrps = cpuid_feature_extract_unsigned_field(dfr0, ID_AA64DFR0_EL1_WRPs_SHIFT); + } + return 1 + wrps; } #ifdef CONFIG_CPU_PM diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 64f2ecbdfe5c..3299d1e8dc61 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c @@ -23,6 +23,7 @@ #include #include #include +#include /* Determine debug architecture. */ u8 debug_monitors_arch(void) @@ -34,7 +35,7 @@ u8 debug_monitors_arch(void) /* * MDSCR access routines. */ -static void mdscr_write(u32 mdscr) +static void mdscr_write(u64 mdscr) { unsigned long flags; flags = local_daif_save(); @@ -43,7 +44,7 @@ static void mdscr_write(u32 mdscr) } NOKPROBE_SYMBOL(mdscr_write); -static u32 mdscr_read(void) +static u64 mdscr_read(void) { return read_sysreg(mdscr_el1); } @@ -76,10 +77,11 @@ early_param("nodebugmon", early_debug_disable); */ static DEFINE_PER_CPU(int, mde_ref_count); static DEFINE_PER_CPU(int, kde_ref_count); +static DEFINE_PER_CPU(int, embwe_ref_count); void enable_debug_monitors(enum dbg_active_el el) { - u32 mdscr, enable = 0; + u64 mdscr, enable = 0; WARN_ON(preemptible()); @@ -90,6 +92,9 @@ void enable_debug_monitors(enum dbg_active_el el) this_cpu_inc_return(kde_ref_count) == 1) enable |= DBG_MDSCR_KDE; + if (is_debug_v8p9_enabled() && this_cpu_inc_return(embwe_ref_count) == 1) + enable |= DBG_MDSCR_EMBWE; + if (enable && debug_enabled) { mdscr = mdscr_read(); mdscr |= enable; @@ -100,7 +105,7 @@ NOKPROBE_SYMBOL(enable_debug_monitors); void disable_debug_monitors(enum dbg_active_el el) { - u32 mdscr, disable = 0; + u64 mdscr, disable = 0; WARN_ON(preemptible()); @@ -111,6 +116,9 @@ void disable_debug_monitors(enum dbg_active_el el) this_cpu_dec_return(kde_ref_count) == 0) disable &= ~DBG_MDSCR_KDE; + if (is_debug_v8p9_enabled() && this_cpu_dec_return(embwe_ref_count) == 0) + disable &= ~DBG_MDSCR_EMBWE; + if (disable) { mdscr = mdscr_read(); mdscr &= disable; diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c index 722ac45f9f7b..30156d732284 100644 --- a/arch/arm64/kernel/hw_breakpoint.c +++ b/arch/arm64/kernel/hw_breakpoint.c @@ -103,10 +103,40 @@ int hw_breakpoint_slots(int type) WRITE_WB_REG_CASE(OFF, 14, REG, VAL); \ WRITE_WB_REG_CASE(OFF, 15, REG, VAL) +static int set_bank_index(int n) +{ + int mdsel_bank; + int bank = n / 16, index = n % 16; + + switch (bank) { + case 0: + mdsel_bank = MDSELR_EL1_BANK_BANK_0; + break; + case 1: + mdsel_bank = MDSELR_EL1_BANK_BANK_1; + break; + case 2: + mdsel_bank = MDSELR_EL1_BANK_BANK_2; + break; + case 3: + mdsel_bank = MDSELR_EL1_BANK_BANK_3; + break; + default: + pr_warn("Unknown register bank %d\n", bank); + } + preempt_disable(); + write_sysreg_s(mdsel_bank << MDSELR_EL1_BANK_SHIFT, SYS_MDSELR_EL1); + isb(); + return index; +} + static u64 read_wb_reg(int reg, int n) { u64 val = 0; + if (is_debug_v8p9_enabled()) + n = set_bank_index(n); + switch (reg + n) { GEN_READ_WB_REG_CASES(AARCH64_DBG_REG_BVR, AARCH64_DBG_REG_NAME_BVR, val); GEN_READ_WB_REG_CASES(AARCH64_DBG_REG_BCR, AARCH64_DBG_REG_NAME_BCR, val); @@ -122,6 +152,9 @@ NOKPROBE_SYMBOL(read_wb_reg); static void write_wb_reg(int reg, int n, u64 val) { + if (is_debug_v8p9_enabled()) + n = set_bank_index(n); + switch (reg + n) { GEN_WRITE_WB_REG_CASES(AARCH64_DBG_REG_BVR, AARCH64_DBG_REG_NAME_BVR, val); GEN_WRITE_WB_REG_CASES(AARCH64_DBG_REG_BCR, AARCH64_DBG_REG_NAME_BCR, val); -- 2.25.1