From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AF7FDC433F5 for ; Mon, 9 May 2022 14:44:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=a5yIhxFkmAGsaBYxtFuJe/uhCpBXfHFdU8Jp9KgyE9c=; b=P3fLxSTjDnWO1X tO5YxKZcinOBesGMo2C/INFvZinSpFADjxuvM9uQpS6DMeUeV6hDCEp2LOXBmjnnkbY2Z2nkHZCeX nfLsZi2Yfn29rzTuz8y/HPJLyH/7GsXVJQMFZD8wOfko/izICU0xRKSTejEWI+O0xdoikL32XDb3y ez+3rX5pVfZtdZZkzpgh8vylpR0UGKCekEiGM73Ism/GpKk7EFfs25HXog60zXrV3DWY7b+lJgqe8 FUr9Kg656OVENOgNSia4Hm3CEGuFw2cDE+tuCvXVM7+chvGOfo0Z+N/lzDfe1DmyuubK2UCi6V3pI s8RCow/tWi2w6XP3jEHA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1no4bs-00EuPl-GP; Mon, 09 May 2022 14:43:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1no4bi-00EuMf-ID for linux-arm-kernel@lists.infradead.org; Mon, 09 May 2022 14:43:32 +0000 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 B1F87153B; Mon, 9 May 2022 07:43:29 -0700 (PDT) Received: from e121896.arm.com (unknown [10.57.4.213]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 61FD93F73D; Mon, 9 May 2022 07:43:27 -0700 (PDT) From: James Clark To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, broonie@kernel.org Cc: german.gomez@arm.com, James Clark , John Garry , Will Deacon , Mathieu Poirier , Leo Yan , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-doc@vger.kernel.org Subject: [PATCH v1 1/6] perf: arm64: Add SVE vector granule register to user regs Date: Mon, 9 May 2022 15:42:49 +0100 Message-Id: <20220509144257.1623063-2-james.clark@arm.com> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20220509144257.1623063-1-james.clark@arm.com> References: <20220509144257.1623063-1-james.clark@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220509_074330_736967_0D78D949 X-CRM114-Status: GOOD ( 19.06 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Dwarf based unwinding in a function that pushes SVE registers onto the stack requires the unwinder to know the length of the SVE register to calculate the stack offsets correctly. This was added to the Arm specific Dwarf spec as the VG pseudo register[1]. Add the vector length at position 46 if it's requested by userspace and SVE is supported. If it's not supported then fail to open the event. The vector length must be on each sample because it can be changed at runtime via a prctl or ptrace call. Also by adding it as a register rather than a separate attribute, minimal changes will be required in an unwinder that already indexes into the register list. [1]: https://github.com/ARM-software/abi-aa/blob/main/aadwarf64/aadwarf64.rst Signed-off-by: James Clark --- arch/arm64/include/uapi/asm/perf_regs.h | 7 +++++- arch/arm64/kernel/perf_regs.c | 30 +++++++++++++++++++++++-- drivers/perf/arm_pmu.c | 2 +- 3 files changed, 35 insertions(+), 4 deletions(-) diff --git a/arch/arm64/include/uapi/asm/perf_regs.h b/arch/arm64/include/uapi/asm/perf_regs.h index d54daafa89e3..fd157f46727e 100644 --- a/arch/arm64/include/uapi/asm/perf_regs.h +++ b/arch/arm64/include/uapi/asm/perf_regs.h @@ -36,6 +36,11 @@ enum perf_event_arm_regs { PERF_REG_ARM64_LR, PERF_REG_ARM64_SP, PERF_REG_ARM64_PC, - PERF_REG_ARM64_MAX, + + /* Extended/pseudo registers */ + PERF_REG_ARM64_VG = 46, // SVE Vector Granule + + PERF_REG_ARM64_MAX = PERF_REG_ARM64_PC + 1, + PERF_REG_ARM64_EXTENDED_MAX = PERF_REG_ARM64_VG + 1 }; #endif /* _ASM_ARM64_PERF_REGS_H */ diff --git a/arch/arm64/kernel/perf_regs.c b/arch/arm64/kernel/perf_regs.c index f6f58e6265df..b4eece3eb17d 100644 --- a/arch/arm64/kernel/perf_regs.c +++ b/arch/arm64/kernel/perf_regs.c @@ -9,9 +9,27 @@ #include #include +static u64 perf_ext_regs_value(int idx) +{ + switch (idx) { + case PERF_REG_ARM64_VG: + if (WARN_ON_ONCE(!system_supports_sve())) + return 0; + + /* + * Vector granule is current length in bits of SVE registers + * divided by 64. + */ + return (task_get_sve_vl(current) * 8) / 64; + default: + WARN_ON_ONCE(true); + return 0; + } +} + u64 perf_reg_value(struct pt_regs *regs, int idx) { - if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_MAX)) + if (WARN_ON_ONCE((u32)idx >= PERF_REG_ARM64_EXTENDED_MAX)) return 0; /* @@ -51,6 +69,9 @@ u64 perf_reg_value(struct pt_regs *regs, int idx) if ((u32)idx == PERF_REG_ARM64_PC) return regs->pc; + if ((u32)idx >= PERF_REG_ARM64_MAX) + return perf_ext_regs_value(idx); + return regs->regs[idx]; } @@ -58,7 +79,12 @@ u64 perf_reg_value(struct pt_regs *regs, int idx) int perf_reg_validate(u64 mask) { - if (!mask || mask & REG_RESERVED) + u64 reserved_mask = REG_RESERVED; + + if (system_supports_sve()) + reserved_mask &= ~(1ULL << PERF_REG_ARM64_VG); + + if (!mask || mask & reserved_mask) return -EINVAL; return 0; diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c index 59d3980b8ca2..3f07df5a7e95 100644 --- a/drivers/perf/arm_pmu.c +++ b/drivers/perf/arm_pmu.c @@ -894,7 +894,7 @@ static struct arm_pmu *__armpmu_alloc(gfp_t flags) * pmu::filter_match callback and pmu::event_init group * validation). */ - .capabilities = PERF_PMU_CAP_HETEROGENEOUS_CPUS, + .capabilities = PERF_PMU_CAP_HETEROGENEOUS_CPUS | PERF_PMU_CAP_EXTENDED_REGS, }; pmu->attr_groups[ARMPMU_ATTR_GROUP_COMMON] = -- 2.28.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel