From patchwork Mon May 27 09:43:19 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jani Nikula X-Patchwork-Id: 13674967 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 20502C25B74 for ; Mon, 27 May 2024 09:43:35 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 7E13A10F9DA; Mon, 27 May 2024 09:43:34 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="NTd9Ovw7"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id 0339510F9DA; Mon, 27 May 2024 09:43:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1716803012; x=1748339012; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=V7W+PZvSNN60O9e3tJb1hk9bjQ3NW3P32Xw/JTV/pUQ=; b=NTd9Ovw7NLmfLq1ecFQNsFE/0AtFsx2+RCxV8ry2nU+D2e9fNiZl0ilX kzxnI673QTMZ9sChTpU0oElTDYiqaHCa1H1RCitDonYo2tIQWFhVZ1hUN UjVQ5ZXSB52tmcr1dFfknp+qTgoHfNv+SalOM4ehIy6Ctz8M2/oagYmou DHnGXKInJgiu5YktXSZWmB/cdCKJL81JxAP0T8bU/DWvZprZyvgi+mb4M 4JT0WYDUD6ozZjWYYZ7m/80Ifww9DzFht2U3PizrBje6kpO2o693PN7iG GYpGrktKDEoujiWknNTMi526Ow81+PrIywLex+Ibq4AJmUI7TT7eAN3r0 g==; X-CSE-ConnectionGUID: gu+GO2FdQY6CoX53UeLXFw== X-CSE-MsgGUID: ggc55xGlQx2VGFrfuragOg== X-IronPort-AV: E=McAfee;i="6600,9927,11084"; a="30621981" X-IronPort-AV: E=Sophos;i="6.08,192,1712646000"; d="scan'208";a="30621981" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2024 02:43:31 -0700 X-CSE-ConnectionGUID: AwnyfvCXQgWn9JMdt8o7SA== X-CSE-MsgGUID: YJPCK6WAQ8a7+D1XJxu9CA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,192,1712646000"; d="scan'208";a="35187606" Received: from lfiedoro-mobl.ger.corp.intel.com (HELO localhost) ([10.245.246.200]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2024 02:43:28 -0700 From: Jani Nikula To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: intel-gfx@lists.freedesktop.org, jani.nikula@intel.com, Kees Cook , Andy Shevchenko Subject: [PATCH 1/2] string: add mem_is_zero() helper to check if memory area is all zeros Date: Mon, 27 May 2024 12:43:19 +0300 Message-Id: <20240527094320.2653177-1-jani.nikula@intel.com> X-Mailer: git-send-email 2.39.2 MIME-Version: 1.0 Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Almost two thirds of the memchr_inv() usages check if the memory area is all zeros, with no interest in where in the buffer the first non-zero byte is located. Checking for !memchr_inv(s, 0, n) is also not very intuitive or discoverable. Add an explicit mem_is_zero() helper for this use case. Signed-off-by: Jani Nikula --- Cc: Kees Cook Cc: Andy Shevchenko --- include/linux/string.h | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/include/linux/string.h b/include/linux/string.h index 60168aa2af07..3da305dab927 100644 --- a/include/linux/string.h +++ b/include/linux/string.h @@ -279,6 +279,18 @@ static inline void memcpy_flushcache(void *dst, const void *src, size_t cnt) void *memchr_inv(const void *s, int c, size_t n); char *strreplace(char *str, char old, char new); +/** + * mem_is_zero - Check if an area of memory is all 0's. + * @s: The memory area + * @n: The size of the area + * + * Return: True if the area of memory is all 0's. + */ +static inline bool mem_is_zero(const void *s, size_t n) +{ + return !memchr_inv(s, 0, n); +} + extern void kfree_const(const void *x); extern char *kstrdup(const char *s, gfp_t gfp) __malloc; From patchwork Mon May 27 09:43:20 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jani Nikula X-Patchwork-Id: 13674968 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 52CF3C25B74 for ; Mon, 27 May 2024 09:43:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B88E610F46F; Mon, 27 May 2024 09:43:43 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="kjPVcqnm"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.10]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2CD1710F9DC; Mon, 27 May 2024 09:43:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1716803017; x=1748339017; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=kX/sBp/2yGju2wTUjHprdWNQAUXdkMNFUKH9WEbbo14=; b=kjPVcqnmOMPrqzgbCXWGaPPOf2pzswVGs2vZmsZiBNK57ya1hQkUc3AH o5qE0L+X54ZM5TFHM+F8kIt8dlKmb0aPS50o0SaVyHue6lngTI8y52bh7 ot9+TwDtW6NwcPTQjN2XfMZw5oGg73GH5LQhDsWuTNuHrkdnLPBKUwbm1 oA1bVjxvfN7fTXS6OcO288zNfZMe6VN0kzpJLhiUL/hjQtOHDyw+Ia6cC ZwjWsqmts+Wxm3ms/rZv2R0NUdH6l6b8Vnf2Jks3mvefysf8Mk3WvY9JM LQtGJHCygfwAa1OTrxc7cse6HGyOA0xZ0zsSe7AwGmpi3KjGbJf9Dk3SJ Q==; X-CSE-ConnectionGUID: 3K5mzBIQRXyECEPvhXhDkA== X-CSE-MsgGUID: PDlTKCs/Say0DNLNCN3DUA== X-IronPort-AV: E=McAfee;i="6600,9927,11084"; a="30622011" X-IronPort-AV: E=Sophos;i="6.08,192,1712646000"; d="scan'208";a="30622011" Received: from orviesa008.jf.intel.com ([10.64.159.148]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2024 02:43:37 -0700 X-CSE-ConnectionGUID: BU8w17P/RTOaD3mKYYsjRg== X-CSE-MsgGUID: ltom8v50RYuZpBF6zoHqSA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.08,192,1712646000"; d="scan'208";a="35187640" Received: from lfiedoro-mobl.ger.corp.intel.com (HELO localhost) ([10.245.246.200]) by orviesa008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 May 2024 02:43:35 -0700 From: Jani Nikula To: linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org Cc: intel-gfx@lists.freedesktop.org, jani.nikula@intel.com, Kees Cook , Andy Shevchenko Subject: [PATCH 2/2] drm: use mem_is_zero() instead of !memchr_inv(s, 0, n) Date: Mon, 27 May 2024 12:43:20 +0300 Message-Id: <20240527094320.2653177-2-jani.nikula@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240527094320.2653177-1-jani.nikula@intel.com> References: <20240527094320.2653177-1-jani.nikula@intel.com> MIME-Version: 1.0 Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" Use the mem_is_zero() helper where possible. Conversion done using cocci: | @@ | expression PTR; | expression SIZE; | @@ | | <... | ( | - memchr_inv(PTR, 0, SIZE) == NULL | + mem_is_zero(PTR, SIZE) | | | - !memchr_inv(PTR, 0, SIZE) | + mem_is_zero(PTR, SIZE) | | | - memchr_inv(PTR, 0, SIZE) | + !mem_is_zero(PTR, SIZE) | ) | ...> Signed-off-by: Jani Nikula --- Cc: Kees Cook Cc: Andy Shevchenko --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +- drivers/gpu/drm/display/drm_dp_mst_topology.c | 2 +- drivers/gpu/drm/drm_edid.c | 2 +- drivers/gpu/drm/i915/display/intel_dp.c | 2 +- drivers/gpu/drm/i915/display/intel_opregion.c | 2 +- drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c | 2 +- drivers/gpu/drm/imagination/pvr_device.h | 2 +- drivers/gpu/drm/udl/udl_edid.c | 2 +- 8 files changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 516eb3968e26..7d847021ddc9 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -2432,7 +2432,7 @@ static void resume_mst_branch_status(struct drm_dp_mst_topology_mgr *mgr) goto out_fail; } - if (memchr_inv(guid, 0, 16) == NULL) { + if (mem_is_zero(guid, 16)) { tmp64 = get_jiffies_64(); memcpy(&guid[0], &tmp64, sizeof(u64)); memcpy(&guid[8], &tmp64, sizeof(u64)); diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 7f8e1cfbe19d..3d3097422235 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -2697,7 +2697,7 @@ static bool drm_dp_validate_guid(struct drm_dp_mst_topology_mgr *mgr, { u64 salt; - if (memchr_inv(guid, 0, 16)) + if (!mem_is_zero(guid, 16)) return true; salt = get_jiffies_64(); diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index f68a41eeb1fa..9970c22f616b 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -1817,7 +1817,7 @@ static int edid_block_tag(const void *_block) static bool edid_block_is_zero(const void *edid) { - return !memchr_inv(edid, 0, EDID_LENGTH); + return mem_is_zero(edid, EDID_LENGTH); } static bool drm_edid_eq(const struct drm_edid *drm_edid, diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index c0a3b6d50681..be3685e115ab 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -5055,7 +5055,7 @@ intel_dp_check_mst_status(struct intel_dp *intel_dp) ack[3] |= DP_TUNNELING_IRQ; } - if (!memchr_inv(ack, 0, sizeof(ack))) + if (mem_is_zero(ack, sizeof(ack))) break; if (!intel_dp_ack_sink_irq_esi(intel_dp, ack)) diff --git a/drivers/gpu/drm/i915/display/intel_opregion.c b/drivers/gpu/drm/i915/display/intel_opregion.c index 68bd5101ec89..293c4d920cf9 100644 --- a/drivers/gpu/drm/i915/display/intel_opregion.c +++ b/drivers/gpu/drm/i915/display/intel_opregion.c @@ -1117,7 +1117,7 @@ const struct drm_edid *intel_opregion_get_edid(struct intel_connector *intel_con /* Validity corresponds to number of 128-byte blocks */ len = (opregion->asle_ext->phed & ASLE_PHED_EDID_VALID_MASK) * 128; - if (!len || !memchr_inv(edid, 0, len)) + if (!len || mem_is_zero(edid, len)) return NULL; drm_edid = drm_edid_alloc(edid, len); diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c index 3527b8f446fe..2fda549dd82d 100644 --- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c +++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c @@ -506,7 +506,7 @@ static int igt_dmabuf_export_vmap(void *arg) goto out; } - if (memchr_inv(ptr, 0, dmabuf->size)) { + if (!mem_is_zero(ptr, dmabuf->size)) { pr_err("Exported object not initialised to zero!\n"); err = -EINVAL; goto out; diff --git a/drivers/gpu/drm/imagination/pvr_device.h b/drivers/gpu/drm/imagination/pvr_device.h index ecdd5767d8ef..b574e23d484b 100644 --- a/drivers/gpu/drm/imagination/pvr_device.h +++ b/drivers/gpu/drm/imagination/pvr_device.h @@ -668,7 +668,7 @@ pvr_ioctl_union_padding_check(void *instance, size_t union_offset, void *padding_start = ((u8 *)instance) + union_offset + member_size; size_t padding_size = union_size - member_size; - return !memchr_inv(padding_start, 0, padding_size); + return mem_is_zero(padding_start, padding_size); } /** diff --git a/drivers/gpu/drm/udl/udl_edid.c b/drivers/gpu/drm/udl/udl_edid.c index d67e6bf1f2ae..12f48ae17073 100644 --- a/drivers/gpu/drm/udl/udl_edid.c +++ b/drivers/gpu/drm/udl/udl_edid.c @@ -69,7 +69,7 @@ bool udl_probe_edid(struct udl_device *udl) * The adapter sends all-zeros if no monitor has been * connected. We consider anything else a connection. */ - return !!memchr_inv(hdr, 0, sizeof(hdr)); + return !mem_is_zero(hdr, sizeof(hdr)); } const struct drm_edid *udl_edid_read(struct drm_connector *connector)