From nobody Fri Apr 3 12:47:26 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 05B08396D30 for ; Tue, 24 Mar 2026 18:13:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774375988; cv=none; b=bm7vdUTuPMl5YUM4XT6wVfc4JSIdk/pn/Vqr1mOdb7fVnCerTnqGiR8OKhABKA/gYwubiWD9EgctbGAI2H+a1qfIvY2QbqlnqxXT3sASJ0ZCVQr6k+1p6+9VCbdFJx7ZDokRLxgYXc5UUukymQYNxoGIF6Hpv1NUfnod1O4+Nrs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774375988; c=relaxed/simple; bh=NVqoURi6GkLCUA6hulCm/FUPyOAGzXe36crCDX+t3B4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VlXw1WiX/PPbroAhsCOmv1i0lrVHpERl5d/RqGI7TUPnZDrl29JNTI8yVaDXNh8at2/MF4tPffApWq4coax776uJEJbEpwtJpXqevZ3dQKRljyX1m40qYt7uovJujki2xi8kMgsgr7PeT2DsLhjQyw+Jv+taoMKEMGKl6Zp1xQk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=bOt0XwfJ; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b=ChRQdfky; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="bOt0XwfJ"; dkim=pass (2048-bit key) header.d=redhat.com header.i=@redhat.com header.b="ChRQdfky" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1774375986; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=qjOFiAc+loOVh0FFRv70s4LnEAsNKmBF0aaLgN5vhcY=; b=bOt0XwfJ1HpzqDfxHzMGPtEkM+Los43FMP5n8EgqfwNu5C4Dd6wYMnr8I+MmAZUWGFeNHm QfKKiz1/i5Je63Ab8GydYm80VQBqOLF4c+sZ7cNTv8wzMqYKisi2hFx51W5nuUPe/OCFcj kLIziyTiHIIh1XP00Lubgm8/Hn8rLiM= Received: from mail-pf1-f199.google.com (mail-pf1-f199.google.com [209.85.210.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-59-I7L8GNk4NW6xJpi5wCLc9g-1; Tue, 24 Mar 2026 14:13:04 -0400 X-MC-Unique: I7L8GNk4NW6xJpi5wCLc9g-1 X-Mimecast-MFC-AGG-ID: I7L8GNk4NW6xJpi5wCLc9g_1774375983 Received: by mail-pf1-f199.google.com with SMTP id d2e1a72fcca58-82a6c70f1f8so4872509b3a.0 for ; Tue, 24 Mar 2026 11:13:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=google; t=1774375983; x=1774980783; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=qjOFiAc+loOVh0FFRv70s4LnEAsNKmBF0aaLgN5vhcY=; b=ChRQdfkybmRvpdr0WrG4YksrkfpVxC1tSrRxecVzOzSL/zqjaHpqUm684ORDdeDGak OCGYSbMA8jTYH7Ud831Y1zADs7BulHlX/d031r5oKtDMBz/AGNwgxj3yHN/diqxFN3hX 1DX2fak124+MSpdvJTsZKy2H7za+qD/mZNY0WOltmtLqNfC1KntqSWJlzp7YGIM75yBr ZlDNYWybhAyIVoK2crDDE0Zz7Rid2l1Se/wT5/va8Nw0P6O6rnnqof5k9at33qseMuwR 31/BydTN6ythUwjGFSGCul6aIRGaVbqS1PWJZjBTjFgNHltQV455pZrS4h/YpyJikAuP hSHw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1774375983; x=1774980783; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=qjOFiAc+loOVh0FFRv70s4LnEAsNKmBF0aaLgN5vhcY=; b=GEVqG31gN50iKpRGqI97sIRCQkGOBeqeXuOCNxHFBcGGqO0Ou3uiiI8LMZuiLeNQQN AArICks1bagOAC6DJAuzyBmojfXNCfiTrkaLpkNuWndv9EsQHQRYo4zqq5DC8X++TOe7 eOxch33iB1wfrYi1pH0CoUtTlNAxitnuTFXHUyPjPn2PLkvsWfjMxj05dBZPKukEvPko ePQJEYmfN4jM60vcq+8m/AjzQjWtUk0zivkT4vYqLnXaGf4kMlbxcVhl4OY1BDsCPfbI DQTZrdPRfmRvDgD9wN3OLykBD2LsqId8bGlOa2nZ1ZDjSnYBoODqeDIPNP625DBX4Q1V Il4g== X-Gm-Message-State: AOJu0Yz04xm/nPBqcDgmIhBCzu3GG7K4XlUseExgjEgKyFmTmDL5KNZ9 QgQH5vI9D8BIXIMJQmt5ec9F93iGTcR1D0LxSL4oTLmyCCaZ2QROjzWtzqOuAhy55O5BpilnjN0 cISTYCxiNrwbfkZsE1ozzjdWRjiQoNhAzO9WL/c38EDh0XIwTcJ8dS41b0LMpjUStXSBLENTTQK rABvx1a6a5vbAbekGqLYQ92JwwQFZ9JlpXXO69L2cZaipvbdX0 X-Gm-Gg: ATEYQzwz4xUXnibc+lImSurYcEID5sUPGZTj+3C0a9iSUi0xkQTfqrMZF9gXV1uHDot DUUGH9JtMl9RF7ar2UdafKBr3N4jMyUNTbk2cdO3thSY7+q900Sk72JOBQxKRkXcMLzXKU4hzoM umcgTCWue79k2WRpxxLi/7upO6lfXs+SSybtgT0P8kmDBHi595XyIvXGbYDJ5VqxSYptFKeqhQ+ kPKBxPPRM3bDG1Hn7p2HzH++Ek5x4LG1EgLKx0VHH+iMbpPKnS42M4mPNbwA/d3SIrMU8T8U/24 hLrVsf63i+Idg0terxmuWFrJzjtu3r0MyyY6yyXTQhHfneLP1lQkwQ6yVgbAlji7GJpJgmUECXL fvCSNZeR4rGRlvEg9h/38/BYx7bJvRyAEfTxHwLnHxNym36XpFYip6iBBljLv3Q== X-Received: by 2002:a05:6a00:27a7:b0:82c:6da7:2d3d with SMTP id d2e1a72fcca58-82c6de7adbfmr532189b3a.11.1774375983021; Tue, 24 Mar 2026 11:13:03 -0700 (PDT) X-Received: by 2002:a05:6a00:27a7:b0:82c:6da7:2d3d with SMTP id d2e1a72fcca58-82c6de7adbfmr532160b3a.11.1774375982417; Tue, 24 Mar 2026 11:13:02 -0700 (PDT) Received: from fedora.armenon-thinkpadp16vgen1.bengluru.csb ([49.36.108.16]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82b0410b1bdsm16654229b3a.57.2026.03.24.11.13.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Mar 2026 11:13:01 -0700 (PDT) From: Arun Menon To: linux-kernel@vger.kernel.org Cc: Jarkko Sakkinen , linux-integrity@vger.kernel.org, Peter Huewe , Jason Gunthorpe , Arun Menon Subject: [RFC v2 5/5] tpm: tis_i2c: Use local 4KB buffer to limit memory usage Date: Tue, 24 Mar 2026 23:42:44 +0530 Message-ID: <20260324181244.17741-6-armenon@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260324181244.17741-1-armenon@redhat.com> References: <20260324181244.17741-1-armenon@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The global increase of TPM_BUFSIZE to 8KB is necessary to support Post-Quantum Cryptography (PQC) payloads. However, applying this increase to the tpm_tis_i2c driver is unnecessary and wasteful due to physical transport limitations as pointed out in [1] This commit introduces a local buffer limit that is used in the i2c driver. [1] https://sashiko.dev/#/patchset/20260324071803.324774-1-armenon%40redhat= .com?patch=3D8319 Signed-off-by: Arun Menon --- drivers/char/tpm/tpm_tis_i2c.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/char/tpm/tpm_tis_i2c.c b/drivers/char/tpm/tpm_tis_i2c.c index 6cd07dd34507e..db19d459ea1e1 100644 --- a/drivers/char/tpm/tpm_tis_i2c.c +++ b/drivers/char/tpm/tpm_tis_i2c.c @@ -54,6 +54,8 @@ #define TPM_INTF_CAPABILITY_ZERO 0x0FFFF000 #define TPM_I2C_INTERFACE_CAPABILITY_ZERO 0x80000000 =20 +#define TPM_I2C_BUFSIZE 4096 + struct tpm_tis_i2c_phy { struct tpm_tis_data priv; struct i2c_client *i2c_client; @@ -232,7 +234,7 @@ static int tpm_tis_i2c_write_bytes(struct tpm_tis_data = *data, u32 addr, u16 len, int ret; u16 wrote =3D 0; =20 - if (len > TPM_BUFSIZE - 1) + if (len > TPM_I2C_BUFSIZE - 1) return -EIO; =20 phy->io_buf[0] =3D reg; @@ -339,7 +341,7 @@ static int tpm_tis_i2c_probe(struct i2c_client *dev) if (!phy) return -ENOMEM; =20 - phy->io_buf =3D devm_kzalloc(&dev->dev, TPM_BUFSIZE, GFP_KERNEL); + phy->io_buf =3D devm_kzalloc(&dev->dev, TPM_I2C_BUFSIZE, GFP_KERNEL); if (!phy->io_buf) return -ENOMEM; =20 --=20 2.53.0