From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 AB3E537754B for ; Tue, 7 Jul 2026 07:08:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783408130; cv=none; b=nTRSCbYriRRFVGVslpwEg4BxLum8o6oh57qLjTfRImguKAQRxCL7S7R6qjSZm/8xiT0YqkCOOmGUZH4pqRYSXfZZXhgLX9s2KCrMjRxp9a1zcTDGJZsSLYmYujbRUpyD6XW7YseBaZ1wLJDdSifA6y6ZA7oE0TnAUiS+dFQrJEo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783408130; c=relaxed/simple; bh=mnRljLz92l7ji/dG5pRq1x4xF27pBBy8YypANQsD5xw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=YqXq3OTzs++6oPcY7cOv5Wv4OYQdGSnnVRLQcVmFESxh9/I2tpvRdVrbjF3lNoD/M8n2+P05HP+yInfRg3UVSqAe/53M76UV0xt8KeI/1iLQpgMmhZIw8UkTLy8ox/NZ5nMVd+CavrN49n1LfzZa88qeXeyx+yO5yshEl4UeC4I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=axXuCzSC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="axXuCzSC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3385E1F00A3A; Tue, 7 Jul 2026 07:08:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783408129; bh=jQBPzeQTUsoBAHhbAd8CqcjmLxqDEHm995n/RdJoJgY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=axXuCzSCHG3TVFRpTNM+eLZBHMPfC/7NofeFrQivYgsRWxkB5/J9Vb1VFoZziynpY yd3nsNrYGymf25QqoYLv1xUuAlvRSFRCiPLdKWA8uLpQ3XNa2IcisnCdjLEuBCFM+A FNkuawlX37GGYsreHhw4vqCFAVFiQ2vFDJJIL13lX4YNtJnU223jUvRf2xA9Bg8NqZ hm5xNtoVBVHKAsGkHSC24yWf8LGaYFjQGNInNag9q2wNAd0Wda0Amfakhwxvu59pEZ D7enSH8vK6l5jPOJq+NcKUvvSp6XBuJns6snER07SRxbmKSFFROfSS1bzqGQYqRq/Y Hovjc6Cl96Vgg== Message-ID: <5c128db1-7f82-4e2c-b029-5623880ea56d@kernel.org> Date: Tue, 7 Jul 2026 09:08:45 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] mm: Standardize printing for pgtable entries To: Anshuman Khandual , linux-mm@kvack.org Cc: andriy.shevchenko@linux.intel.com, usama.arif@linux.dev, hughd@google.com, willy@infradead.org, Andrew Morton , linux-kernel@vger.kernel.org References: <20260707041703.658021-1-anshuman.khandual@arm.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/7/26 06:17, Anshuman Khandual wrote: > From: "David Hildenbrand (Arm)" > > Bad page map reporting currently stores page table entry values in an > unsigned long long and prints them with fixed 64-bit-oriented format > strings. This is inconsistent across call sites and does not work well for > architectures where page table entry values are not naturally represented > as 64-bit values, such as 32-bit or 128-bit entries. > > Introduce a common helper to convert raw page table entry values into a > fixed-width hexadecimal string based on the actual entry size. Use it for > bad page map reporting and for dumping the page table walk in > __print_bad_page_map_pgtable(). > > Pass page table entry values to the reporting path as raw bytes together > with their size, instead of forcing them through an unsigned long long. > It keeps the printed output consistent and avoids truncation or misleading > formatting for non-64-bit page table entries. > > Cc: Andrew Morton > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) You should add a Co-developed-by here :) > Signed-off-by: Anshuman Khandual > --- [...] > + > +static void ptval_bytes_to_hex_str(char *buf, size_t buf_size, const void *entry, size_t entry_size) > +{ > + if (WARN_ON_ONCE(buf_size < entry_size * 2 + 1)) { > + snprintf(buf, buf_size, "overflow"); > + return; > + } > + > + switch (entry_size) { > + case sizeof(u32): > + snprintf(buf, buf_size, "%08x", *(const u32 *)entry); > + break; > + case sizeof(u64): > + snprintf(buf, buf_size, "%016llx", *(const u64 *)entry); > + break; > +#if defined(__SIZEOF_INT128__) > + case sizeof(u128): { > + const u64 *val = entry; > + > + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) > + snprintf(buf, buf_size, "%016llx%016llx", val[0], val[1]); > + else > + snprintf(buf, buf_size, "%016llx%016llx", val[1], val[0]); > + break; As discussed, can we simplify that by casting to (u128) and then shifting the values into place? -- Cheers, David