From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-182.mta0.migadu.com (out-182.mta0.migadu.com [91.218.175.182]) (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 61B2D2727F3 for ; Wed, 10 Jun 2026 11:13:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.182 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781090045; cv=none; b=iODRV82RPYghsLmP5ieu+BnVpC1It30BjIRu1G5D4eZbvU73NXoUiEfKKn+7Kyw7c8LaYwLxsTg7X9ZDXQsd+uWN9KgDa7S2pPyS+9VK93EsLKfAu1FRAREBHEKg8f9gDQEsqcgDCQ36pAKknPaB47RSrxOaRCJ8dJ/wguBqozc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781090045; c=relaxed/simple; bh=S3536OaD2rrB5ANg5J/DkGkffC3Xn3yEDFZ1krQowYA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=O8y97HMOzMlcaxPBEuowU87orIGG+DT7U/moEo8QOZfWsR5eJzBHqWa8r5EQQIEayYkJQexzLGmgERJl54/ic80ZqNVudxOYlGZDu7NKCtPIOe56CAgfSxXnxumZLGCdCPlWVb2Tm85ItYfEIuvz9WH20G7iloKENL7q+S+qvIM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=w0aN4h2i; arc=none smtp.client-ip=91.218.175.182 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="w0aN4h2i" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1781090025; 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=tz1M0e8T/EgKbgpgwsMN3TPc5zEkKMmlMDxPlf4j5nw=; b=w0aN4h2iVp540yjSpDVq5LAfaIPC5S7ZhaRdvO+FrwYkC7WY9AXjgPlZZfX+abU+ikyuFR kcqVmLTrtAuTzpr/ZKqhAZan4KxOGzwH8aFEdm4oF9EXR3RxVRSeuwEkOWEiS5Yz6sxCy7 /6XgwW21d5MPjkc5WNDWSZG8OOJwpQY= From: Usama Arif To: Anshuman Khandual Cc: Usama Arif , linux-mm@kvack.org, Andy Shevchenko , Rasmus Villemoes , Sergey Senozhatsky , Petr Mladek , Steven Rostedt , Jonathan Corbet , Andrew Morton , David Hildenbrand , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, David Hildenbrand , Lorenzo Stoakes , Andy Whitcroft Subject: Re: [RFC V2 1/3] lib/vsprintf: Add support for pgtable entries Date: Wed, 10 Jun 2026 04:13:36 -0700 Message-ID: <20260610111339.2465922-1-usama.arif@linux.dev> In-Reply-To: <20260610043545.3725735-2-anshuman.khandual@arm.com> References: Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Wed, 10 Jun 2026 05:35:43 +0100 Anshuman Khandual wrote: > Add some print formats for pgtable entries at any pgtable level. These new > formats are %pp[g|4|u|m|t][d|e] i.e %ppgd, %pp4d, %ppud, %ppmd, and %ppte. > These currently support both 32 bit and 64 bit pgtable entries that can be > extended up to 128 bit when required. > > Signed-off-by: Anshuman Khandual > --- > Cc: Andrew Morton > Cc: David Hildenbrand > Cc: Lorenzo Stoakes > Cc: Petr Mladek > Cc: Steven Rostedt > Cc: Jonathan Corbet > Cc: Andy Whitcroft > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > Cc: linux-doc@vger.kernel.org > > Documentation/core-api/printk-formats.rst | 19 ++++++++ > lib/vsprintf.c | 58 +++++++++++++++++++++++ > scripts/checkpatch.pl | 2 +- > 3 files changed, 78 insertions(+), 1 deletion(-) > > diff --git a/Documentation/core-api/printk-formats.rst b/Documentation/core-api/printk-formats.rst > index c0b1b6089307..e69f91a9dd9d 100644 > --- a/Documentation/core-api/printk-formats.rst > +++ b/Documentation/core-api/printk-formats.rst > @@ -696,6 +696,25 @@ Rust > Only intended to be used from Rust code to format ``core::fmt::Arguments``. > Do *not* use it from C. > > +Page Table Entry > +---------------- > + > +:: > + > + %p[pgd|p4dp|pud|pmd|pte] s/p4dp/p4d to match others > + > +Print page table entry at any level. > + > +Passed by reference. > + > +Examples for a 64 bit page table entry, given &(u64)0xc0ffee:: > + > + %ppte 0x0000000000c0ffee > + %ppmd 0x0000000000c0ffee > + %ppud 0x0000000000c0ffee > + %pp4d 0x0000000000c0ffee > + %ppgd 0x0000000000c0ffee > + > Thanks > ====== > > diff --git a/lib/vsprintf.c b/lib/vsprintf.c > index 9f359b31c8d1..d4ad3048a4db 100644 > --- a/lib/vsprintf.c > +++ b/lib/vsprintf.c > @@ -856,6 +856,59 @@ static char *default_pointer(char *buf, char *end, const void *ptr, > return ptr_to_id(buf, end, ptr, spec); > } > > +static char *pxd_pointer(char *buf, char *end, const void *ptr, > + struct printf_spec spec, const char *fmt) > +{ > + if (check_pointer(&buf, end, ptr, spec)) > + return buf; > + > + if (fmt[1] == 't' && fmt[2] == 'e') { > + pte_t *pte = (pte_t *)ptr; > + > + static_assert(sizeof(pte_t) == 4 || > + sizeof(pte_t) == 8, > + "pte_t size must be 4 or 8 bytes"); > + return special_hex_number(buf, end, pte_val(ptep_get(pte)), sizeof(pte_t)); > + } > + > + if (fmt[1] == 'm' && fmt[2] == 'd') { > + pmd_t *pmd = (pmd_t *)ptr; > + > + static_assert(sizeof(pmd_t) == 4 || > + sizeof(pmd_t) == 8, > + "pmd_t size must be 4 or 8 bytes"); > + return special_hex_number(buf, end, pmd_val(pmdp_get(pmd)), sizeof(pmd_t)); > + } > + > + if (fmt[1] == 'u' && fmt[2] == 'd') { > + pud_t *pud = (pud_t *)ptr; > + > + static_assert(sizeof(pud_t) == 4 || > + sizeof(pud_t) == 8, > + "pud_t size must be 4 or 8 bytes"); > + return special_hex_number(buf, end, pud_val(pudp_get(pud)), sizeof(pud_t)); > + } > + > + if (fmt[1] == '4' && fmt[2] == 'd') { > + p4d_t *p4d = (p4d_t *)ptr; > + > + static_assert(sizeof(p4d_t) == 4 || > + sizeof(p4d_t) == 8, > + "p4d_t size must be 4 or 8 bytes"); > + return special_hex_number(buf, end, p4d_val(p4dp_get(p4d)), sizeof(p4d_t)); > + } > + > + if (fmt[1] == 'g' && fmt[2] == 'd') { > + pgd_t *pgd = (pgd_t *)ptr; > + > + static_assert(sizeof(pgd_t) == 4 || > + sizeof(pgd_t) == 8, > + "pgd_t size must be 4 or 8 bytes"); > + return special_hex_number(buf, end, pgd_val(pgdp_get(pgd)), sizeof(pgd_t)); You mentioned in the coverletter that pgdp_get() is the reason arm32 builds dont work. Just wanted to check what the issue is? I had a look at arch/arm/include/asm/pgtable.h and I couldnt understand why it reads pgdp_get(pgpd) instead of pgdp_get(pgdp)? > + } > + return default_pointer(buf, end, ptr, spec); > +} > + > int kptr_restrict __read_mostly; > > static noinline_for_stack > @@ -2506,6 +2559,9 @@ early_param("no_hash_pointers", no_hash_pointers_enable); > * Without an option prints the full name of the node > * f full name > * P node name, including a possible unit address > + * - 'p[g|4|u|m|t|][d|e]' For a page table entry, this prints its > + * contents in a hexadecimal format > + * > * - 'x' For printing the address unmodified. Equivalent to "%lx". > * Please read the documentation (path below) before using! > * - '[ku]s' For a BPF/tracing related format specifier, e.g. used out of > @@ -2615,6 +2671,8 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, > default: > return error_string(buf, end, "(einval)", spec); > } > + case 'p': > + return pxd_pointer(buf, end, ptr, spec, fmt); > default: > return default_pointer(buf, end, ptr, spec); > } > diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl > index 0492d6afc9a1..f68955858e29 100755 > --- a/scripts/checkpatch.pl > +++ b/scripts/checkpatch.pl > @@ -6975,7 +6975,7 @@ sub process { > my $fmt = get_quoted_string($lines[$count - 1], raw_line($count, 0)); > $fmt =~ s/%%//g; > > - while ($fmt =~ /(\%[\*\d\.]*p(\w)(\w*))/g) { > + while ($fmt =~ /(\%[\*\d\.]*p(\w)(\w*)(pte|pmd|pud|p4d|pgd))/g) { > $specifier = $1; > $extension = $2; > $qualifier = $3; > -- > 2.30.2 > >