From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <ammarfaizi2@gnuweeb.org>
X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org
X-Spam-Level: 
X-Spam-Status: No, score=-0.8 required=5.0 tests=ALL_TRUSTED,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NO_DNS_FOR_FROM,URIBL_BLOCKED
	autolearn=no autolearn_force=no version=3.4.6
Received: from integral2.. (unknown [180.245.197.13])
	by gnuweeb.org (Postfix) with ESMTPSA id 0E54D7FC83;
	Wed, 29 Jun 2022 00:28:35 +0000 (UTC)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gnuweeb.org;
	s=default; t=1656462519;
	bh=3t9IpOHWlckPWbRMiMlxoC7Reb/Esot+xgFrYIRtRsU=;
	h=From:To:Cc:Subject:Date:In-Reply-To:References:From;
	b=Cpj6b30urcMoQ39J8nmVlWFqthHZHi7u6Z3+gzJjDBiLs14HVW1uZNrr4NCp6asL1
	 JYf0eKp0AZtGdzEJHgfS03ccfH7f2vQabwomTxxLOGF/eyxTyiHDZ2d6VtMzT1nygG
	 knPcWh1iWEL6S3XD4/u26lx2XnoywkADwrXCmvuS52rtfsc40cEqf7G/EarpUj1OAa
	 IRpI26FSL85EqGgL5BJiu0SkJobb/JJa+G98l6Nf+5w9vCAC0EuX213ejXbZifGrY5
	 hmC5qT2DMR3chS5pvplgGX+WV9JSRAo2MOb67s6KOMXYZ0JOPxcbBwIY6M5jR5bITr
	 nz4H+6LkhPdyQ==
From: Ammar Faizi <ammarfaizi2@gnuweeb.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Ammar Faizi <ammarfaizi2@gnuweeb.org>,
	Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>,
	Fernanda Ma'rouf <fernandafmr12@gnuweeb.org>,
	Pavel Begunkov <asml.silence@gmail.com>,
	Hao Xu <howeyxu@tencent.com>,
	io-uring Mailing List <io-uring@vger.kernel.org>,
	GNU/Weeb Mailing List <gwml@gnuweeb.org>
Subject: [PATCH liburing v1 7/9] arch/arm64: Add `get_page_size()` function
Date: Wed, 29 Jun 2022 07:27:51 +0700
Message-Id: <20220629002028.1232579-8-ammar.faizi@intel.com>
X-Mailer: git-send-email 2.34.1
In-Reply-To: <20220629002028.1232579-1-ammar.faizi@intel.com>
References: <20220629002028.1232579-1-ammar.faizi@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
List-Id: <gwml.vger.gnuweeb.org>

From: Ammar Faizi <ammarfaizi2@gnuweeb.org>

This is a preparation patch to add aarch64 nolibc support.

aarch64 supports three values of page size: 4K, 16K, and 64K which are
selected at kernel compilation time. Therefore, we can't hard code the
page size for this arch. Utilize open(), read() and close() syscall to
find the page size from /proc/self/auxv. For more details about the
auxv data structure, check the link below.

Link: https://github.com/torvalds/linux/blob/v5.19-rc4/fs/binfmt_elf.c#L260
Signed-off-by: Ammar Faizi <ammarfaizi2@gnuweeb.org>
---
 src/arch/arm64/lib.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)
 create mode 100644 src/arch/arm64/lib.h

diff --git a/src/arch/arm64/lib.h b/src/arch/arm64/lib.h
new file mode 100644
index 0000000..4dc39a8
--- /dev/null
+++ b/src/arch/arm64/lib.h
@@ -0,0 +1,44 @@
+/* SPDX-License-Identifier: MIT */
+
+#ifndef LIBURING_ARCH_ARM64_LIB_H
+#define LIBURING_ARCH_ARM64_LIB_H
+
+#include <elf.h>
+#include <sys/auxv.h>
+#include "../../syscall.h"
+
+static inline long get_page_size(void)
+{
+	Elf64_Off buf[2];
+	long page_size;
+	int fd;
+
+	fd = __sys_open("/proc/self/auxv", O_RDONLY, 0);
+	if (fd < 0)
+		return fd;
+
+	while (1) {
+		ssize_t ret;
+
+		ret = __sys_read(fd, buf, sizeof(buf));
+		if (ret < 0) {
+			page_size = -errno;
+			break;
+		}
+
+		if (ret < sizeof(buf)) {
+			page_size = -ENOENT;
+			break;
+		}
+
+		if (buf[0] == AT_PAGESZ) {
+			page_size = buf[1];
+			break;
+		}
+	}
+
+	__sys_close(fd);
+	return page_size;
+}
+
+#endif /* #ifndef LIBURING_ARCH_ARM64_LIB_H */
-- 
Ammar Faizi