linux-kernel - [PATCH RFC v2 1/4] mm: Add MAP_BELOW

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20240829-patches-below_hint_mmap-v2-1-638a28d9eae0@rivosinc.com>
Date: Thu, 29 Aug 2024 00:15:58 -0700
From: Charlie Jenkins <charlie@...osinc.com>
To: Arnd Bergmann <arnd@...db.de>, 
 Richard Henderson <richard.henderson@...aro.org>, 
 Ivan Kokshaysky <ink@...assic.park.msu.ru>, 
 Matt Turner <mattst88@...il.com>, Vineet Gupta <vgupta@...nel.org>, 
 Russell King <linux@...linux.org.uk>, Guo Ren <guoren@...nel.org>, 
 Huacai Chen <chenhuacai@...nel.org>, WANG Xuerui <kernel@...0n.name>, 
 Thomas Bogendoerfer <tsbogend@...ha.franken.de>, 
 "James E.J. Bottomley" <James.Bottomley@...senPartnership.com>, 
 Helge Deller <deller@....de>, Michael Ellerman <mpe@...erman.id.au>, 
 Nicholas Piggin <npiggin@...il.com>, 
 Christophe Leroy <christophe.leroy@...roup.eu>, 
 Naveen N Rao <naveen@...nel.org>, 
 Alexander Gordeev <agordeev@...ux.ibm.com>, 
 Gerald Schaefer <gerald.schaefer@...ux.ibm.com>, 
 Heiko Carstens <hca@...ux.ibm.com>, Vasily Gorbik <gor@...ux.ibm.com>, 
 Christian Borntraeger <borntraeger@...ux.ibm.com>, 
 Sven Schnelle <svens@...ux.ibm.com>, 
 Yoshinori Sato <ysato@...rs.sourceforge.jp>, Rich Felker <dalias@...c.org>, 
 John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>, 
 "David S. Miller" <davem@...emloft.net>, 
 Andreas Larsson <andreas@...sler.com>, Thomas Gleixner <tglx@...utronix.de>, 
 Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, 
 Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org, 
 "H. Peter Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...nel.org>, 
 Peter Zijlstra <peterz@...radead.org>, Muchun Song <muchun.song@...ux.dev>, 
 Andrew Morton <akpm@...ux-foundation.org>, 
 "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
 Vlastimil Babka <vbabka@...e.cz>, 
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, Shuah Khan <shuah@...nel.org>
Cc: linux-arch@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-alpha@...r.kernel.org, linux-snps-arc@...ts.infradead.org, 
 linux-arm-kernel@...ts.infradead.org, linux-csky@...r.kernel.org, 
 loongarch@...ts.linux.dev, linux-mips@...r.kernel.org, 
 linux-parisc@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org, 
 linux-s390@...r.kernel.org, linux-sh@...r.kernel.org, 
 sparclinux@...r.kernel.org, linux-mm@...ck.org, 
 linux-kselftest@...r.kernel.org, Charlie Jenkins <charlie@...osinc.com>
Subject: [PATCH RFC v2 1/4] mm: Add MAP_BELOW_HINT

Some applications rely on placing data in free bits addresses allocated
by mmap. Various architectures (eg. x86, arm64, powerpc) restrict the
address returned by mmap to be less than the 48-bit address space,
unless the hint address uses more than 47 bits (the 48th bit is reserved
for the kernel address space).

To make this behavior explicit and more versatile across all
architectures, define a mmap flag that allows users to define an
arbitrary upper limit on addresses returned by mmap.

Signed-off-by: Charlie Jenkins <charlie@...osinc.com>
---
 include/uapi/asm-generic/mman-common.h       | 1 +
 tools/include/uapi/asm-generic/mman-common.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index 6ce1f1ceb432..03ac13d9aa37 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -32,6 +32,7 @@

 #define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be
 					 * uninitialized */
+#define MAP_BELOW_HINT	  0x8000000	/* give out address that is below (inclusive) hint address */

 /*
  * Flags for mlock
diff --git a/tools/include/uapi/asm-generic/mman-common.h b/tools/include/uapi/asm-generic/mman-common.h
index 6ce1f1ceb432..03ac13d9aa37 100644
--- a/tools/include/uapi/asm-generic/mman-common.h
+++ b/tools/include/uapi/asm-generic/mman-common.h
@@ -32,6 +32,7 @@

 #define MAP_UNINITIALIZED 0x4000000	/* For anonymous mmap, memory could be
 					 * uninitialized */
+#define MAP_BELOW_HINT	  0x8000000	/* give out address that is below (inclusive) hint address */

 /*
  * Flags for mlock

-- 
2.45.0