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From: peterz@infradead.org
To: tglx@linutronix.de, axboe@kernel.dk
Cc: linux-kernel@vger.kernel.org, peterz@infradead.org,
	mingo@redhat.com, dvhart@infradead.org, dave@stgolabs.net,
	andrealmeid@igalia.com, Andrew Morton <akpm@linux-foundation.org>,
	urezki@gmail.com, hch@infradead.org, lstoakes@gmail.com,
	Arnd Bergmann <arnd@arndb.de>,
	linux-api@vger.kernel.org, linux-mm@kvack.org,
	linux-arch@vger.kernel.org, malteskarupke@web.de
Subject: [PATCH v3 02/15] futex: Extend the FUTEX2 flags
Date: Thu, 21 Sep 2023 12:45:07 +0200	[thread overview]
Message-ID: <20230921105247.617057368@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: 20230921104505.717750284@noisy.programming.kicks-ass.net

[-- Attachment #1: peterz-futex2-flags-2.patch --]
[-- Type: text/plain, Size: 2339 bytes --]

Add the definition for the missing but always intended extra sizes,
and add a NUMA flag for the planned numa extention.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: André Almeida <andrealmeid@igalia.com>
---
 include/uapi/linux/futex.h |   21 ++++++++++++++++++---
 kernel/futex/syscalls.c    |    9 +++++++--
 2 files changed, 25 insertions(+), 5 deletions(-)

Index: linux-2.6/include/uapi/linux/futex.h
===================================================================
--- linux-2.6.orig/include/uapi/linux/futex.h
+++ linux-2.6/include/uapi/linux/futex.h
@@ -45,17 +45,32 @@
 
 /*
  * Flags for futex2 syscalls.
+ *
+ * NOTE: these are not pure flags, they can also be seen as:
+ *
+ *   union {
+ *     u32  flags;
+ *     struct {
+ *       u32 size    : 2,
+ *           numa    : 1,
+ *                   : 4,
+ *           private : 1;
+ *     };
+ *   };
  */
-			/*	0x00 */
-			/*	0x01 */
+#define FUTEX2_SIZE_U8		0x00
+#define FUTEX2_SIZE_U16		0x01
 #define FUTEX2_SIZE_U32		0x02
-			/*	0x04 */
+#define FUTEX2_SIZE_U64		0x03
+#define FUTEX2_NUMA		0x04
 			/*	0x08 */
 			/*	0x10 */
 			/*	0x20 */
 			/*	0x40 */
 #define FUTEX2_PRIVATE		FUTEX_PRIVATE_FLAG
 
+#define FUTEX2_SIZE_MASK	0x03
+
 /* do not use */
 #define FUTEX_32		FUTEX2_SIZE_U32 /* historical accident :-( */
 
Index: linux-2.6/kernel/futex/syscalls.c
===================================================================
--- linux-2.6.orig/kernel/futex/syscalls.c
+++ linux-2.6/kernel/futex/syscalls.c
@@ -183,7 +183,7 @@ SYSCALL_DEFINE6(futex, u32 __user *, uad
 	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
 }
 
-#define FUTEX2_VALID_MASK (FUTEX2_SIZE_U32 | FUTEX2_PRIVATE)
+#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK | FUTEX2_PRIVATE)
 
 /**
  * futex_parse_waitv - Parse a waitv array from userspace
@@ -207,7 +207,12 @@ static int futex_parse_waitv(struct fute
 		if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved)
 			return -EINVAL;
 
-		if (!(aux.flags & FUTEX2_SIZE_U32))
+		if (!IS_ENABLED(CONFIG_64BIT) || in_compat_syscall()) {
+			if ((aux.flags & FUTEX2_SIZE_MASK) == FUTEX2_SIZE_U64)
+				return -EINVAL;
+		}
+
+		if ((aux.flags & FUTEX2_SIZE_MASK) != FUTEX2_SIZE_U32)
 			return -EINVAL;
 
 		futexv[i].w.flags = aux.flags;




  parent reply	other threads:[~2023-09-21 11:01 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-21 10:45 [PATCH v3 00/15] futex: More futex2 bits peterz
2023-09-21 10:45 ` [PATCH v3 01/15] futex: Clarify FUTEX2 flags peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` peterz [this message]
2023-09-21 17:36   ` [tip: locking/core] futex: Extend the " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 03/15] futex: Flag conversion peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 04/15] futex: Validate futex value against futex size peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 05/15] futex: Add sys_futex_wake() peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 06/15] futex: FLAGS_STRICT peterz
2023-09-21 15:14   ` Thomas Gleixner
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 07/15] futex: Add sys_futex_wait() peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 08/15] futex: Propagate flags into get_futex_key() peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 09/15] futex: Add flags2 argument to futex_requeue() peterz
2023-09-21 17:36   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-21 10:45 ` [PATCH v3 10/15] futex: Add sys_futex_requeue() peterz
2023-09-21 17:35   ` [tip: locking/core] " tip-bot2 for peterz@infradead.org
2023-09-22  9:35   ` [PATCH v3 10/15] " Ingo Molnar
2023-09-22 11:03     ` Peter Zijlstra
2023-09-22 13:56       ` Jens Axboe
2023-09-21 10:45 ` [PATCH v3 11/15] mm: Add vmalloc_huge_node() peterz
2023-09-21 10:45 ` [PATCH v3 12/15] futex: Implement FUTEX2_NUMA peterz
2023-09-21 10:45 ` [PATCH v3 13/15] futex: Propagate flags into futex_get_value_locked() peterz
2023-09-21 10:45 ` [PATCH v3 14/15] futex: Enable FUTEX2_{8,16} peterz
2023-09-21 10:45 ` [PATCH v3 15/15] futex,selftests: Extend the futex selftests peterz
2023-09-21 11:41   ` Peter Zijlstra
2023-09-22 20:01 ` futex2 numa stuff Peter Zijlstra
2023-09-22 20:01   ` [PATCH 15/15] futex,selftests: Extend the futex selftests Peter Zijlstra
2023-09-22 20:01   ` [PATCH 16/15] futex,selftests: Extend the futex selftests for NUMA Peter Zijlstra
2023-09-22 20:01   ` [PATCH 17/15] [HACK] futex: Force futex hash collision Peter Zijlstra
2023-09-28 13:40   ` futex2 numa stuff Davidlohr Bueso

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