From: Peter Zijlstra <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: [HACK][PATCH 10/10] futex: Munge size and numa into the legacy interface
Date: Fri, 14 Jul 2023 15:39:09 +0200 [thread overview]
Message-ID: <20230714141219.282650897@infradead.org> (raw)
In-Reply-To: 20230714133859.305719029@infradead.org
Avert your eyes...
Arguably just the NUMA thing wouldn't be too bad.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/uapi/linux/futex.h | 15 ++++++++++++---
kernel/futex/futex.h | 9 ++++++++-
kernel/futex/syscalls.c | 18 ++++++++++++++++++
3 files changed, 38 insertions(+), 4 deletions(-)
--- a/include/uapi/linux/futex.h
+++ b/include/uapi/linux/futex.h
@@ -23,9 +23,18 @@
#define FUTEX_CMP_REQUEUE_PI 12
#define FUTEX_LOCK_PI2 13
-#define FUTEX_PRIVATE_FLAG 128
-#define FUTEX_CLOCK_REALTIME 256
-#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME)
+#define FUTEX_PRIVATE_FLAG (1 << 7)
+#define FUTEX_CLOCK_REALTIME (1 << 8)
+#define FUTEX_NUMA (1 << 9)
+#define FUTEX_SIZE_32 (0 << 10) /* backwards compat */
+#define FUTEX_SIZE_64 (1 << 10)
+#define FUTEX_SIZE_8 (2 << 10)
+#define FUTEX_SIZE_16 (3 << 10)
+
+#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | \
+ FUTEX_CLOCK_REALTIME | \
+ FUTEX_NUMA | \
+ FUTEX_SIZE_16)
#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
--- a/kernel/futex/futex.h
+++ b/kernel/futex/futex.h
@@ -39,7 +39,7 @@
/* FUTEX_ to FLAGS_ */
static inline unsigned int futex_to_flags(unsigned int op)
{
- unsigned int flags = FLAGS_SIZE_32;
+ unsigned int sz, flags = 0;
if (!(op & FUTEX_PRIVATE_FLAG))
flags |= FLAGS_SHARED;
@@ -47,6 +47,13 @@ static inline unsigned int futex_to_flag
if (op & FUTEX_CLOCK_REALTIME)
flags |= FLAGS_CLOCKRT;
+ if (op & FUTEX_NUMA)
+ flags |= FLAGS_NUMA;
+
+ /* { 2,3,0,1 } -> { 0,1,2,3 } */
+ sz = ((op + FUTEX_SIZE_8) & FUTEX_SIZE_16) >> 10;
+ flags |= sz;
+
return flags;
}
--- a/kernel/futex/syscalls.c
+++ b/kernel/futex/syscalls.c
@@ -95,6 +95,24 @@ long do_futex(u32 __user *uaddr, int op,
return -ENOSYS;
}
+ /* can't support u64 with a u32 based interface */
+ if ((flags & FLAGS_SIZE_MASK) == FLAGS_SIZE_64)
+ return -ENOSYS;
+
+ switch (cmd) {
+ case FUTEX_WAIT:
+ case FUTEX_WAIT_BITSET:
+ case FUTEX_WAKE:
+ case FUTEX_WAKE_BITSET:
+ /* u8, u16, u32 */
+ break;
+
+ default:
+ /* only u32 for now */
+ if ((flags & FLAGS_SIZE_MASK) != FLAGS_SIZE_32)
+ return -ENOSYS;
+ }
+
switch (cmd) {
case FUTEX_WAIT:
val3 = FUTEX_BITSET_MATCH_ANY;
prev parent reply other threads:[~2023-07-14 14:16 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-14 13:38 [RFC][PATCH 00/10] futex: More Futex2 bits Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 01/10] futex: Clarify FUTEX2 flags Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 02/10] futex: Extend the " Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 03/10] futex: Flag conversion Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 04/10] futex: Add sys_futex_wake() Peter Zijlstra
2023-07-14 14:26 ` Arnd Bergmann
2023-07-14 14:47 ` Peter Zijlstra
2023-07-14 20:10 ` Arnd Bergmann
2023-07-14 13:39 ` [RFC][PATCH 05/10] mm: Add vmalloc_huge_node() Peter Zijlstra
2023-07-14 14:37 ` Matthew Wilcox
2023-07-14 15:09 ` Peter Zijlstra
2023-07-14 15:11 ` Matthew Wilcox
2023-07-14 15:26 ` Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 06/10] futex: Propagate flags into get_futex_key() Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 07/10] futex: Implement FUTEX2_NUMA Peter Zijlstra
2023-07-14 15:22 ` Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 08/10] futex: Propagate flags into futex_get_value_locked() Peter Zijlstra
2023-07-14 13:39 ` [RFC][PATCH 09/10] futex: Enable FUTEX2_{8,16} Peter Zijlstra
2023-07-14 13:39 ` Peter Zijlstra [this message]
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