From fc00c656c96528112d05cf0edf8631bd5eaea446 Mon Sep 17 00:00:00 2001 From: Kacper Date: Sun, 7 Dec 2025 20:10:31 +0100 Subject: Add build system scaffolding and libc headers --- include/arch/x86_64/linux/futex.h | 208 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 208 insertions(+) create mode 100644 include/arch/x86_64/linux/futex.h (limited to 'include/arch/x86_64/linux/futex.h') diff --git a/include/arch/x86_64/linux/futex.h b/include/arch/x86_64/linux/futex.h new file mode 100644 index 00000000..48689f00 --- /dev/null +++ b/include/arch/x86_64/linux/futex.h @@ -0,0 +1,208 @@ +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ +#ifndef _LINUX_FUTEX_H +#define _LINUX_FUTEX_H + +#include + +/* Second argument to futex syscall */ + +#define FUTEX_WAIT 0 +#define FUTEX_WAKE 1 +#define FUTEX_FD 2 +#define FUTEX_REQUEUE 3 +#define FUTEX_CMP_REQUEUE 4 +#define FUTEX_WAKE_OP 5 +#define FUTEX_LOCK_PI 6 +#define FUTEX_UNLOCK_PI 7 +#define FUTEX_TRYLOCK_PI 8 +#define FUTEX_WAIT_BITSET 9 +#define FUTEX_WAKE_BITSET 10 +#define FUTEX_WAIT_REQUEUE_PI 11 +#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_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG) +#define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG) +#define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG) +#define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG) +#define FUTEX_LOCK_PI2_PRIVATE (FUTEX_LOCK_PI2 | FUTEX_PRIVATE_FLAG) +#define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG) +#define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG) +#define FUTEX_WAIT_REQUEUE_PI_PRIVATE \ + (FUTEX_WAIT_REQUEUE_PI | FUTEX_PRIVATE_FLAG) +#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | FUTEX_PRIVATE_FLAG) + +/* + * 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; + * }; + * }; + */ +#define FUTEX2_SIZE_U8 0x00 +#define FUTEX2_SIZE_U16 0x01 +#define FUTEX2_SIZE_U32 0x02 +#define FUTEX2_SIZE_U64 0x03 +#define FUTEX2_NUMA 0x04 +#define FUTEX2_MPOL 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 :-( */ + +/* + * When FUTEX2_NUMA doubles the futex word, the second word is a node value. + * The special value -1 indicates no-node. This is the same value as + * NUMA_NO_NODE, except that value is not ABI, this is. + */ +#define FUTEX_NO_NODE (-1) + +/* + * Max numbers of elements in a futex_waitv array + */ +#define FUTEX_WAITV_MAX 128 + +/** + * struct futex_waitv - A waiter for vectorized wait + * @val: Expected value at uaddr + * @uaddr: User address to wait on + * @flags: Flags for this waiter + * @__reserved: Reserved member to preserve data alignment. Should be 0. + */ +struct futex_waitv { + __u64 val; + __u64 uaddr; + __u32 flags; + __u32 __reserved; +}; + +/* + * Support for robust futexes: the kernel cleans up held futexes at + * thread exit time. + */ + +/* + * Per-lock list entry - embedded in user-space locks, somewhere close + * to the futex field. (Note: user-space uses a double-linked list to + * achieve O(1) list add and remove, but the kernel only needs to know + * about the forward link) + * + * NOTE: this structure is part of the syscall ABI, and must not be + * changed. + */ +struct robust_list { + struct robust_list *next; +}; + +/* + * Per-thread list head: + * + * NOTE: this structure is part of the syscall ABI, and must only be + * changed if the change is first communicated with the glibc folks. + * (When an incompatible change is done, we'll increase the structure + * size, which glibc will detect) + */ +struct robust_list_head { + /* + * The head of the list. Points back to itself if empty: + */ + struct robust_list list; + + /* + * This relative offset is set by user-space, it gives the kernel + * the relative position of the futex field to examine. This way + * we keep userspace flexible, to freely shape its data-structure, + * without hardcoding any particular offset into the kernel: + */ + long futex_offset; + + /* + * The death of the thread may race with userspace setting + * up a lock's links. So to handle this race, userspace first + * sets this field to the address of the to-be-taken lock, + * then does the lock acquire, and then adds itself to the + * list, and then clears this field. Hence the kernel will + * always have full knowledge of all locks that the thread + * _might_ have taken. We check the owner TID in any case, + * so only truly owned locks will be handled. + */ + struct robust_list *list_op_pending; +}; + +/* + * Are there any waiters for this robust futex: + */ +#define FUTEX_WAITERS 0x80000000 + +/* + * The kernel signals via this bit that a thread holding a futex + * has exited without unlocking the futex. The kernel also does + * a FUTEX_WAKE on such futexes, after setting the bit, to wake + * up any possible waiters: + */ +#define FUTEX_OWNER_DIED 0x40000000 + +/* + * The rest of the robust-futex field is for the TID: + */ +#define FUTEX_TID_MASK 0x3fffffff + +/* + * This limit protects against a deliberately circular list. + * (Not worth introducing an rlimit for it) + */ +#define ROBUST_LIST_LIMIT 2048 + +/* + * bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a + * match of any bit. + */ +#define FUTEX_BITSET_MATCH_ANY 0xffffffff + +#define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */ +#define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */ +#define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */ +#define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */ +#define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */ + +#define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */ + +#define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */ +#define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */ +#define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */ +#define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */ +#define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */ +#define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */ + +/* FUTEX_WAKE_OP will perform atomically + int oldval = *(int *)UADDR2; + *(int *)UADDR2 = oldval OP OPARG; + if (oldval CMP CMPARG) + wake UADDR2; */ + +#define FUTEX_OP(op, oparg, cmp, cmparg) \ + (((op & 0xf) << 28) | ((cmp & 0xf) << 24) | ((oparg & 0xfff) << 12) | \ + (cmparg & 0xfff)) + +#endif /* _LINUX_FUTEX_H */ -- cgit v1.2.3