From 2e69ebf6999102c27c21615b610400a0d922e8c9 Mon Sep 17 00:00:00 2001 From: Agustina Arzille Date: Mon, 4 Apr 2016 19:16:31 -0300 Subject: Lightweight synchronization mechanism * Makefrag.am (libkernel_a_SOURCES): Add kern/gsync.c and kern/gsync.h. * include/mach/gnumach.defs (gsync_wait, gsync_wake, gsync_requeue): New routines. * include/mach/kern_return.h (KERN_TIMEDOUT, KERN_INTERRUPTED): New error codes. * kern/gsync.c: New file. * kern/gsync.h: New file. * kern/startup.c: Include (setup_main): Call gsync_setup. --- include/mach/gnumach.defs | 52 ++++++++++++++++++++++++++++++++++++++++++++++ include/mach/kern_return.h | 6 ++++++ 2 files changed, 58 insertions(+) (limited to 'include') diff --git a/include/mach/gnumach.defs b/include/mach/gnumach.defs index dd4da870..5235df63 100644 --- a/include/mach/gnumach.defs +++ b/include/mach/gnumach.defs @@ -84,3 +84,55 @@ simpleroutine task_set_name( routine register_new_task_notification( host_priv : host_priv_t; notification : mach_port_send_t); + +/* Test that the contents of ADDR are equal to the 32-bit integer VAL1. + * If they are not, return immediately, otherwise, block until a + * matching 'gsync_wake' is done on the same address. FLAGS is used + * to control how the thread waits, and may be composed of: + * - GSYNC_SHARED: The address may be shared among tasks. If this + bit is not set, the address is assumed to be task-local. + * - GSYNC_QUAD: Additionally check that the adjacent 32-bit word + following ADDR matches the value VAL2. + * - GSYNC_TIMED: The call only blocks for MSEC milliseconds. */ +routine gsync_wait( + task : task_t; + addr : vm_offset_t; + val1 : unsigned; + val2 : unsigned; + msec : natural_t; + flags : int); + +/* Wake up threads waiting on the address ADDR. Much like with + * 'gsync_wait', the parameter FLAGS controls how it is done. In this + * case, it may be composed of the following: + * - GSYNC_SHARED: Same as with 'gsync_wait'. + * - GSYNC_BROADCAST: Wake up every thread waiting on the address. If + * this flag is not set, the call wakes (at most) 1 thread. + * - GSYNC_MUTATE: Before waking any potential waiting threads, set the + * contents of ADDR to VAL. + * + * This RPC is implemented as a simple routine for efficiency reasons, + * and because the return value rarely matters. */ +simpleroutine gsync_wake( + task : task_t; + addr : vm_offset_t; + val : unsigned; + flags : int); + +/* Arrange for threads waiting on address SRC_ADDR to instead + * wait on address DST_ADDR. If WAKE_ONE is true, additionally + * wake one of the threads waiting on SRC_ADDR. For this function, + * the parameter flags may be a combination of: + * - GSYNC_SHARED: Just like with 'gsync_wait' and 'gsync_wake'. + * - GSYNC_BROADCAST: Move all the threads waiting on SRC_ADDR. If + this flag is not set, the call moves (at most) 1 thread. + * + * This RPC is also a simple routine, and for the same reasons as + * with 'gsync_wake'. */ +simpleroutine gsync_requeue( + task : task_t; + src_addr : vm_offset_t; + dst_addr : vm_offset_t; + wake_one : boolean_t; + flags : int); + diff --git a/include/mach/kern_return.h b/include/mach/kern_return.h index 2274328b..a9d16e94 100644 --- a/include/mach/kern_return.h +++ b/include/mach/kern_return.h @@ -157,4 +157,10 @@ /* Object has been terminated and is no longer available. */ +#define KERN_TIMEDOUT 27 + /* Kernel operation timed out. */ + +#define KERN_INTERRUPTED 28 + /* Kernel operation was interrupted. */ + #endif /* _MACH_KERN_RETURN_H_ */ -- cgit v1.2.3