d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Grok async contexts. When a thread is interrupted and an upcall

Browse Source 
happens, the context of the interrupted thread is exported to
userland. Unlike most contexts, it will be an async context and
we cannot easily use our existing functions to set such a
context.
To avoid a lot of complexity that may possibly interfere with
the common case, we simply let the kernel deal with it. However,
we don't use the EPC based syscall path to invoke setcontext(2).
No, we use the break-based syscall path. That way the trapframe
will be compatible with the context we're trying to restore and
we save the kernel a lot of trouble. The kind of trouble we did
not want to go though ourselves...

However, we also need to set the threads mailbox and there's no
syscall to help us out. To avoid creating a new syscall, we use
the context itself to pass the information to the kernel so that
the kernel can update the mailbox. This involves setting a flag
(_MC_FLAGS_KSE_SET_MBOX) and setting ifa (the address) and isr
(the value).
This commit is contained in:
marcel 2003-08-07 08:03:05 +00:00
parent b88da9d9aa
commit 0dae148272
4 changed files with 82 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
lib/libkse/arch/ia64/ia64/context.S
View File

@ -27,6 +27,8 @@
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#include <sys/syscall.h>
#define SIZEOF_SPECIAL (18*8)
/*
@ -335,3 +337,15 @@ ENTRY(_ia64_save_context, 1)
;;
}
END(_ia64_save_context)
/*
* void _ia64_break_setcontext(ucontext_t *ucp);
*/
ENTRY(_ia64_break_setcontext, 1)
{ .mib
mov r15=SYS_setcontext
break 0x100000
br.ret.sptk rp
;;
}
END(_ia64_break_setcontext)

36
lib/libkse/arch/ia64/include/pthread_md.h
View File

@ -34,8 +34,14 @@
#include <ucontext.h>
#define THR_GETCONTEXT(ucp) _ia64_save_context(&(ucp)->uc_mcontext)
#define THR_SETCONTEXT(ucp) _ia64_restore_context(&(ucp)->uc_mcontext, \
0, NULL)
#define THR_SETCONTEXT(ucp) \
do { \
if ((ucp)->uc_mcontext.mc_flags & _MC_FLAGS_ASYNC_CONTEXT) \
_ia64_break_setcontext(ucp); \
else \
_ia64_restore_context(&(ucp)->uc_mcontext, 0, \
NULL); \
} while (0)
#define PER_THREAD
@ -194,6 +200,7 @@ _get_curkse(void)
return (_tcb->tcb_curkcb->kcb_kse);
}
void _ia64_break_setcontext(ucontext_t *ucp);
void _ia64_enter_uts(kse_func_t uts, struct kse_mailbox *km, void *stack,
size_t stacksz);
int _ia64_restore_context(mcontext_t *mc, intptr_t val, intptr_t *loc);
@ -218,14 +225,25 @@ _thread_enter_uts(struct tcb *tcb, struct kcb *kcb)
static __inline int
_thread_switch(struct kcb *kcb, struct tcb *tcb, int setmbox)
{
mcontext_t *mc;
_tcb_set(kcb, tcb);
if (setmbox != 0)
_ia64_restore_context(&tcb->tcb_tmbx.tm_context.uc_mcontext,
(intptr_t)&tcb->tcb_tmbx,
(intptr_t *)&kcb->kcb_kmbx.km_curthread);
else
_ia64_restore_context(&tcb->tcb_tmbx.tm_context.uc_mcontext,
0, NULL);
mc = &tcb->tcb_tmbx.tm_context.uc_mcontext;
if (mc->mc_flags & _MC_FLAGS_ASYNC_CONTEXT) {
if (setmbox) {
mc->mc_flags |= _MC_FLAGS_KSE_SET_MBOX;
mc->mc_special.ifa =
(intptr_t)&kcb->kcb_kmbx.km_curthread;
mc->mc_special.isr = (intptr_t)&tcb->tcb_tmbx;
}
_ia64_break_setcontext(&tcb->tcb_tmbx.tm_context);
} else {
if (setmbox)
_ia64_restore_context(mc, (intptr_t)&tcb->tcb_tmbx,
(intptr_t *)&kcb->kcb_kmbx.km_curthread);
else
_ia64_restore_context(mc, 0, NULL);
}
/* We should not reach here. */
return (-1);
}

14
lib/libpthread/arch/ia64/ia64/context.S
View File

@ -27,6 +27,8 @@
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#include <sys/syscall.h>
#define SIZEOF_SPECIAL (18*8)
/*
@ -335,3 +337,15 @@ ENTRY(_ia64_save_context, 1)
;;
}
END(_ia64_save_context)
/*
* void _ia64_break_setcontext(ucontext_t *ucp);
*/
ENTRY(_ia64_break_setcontext, 1)
{ .mib
mov r15=SYS_setcontext
break 0x100000
br.ret.sptk rp
;;
}
END(_ia64_break_setcontext)

36
lib/libpthread/arch/ia64/include/pthread_md.h
View File

@ -34,8 +34,14 @@
#include <ucontext.h>
#define THR_GETCONTEXT(ucp) _ia64_save_context(&(ucp)->uc_mcontext)
#define THR_SETCONTEXT(ucp) _ia64_restore_context(&(ucp)->uc_mcontext, \
0, NULL)
#define THR_SETCONTEXT(ucp) \
do { \
if ((ucp)->uc_mcontext.mc_flags & _MC_FLAGS_ASYNC_CONTEXT) \
_ia64_break_setcontext(ucp); \
else \
_ia64_restore_context(&(ucp)->uc_mcontext, 0, \
NULL); \
} while (0)
#define PER_THREAD
@ -194,6 +200,7 @@ _get_curkse(void)
return (_tcb->tcb_curkcb->kcb_kse);
}
void _ia64_break_setcontext(ucontext_t *ucp);
void _ia64_enter_uts(kse_func_t uts, struct kse_mailbox *km, void *stack,
size_t stacksz);
int _ia64_restore_context(mcontext_t *mc, intptr_t val, intptr_t *loc);
@ -218,14 +225,25 @@ _thread_enter_uts(struct tcb *tcb, struct kcb *kcb)
static __inline int
_thread_switch(struct kcb *kcb, struct tcb *tcb, int setmbox)
{
mcontext_t *mc;
_tcb_set(kcb, tcb);
if (setmbox != 0)
_ia64_restore_context(&tcb->tcb_tmbx.tm_context.uc_mcontext,
(intptr_t)&tcb->tcb_tmbx,
(intptr_t *)&kcb->kcb_kmbx.km_curthread);
else
_ia64_restore_context(&tcb->tcb_tmbx.tm_context.uc_mcontext,
0, NULL);
mc = &tcb->tcb_tmbx.tm_context.uc_mcontext;
if (mc->mc_flags & _MC_FLAGS_ASYNC_CONTEXT) {
if (setmbox) {
mc->mc_flags |= _MC_FLAGS_KSE_SET_MBOX;
mc->mc_special.ifa =
(intptr_t)&kcb->kcb_kmbx.km_curthread;
mc->mc_special.isr = (intptr_t)&tcb->tcb_tmbx;
}
_ia64_break_setcontext(&tcb->tcb_tmbx.tm_context);
} else {
if (setmbox)
_ia64_restore_context(mc, (intptr_t)&tcb->tcb_tmbx,
(intptr_t *)&kcb->kcb_kmbx.km_curthread);
else
_ia64_restore_context(mc, 0, NULL);
}
/* We should not reach here. */
return (-1);
}