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Install machinery for cpu_set_kpc().

This commit is contained in:
pk 1996-03-14 00:54:06 +00:00
parent 808df5543f
commit d48d8e1512
1 changed files with 30 additions and 33 deletions
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63
sys/arch/sparc/sparc/locore.s
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@ -1558,8 +1558,8 @@ syscall:
ldd [%sp + CCFSZ + 0], %l0 ! new %psr, new pc
ldd [%sp + CCFSZ + 8], %l2 ! new npc, new %y
wr %l3, 0, %y
/* see `dostart' for the reason for this label */
init_syscall_ret:
/* see `proc_trampoline' for the reason for this label */
return_from_syscall:
ld [%sp + CCFSZ + 20], %g1
ldd [%sp + CCFSZ + 24], %g2
ldd [%sp + CCFSZ + 32], %g4
@ -2854,9 +2854,6 @@ noplab: nop
set wb1, %l0
st %l1, [%l0 + 6*4]
st %l1, [%l0 + 7*4]
set wb2, %l0
st %l1, [%l0 + 6*4]
st %l1, [%l0 + 7*4]
1:
#endif
@ -2881,17 +2878,7 @@ noplab: nop
*/
call _main
clr %o0 ! our frame arg is ignored
/*
* Here we finish up as in syscall, but simplified. We need to
* fiddle pc and npc a bit, as execve() / setregs() have only set
* npc, in anticipation that trap.c will advance past the trap
* instruction; but we bypass that, so we must do it manually.
*/
mov PSR_S, %l0 ! user psr (no need to load it)
ld [%sp + CCFSZ + 8], %l1 ! pc = npc from execve
b init_syscall_ret
add %l1, 4, %l2 ! npc = pc+4
/*NOTREACHED*/
/*
* The following code is copied to the top of the user stack when each
@ -3801,21 +3788,10 @@ Lsw_sameproc:
/*
* Snapshot the current process so that stack frames are up to date.
* This is called from two places:
* - just before a crash dump, for the stack update;
* - in cpu_fork(), before copying the kernel stack.
* In the latter case the pcb and stack will be copied to the child,
* and the child will be made runnable. Eventually switch() will run
* it. When it does, we want its pcb_pc set so that we can appear
* to return 1 from cpu_fork(), so we store the current sp and psr
* in the given pcb, and set its pcb_pc to our return-1 code (offset
* by -8 due to call/ret conventions). This is not useful in the crash
* dump code but it is easiest to do it anyway.
* Only used just before a crash dump.
*/
ENTRY(snapshot)
st %o6, [%o0 + PCB_SP] ! save sp
set 1f - 8, %o1 ! set child-return pc
st %o1, [%o0 + PCB_PC]
rd %psr, %o1 ! save psr
st %o1, [%o0 + PCB_PSR]
@ -3824,13 +3800,34 @@ ENTRY(snapshot)
* 7 of each. Minor tweak: the 7th restore is
* done after a ret.
*/
wb2: SAVE; SAVE; SAVE; SAVE; SAVE; SAVE; SAVE
SAVE; SAVE; SAVE; SAVE; SAVE; SAVE; SAVE
restore; restore; restore; restore; restore; restore; ret; restore
1: /* this is reached only after a child gets chosen in switch() */
mov 1, %i0 ! return 1 from cpu_fork
ret
restore
/*
* cpu_set_kpc() and cpu_fork() arrange for proc_trampoline() to run
* after after a process gets chosen in switch(). The stack frame will
* contain a function pointer in %l0, and an argument to pass to it in %l2.
*
* If the function *(%l0) returns, we arrange for an immediate return
* to user mode. This happens in two known cases: after execve(2) of init,
* and when returning a child to user mode after a fork(2).
*/
ENTRY(proc_trampoline)
call %l0 ! re-use current frame
mov %l1, %o0
/*
* Here we finish up as in syscall, but simplified. We need to
* fiddle pc and npc a bit, as execve() / setregs() /cpu_set_kpc()
* have only set npc, in anticipation that trap.c will advance past
* the trap instruction; but we bypass that, so we must do it manually.
*/
mov PSR_S, %l0 ! user psr (no need to load it)
!?wr %g0, 2, %wim ! %wim = 2
ld [%sp + CCFSZ + 8], %l1 ! pc = tf->tf_npc from execve/fork
b return_from_syscall
add %l1, 4, %l2 ! npc = pc+4
/*
* {fu,su}{,i}{byte,word}