[src/trunk]: src/sys/arch/usermode/dev Make cpu_lwp_trampo only jump once and...

[reinoud <reinoud%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c8f1015ed3ff
branches:  trunk
changeset: 769441:c8f1015ed3ff
user:      reinoud <reinoud%NetBSD.org@localhost>
date:      Sat Sep 10 10:37:06 2011 +0000

description:
Make cpu_lwp_trampo only jump once and make successive jumps go to the func
only

diffstat:

 sys/arch/usermode/dev/cpu.c |  42 ++++++++++++++++++++++++------------------
 1 files changed, 24 insertions(+), 18 deletions(-)

diffs (123 lines):

diff -r 950f6e82849f -r c8f1015ed3ff sys/arch/usermode/dev/cpu.c
--- a/sys/arch/usermode/dev/cpu.c       Sat Sep 10 10:35:21 2011 +0000
+++ b/sys/arch/usermode/dev/cpu.c       Sat Sep 10 10:37:06 2011 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: cpu.c,v 1.44 2011/09/09 20:14:33 reinoud Exp $ */
+/* $NetBSD: cpu.c,v 1.45 2011/09/10 10:37:06 reinoud Exp $ */
 
 /*-
  * Copyright (c) 2007 Jared D. McNeill <jmcneill%invisible.ca@localhost>
@@ -30,7 +30,7 @@
 #include "opt_hz.h"
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.44 2011/09/09 20:14:33 reinoud Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpu.c,v 1.45 2011/09/10 10:37:06 reinoud Exp $");
 
 #include <sys/param.h>
 #include <sys/conf.h>
@@ -187,15 +187,16 @@
 #endif /* !CPU_DEBUG */
 
        ci->ci_stash = oldlwp;
-       curlwp = newlwp;
 
        if (oldpcb) {
                oldpcb->pcb_errno = thunk_geterrno();
                thunk_seterrno(newpcb->pcb_errno);
+               curlwp = newlwp;
                if (thunk_swapcontext(&oldpcb->pcb_ucp, &newpcb->pcb_ucp))
                        panic("swapcontext failed");
        } else {
                thunk_seterrno(newpcb->pcb_errno);
+               curlwp = newlwp;
                if (thunk_setcontext(&newpcb->pcb_ucp))
                        panic("setcontext failed");
        }
@@ -273,6 +274,11 @@
                free(pcb->pcb_ucp.uc_stack.ss_sp, M_TEMP);
                pcb->pcb_ucp.uc_stack.ss_sp = NULL;
                pcb->pcb_ucp.uc_stack.ss_size = 0;
+
+               free(pcb->pcb_syscall_ucp.uc_stack.ss_sp, M_TEMP);
+               pcb->pcb_syscall_ucp.uc_stack.ss_sp = NULL;
+               pcb->pcb_syscall_ucp.uc_stack.ss_size = 0;
+
                pcb->pcb_needfree = false;
        }
 }
@@ -286,11 +292,9 @@
        /* init lwp */
        lwp_startup(curcpu()->ci_stash, curlwp);
 
-       /* adjust context so the next switch bypasses the trampoline */
+       /* actual jump */
        thunk_makecontext(ucp, (void (*)(void)) func, 1, arg, NULL, NULL);
-
-       /* issue for the 1st time */
-       func(arg);
+       thunk_setcontext(ucp);
 }
 
 void
@@ -299,6 +303,7 @@
 {
        struct pcb *pcb1 = lwp_getpcb(l1);
        struct pcb *pcb2 = lwp_getpcb(l2);
+       void *stack_ucp, *stack_syscall_ucp;
 
 #ifdef CPU_DEBUG
        printf("cpu_lwp_fork [%s/%p] -> [%s/%p] stack=%p stacksize=%d\n",
@@ -307,32 +312,34 @@
            stack, (int)stacksize);
 #endif
 
+       if (stack)
+               panic("%s: stack passed, can't handle\n", __func__);
+
        /* copy the PCB and its switchframes from parent */
        memcpy(pcb2, pcb1, sizeof(struct pcb));
 
-       /* XXXJDM */
-       if (stack == NULL) {
-               stack = malloc(PAGE_SIZE, M_TEMP, M_NOWAIT);
-               stacksize = PAGE_SIZE;
-               pcb2->pcb_needfree = true;
-       } else
-               pcb2->pcb_needfree = false;
+       stacksize = PAGE_SIZE;
+       stack_ucp          = malloc(PAGE_SIZE, M_TEMP, M_NOWAIT);
+       stack_syscall_ucp  = malloc(PAGE_SIZE, M_TEMP, M_NOWAIT);
+       pcb2->pcb_needfree = true;
 
        if (thunk_getcontext(&pcb2->pcb_ucp))
                panic("getcontext failed");
 
        /* set up the ucontext for the userland switch */
-       pcb2->pcb_ucp.uc_stack.ss_sp = stack;
+       pcb2->pcb_ucp.uc_stack.ss_sp = stack_ucp;
        pcb2->pcb_ucp.uc_stack.ss_size = stacksize;
        pcb2->pcb_ucp.uc_link = &pcb2->pcb_userland_ucp;
        pcb2->pcb_ucp.uc_flags = _UC_STACK | _UC_CPU;
-       thunk_makecontext(&pcb2->pcb_ucp, (void (*)(void)) cpu_lwp_trampoline,
+       thunk_makecontext(&pcb2->pcb_ucp,
+           (void (*)(void)) cpu_lwp_trampoline,
            3, &pcb2->pcb_ucp, func, arg);
 
        /* set up the ucontext for the syscall */
+       pcb2->pcb_syscall_ucp.uc_stack.ss_sp = stack_syscall_ucp;
+       pcb2->pcb_syscall_ucp.uc_stack.ss_size = stacksize;
        pcb2->pcb_syscall_ucp.uc_flags = _UC_CPU;
        pcb2->pcb_syscall_ucp.uc_link = &pcb2->pcb_userland_ucp;
-       pcb2->pcb_syscall_ucp.uc_stack.ss_size = 0;     /* no stack move */
        thunk_makecontext(&pcb2->pcb_syscall_ucp, (void (*)(void)) syscall,
            0, NULL, NULL, NULL);
 }
@@ -366,7 +373,6 @@
        /* init trapframe (going nowhere!), maybe a panic func? */
        memcpy(&lwp0pcb.pcb_userland_ucp, &lwp0pcb.pcb_ucp, sizeof(ucontext_t));
        memcpy(&lwp0pcb.pcb_syscall_ucp,  &lwp0pcb.pcb_ucp, sizeof(ucontext_t));
-//     thunk_makecontext_trapframe2go(&lwp0pcb.pcb_userland_ucp, NULL, NULL);
 }
 
 void