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MFi386: handle PSL_T properly across fork. Typo fix.

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This commit is contained in:
Peter Wemm 2005-01-21 05:57:45 +00:00
parent ba2426ff44
commit 4fe91893a6
1 changed files with 13 additions and 1 deletions
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14
sys/amd64/amd64/vm_machdep.c
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@ -57,6 +57,7 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/mutex.h>
#include <sys/pioctl.h>
#include <sys/proc.h>
#include <sys/sf_buf.h>
#include <sys/smp.h>
@ -132,6 +133,17 @@ cpu_fork(td1, p2, td2, flags)
td2->td_frame->tf_rflags &= ~PSL_C; /* success */
td2->td_frame->tf_rdx = 1;
/*
* If the parent process has the trap bit set (i.e. a debugger had
* single stepped the process to the system call), we need to clear
* the trap flag from the new frame unless the debugger had set PF_FORK
* on the parent. Otherwise, the child will receive a (likely
* unexpected) SIGTRAP when it executes the first instruction after
* returning to userland.
*/
if ((p1->p_pfsflags & PF_FORK) == 0)
td2->td_frame->tf_rflags &= ~PSL_T;
/*
* Set registers for trampoline to user mode. Leave space for the
* return address on stack. These are the kernel mode register values.
@ -227,7 +239,7 @@ cpu_thread_setup(struct thread *td)
/*
* Initialize machine state (pcb and trap frame) for a new thread about to
* upcall. Pu t enough state in the new thread's PCB to get it to go back
* upcall. Put enough state in the new thread's PCB to get it to go back
* userret(), where we can intercept it again to set the return (upcall)
* Address and stack, along with those from upcals that are from other sources
* such as those generated in thread_userret() itself.