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From: Peter Wemm <peter@FreeBSD.org>
Date: Sun, 11 May 2003 19:37:29 -0700 (PDT)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org,
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X-FreeBSD-CVS-Branch: HEAD
Subject: cvs commit: src/sys/amd64/amd64 cpu_switch.S exception.S
 genassym.c machdep.c sys_machdep.c src/sys/amd64/include pcb.h
 sysarch.h src/sys/amd64/isa icu_vector.S
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peter       2003/05/11 19:37:29 PDT

  FreeBSD src repository

  Modified files:
    sys/amd64/amd64      cpu_switch.S exception.S genassym.c 
                         machdep.c sys_machdep.c 
    sys/amd64/include    pcb.h sysarch.h 
    sys/amd64/isa        icu_vector.S 
  Log:
  Give a %fs and %gs to userland.  Use swapgs to obtain the kernel %GS.base
  value on entry and exit.  This isn't as easy as it sounds because when
  we recursively trap or interrupt, we have to avoid duplicating the
  swapgs instruction or we end up back with the userland %gs.  I implemented
  this by testing TF_CS to see if we're coming from supervisor mode
  already, and check for returning to supervisor. To avoid a race with
  interrupts in the brief period after beginning executing the handler and
  before the swapgs, convert all trap gates to interrupt gates, and reenable
  interrupts immediately after the swapgs.  I am not happy with this.
  There are other possible ways to do this that should be investigated.
  (eg: storing the GS.base MSR value in the trapframe)
  
  Add some sysarch functions to let the userland code get to this.
  
  Approved by:    re (blanket amd64/*)
  
  Revision  Changes    Path
  1.139     +50 -26    src/sys/amd64/amd64/cpu_switch.S
  1.108     +74 -37    src/sys/amd64/amd64/exception.S
  1.143     +5 -0      src/sys/amd64/amd64/genassym.c
  1.572     +28 -24    src/sys/amd64/amd64/machdep.c
  1.83      +25 -1     src/sys/amd64/amd64/sys_machdep.c
  1.51      +2 -0      src/sys/amd64/include/pcb.h
  1.19      +19 -1     src/sys/amd64/include/sysarch.h
  1.39      +8 -2      src/sys/amd64/isa/icu_vector.S