Author: kib
Date: Wed Dec 15 15:25:56 2010
New Revision: 216458
URL: http://svn.freebsd.org/changeset/base/216458
Log:
MFC r216255:
Update some comments related to use of amd64 full context switch.
In exec_linux_setregs(), use locally cached pointer to pcb to set
pcb_full_iret.
In set_regs(), note that full return is needed when code that sets
segment registers is enabled.
Approved by: re (bz)
Modified:
stable/8/sys/amd64/amd64/machdep.c
stable/8/sys/amd64/amd64/vm_machdep.c
stable/8/sys/amd64/linux32/linux32_sysvec.c
Directory Properties:
stable/8/sys/ (props changed)
stable/8/sys/amd64/include/xen/ (props changed)
stable/8/sys/cddl/contrib/opensolaris/ (props changed)
stable/8/sys/contrib/dev/acpica/ (props changed)
stable/8/sys/contrib/pf/ (props changed)
Modified: stable/8/sys/amd64/amd64/machdep.c
==============================================================================
--- stable/8/sys/amd64/amd64/machdep.c Wed Dec 15 15:23:25 2010
(r216457)
+++ stable/8/sys/amd64/amd64/machdep.c Wed Dec 15 15:25:56 2010
(r216458)
@@ -1895,6 +1895,7 @@ set_regs(struct thread *td, struct reg *
tp->tf_fs = regs->r_fs;
tp->tf_gs = regs->r_gs;
tp->tf_flags = TF_HASSEGS;
+ td->td_pcb->pcb_full_iret = 1;
}
return (0);
}
Modified: stable/8/sys/amd64/amd64/vm_machdep.c
==============================================================================
--- stable/8/sys/amd64/amd64/vm_machdep.c Wed Dec 15 15:23:25 2010
(r216457)
+++ stable/8/sys/amd64/amd64/vm_machdep.c Wed Dec 15 15:25:56 2010
(r216458)
@@ -339,10 +339,9 @@ cpu_set_syscall_retval(struct thread *td
* Reconstruct pc, we know that 'syscall' is 2 bytes,
* lcall $X,y is 7 bytes, int 0x80 is 2 bytes.
* We saved this in tf_err.
- * We have to do a full context restore so that %r10
- * (which was holding the value of %rcx) is restored
+ * %r10 (which was holding the value of %rcx) is restored
* for the next iteration.
- * r10 restore is only required for freebsd/amd64 processes,
+ * %r10 restore is only required for freebsd/amd64 processes,
* but shall be innocent for any ia32 ABI.
*/
td->td_frame->tf_rip -= td->td_frame->tf_err;
Modified: stable/8/sys/amd64/linux32/linux32_sysvec.c
==============================================================================
--- stable/8/sys/amd64/linux32/linux32_sysvec.c Wed Dec 15 15:23:25 2010
(r216457)
+++ stable/8/sys/amd64/linux32/linux32_sysvec.c Wed Dec 15 15:25:56 2010
(r216458)
@@ -875,13 +875,13 @@ exec_linux_setregs(td, entry, stack, ps_
regs->tf_flags = TF_HASSEGS;
regs->tf_cs = _ucode32sel;
regs->tf_rbx = ps_strings;
- td->td_pcb->pcb_full_iret = 1;
load_cr0(rcr0() | CR0_MP | CR0_TS);
fpstate_drop(td);
- /* Return via doreti so that we can change to a different %cs */
+ /* Do full restore on return so that we can change to a different %cs */
pcb->pcb_flags |= PCB_32BIT;
pcb->pcb_flags &= ~PCB_GS32BIT;
+ pcb->pcb_full_iret = 1;
td->td_retval[1] = 0;
}
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