Author: nwhitehorn
Date: Sun Oct 31 22:55:51 2010
New Revision: 214607
URL: http://svn.freebsd.org/changeset/base/214607
Log:
Next-to-leading-order perturbation of synchronization operations for
switching the user segment register. All races should now be closed and
a minimum of pipelines flushes be required to close them.
Modified:
head/sys/powerpc/aim/copyinout.c
head/sys/powerpc/aim/swtch32.S
head/sys/powerpc/aim/swtch64.S
Modified: head/sys/powerpc/aim/copyinout.c
==============================================================================
--- head/sys/powerpc/aim/copyinout.c Sun Oct 31 22:46:39 2010
(r214606)
+++ head/sys/powerpc/aim/copyinout.c Sun Oct 31 22:55:51 2010
(r214607)
@@ -117,9 +117,9 @@ set_user_sr(pmap_t pm, const void *addr)
if (curthread->td_pcb->pcb_cpu.aim.usr_vsid == vsid)
return;
- __asm __volatile ("sync; mtsr %0,%1; sync; isync" :: "n"(USER_SR),
- "r"(vsid));
+ __asm __volatile("isync");
curthread->td_pcb->pcb_cpu.aim.usr_vsid = vsid;
+ __asm __volatile("mtsr %0,%1; isync" :: "n"(USER_SR), "r"(vsid));
}
#endif
Modified: head/sys/powerpc/aim/swtch32.S
==============================================================================
--- head/sys/powerpc/aim/swtch32.S Sun Oct 31 22:46:39 2010
(r214606)
+++ head/sys/powerpc/aim/swtch32.S Sun Oct 31 22:55:51 2010
(r214607)
@@ -89,7 +89,6 @@ ENTRY(cpu_switch)
mflr %r16 /* Save the link register */
stw %r16,PCB_LR(%r6)
mfsr %r16,USER_SR /* Save USER_SR for copyin/out */
- isync
stw %r16,PCB_AIM_USR_VSID(%r6)
stw %r1,PCB_SP(%r6) /* Save the stack pointer */
stw %r2,PCB_TOC(%r6) /* Save the TOC pointer */
@@ -162,6 +161,7 @@ blocked_loop:
lwz %r5,PCB_LR(%r3) /* Load the link register */
mtlr %r5
lwz %r5,PCB_AIM_USR_VSID(%r3) /* Load the USER_SR segment reg */
+ isync
mtsr USER_SR,%r5
isync
lwz %r1,PCB_SP(%r3) /* Load the stack pointer */
Modified: head/sys/powerpc/aim/swtch64.S
==============================================================================
--- head/sys/powerpc/aim/swtch64.S Sun Oct 31 22:46:39 2010
(r214606)
+++ head/sys/powerpc/aim/swtch64.S Sun Oct 31 22:55:51 2010
(r214607)
@@ -113,7 +113,6 @@ ENTRY(cpu_switch)
li %r15,0 /* Save user segment for copyin/out */
li %r16,USER_SLB_SLOT
slbmfev %r15, %r16
- isync
std %r15,PCB_AIM_USR_VSID(%r6)
mr %r14,%r3 /* Copy the old thread ptr... */
@@ -222,6 +221,7 @@ blocked_loop:
ori %r5,%r5,user_a...@highera
sldi %r5,%r5,32
oris %r5,%r5,user_a...@ha
+ isync
slbie %r5
lis %r6,user_slb_s...@highesta
ori %r6,%r6,user_slb_s...@highera
@@ -230,8 +230,8 @@ blocked_loop:
ori %r6,%r6,user_slb_s...@l
ld %r5,PCB_AIM_USR_VSID(%r3)
slbmte %r5,%r6
-
isync
+
/*
* Perform a dummy stdcx. to clear any reservations we may have
* inherited from the previous thread. It doesn't matter if the
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