summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2012-04-13 03:35:13 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-22 16:21:24 -0700
commit81cc5e7c4ed5bf9172b26bb3a7d019362dd3d204 (patch)
tree27d2366c0f53a43345a39fe4bcd38c8a0feab032 /arch
parenta2646264907ed038852b3ffdea9901cd5ea2305f (diff)
sparc64: Eliminate obsolete __handle_softirq() function
commit 3d3eeb2ef26112a200785e5fca58ec58dd33bf1e upstream. The invocation of softirq is now handled by irq_exit(), so there is no need for sparc64 to invoke it on the trap-return path. In fact, doing so is a bug because if the trap occurred in the idle loop, this invocation can result in lockdep-RCU failures. The problem is that RCU ignores idle CPUs, and the sparc64 trap-return path to the softirq handlers fails to tell RCU that the CPU must be considered non-idle while those handlers are executing. This means that RCU is ignoring any RCU read-side critical sections in those handlers, which in turn means that RCU-protected data can be yanked out from under those read-side critical sections. The shiny new lockdep-RCU ability to detect RCU read-side critical sections that RCU is ignoring located this problem. The fix is straightforward: Make sparc64 stop manually invoking the softirq handlers. Reported-by: Meelis Roos <mroos@linux.ee> Suggested-by: David Miller <davem@davemloft.net> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Meelis Roos <mroos@linux.ee> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/sparc/kernel/rtrap_64.S7
1 files changed, 0 insertions, 7 deletions
diff --git a/arch/sparc/kernel/rtrap_64.S b/arch/sparc/kernel/rtrap_64.S
index 77f1b95e0806..9171fc238def 100644
--- a/arch/sparc/kernel/rtrap_64.S
+++ b/arch/sparc/kernel/rtrap_64.S
@@ -20,11 +20,6 @@
.text
.align 32
-__handle_softirq:
- call do_softirq
- nop
- ba,a,pt %xcc, __handle_softirq_continue
- nop
__handle_preemption:
call schedule
wrpr %g0, RTRAP_PSTATE, %pstate
@@ -89,9 +84,7 @@ rtrap:
cmp %l1, 0
/* mm/ultra.S:xcall_report_regs KNOWS about this load. */
- bne,pn %icc, __handle_softirq
ldx [%sp + PTREGS_OFF + PT_V9_TSTATE], %l1
-__handle_softirq_continue:
rtrap_xcall:
sethi %hi(0xf << 20), %l4
and %l1, %l4, %l4