[linuxsh-dev] Problem w/SR macros?

[Jeremy S. <js...@mv...>]

I've been having a problem with recent kernels, apparently due
to the definition of include/asm-sh/system.h:__save_and_cli();
looks like "volatile" was inadvertently left out, resulting in the
occasional demise of the cli due to compiler optimization...

[In my case, the netif_rx() reference to __cpu_raise_softirq()
expanded to an unprotected set_bit(): a timer interrupt right at
that point scheduled the tasklet but lost the softirq; timer_bh
would then never run until some other interrupt caused another
HI_SOFTIRQ... but I suspect other things could go wrong too.]

Any reason NOT to commit the following patch?  (It's really
just adding volatile; the rest is whitespace ;-)

--- system.h~ Tue Jul 31 03:12:05 2001
+++ system.h Thu Aug 30 12:11:54 2001
@@ -136,13 +136,15 @@
 {
  unsigned long flags, __dummy;

- __asm__("stc sr, %1\n\t"
-  "mov %1, %0\n\t"
-  "or #0xf0, %0\n\t"
-  "ldc %0, sr\n\t"
-  "mov %1, %0\n\t"
-  "and #0xf0, %0"
-  : "=&z" (flags), "=&r" (__dummy) :/**/: "memory" );
+ __asm__ __volatile__ ("stc sr, %1\n\t"
+         "mov %1, %0\n\t"
+         "or #0xf0, %0\n\t"
+         "ldc %0, sr\n\t"
+         "mov %1, %0\n\t"
+         "and #0xf0, %0"
+         : "=&z" (flags), "=&r" (__dummy)
+         :/**/
+         : "memory");
  return flags;
 }