---

yaml --- r: 40927 b: refs/heads/master c: 9446868 h: refs/heads/master i: 40925: 6d183d6 40923: 7669173 40919: 9e7e1f6 40911: d1f5127 40895: 8a2e5c6 v: v3
git-mirror · Nov 14, 2006 · 9b6ec94 · 9b6ec94
1 parent c43eac9
commit 9b6ec94
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Showing 3 changed files with 11 additions and 3 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 8c131af1db510793f87dc43edbc8950a35370df3
+refs/heads/master: 9446868b5383eb87f76b2d4389dea4bb968a6657
diff --git a/trunk/arch/x86_64/kernel/process.c b/trunk/arch/x86_64/kernel/process.c
@@ -88,9 +88,8 @@ void enter_idle(void)
 
 static void __exit_idle(void)
 {
-	if (read_pda(isidle) == 0)
+	if (test_and_clear_bit_pda(0, isidle) == 0)
 		return;
-	write_pda(isidle, 0);
 	atomic_notifier_call_chain(&idle_notifier, IDLE_END, NULL);
 }
 

diff --git a/trunk/include/asm-x86_64/pda.h b/trunk/include/asm-x86_64/pda.h
@@ -109,6 +109,15 @@ extern struct x8664_pda _proxy_pda;
 #define sub_pda(field,val) pda_to_op("sub",field,val)
 #define or_pda(field,val) pda_to_op("or",field,val)
 
+/* This is not atomic against other CPUs -- CPU preemption needs to be off */
+#define test_and_clear_bit_pda(bit,field) ({		\
+	int old__;						\
+	asm volatile("btr %2,%%gs:%c3\n\tsbbl %0,%0"		\
+	    : "=r" (old__), "+m" (_proxy_pda.field) 		\
+	    : "dIr" (bit), "i" (pda_offset(field)) : "memory");	\
+	old__;							\
+})
+
 #endif
 
 #define PDA_STACKOFFSET (5*8)