Fedora kernel-2.6.17-1.2142_FC4 patched with stable patch-2.6.17.4-vs2.0.2-rc26.diff
[linux-2.6.git] / include / asm-sparc64 / system.h
index fd12ca3..a18ec87 100644 (file)
@@ -28,6 +28,49 @@ enum sparc_cpu {
 #define ARCH_SUN4C_SUN4 0
 #define ARCH_SUN4 0
 
+/* These are here in an effort to more fully work around Spitfire Errata
+ * #51.  Essentially, if a memory barrier occurs soon after a mispredicted
+ * branch, the chip can stop executing instructions until a trap occurs.
+ * Therefore, if interrupts are disabled, the chip can hang forever.
+ *
+ * It used to be believed that the memory barrier had to be right in the
+ * delay slot, but a case has been traced recently wherein the memory barrier
+ * was one instruction after the branch delay slot and the chip still hung.
+ * The offending sequence was the following in sym_wakeup_done() of the
+ * sym53c8xx_2 driver:
+ *
+ *     call    sym_ccb_from_dsa, 0
+ *      movge  %icc, 0, %l0
+ *     brz,pn  %o0, .LL1303
+ *      mov    %o0, %l2
+ *     membar  #LoadLoad
+ *
+ * The branch has to be mispredicted for the bug to occur.  Therefore, we put
+ * the memory barrier explicitly into a "branch always, predicted taken"
+ * delay slot to avoid the problem case.
+ */
+#define membar_safe(type) \
+do {   __asm__ __volatile__("ba,pt     %%xcc, 1f\n\t" \
+                            " membar   " type "\n" \
+                            "1:\n" \
+                            : : : "memory"); \
+} while (0)
+
+#define mb()   \
+       membar_safe("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")
+#define rmb()  \
+       membar_safe("#LoadLoad")
+#define wmb()  \
+       membar_safe("#StoreStore")
+#define membar_storeload() \
+       membar_safe("#StoreLoad")
+#define membar_storeload_storestore() \
+       membar_safe("#StoreLoad | #StoreStore")
+#define membar_storeload_loadload() \
+       membar_safe("#StoreLoad | #LoadLoad")
+#define membar_storestore_loadstore() \
+       membar_safe("#StoreStore | #LoadStore")
+
 #endif
 
 #define setipl(__new_ipl) \
@@ -78,16 +121,11 @@ enum sparc_cpu {
 
 #define nop()          __asm__ __volatile__ ("nop")
 
-#define membar(type)   __asm__ __volatile__ ("membar " type : : : "memory")
-#define mb()           \
-       membar("#LoadLoad | #LoadStore | #StoreStore | #StoreLoad")
-#define rmb()          membar("#LoadLoad")
-#define wmb()          membar("#StoreStore")
 #define read_barrier_depends()         do { } while(0)
 #define set_mb(__var, __value) \
-       do { __var = __value; membar("#StoreLoad | #StoreStore"); } while(0)
+       do { __var = __value; membar_storeload_storestore(); } while(0)
 #define set_wmb(__var, __value) \
-       do { __var = __value; membar("#StoreStore"); } while(0)
+       do { __var = __value; wmb(); } while(0)
 
 #ifdef CONFIG_SMP
 #define smp_mb()       mb()
@@ -139,19 +177,13 @@ extern void __flushw_user(void);
 #define flush_user_windows flushw_user
 #define flush_register_windows flushw_all
 
-#define prepare_arch_switch(rq, next)          \
-do {   spin_lock(&(next)->switch_lock);        \
-       spin_unlock(&(rq)->lock);               \
+/* Don't hold the runqueue lock over context switch */
+#define __ARCH_WANT_UNLOCKED_CTXSW
+#define prepare_arch_switch(next)              \
+do {                                           \
        flushw_all();                           \
 } while (0)
 
-#define finish_arch_switch(rq, prev)           \
-do {   spin_unlock_irq(&(prev)->switch_lock);  \
-} while (0)
-
-#define task_running(rq, p) \
-       ((rq)->curr == (p) || spin_is_locked(&(p)->switch_lock))
-
        /* See what happens when you design the chip correctly?
         *
         * We tell gcc we clobber all non-fixed-usage registers except
@@ -161,11 +193,7 @@ do {       spin_unlock_irq(&(prev)->switch_lock);  \
         * not preserve it's value.  Hairy, but it lets us remove 2 loads
         * and 2 stores in this critical code path.  -DaveM
         */
-#if __GNUC__ >= 3
 #define EXTRA_CLOBBER ,"%l1"
-#else
-#define EXTRA_CLOBBER
-#endif
 #define switch_to(prev, next, last)                                    \
 do {   if (test_thread_flag(TIF_PERFCTR)) {                            \
                unsigned long __tmp;                                    \
@@ -180,10 +208,11 @@ do {      if (test_thread_flag(TIF_PERFCTR)) {                            \
        /* If you are tempted to conditionalize the following */        \
        /* so that ASI is only written if it changes, think again. */   \
        __asm__ __volatile__("wr %%g0, %0, %%asi"                       \
-       : : "r" (__thread_flag_byte_ptr(next->thread_info)[TI_FLAG_BYTE_CURRENT_DS]));\
+       : : "r" (__thread_flag_byte_ptr(task_thread_info(next))[TI_FLAG_BYTE_CURRENT_DS]));\
+       trap_block[current_thread_info()->cpu].thread =                 \
+               task_thread_info(next);                                 \
        __asm__ __volatile__(                                           \
        "mov    %%g4, %%g7\n\t"                                         \
-       "wrpr   %%g0, 0x95, %%pstate\n\t"                               \
        "stx    %%i6, [%%sp + 2047 + 0x70]\n\t"                         \
        "stx    %%i7, [%%sp + 2047 + 0x78]\n\t"                         \
        "rdpr   %%wstate, %%o5\n\t"                                     \
@@ -196,24 +225,19 @@ do {      if (test_thread_flag(TIF_PERFCTR)) {                            \
        "wrpr   %%g1, %%cwp\n\t"                                        \
        "ldx    [%%g6 + %3], %%o6\n\t"                                  \
        "ldub   [%%g6 + %2], %%o5\n\t"                                  \
-       "ldx    [%%g6 + %4], %%o7\n\t"                                  \
-       "mov    %%g6, %%l2\n\t"                                         \
+       "ldub   [%%g6 + %4], %%o7\n\t"                                  \
        "wrpr   %%o5, 0x0, %%wstate\n\t"                                \
        "ldx    [%%sp + 2047 + 0x70], %%i6\n\t"                         \
        "ldx    [%%sp + 2047 + 0x78], %%i7\n\t"                         \
-       "wrpr   %%g0, 0x94, %%pstate\n\t"                               \
-       "mov    %%l2, %%g6\n\t"                                         \
-       "ldx    [%%g6 + %7], %%g4\n\t"                                  \
-       "wrpr   %%g0, 0x96, %%pstate\n\t"                               \
-       "andcc  %%o7, %6, %%g0\n\t"                                     \
-       "beq,pt %%icc, 1f\n\t"                                          \
+       "ldx    [%%g6 + %6], %%g4\n\t"                                  \
+       "brz,pt %%o7, 1f\n\t"                                           \
        " mov   %%g7, %0\n\t"                                           \
        "b,a ret_from_syscall\n\t"                                      \
        "1:\n\t"                                                        \
        : "=&r" (last)                                                  \
-       : "0" (next->thread_info),                                      \
-         "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_FLAGS), "i" (TI_CWP),  \
-         "i" (_TIF_NEWCHILD), "i" (TI_TASK)                            \
+       : "0" (task_thread_info(next)),                                 \
+         "i" (TI_WSTATE), "i" (TI_KSP), "i" (TI_NEW_CHILD),            \
+         "i" (TI_CWP), "i" (TI_TASK)                                   \
        : "cc",                                                         \
                "g1", "g2", "g3",                   "g7",               \
                      "l2", "l3", "l4", "l5", "l6", "l7",               \
@@ -226,6 +250,16 @@ do {       if (test_thread_flag(TIF_PERFCTR)) {                            \
        }                                                               \
 } while(0)
 
+/*
+ * On SMP systems, when the scheduler does migration-cost autodetection,
+ * it needs a way to flush as much of the CPU's caches as possible.
+ *
+ * TODO: fill this in!
+ */
+static inline void sched_cacheflush(void)
+{
+}
+
 static inline unsigned long xchg32(__volatile__ unsigned int *m, unsigned int val)
 {
        unsigned long tmp1, tmp2;