powerpc: Rework runlatch code

This moves the inlines into system.h and changes the runlatch
code to use the thread local flags (non-atomic) rather than
the TIF flags (atomic) to keep track of the latch state.

The code to turn it back on in an asynchronous interrupt is
now simplified and partially inlined.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/exception-64s.h b/arch/powerpc/include/asm/exception-64s.h
index 041b2227967d04bbddff05b1cfbd3a90b5bfc27b..bdc9eebd1d442fb3afdc0a7cce575d749285aad6 100644 (file)
--- a/arch/powerpc/include/asm/exception-64s.h
+++ b/arch/powerpc/include/asm/exception-64s.h
@@ -284,35 +284,39 @@ label##_hv:                                                               \
        rlwimi  r11,r12,0,MSR_EE;               \
        mtmsrd  r11,1
 
-#define STD_EXCEPTION_COMMON(trap, label, hdlr)                \
-       .align  7;                                      \
-       .globl label##_common;                          \
-label##_common:                                                \
-       EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
-       DISABLE_INTS;                                   \
-       bl      .save_nvgprs;                           \
-       addi    r3,r1,STACK_FRAME_OVERHEAD;             \
-       bl      hdlr;                                   \
-       b       .ret_from_except
+#define ADD_NVGPRS                             \
+       bl      .save_nvgprs
+
+#define RUNLATCH_ON                            \
+BEGIN_FTR_SECTION                              \
+       clrrdi  r3,r1,THREAD_SHIFT;             \
+       ld      r4,TI_LOCAL_FLAGS(r3);          \
+       andi.   r0,r4,_TLF_RUNLATCH;            \
+       beql    ppc64_runlatch_on_trampoline;   \
+END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
+
+#define EXCEPTION_COMMON(trap, label, hdlr, ret, additions)    \
+       .align  7;                                              \
+       .globl label##_common;                                  \
+label##_common:                                                        \
+       EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);              \
+       additions;                                              \
+       addi    r3,r1,STACK_FRAME_OVERHEAD;                     \
+       bl      hdlr;                                           \
+       b       ret
+
+#define STD_EXCEPTION_COMMON(trap, label, hdlr)                        \
+       EXCEPTION_COMMON(trap, label, hdlr, ret_from_except,    \
+                        ADD_NVGPRS;DISABLE_INTS)
 
 /*
  * Like STD_EXCEPTION_COMMON, but for exceptions that can occur
  * in the idle task and therefore need the special idle handling
  * (finish nap and runlatch)
  */
-#define STD_EXCEPTION_COMMON_ASYNC(trap, label, hdlr)  \
-       .align  7;                                      \
-       .globl label##_common;                          \
-label##_common:                                                \
-       EXCEPTION_PROLOG_COMMON(trap, PACA_EXGEN);      \
-       FINISH_NAP;                                     \
-       DISABLE_INTS;                                   \
-BEGIN_FTR_SECTION                                      \
-       bl      .ppc64_runlatch_on;                     \
-END_FTR_SECTION_IFSET(CPU_FTR_CTRL)                    \
-       addi    r3,r1,STACK_FRAME_OVERHEAD;             \
-       bl      hdlr;                                   \
-       b       .ret_from_except_lite
+#define STD_EXCEPTION_COMMON_ASYNC(trap, label, hdlr)            \
+       EXCEPTION_COMMON(trap, label, hdlr, ret_from_except_lite, \
+                        FINISH_NAP;RUNLATCH_ON;DISABLE_INTS)
 
 /*
  * When the idle code in power4_idle puts the CPU into NAP mode,

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 7fdc2c0b7fa057bd1f9391e93d0332b9f8ccebb8..b1a215eabef6abc872ae94107a1be3af3c2bdad6 100644 (file)
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h
@@ -1079,30 +1079,12 @@
 
 #define proc_trap()    asm volatile("trap")
 
-#ifdef CONFIG_PPC64
-
-extern void ppc64_runlatch_on(void);
-extern void __ppc64_runlatch_off(void);
-
-#define ppc64_runlatch_off()                                   \
-       do {                                                    \
-               if (cpu_has_feature(CPU_FTR_CTRL) &&            \
-                   test_thread_flag(TIF_RUNLATCH))             \
-                       __ppc64_runlatch_off();                 \
-       } while (0)
+#define __get_SP()     ({unsigned long sp; \
+                       asm volatile("mr %0,1": "=r" (sp)); sp;})
 
 extern unsigned long scom970_read(unsigned int address);
 extern void scom970_write(unsigned int address, unsigned long value);
 
-#else
-#define ppc64_runlatch_on()
-#define ppc64_runlatch_off()
-
-#endif /* CONFIG_PPC64 */
-
-#define __get_SP()     ({unsigned long sp; \
-                       asm volatile("mr %0,1": "=r" (sp)); sp;})
-
 struct pt_regs;
 
 extern void ppc_save_regs(struct pt_regs *regs);

diff --git a/arch/powerpc/include/asm/system.h b/arch/powerpc/include/asm/system.h
index c377457d1b898a13ce2ba24b6e0aab108069f91f..a02883d5af435f798bc0b174a6432134c084060c 100644 (file)
--- a/arch/powerpc/include/asm/system.h
+++ b/arch/powerpc/include/asm/system.h
@@ -550,5 +550,43 @@ extern void reloc_got2(unsigned long);
 
 extern struct dentry *powerpc_debugfs_root;
 
+#ifdef CONFIG_PPC64
+
+extern void __ppc64_runlatch_on(void);
+extern void __ppc64_runlatch_off(void);
+
+/*
+ * We manually hard enable-disable, this is called
+ * in the idle loop and we don't want to mess up
+ * with soft-disable/enable & interrupt replay.
+ */
+#define ppc64_runlatch_off()                                   \
+       do {                                                    \
+               if (cpu_has_feature(CPU_FTR_CTRL) &&            \
+                   test_thread_local_flags(_TLF_RUNLATCH)) {   \
+                       unsigned long msr = mfmsr();            \
+                       __hard_irq_disable();                   \
+                       __ppc64_runlatch_off();                 \
+                       if (msr & MSR_EE)                       \
+                               __hard_irq_enable();            \
+               }                                               \
+       } while (0)
+
+#define ppc64_runlatch_on()                                    \
+       do {                                                    \
+               if (cpu_has_feature(CPU_FTR_CTRL) &&            \
+                   !test_thread_local_flags(_TLF_RUNLATCH)) {  \
+                       unsigned long msr = mfmsr();            \
+                       __hard_irq_disable();                   \
+                       __ppc64_runlatch_on();                  \
+                       if (msr & MSR_EE)                       \
+                               __hard_irq_enable();            \
+               }                                               \
+       } while (0)
+#else
+#define ppc64_runlatch_on()
+#define ppc64_runlatch_off()
+#endif /* CONFIG_PPC64 */
+
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_SYSTEM_H */

diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 964714940961a729c9b8d7404abb133dedb94c28..4a741c7efd02743a33d53bd6c56b24c8e4075596 100644 (file)
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -110,7 +110,6 @@ static inline struct thread_info *current_thread_info(void)
 #define TIF_NOERROR            12      /* Force successful syscall return */
 #define TIF_NOTIFY_RESUME      13      /* callback before returning to user */
 #define TIF_SYSCALL_TRACEPOINT 15      /* syscall tracepoint instrumentation */
-#define TIF_RUNLATCH           16      /* Is the runlatch enabled? */
 
 /* as above, but as bit values */
 #define _TIF_SYSCALL_TRACE     (1<<TIF_SYSCALL_TRACE)
@@ -141,11 +140,13 @@ static inline struct thread_info *current_thread_info(void)
 #define TLF_SLEEPING           1       /* suspend code enabled SLEEP mode */
 #define TLF_RESTORE_SIGMASK    2       /* Restore signal mask in do_signal */
 #define TLF_LAZY_MMU           3       /* tlb_batch is active */
+#define TLF_RUNLATCH           4       /* Is the runlatch enabled? */
 
 #define _TLF_NAPPING           (1 << TLF_NAPPING)
 #define _TLF_SLEEPING          (1 << TLF_SLEEPING)
 #define _TLF_RESTORE_SIGMASK   (1 << TLF_RESTORE_SIGMASK)
 #define _TLF_LAZY_MMU          (1 << TLF_LAZY_MMU)
+#define _TLF_RUNLATCH          (1 << TLF_RUNLATCH)
 
 #ifndef __ASSEMBLY__
 #define HAVE_SET_RESTORE_SIGMASK       1
@@ -156,6 +157,12 @@ static inline void set_restore_sigmask(void)
        set_bit(TIF_SIGPENDING, &ti->flags);
 }
 
+static inline bool test_thread_local_flags(unsigned int flags)
+{
+       struct thread_info *ti = current_thread_info();
+       return (ti->local_flags & flags) != 0;
+}
+
 #ifdef CONFIG_PPC64
 #define is_32bit_task()        (test_thread_flag(TIF_32BIT))
 #else

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 2240d4ecec028ab7375e150b56771a7dbe4e2ca9..3af80e82830bc82f6562dc169001f9a059e3c3a5 100644 (file)
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -483,6 +483,9 @@ machine_check_common:
 system_call_entry:
        b       system_call_common
 
+ppc64_runlatch_on_trampoline:
+       b       .__ppc64_runlatch_on
+
 /*
  * Here we have detected that the kernel stack pointer is bad.
  * R9 contains the saved CR, r13 points to the paca,

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index d817ab018486d71b8c06bb9b6275bd0f533d8c89..bf80a1d5f8fe8a56b5fdf1883293b79da97aa002 100644 (file)
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1220,34 +1220,32 @@ void dump_stack(void)
 EXPORT_SYMBOL(dump_stack);
 
 #ifdef CONFIG_PPC64
-void ppc64_runlatch_on(void)
+/* Called with hard IRQs off */
+void __ppc64_runlatch_on(void)
 {
+       struct thread_info *ti = current_thread_info();
        unsigned long ctrl;
 
-       if (cpu_has_feature(CPU_FTR_CTRL) && !test_thread_flag(TIF_RUNLATCH)) {
-               HMT_medium();
-
-               ctrl = mfspr(SPRN_CTRLF);
-               ctrl |= CTRL_RUNLATCH;
-               mtspr(SPRN_CTRLT, ctrl);
+       ctrl = mfspr(SPRN_CTRLF);
+       ctrl |= CTRL_RUNLATCH;
+       mtspr(SPRN_CTRLT, ctrl);
 
-               set_thread_flag(TIF_RUNLATCH);
-       }
+       ti->local_flags |= TLF_RUNLATCH;
 }
 
+/* Called with hard IRQs off */
 void __ppc64_runlatch_off(void)
 {
+       struct thread_info *ti = current_thread_info();
        unsigned long ctrl;
 
-       HMT_medium();
-
-       clear_thread_flag(TIF_RUNLATCH);
+       ti->local_flags &= ~TLF_RUNLATCH;
 
        ctrl = mfspr(SPRN_CTRLF);
        ctrl &= ~CTRL_RUNLATCH;
        mtspr(SPRN_CTRLT, ctrl);
 }
-#endif
+#endif /* CONFIG_PPC64 */
 
 #if THREAD_SHIFT < PAGE_SHIFT