8 files changed, 116 insertions, 23 deletions

diff --git a/arch/sparc/include/asm/atomic_64.h b/arch/sparc/include/asm/atomic_64.h
index ce35a1cf1a20..be56a244c9cf 100644
--- a/arch/sparc/include/asm/atomic_64.h
+++ b/arch/sparc/include/asm/atomic_64.h
@@ -1,7 +1,7 @@
 /* atomic.h: Thankfully the V9 is at least reasonable for this
  *           stuff.
  *
- * Copyright (C) 1996, 1997, 2000 David S. Miller (davem@redhat.com)
+ * Copyright (C) 1996, 1997, 2000, 2012 David S. Miller (davem@redhat.com)
  */
 
 #ifndef __ARCH_SPARC64_ATOMIC__
@@ -106,6 +106,8 @@ static inline long atomic64_add_unless(atomic64_t *v, long a, long u)
 
 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
+extern long atomic64_dec_if_positive(atomic64_t *v);
+
 /* Atomic operations are already serializing */
 #define smp_mb__before_atomic_dec()     barrier()
 #define smp_mb__after_atomic_dec()      barrier()
diff --git a/arch/sparc/include/asm/backoff.h b/arch/sparc/include/asm/backoff.h
index db3af0d30fb1..4e02086b839c 100644
--- a/arch/sparc/include/asm/backoff.h
+++ b/arch/sparc/include/asm/backoff.h
@@ -1,6 +1,46 @@
 #ifndef _SPARC64_BACKOFF_H
 #define _SPARC64_BACKOFF_H
 
+/* The macros in this file implement an exponential backoff facility
+ * for atomic operations.
+ *
+ * When multiple threads compete on an atomic operation, it is
+ * possible for one thread to be continually denied a successful
+ * completion of the compare-and-swap instruction.  Heavily
+ * threaded cpu implementations like Niagara can compound this
+ * problem even further.
+ *
+ * When an atomic operation fails and needs to be retried, we spin a
+ * certain number of times.  At each subsequent failure of the same
+ * operation we double the spin count, realizing an exponential
+ * backoff.
+ *
+ * When we spin, we try to use an operation that will cause the
+ * current cpu strand to block, and therefore make the core fully
+ * available to any other other runnable strands.  There are two
+ * options, based upon cpu capabilities.
+ *
+ * On all cpus prior to SPARC-T4 we do three dummy reads of the
+ * condition code register.  Each read blocks the strand for something
+ * between 40 and 50 cpu cycles.
+ *
+ * For SPARC-T4 and later we have a special "pause" instruction
+ * available.  This is implemented using writes to register %asr27.
+ * The cpu will block the number of cycles written into the register,
+ * unless a disrupting trap happens first.  SPARC-T4 specifically
+ * implements pause with a granularity of 8 cycles.  Each strand has
+ * an internal pause counter which decrements every 8 cycles.  So the
+ * chip shifts the %asr27 value down by 3 bits, and writes the result
+ * into the pause counter.  If a value smaller than 8 is written, the
+ * chip blocks for 1 cycle.
+ *
+ * To achieve the same amount of backoff as the three %ccr reads give
+ * on earlier chips, we shift the backoff value up by 7 bits.  (Three
+ * %ccr reads block for about 128 cycles, 1 << 7 == 128) We write the
+ * whole amount we want to block into the pause register, rather than
+ * loop writing 128 each time.
+ */
+
 #define BACKOFF_LIMIT   (4 * 1024)
 
 #ifdef CONFIG_SMP
@@ -11,16 +51,25 @@
 #define BACKOFF_LABEL(spin_label, continue_label) \
         spin_label
 
-#define BACKOFF_SPIN(reg, tmp, label)   \
-        mov     reg, tmp; \
-88:     brnz,pt tmp, 88b; \
-         sub    tmp, 1, tmp; \
-        set     BACKOFF_LIMIT, tmp; \
-        cmp     reg, tmp; \
-        bg,pn   %xcc, label; \
-         nop; \
-        ba,pt   %xcc, label; \
-         sllx   reg, 1, reg;
+#define BACKOFF_SPIN(reg, tmp, label)           \
+        mov             reg, tmp;               \
+88:     rd              %ccr, %g0;              \
+        rd              %ccr, %g0;              \
+        rd              %ccr, %g0;              \
+        .section        .pause_3insn_patch,"ax";\
+        .word           88b;                    \
+        sllx            tmp, 7, tmp;            \
+        wr              tmp, 0, %asr27;         \
+        clr             tmp;                    \
+        .previous;                              \
+        brnz,pt         tmp, 88b;               \
+         sub            tmp, 1, tmp;            \
+        set             BACKOFF_LIMIT, tmp;     \
+        cmp             reg, tmp;               \
+        bg,pn           %xcc, label;            \
+         nop;                                   \
+        ba,pt           %xcc, label;            \
+         sllx           reg, 1, reg;
 
 #else
 
diff --git a/arch/sparc/include/asm/compat.h b/arch/sparc/include/asm/compat.h
index cef99fbc0a21..830502fe62b4 100644
--- a/arch/sparc/include/asm/compat.h
+++ b/arch/sparc/include/asm/compat.h
@@ -232,9 +232,10 @@ static inline void __user *arch_compat_alloc_user_space(long len)
         struct pt_regs *regs = current_thread_info()->kregs;
         unsigned long usp = regs->u_regs[UREG_I6];
 
-        if (!(test_thread_flag(TIF_32BIT)))
+        if (test_thread_64bit_stack(usp))
                 usp += STACK_BIAS;
-        else
+
+        if (test_thread_flag(TIF_32BIT))
                 usp &= 0xffffffffUL;
 
         usp -= len;
diff --git a/arch/sparc/include/asm/processor_64.h b/arch/sparc/include/asm/processor_64.h
index 4e5a483122a0..721e25f0e2ea 100644
--- a/arch/sparc/include/asm/processor_64.h
+++ b/arch/sparc/include/asm/processor_64.h
@@ -196,7 +196,22 @@ extern unsigned long get_wchan(struct task_struct *task);
 #define KSTK_EIP(tsk)  (task_pt_regs(tsk)->tpc)
 #define KSTK_ESP(tsk)  (task_pt_regs(tsk)->u_regs[UREG_FP])
 
-#define cpu_relax()     barrier()
+/* Please see the commentary in asm/backoff.h for a description of
+ * what these instructions are doing and how they have been choosen.
+ * To make a long story short, we are trying to yield the current cpu
+ * strand during busy loops.
+ */
+#define cpu_relax()     asm volatile("\n99:\n\t"                        \
+                                     "rd        %%ccr, %%g0\n\t"        \
+                                     "rd        %%ccr, %%g0\n\t"        \
+                                     "rd        %%ccr, %%g0\n\t"        \
+                                     ".section  .pause_3insn_patch,\"ax\"\n\t"\
+                                     ".word     99b\n\t"                \
+                                     "wr        %%g0, 128, %%asr27\n\t" \
+                                     "nop\n\t"                          \
+                                     "nop\n\t"                          \
+                                     ".previous"                        \
+                                     ::: "memory")
 
 /* Prefetch support.  This is tuned for UltraSPARC-III and later.
  * UltraSPARC-I will treat these as nops, and UltraSPARC-II has
diff --git a/arch/sparc/include/asm/prom.h b/arch/sparc/include/asm/prom.h
index c28765110706..67c62578d170 100644
--- a/arch/sparc/include/asm/prom.h
+++ b/arch/sparc/include/asm/prom.h
@@ -63,5 +63,13 @@ extern char *of_console_options;
 extern void irq_trans_init(struct device_node *dp);
 extern char *build_path_component(struct device_node *dp);
 
+/* SPARC has local implementations */
+extern int of_address_to_resource(struct device_node *dev, int index,
+                                  struct resource *r);
+#define of_address_to_resource of_address_to_resource
+
+void __iomem *of_iomap(struct device_node *node, int index);
+#define of_iomap of_iomap
+
 #endif /* __KERNEL__ */
 #endif /* _SPARC_PROM_H */
diff --git a/arch/sparc/include/asm/thread_info_64.h b/arch/sparc/include/asm/thread_info_64.h
index 4e2276631081..a3fe4dcc0aa6 100644
--- a/arch/sparc/include/asm/thread_info_64.h
+++ b/arch/sparc/include/asm/thread_info_64.h
@@ -259,6 +259,11 @@ static inline bool test_and_clear_restore_sigmask(void)
 
 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
 
+#define thread32_stack_is_64bit(__SP) (((__SP) & 0x1) != 0)
+#define test_thread_64bit_stack(__SP) \
+        ((test_thread_flag(TIF_32BIT) && !thread32_stack_is_64bit(__SP)) ? \
+         false : true)
+
 #endif  /* !__ASSEMBLY__ */
 
 #endif /* __KERNEL__ */
diff --git a/arch/sparc/include/asm/ttable.h b/arch/sparc/include/asm/ttable.h
index 48f2807d3265..71b5a67522ab 100644
--- a/arch/sparc/include/asm/ttable.h
+++ b/arch/sparc/include/asm/ttable.h
@@ -372,7 +372,9 @@ etrap_spill_fixup_64bit:				\
 
 /* Normal 32bit spill */
 #define SPILL_2_GENERIC(ASI)                            \
-        srl     %sp, 0, %sp;                            \
+        and     %sp, 1, %g3;                            \
+        brnz,pn %g3, (. - (128 + 4));                   \
+         srl    %sp, 0, %sp;                            \
         stwa    %l0, [%sp + %g0] ASI;                   \
         mov     0x04, %g3;                              \
         stwa    %l1, [%sp + %g3] ASI;                   \
@@ -398,14 +400,16 @@ etrap_spill_fixup_64bit:				\
         stwa    %i6, [%g1 + %g0] ASI;                   \
         stwa    %i7, [%g1 + %g3] ASI;                   \
         saved;                                          \
-        retry; nop; nop;                                \
+        retry;                                          \
         b,a,pt  %xcc, spill_fixup_dax;                  \
         b,a,pt  %xcc, spill_fixup_mna;                  \
         b,a,pt  %xcc, spill_fixup;
 
 #define SPILL_2_GENERIC_ETRAP           \
 etrap_user_spill_32bit:                 \
-        srl     %sp, 0, %sp;            \
+        and     %sp, 1, %g3;            \
+        brnz,pn %g3, etrap_user_spill_64bit;    \
+         srl    %sp, 0, %sp;            \
         stwa    %l0, [%sp + 0x00] %asi; \
         stwa    %l1, [%sp + 0x04] %asi; \
         stwa    %l2, [%sp + 0x08] %asi; \
@@ -427,7 +431,7 @@ etrap_user_spill_32bit:			\
         ba,pt   %xcc, etrap_save;       \
          wrpr   %g1, %cwp;              \
         nop; nop; nop; nop;             \
-        nop; nop; nop; nop;             \
+        nop; nop;                       \
         ba,a,pt %xcc, etrap_spill_fixup_32bit; \
         ba,a,pt %xcc, etrap_spill_fixup_32bit; \
         ba,a,pt %xcc, etrap_spill_fixup_32bit;
@@ -592,7 +596,9 @@ user_rtt_fill_64bit:					\
 
 /* Normal 32bit fill */
 #define FILL_2_GENERIC(ASI)                             \
-        srl     %sp, 0, %sp;                            \
+        and     %sp, 1, %g3;                            \
+        brnz,pn %g3, (. - (128 + 4));                   \
+         srl    %sp, 0, %sp;                            \
         lduwa   [%sp + %g0] ASI, %l0;                   \
         mov     0x04, %g2;                              \
         mov     0x08, %g3;                              \
@@ -616,14 +622,16 @@ user_rtt_fill_64bit:					\
         lduwa   [%g1 + %g3] ASI, %i6;                   \
         lduwa   [%g1 + %g5] ASI, %i7;                   \
         restored;                                       \
-        retry; nop; nop; nop; nop;                      \
+        retry; nop; nop;                                \
         b,a,pt  %xcc, fill_fixup_dax;                   \
         b,a,pt  %xcc, fill_fixup_mna;                   \
         b,a,pt  %xcc, fill_fixup;
 
 #define FILL_2_GENERIC_RTRAP                            \
 user_rtt_fill_32bit:                                    \
-        srl     %sp, 0, %sp;                            \
+        and     %sp, 1, %g3;                            \
+        brnz,pn %g3, user_rtt_fill_64bit;               \
+         srl    %sp, 0, %sp;                            \
         lduwa   [%sp + 0x00] %asi, %l0;                 \
         lduwa   [%sp + 0x04] %asi, %l1;                 \
         lduwa   [%sp + 0x08] %asi, %l2;                 \
@@ -643,7 +651,7 @@ user_rtt_fill_32bit:					\
         ba,pt   %xcc, user_rtt_pre_restore;             \
          restored;                                      \
         nop; nop; nop; nop; nop;                        \
-        nop; nop; nop; nop; nop;                        \
+        nop; nop; nop;                                  \
         ba,a,pt %xcc, user_rtt_fill_fixup;              \
         ba,a,pt %xcc, user_rtt_fill_fixup;              \
         ba,a,pt %xcc, user_rtt_fill_fixup;
diff --git a/arch/sparc/include/uapi/asm/unistd.h b/arch/sparc/include/uapi/asm/unistd.h
index 8974ef7ae920..cac719d1bc5c 100644
--- a/arch/sparc/include/uapi/asm/unistd.h
+++ b/arch/sparc/include/uapi/asm/unistd.h
@@ -405,8 +405,13 @@
 #define __NR_setns              337
 #define __NR_process_vm_readv   338
 #define __NR_process_vm_writev  339
+#define __NR_kern_features      340
+#define __NR_kcmp               341
 
-#define NR_syscalls             340
+#define NR_syscalls             342
+
+/* Bitmask values returned from kern_features system call.  */
+#define KERN_FEATURE_MIXED_MODE_STACK   0x00000001
 
 #ifdef __32bit_syscall_numbers__
 /* Sparc 32-bit only has the "setresuid32", "getresuid32" variants,