[MIPS] MT: Improved multithreading support.

    
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 116 insertions, 8 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 081e6ed5bb62..6336fe8008ec 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -280,9 +280,16 @@ static DEFINE_SPINLOCK(die_lock);
 NORET_TYPE void ATTRIB_NORET die(const char * str, struct pt_regs * regs)
 {
         static int die_counter;
+#ifdef CONFIG_MIPS_MT_SMTC
+        unsigned long dvpret = dvpe();
+#endif /* CONFIG_MIPS_MT_SMTC */
 
         console_verbose();
         spin_lock_irq(&die_lock);
+        bust_spinlocks(1);
+#ifdef CONFIG_MIPS_MT_SMTC
+        mips_mt_regdump(dvpret);
+#endif /* CONFIG_MIPS_MT_SMTC */
         printk("%s[#%d]:\n", str, ++die_counter);
         show_registers(regs);
         spin_unlock_irq(&die_lock);
@@ -757,6 +764,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 
         case 2:
         case 3:
+                die_if_kernel("do_cpu invoked from kernel context!", regs);
                 break;
         }
 
@@ -794,6 +802,36 @@ asmlinkage void do_mcheck(struct pt_regs *regs)
 
 asmlinkage void do_mt(struct pt_regs *regs)
 {
+        int subcode;
+
+        die_if_kernel("MIPS MT Thread exception in kernel", regs);
+
+        subcode = (read_vpe_c0_vpecontrol() & VPECONTROL_EXCPT)
+                        >> VPECONTROL_EXCPT_SHIFT;
+        switch (subcode) {
+        case 0:
+                printk(KERN_ERR "Thread Underflow\n");
+                break;
+        case 1:
+                printk(KERN_ERR "Thread Overflow\n");
+                break;
+        case 2:
+                printk(KERN_ERR "Invalid YIELD Qualifier\n");
+                break;
+        case 3:
+                printk(KERN_ERR "Gating Storage Exception\n");
+                break;
+        case 4:
+                printk(KERN_ERR "YIELD Scheduler Exception\n");
+                break;
+        case 5:
+                printk(KERN_ERR "Gating Storage Schedulier Exception\n");
+                break;
+        default:
+                printk(KERN_ERR "*** UNKNOWN THREAD EXCEPTION %d ***\n",
+                        subcode);
+                break;
+        }
         die_if_kernel("MIPS MT Thread exception in kernel", regs);
 
         force_sig(SIGILL, current);
@@ -929,7 +967,15 @@ void ejtag_exception_handler(struct pt_regs *regs)
  */
 void nmi_exception_handler(struct pt_regs *regs)
 {
+#ifdef CONFIG_MIPS_MT_SMTC
+        unsigned long dvpret = dvpe();
+        bust_spinlocks(1);
+        printk("NMI taken!!!!\n");
+        mips_mt_regdump(dvpret);
+#else
+        bust_spinlocks(1);
         printk("NMI taken!!!!\n");
+#endif /* CONFIG_MIPS_MT_SMTC */
         die("NMI", regs);
         while(1) ;
 }
@@ -1007,7 +1053,7 @@ again:
         return set;
 }
 
-void mips_srs_free (int set)
+void mips_srs_free(int set)
 {
         struct shadow_registers *sr = &shadow_registers;
 
@@ -1027,8 +1073,7 @@ static void *set_vi_srs_handler(int n, void *addr, int srs)
         if (addr == NULL) {
                 handler = (unsigned long) do_default_vi;
                 srs = 0;
-        }
-        else
+        } else
                 handler = (unsigned long) addr;
         vi_handlers[n] = (unsigned long) addr;
 
@@ -1040,8 +1085,7 @@ static void *set_vi_srs_handler(int n, void *addr, int srs)
         if (cpu_has_veic) {
                 if (board_bind_eic_interrupt)
                         board_bind_eic_interrupt (n, srs);
-        }
-        else if (cpu_has_vint) {
+        } else if (cpu_has_vint) {
                 /* SRSMap is only defined if shadow sets are implemented */
                 if (mips_srs_max() > 1)
                         change_c0_srsmap (0xf << n*4, srs << n*4);
@@ -1055,6 +1099,15 @@ static void *set_vi_srs_handler(int n, void *addr, int srs)
 
                 extern char except_vec_vi, except_vec_vi_lui;
                 extern char except_vec_vi_ori, except_vec_vi_end;
+#ifdef CONFIG_MIPS_MT_SMTC
+                /*
+                 * We need to provide the SMTC vectored interrupt handler
+                 * not only with the address of the handler, but with the
+                 * Status.IM bit to be masked before going there.
+                 */
+                extern char except_vec_vi_mori;
+                const int mori_offset = &except_vec_vi_mori - &except_vec_vi;
+#endif /* CONFIG_MIPS_MT_SMTC */
                 const int handler_len = &except_vec_vi_end - &except_vec_vi;
                 const int lui_offset = &except_vec_vi_lui - &except_vec_vi;
                 const int ori_offset = &except_vec_vi_ori - &except_vec_vi;
@@ -1068,6 +1121,12 @@ static void *set_vi_srs_handler(int n, void *addr, int srs)
                 }
 
                 memcpy (b, &except_vec_vi, handler_len);
+#ifdef CONFIG_MIPS_MT_SMTC
+                if (n > 7)
+                        printk("Vector index %d exceeds SMTC maximum\n", n);
+                w = (u32 *)(b + mori_offset);
+                *w = (*w & 0xffff0000) | (0x100 << n);
+#endif /* CONFIG_MIPS_MT_SMTC */
                 w = (u32 *)(b + lui_offset);
                 *w = (*w & 0xffff0000) | (((u32)handler >> 16) & 0xffff);
                 w = (u32 *)(b + ori_offset);
@@ -1090,7 +1149,7 @@ static void *set_vi_srs_handler(int n, void *addr, int srs)
         return (void *)old_handler;
 }
 
-void *set_vi_handler (int n, void *addr)
+void *set_vi_handler(int n, void *addr)
 {
         return set_vi_srs_handler(n, addr, 0);
 }
@@ -1108,8 +1167,29 @@ extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
 extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
 extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
 
+#ifdef CONFIG_SMP
+static int smp_save_fp_context(struct sigcontext *sc)
+{
+        return cpu_has_fpu
+               ? _save_fp_context(sc)
+               : fpu_emulator_save_context(sc);
+}
+
+static int smp_restore_fp_context(struct sigcontext *sc)
+{
+        return cpu_has_fpu
+               ? _restore_fp_context(sc)
+               : fpu_emulator_restore_context(sc);
+}
+#endif
+
 static inline void signal_init(void)
 {
+#ifdef CONFIG_SMP
+        /* For now just do the cpu_has_fpu check when the functions are invoked */
+        save_fp_context = smp_save_fp_context;
+        restore_fp_context = smp_restore_fp_context;
+#else
         if (cpu_has_fpu) {
                 save_fp_context = _save_fp_context;
                 restore_fp_context = _restore_fp_context;
@@ -1117,6 +1197,7 @@ static inline void signal_init(void)
                 save_fp_context = fpu_emulator_save_context;
                 restore_fp_context = fpu_emulator_restore_context;
         }
+#endif
 }
 
 #ifdef CONFIG_MIPS32_COMPAT
@@ -1153,6 +1234,20 @@ void __init per_cpu_trap_init(void)
 {
         unsigned int cpu = smp_processor_id();
         unsigned int status_set = ST0_CU0;
+#ifdef CONFIG_MIPS_MT_SMTC
+        int secondaryTC = 0;
+        int bootTC = (cpu == 0);
+
+        /*
+         * Only do per_cpu_trap_init() for first TC of Each VPE.
+         * Note that this hack assumes that the SMTC init code
+         * assigns TCs consecutively and in ascending order.
+         */
+
+        if (((read_c0_tcbind() & TCBIND_CURTC) != 0) &&
+            ((read_c0_tcbind() & TCBIND_CURVPE) == cpu_data[cpu - 1].vpe_id))
+                secondaryTC = 1;
+#endif /* CONFIG_MIPS_MT_SMTC */
 
         /*
          * Disable coprocessors and select 32-bit or 64-bit addressing
@@ -1175,6 +1270,10 @@ void __init per_cpu_trap_init(void)
         write_c0_hwrena (0x0000000f); /* Allow rdhwr to all registers */
 #endif
 
+#ifdef CONFIG_MIPS_MT_SMTC
+        if (!secondaryTC) {
+#endif /* CONFIG_MIPS_MT_SMTC */
+
         /*
          * Interrupt handling.
          */
@@ -1191,6 +1290,9 @@ void __init per_cpu_trap_init(void)
                 } else
                         set_c0_cause(CAUSEF_IV);
         }
+#ifdef CONFIG_MIPS_MT_SMTC
+        }
+#endif /* CONFIG_MIPS_MT_SMTC */
 
         cpu_data[cpu].asid_cache = ASID_FIRST_VERSION;
         TLBMISS_HANDLER_SETUP();
@@ -1200,8 +1302,14 @@ void __init per_cpu_trap_init(void)
         BUG_ON(current->mm);
         enter_lazy_tlb(&init_mm, current);
 
-        cpu_cache_init();
-        tlb_init();
+#ifdef CONFIG_MIPS_MT_SMTC
+        if (bootTC) {
+#endif /* CONFIG_MIPS_MT_SMTC */
+                cpu_cache_init();
+                tlb_init();
+#ifdef CONFIG_MIPS_MT_SMTC
+        }
+#endif /* CONFIG_MIPS_MT_SMTC */
 }
 
 /* Install CPU exception handler */