MIPS: For Cavium OCTEON set hwrena and lazily restore CP2 state.

If on Cavium, be aware of cop2 and hwrena during do_cpu().

Signed-off-by: Tomaso Paoletti <tpaoletti@caviumnetworks.com>
Signed-off-by: Paul Gortmaker <Paul.Gortmaker@windriver.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 21 insertions, 0 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 353056110f2b..f6083c6bfaa4 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -47,6 +47,7 @@
 #include <asm/mmu_context.h>
 #include <asm/types.h>
 #include <asm/stacktrace.h>
+#include <asm/irq.h>
 
 extern void check_wait(void);
 extern asmlinkage void r4k_wait(void);
@@ -78,6 +79,10 @@ extern asmlinkage void handle_reserved(void);
 extern int fpu_emulator_cop1Handler(struct pt_regs *xcp,
         struct mips_fpu_struct *ctx, int has_fpu);
 
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+extern asmlinkage void octeon_cop2_restore(struct octeon_cop2_state *task);
+#endif
+
 void (*board_be_init)(void);
 int (*board_be_handler)(struct pt_regs *regs, int is_fixup);
 void (*board_nmi_handler_setup)(void);
@@ -860,6 +865,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
         unsigned int opcode;
         unsigned int cpid;
         int status;
+        unsigned long __maybe_unused flags;
 
         die_if_kernel("do_cpu invoked from kernel context!", regs);
 
@@ -915,6 +921,17 @@ asmlinkage void do_cpu(struct pt_regs *regs)
                 return;
 
         case 2:
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+                prefetch(&current->thread.cp2);
+                local_irq_save(flags);
+                KSTK_STATUS(current) |= ST0_CU2;
+                status = read_c0_status();
+                write_c0_status(status | ST0_CU2);
+                octeon_cop2_restore(&(current->thread.cp2));
+                write_c0_status(status & ~ST0_CU2);
+                local_irq_restore(flags);
+                return;
+#endif
         case 3:
                 break;
         }
@@ -1488,6 +1505,10 @@ void __cpuinit per_cpu_trap_init(void)
                 write_c0_hwrena(enable);
         }
 
+#ifdef CONFIG_CPU_CAVIUM_OCTEON
+        write_c0_hwrena(0xc000000f); /* Octeon has register 30 and 31 */
+#endif
+
 #ifdef CONFIG_MIPS_MT_SMTC
         if (!secondaryTC) {
 #endif /* CONFIG_MIPS_MT_SMTC */