MIPS: Use per-mm page to execute branch delay slot instructions

[cascardo/linux.git] / arch / mips / include / asm / processor.h

diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 7e78b62..0d36c87 100644 (file)
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -11,12 +11,14 @@
 #ifndef _ASM_PROCESSOR_H
 #define _ASM_PROCESSOR_H
 
+#include <linux/atomic.h>
 #include <linux/cpumask.h>
 #include <linux/threads.h>
 
 #include <asm/cachectl.h>
 #include <asm/cpu.h>
 #include <asm/cpu-info.h>
+#include <asm/dsemul.h>
 #include <asm/mipsregs.h>
 #include <asm/prefetch.h>
 
@@ -78,7 +80,11 @@ extern unsigned int vced_count, vcei_count;
 
 #endif
 
-#define STACK_TOP      (TASK_SIZE & PAGE_MASK)
+/*
+ * One page above the stack is used for branch delay slot "emulation".
+ * See dsemul.c for details.
+ */
+#define STACK_TOP      ((TASK_SIZE & PAGE_MASK) - PAGE_SIZE)
 
 /*
  * This decides where the kernel will search for a free chunk of vm
@@ -256,6 +262,12 @@ struct thread_struct {
 
        /* Saved fpu/fpu emulator stuff. */
        struct mips_fpu_struct fpu FPU_ALIGN;
+       /* Assigned branch delay slot 'emulation' frame */
+       atomic_t bd_emu_frame;
+       /* PC of the branch from a branch delay slot 'emulation' */
+       unsigned long bd_emu_branch_pc;
+       /* PC to continue from following a branch delay slot 'emulation' */
+       unsigned long bd_emu_cont_pc;
 #ifdef CONFIG_MIPS_MT_FPAFF
        /* Emulated instruction count */
        unsigned long emulated_fp;
@@ -323,6 +335,10 @@ struct thread_struct {
         * FPU affinity state (null if not FPAFF)               \
         */                                                     \
        FPAFF_INIT                                              \
+       /* Delay slot emulation */                              \
+       .bd_emu_frame = ATOMIC_INIT(BD_EMUFRAME_NONE),          \
+       .bd_emu_branch_pc = 0,                                  \
+       .bd_emu_cont_pc = 0,                                    \
        /*                                                      \
         * Saved DSP stuff                                      \
         */                                                     \