patch-2.4.5 linux/include/asm-cris/processor.h

• Lines: 111
• Date: Tue May 1 16:05:00 2001
• Orig file: v2.4.4/linux/include/asm-cris/processor.h
• Orig date: Fri Apr 6 10:51:19 2001

diff -u --recursive --new-file v2.4.4/linux/include/asm-cris/processor.h linux/include/asm-cris/processor.h
@@ -18,7 +18,7 @@
  * Default implementation of macro that returns current
  * instruction pointer ("program counter").
  */
-#define current_text_addr() ({ __label__ _l; _l: &&_l;})
+#define current_text_addr() ({void *pc; __asm__ ("move.d pc,%0" : "=rm" (pc)); pc; })
 
 /* CRIS has no problems with write protection */
 
@@ -40,6 +40,14 @@
  */
 #define TASK_UNMAPPED_BASE      (TASK_SIZE / 3)
 
+/* THREAD_SIZE is the size of the task_struct/kernel_stack combo.
+ * normally, the stack is found by doing something like p + THREAD_SIZE
+ * in CRIS, a page is 8192 bytes, which seems like a sane size
+ */
+
+#define THREAD_SIZE       PAGE_SIZE
+#define KERNEL_STACK_SIZE PAGE_SIZE
+
 /* CRIS thread_struct. this really has nothing to do with the processor itself, since
  * CRIS does not do any hardware task-switching, but it's here for legacy reasons.
  * The thread_struct here is used when task-switching using _resume defined in entry.S.
@@ -50,13 +58,24 @@
 struct thread_struct {
 	unsigned long ksp;     /* kernel stack pointer */
 	unsigned long usp;     /* user stack pointer */
-	unsigned long esp0;    /* points to start of saved stack frame, set in entry.S */  
 	unsigned long dccr;    /* saved flag register */
 };
 
-/* saved stack-frame upon syscall entry, points to registers */
+/*
+ * At user->kernel entry, the pt_regs struct is stacked on the top of the kernel-stack.
+ * This macro allows us to find those regs for a task.
+ * Notice that subsequent pt_regs stackings, like recursive interrupts occuring while
+ * we're in the kernel, won't affect this - only the first user->kernel transition
+ * registers are reached by this.
+ */
 
-#define current_regs() (current->thread.esp0)
+#define user_regs(task) (((struct pt_regs *)((unsigned long)(task) + THREAD_SIZE)) - 1)
+
+/*
+ * Dito but for the currently running task
+ */
+
+#define current_regs() user_regs(current)
 
 /* INIT_MMAP is the kernels map of memory, between KSEG_C and KSEG_D */
 
@@ -69,11 +88,7 @@
 #endif
 
 #define INIT_THREAD  { \
-   0, 0, 0, 0x20 }  /* ccr = int enable, nothing else */
-
-/* TODO: REMOVE */
-#define alloc_kernel_stack()    __get_free_page(GFP_KERNEL)
-#define free_kernel_stack(page) free_page((page))
+   0, 0, 0x20 }  /* ccr = int enable, nothing else */
 
 extern int kernel_thread(int (*fn)(void *), void * arg, unsigned long flags);
 
@@ -94,9 +109,10 @@
 #define KSTK_EIP(tsk)   \
     ({                  \
         unsigned long eip = 0;   \
-        if ((tsk)->thread.esp0 > PAGE_SIZE && \
-            VALID_PAGE(virt_to_page((tsk)->thread.esp0))) \
-              eip = ((struct pt_regs *) (tsk)->thread.esp0)->irp; \
+        unsigned long regs = (unsigned long)user_regs(tsk); \
+        if (regs > PAGE_SIZE && \
+            VALID_PAGE(virt_to_page(regs))) \
+              eip = ((struct pt_regs *)regs)->irp; \
         eip; })
 
 #define KSTK_ESP(tsk)   ((tsk) == current ? rdusp() : (tsk)->thread.usp)
@@ -111,11 +127,13 @@
 
 static inline void exit_thread(void)
 {
+        /* Nothing needs to be done.  */
 }
 
 /* Free all resources held by a thread. */
 static inline void release_thread(struct task_struct *dead_task)
 {
+        /* Nothing needs to be done.  */
 }
 
 /*
@@ -123,16 +141,8 @@
  */
 extern inline unsigned long thread_saved_pc(struct thread_struct *t)
 {
-	return (unsigned long)((struct pt_regs *)t->esp0)->irp;
+	return (unsigned long)user_regs(t)->irp;
 }
-
-/* THREAD_SIZE is the size of the task_struct/kernel_stack combo.
- * normally, the stack is found by doing something like p + THREAD_SIZE
- * in CRIS, a page is 8192 bytes, which seems like a sane size
- */
-
-#define THREAD_SIZE     PAGE_SIZE
-#define KERNEL_STACK_SIZE PAGE_SIZE
 
 #define alloc_task_struct()  ((struct task_struct *) __get_free_pages(GFP_KERNEL,1))
 #define free_task_struct(p)  free_pages((unsigned long) (p), 1)