1 files changed, 127 insertions, 0 deletions

diff --git a/arch/sparc/kernel/windows.c b/arch/sparc/kernel/windows.c
new file mode 100644
index 000000000000..9cc93eaa4abf
--- /dev/null
+++ b/arch/sparc/kernel/windows.c
@@ -0,0 +1,127 @@
+/* windows.c: Routines to deal with register window management
+ *            at the C-code level.
+ *
+ * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+
+#include <asm/uaccess.h>
+
+/* Do save's until all user register windows are out of the cpu. */
+void flush_user_windows(void)
+{
+        register int ctr asm("g5");
+
+        ctr = 0;
+        __asm__ __volatile__(
+                "\n1:\n\t"
+                "ld     [%%g6 + %2], %%g4\n\t"
+                "orcc   %%g0, %%g4, %%g0\n\t"
+                "add    %0, 1, %0\n\t"
+                "bne    1b\n\t"
+                " save  %%sp, -64, %%sp\n"
+                "2:\n\t"
+                "subcc  %0, 1, %0\n\t"
+                "bne    2b\n\t"
+                " restore %%g0, %%g0, %%g0\n"
+        : "=&r" (ctr)
+        : "0" (ctr),
+          "i" ((const unsigned long)TI_UWINMASK)
+        : "g4", "cc");
+}
+
+static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp)
+{
+        int i;
+
+        for(i = first_win; i < last_win; i++) {
+                tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1];
+                memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window));
+        }
+}
+
+/* Place as many of the user's current register windows 
+ * on the stack that we can.  Even if the %sp is unaligned
+ * we still copy the window there, the only case that we don't
+ * succeed is if the %sp points to a bum mapping altogether.
+ * setup_frame() and do_sigreturn() use this before shifting
+ * the user stack around.  Future instruction and hardware
+ * bug workaround routines will need this functionality as
+ * well.
+ */
+void synchronize_user_stack(void)
+{
+        struct thread_info *tp = current_thread_info();
+        int window;
+
+        flush_user_windows();
+        if(!tp->w_saved)
+                return;
+
+        /* Ok, there is some dirty work to do. */
+        for(window = tp->w_saved - 1; window >= 0; window--) {
+                unsigned long sp = tp->rwbuf_stkptrs[window];
+
+                /* Ok, let it rip. */
+                if (copy_to_user((char __user *) sp, &tp->reg_window[window],
+                                 sizeof(struct reg_window)))
+                        continue;
+
+                shift_window_buffer(window, tp->w_saved - 1, tp);
+                tp->w_saved--;
+        }
+}
+
+#if 0
+/* An optimization. */
+static inline void copy_aligned_window(void *dest, const void *src)
+{
+        __asm__ __volatile__("ldd [%1], %%g2\n\t"
+                             "ldd [%1 + 0x8], %%g4\n\t"
+                             "std %%g2, [%0]\n\t"
+                             "std %%g4, [%0 + 0x8]\n\t"
+                             "ldd [%1 + 0x10], %%g2\n\t"
+                             "ldd [%1 + 0x18], %%g4\n\t"
+                             "std %%g2, [%0 + 0x10]\n\t"
+                             "std %%g4, [%0 + 0x18]\n\t"
+                             "ldd [%1 + 0x20], %%g2\n\t"
+                             "ldd [%1 + 0x28], %%g4\n\t"
+                             "std %%g2, [%0 + 0x20]\n\t"
+                             "std %%g4, [%0 + 0x28]\n\t"
+                             "ldd [%1 + 0x30], %%g2\n\t"
+                             "ldd [%1 + 0x38], %%g4\n\t"
+                             "std %%g2, [%0 + 0x30]\n\t"
+                             "std %%g4, [%0 + 0x38]\n\t" : :
+                             "r" (dest), "r" (src) :
+                             "g2", "g3", "g4", "g5");
+}
+#endif
+
+/* Try to push the windows in a threads window buffer to the
+ * user stack.  Unaligned %sp's are not allowed here.
+ */
+
+void try_to_clear_window_buffer(struct pt_regs *regs, int who)
+{
+        struct thread_info *tp = current_thread_info();
+        int window;
+
+        lock_kernel();
+        flush_user_windows();
+        for(window = 0; window < tp->w_saved; window++) {
+                unsigned long sp = tp->rwbuf_stkptrs[window];
+
+                if ((sp & 7) ||
+                    copy_to_user((char __user *) sp, &tp->reg_window[window],
+                                 sizeof(struct reg_window)))
+                        do_exit(SIGILL);
+        }
+        tp->w_saved = 0;
+        unlock_kernel();
+}