patch-1.3.71 linux/arch/sparc/kernel/windows.c

• Lines: 109
• Date: Mon Mar 4 08:49:57 1996
• Orig file: v1.3.70/linux/arch/sparc/kernel/windows.c
• Orig date: Thu Jan 1 02:00:00 1970

diff -u --recursive --new-file v1.3.70/linux/arch/sparc/kernel/windows.c linux/arch/sparc/kernel/windows.c
@@ -0,0 +1,108 @@
+/* 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>
+
+/* Do save's until all user register windows are out of the cpu. */
+void flush_user_windows(void)
+{
+	if(current->tss.uwinmask)
+		flush_user_windows();
+}
+
+static inline void shift_window_buffer(int first_win, int last_win, struct thread_struct *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_struct *tp = &current->tss;
+	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];
+
+		/* See if %sp is reasonable at all. */
+		if(verify_area(VERIFY_WRITE, (char *) sp, sizeof(struct reg_window)))
+			continue;
+
+		/* Ok, let it rip. */
+		memcpy((char *) sp, &tp->reg_window[window], sizeof(struct reg_window));
+		shift_window_buffer(window, tp->w_saved - 1, tp);
+		tp->w_saved--;
+	}
+}
+
+/* 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");
+}
+
+/* Try to push the windows in a threads window buffer to the
+ * user stack.  Unaligned %sp's are not allowed here.
+ */
+
+#define stack_is_bad(sp, rw) \
+  (((sp) & 7) || verify_area(rw, (char *) (sp), sizeof(struct reg_window)))
+
+void try_to_clear_window_buffer(struct pt_regs *regs, int who)
+{
+	struct thread_struct *tp = &current->tss;
+	int window;
+
+	flush_user_windows();
+	for(window = 0; window < tp->w_saved; window++) {
+		unsigned long sp = tp->rwbuf_stkptrs[window];
+
+		if(stack_is_bad(sp, VERIFY_WRITE))
+			do_exit(SIGILL);
+		else
+			copy_aligned_window((char *) sp, &tp->reg_window[window]);
+	}
+	tp->w_saved = 0;
+}