1 /* windows.c: Routines to deal with register window management
2 * at the C-code level.
3 *
4 * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
5 */
6
7 #include <linux/kernel.h>
8 #include <linux/sched.h>
9 #include <linux/string.h>
10 #include <linux/mm.h>
11 #include <linux/smp.h>
12
13 #include <asm/uaccess.h>
14
15 /* Do save's until all user register windows are out of the cpu. */
flush_user_windows(void)16 void flush_user_windows(void)
17 {
18 register int ctr asm("g5");
19
20 ctr = 0;
21 __asm__ __volatile__(
22 "\n1:\n\t"
23 "ld [%%g6 + %2], %%g4\n\t"
24 "orcc %%g0, %%g4, %%g0\n\t"
25 "add %0, 1, %0\n\t"
26 "bne 1b\n\t"
27 " save %%sp, -64, %%sp\n"
28 "2:\n\t"
29 "subcc %0, 1, %0\n\t"
30 "bne 2b\n\t"
31 " restore %%g0, %%g0, %%g0\n"
32 : "=&r" (ctr)
33 : "0" (ctr),
34 "i" ((const unsigned long)TI_UWINMASK)
35 : "g4", "cc");
36 }
37
shift_window_buffer(int first_win,int last_win,struct thread_info * tp)38 static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp)
39 {
40 int i;
41
42 for(i = first_win; i < last_win; i++) {
43 tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1];
44 memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window32));
45 }
46 }
47
48 /* Place as many of the user's current register windows
49 * on the stack that we can. Even if the %sp is unaligned
50 * we still copy the window there, the only case that we don't
51 * succeed is if the %sp points to a bum mapping altogether.
52 * setup_frame() and do_sigreturn() use this before shifting
53 * the user stack around. Future instruction and hardware
54 * bug workaround routines will need this functionality as
55 * well.
56 */
synchronize_user_stack(void)57 void synchronize_user_stack(void)
58 {
59 struct thread_info *tp = current_thread_info();
60 int window;
61
62 flush_user_windows();
63 if(!tp->w_saved)
64 return;
65
66 /* Ok, there is some dirty work to do. */
67 for(window = tp->w_saved - 1; window >= 0; window--) {
68 unsigned long sp = tp->rwbuf_stkptrs[window];
69
70 /* Ok, let it rip. */
71 if (copy_to_user((char __user *) sp, &tp->reg_window[window],
72 sizeof(struct reg_window32)))
73 continue;
74
75 shift_window_buffer(window, tp->w_saved - 1, tp);
76 tp->w_saved--;
77 }
78 }
79
80 #if 0
81 /* An optimization. */
82 static inline void copy_aligned_window(void *dest, const void *src)
83 {
84 __asm__ __volatile__("ldd [%1], %%g2\n\t"
85 "ldd [%1 + 0x8], %%g4\n\t"
86 "std %%g2, [%0]\n\t"
87 "std %%g4, [%0 + 0x8]\n\t"
88 "ldd [%1 + 0x10], %%g2\n\t"
89 "ldd [%1 + 0x18], %%g4\n\t"
90 "std %%g2, [%0 + 0x10]\n\t"
91 "std %%g4, [%0 + 0x18]\n\t"
92 "ldd [%1 + 0x20], %%g2\n\t"
93 "ldd [%1 + 0x28], %%g4\n\t"
94 "std %%g2, [%0 + 0x20]\n\t"
95 "std %%g4, [%0 + 0x28]\n\t"
96 "ldd [%1 + 0x30], %%g2\n\t"
97 "ldd [%1 + 0x38], %%g4\n\t"
98 "std %%g2, [%0 + 0x30]\n\t"
99 "std %%g4, [%0 + 0x38]\n\t" : :
100 "r" (dest), "r" (src) :
101 "g2", "g3", "g4", "g5");
102 }
103 #endif
104
105 /* Try to push the windows in a threads window buffer to the
106 * user stack. Unaligned %sp's are not allowed here.
107 */
108
try_to_clear_window_buffer(struct pt_regs * regs,int who)109 void try_to_clear_window_buffer(struct pt_regs *regs, int who)
110 {
111 struct thread_info *tp = current_thread_info();
112 int window;
113
114 flush_user_windows();
115 for(window = 0; window < tp->w_saved; window++) {
116 unsigned long sp = tp->rwbuf_stkptrs[window];
117
118 if ((sp & 7) ||
119 copy_to_user((char __user *) sp, &tp->reg_window[window],
120 sizeof(struct reg_window32)))
121 do_exit(SIGILL);
122 }
123 tp->w_saved = 0;
124 }
125