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 #include <linux/smp_lock.h>
13
14 #include <asm/uaccess.h>
15
16 /* Do save's until all user register windows are out of the cpu. */
flush_user_windows(void)17 void flush_user_windows(void)
18 {
19 register int ctr asm("g5");
20
21 ctr = 0;
22 __asm__ __volatile__(
23 "\n1:\n\t"
24 "ld [%%g6 + %2], %%g4\n\t"
25 "orcc %%g0, %%g4, %%g0\n\t"
26 "add %0, 1, %0\n\t"
27 "bne 1b\n\t"
28 " save %%sp, -64, %%sp\n"
29 "2:\n\t"
30 "subcc %0, 1, %0\n\t"
31 "bne 2b\n\t"
32 " restore %%g0, %%g0, %%g0\n"
33 : "=&r" (ctr)
34 : "0" (ctr),
35 "i" ((const unsigned long)TI_UWINMASK)
36 : "g4", "cc");
37 }
38
shift_window_buffer(int first_win,int last_win,struct thread_info * tp)39 static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp)
40 {
41 int i;
42
43 for(i = first_win; i < last_win; i++) {
44 tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1];
45 memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window32));
46 }
47 }
48
49 /* Place as many of the user's current register windows
50 * on the stack that we can. Even if the %sp is unaligned
51 * we still copy the window there, the only case that we don't
52 * succeed is if the %sp points to a bum mapping altogether.
53 * setup_frame() and do_sigreturn() use this before shifting
54 * the user stack around. Future instruction and hardware
55 * bug workaround routines will need this functionality as
56 * well.
57 */
synchronize_user_stack(void)58 void synchronize_user_stack(void)
59 {
60 struct thread_info *tp = current_thread_info();
61 int window;
62
63 flush_user_windows();
64 if(!tp->w_saved)
65 return;
66
67 /* Ok, there is some dirty work to do. */
68 for(window = tp->w_saved - 1; window >= 0; window--) {
69 unsigned long sp = tp->rwbuf_stkptrs[window];
70
71 /* Ok, let it rip. */
72 if (copy_to_user((char __user *) sp, &tp->reg_window[window],
73 sizeof(struct reg_window32)))
74 continue;
75
76 shift_window_buffer(window, tp->w_saved - 1, tp);
77 tp->w_saved--;
78 }
79 }
80
81 #if 0
82 /* An optimization. */
83 static inline void copy_aligned_window(void *dest, const void *src)
84 {
85 __asm__ __volatile__("ldd [%1], %%g2\n\t"
86 "ldd [%1 + 0x8], %%g4\n\t"
87 "std %%g2, [%0]\n\t"
88 "std %%g4, [%0 + 0x8]\n\t"
89 "ldd [%1 + 0x10], %%g2\n\t"
90 "ldd [%1 + 0x18], %%g4\n\t"
91 "std %%g2, [%0 + 0x10]\n\t"
92 "std %%g4, [%0 + 0x18]\n\t"
93 "ldd [%1 + 0x20], %%g2\n\t"
94 "ldd [%1 + 0x28], %%g4\n\t"
95 "std %%g2, [%0 + 0x20]\n\t"
96 "std %%g4, [%0 + 0x28]\n\t"
97 "ldd [%1 + 0x30], %%g2\n\t"
98 "ldd [%1 + 0x38], %%g4\n\t"
99 "std %%g2, [%0 + 0x30]\n\t"
100 "std %%g4, [%0 + 0x38]\n\t" : :
101 "r" (dest), "r" (src) :
102 "g2", "g3", "g4", "g5");
103 }
104 #endif
105
106 /* Try to push the windows in a threads window buffer to the
107 * user stack. Unaligned %sp's are not allowed here.
108 */
109
try_to_clear_window_buffer(struct pt_regs * regs,int who)110 void try_to_clear_window_buffer(struct pt_regs *regs, int who)
111 {
112 struct thread_info *tp = current_thread_info();
113 int window;
114
115 lock_kernel();
116 flush_user_windows();
117 for(window = 0; window < tp->w_saved; window++) {
118 unsigned long sp = tp->rwbuf_stkptrs[window];
119
120 if ((sp & 7) ||
121 copy_to_user((char __user *) sp, &tp->reg_window[window],
122 sizeof(struct reg_window32)))
123 do_exit(SIGILL);
124 }
125 tp->w_saved = 0;
126 unlock_kernel();
127 }
128