1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* windows.c: Routines to deal with register window management |
3 | * at the C-code level. |
4 | * |
5 | * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) |
6 | */ |
7 | |
8 | #include <linux/kernel.h> |
9 | #include <linux/sched.h> |
10 | #include <linux/string.h> |
11 | #include <linux/mm.h> |
12 | #include <linux/smp.h> |
13 | |
14 | #include <asm/cacheflush.h> |
15 | #include <linux/uaccess.h> |
16 | |
17 | #include "kernel.h" |
18 | |
19 | /* Do save's until all user register windows are out of the cpu. */ |
20 | void flush_user_windows(void) |
21 | { |
22 | register int ctr asm("g5" ); |
23 | |
24 | ctr = 0; |
25 | __asm__ __volatile__( |
26 | "\n1:\n\t" |
27 | "ld [%%g6 + %2], %%g4\n\t" |
28 | "orcc %%g0, %%g4, %%g0\n\t" |
29 | "add %0, 1, %0\n\t" |
30 | "bne 1b\n\t" |
31 | " save %%sp, -64, %%sp\n" |
32 | "2:\n\t" |
33 | "subcc %0, 1, %0\n\t" |
34 | "bne 2b\n\t" |
35 | " restore %%g0, %%g0, %%g0\n" |
36 | : "=&r" (ctr) |
37 | : "0" (ctr), |
38 | "i" ((const unsigned long)TI_UWINMASK) |
39 | : "g4" , "cc" ); |
40 | } |
41 | |
42 | static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp) |
43 | { |
44 | int i; |
45 | |
46 | for(i = first_win; i < last_win; i++) { |
47 | tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1]; |
48 | memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window32)); |
49 | } |
50 | } |
51 | |
52 | /* Place as many of the user's current register windows |
53 | * on the stack that we can. Even if the %sp is unaligned |
54 | * we still copy the window there, the only case that we don't |
55 | * succeed is if the %sp points to a bum mapping altogether. |
56 | * setup_frame() and do_sigreturn() use this before shifting |
57 | * the user stack around. Future instruction and hardware |
58 | * bug workaround routines will need this functionality as |
59 | * well. |
60 | */ |
61 | void synchronize_user_stack(void) |
62 | { |
63 | struct thread_info *tp = current_thread_info(); |
64 | int window; |
65 | |
66 | flush_user_windows(); |
67 | if(!tp->w_saved) |
68 | return; |
69 | |
70 | /* Ok, there is some dirty work to do. */ |
71 | for(window = tp->w_saved - 1; window >= 0; window--) { |
72 | unsigned long sp = tp->rwbuf_stkptrs[window]; |
73 | |
74 | /* Ok, let it rip. */ |
75 | if (copy_to_user((char __user *) sp, &tp->reg_window[window], |
76 | sizeof(struct reg_window32))) |
77 | continue; |
78 | |
79 | shift_window_buffer(first_win: window, last_win: tp->w_saved - 1, tp); |
80 | tp->w_saved--; |
81 | } |
82 | } |
83 | |
84 | #if 0 |
85 | /* An optimization. */ |
86 | static inline void copy_aligned_window(void *dest, const void *src) |
87 | { |
88 | __asm__ __volatile__("ldd [%1], %%g2\n\t" |
89 | "ldd [%1 + 0x8], %%g4\n\t" |
90 | "std %%g2, [%0]\n\t" |
91 | "std %%g4, [%0 + 0x8]\n\t" |
92 | "ldd [%1 + 0x10], %%g2\n\t" |
93 | "ldd [%1 + 0x18], %%g4\n\t" |
94 | "std %%g2, [%0 + 0x10]\n\t" |
95 | "std %%g4, [%0 + 0x18]\n\t" |
96 | "ldd [%1 + 0x20], %%g2\n\t" |
97 | "ldd [%1 + 0x28], %%g4\n\t" |
98 | "std %%g2, [%0 + 0x20]\n\t" |
99 | "std %%g4, [%0 + 0x28]\n\t" |
100 | "ldd [%1 + 0x30], %%g2\n\t" |
101 | "ldd [%1 + 0x38], %%g4\n\t" |
102 | "std %%g2, [%0 + 0x30]\n\t" |
103 | "std %%g4, [%0 + 0x38]\n\t" : : |
104 | "r" (dest), "r" (src) : |
105 | "g2" , "g3" , "g4" , "g5" ); |
106 | } |
107 | #endif |
108 | |
109 | /* Try to push the windows in a threads window buffer to the |
110 | * user stack. Unaligned %sp's are not allowed here. |
111 | */ |
112 | |
113 | void try_to_clear_window_buffer(struct pt_regs *regs, int who) |
114 | { |
115 | struct thread_info *tp = current_thread_info(); |
116 | int window; |
117 | |
118 | flush_user_windows(); |
119 | for(window = 0; window < tp->w_saved; window++) { |
120 | unsigned long sp = tp->rwbuf_stkptrs[window]; |
121 | |
122 | if ((sp & 7) || |
123 | copy_to_user((char __user *) sp, &tp->reg_window[window], |
124 | sizeof(struct reg_window32))) { |
125 | force_exit_sig(SIGILL); |
126 | return; |
127 | } |
128 | } |
129 | tp->w_saved = 0; |
130 | } |
131 | |