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. */ 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 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 */ 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 */ 108 109 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