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. */ 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 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 */ 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 */ 109 110 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