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