/* windows.c: Routines to deal with register window management * at the C-code level. * * Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu) */ #include <linux/kernel.h> #include <linux/sched.h> #include <linux/string.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/smp_lock.h> #include <asm/uaccess.h> /* Do save's until all user register windows are out of the cpu. */ void flush_user_windows(void) { register int ctr asm("g5"); ctr = 0; __asm__ __volatile__( "\n1:\n\t" "ld [%%g6 + %2], %%g4\n\t" "orcc %%g0, %%g4, %%g0\n\t" "add %0, 1, %0\n\t" "bne 1b\n\t" " save %%sp, -64, %%sp\n" "2:\n\t" "subcc %0, 1, %0\n\t" "bne 2b\n\t" " restore %%g0, %%g0, %%g0\n" : "=&r" (ctr) : "0" (ctr), "i" ((const unsigned long)TI_UWINMASK) : "g4", "cc"); } static inline void shift_window_buffer(int first_win, int last_win, struct thread_info *tp) { int i; for(i = first_win; i < last_win; i++) { tp->rwbuf_stkptrs[i] = tp->rwbuf_stkptrs[i+1]; memcpy(&tp->reg_window[i], &tp->reg_window[i+1], sizeof(struct reg_window32)); } } /* Place as many of the user's current register windows * on the stack that we can. Even if the %sp is unaligned * we still copy the window there, the only case that we don't * succeed is if the %sp points to a bum mapping altogether. * setup_frame() and do_sigreturn() use this before shifting * the user stack around. Future instruction and hardware * bug workaround routines will need this functionality as * well. */ void synchronize_user_stack(void) { struct thread_info *tp = current_thread_info(); int window; flush_user_windows(); if(!tp->w_saved) return; /* Ok, there is some dirty work to do. */ for(window = tp->w_saved - 1; window >= 0; window--) { unsigned long sp = tp->rwbuf_stkptrs[window]; /* Ok, let it rip. */ if (copy_to_user((char __user *) sp, &tp->reg_window[window], sizeof(struct reg_window32))) continue; shift_window_buffer(window, tp->w_saved - 1, tp); tp->w_saved--; } } #if 0 /* An optimization. */ static inline void copy_aligned_window(void *dest, const void *src) { __asm__ __volatile__("ldd [%1], %%g2\n\t" "ldd [%1 + 0x8], %%g4\n\t" "std %%g2, [%0]\n\t" "std %%g4, [%0 + 0x8]\n\t" "ldd [%1 + 0x10], %%g2\n\t" "ldd [%1 + 0x18], %%g4\n\t" "std %%g2, [%0 + 0x10]\n\t" "std %%g4, [%0 + 0x18]\n\t" "ldd [%1 + 0x20], %%g2\n\t" "ldd [%1 + 0x28], %%g4\n\t" "std %%g2, [%0 + 0x20]\n\t" "std %%g4, [%0 + 0x28]\n\t" "ldd [%1 + 0x30], %%g2\n\t" "ldd [%1 + 0x38], %%g4\n\t" "std %%g2, [%0 + 0x30]\n\t" "std %%g4, [%0 + 0x38]\n\t" : : "r" (dest), "r" (src) : "g2", "g3", "g4", "g5"); } #endif /* Try to push the windows in a threads window buffer to the * user stack. Unaligned %sp's are not allowed here. */ void try_to_clear_window_buffer(struct pt_regs *regs, int who) { struct thread_info *tp = current_thread_info(); int window; lock_kernel(); flush_user_windows(); for(window = 0; window < tp->w_saved; window++) { unsigned long sp = tp->rwbuf_stkptrs[window]; if ((sp & 7) || copy_to_user((char __user *) sp, &tp->reg_window[window], sizeof(struct reg_window32))) do_exit(SIGILL); } tp->w_saved = 0; unlock_kernel(); }