Subversion Repositories or1k

/* 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>

/* Do save's until all user register windows are out of the cpu. */

void flush_user_windows(void)

{

        if(current->tss.uwinmask)

                flush_user_windows();

}

static inline void shift_window_buffer(int first_win, int last_win, struct thread_struct *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_window));

        }

}

/* 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_struct *tp = &current->tss;

        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];

                /* See if %sp is reasonable at all. */

                if(verify_area(VERIFY_WRITE, (char *) sp, sizeof(struct reg_window)))

                        continue;

                /* Ok, let it rip. */

                memcpy((char *) sp, &tp->reg_window[window], sizeof(struct reg_window));

                shift_window_buffer(window, tp->w_saved - 1, tp);

                tp->w_saved--;

        }

}

/* 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");

}

/* Try to push the windows in a threads window buffer to the

 * user stack.  Unaligned %sp's are not allowed here.

 */

#define stack_is_bad(sp, rw) \

  (((sp) & 7) || verify_area(rw, (char *) (sp), sizeof(struct reg_window)))

void try_to_clear_window_buffer(struct pt_regs *regs, int who)

{

        struct thread_struct *tp = &current->tss;

        int window;

        flush_user_windows();

        for(window = 0; window < tp->w_saved; window++) {

                unsigned long sp = tp->rwbuf_stkptrs[window];

                if(stack_is_bad(sp, VERIFY_WRITE))

                        do_exit(SIGILL);

                else

                        copy_aligned_window((char *) sp, &tp->reg_window[window]);

        }

        tp->w_saved = 0;

}