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/* 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 = ¤t->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 = ¤t->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;
}
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