[xtensa-cvscommit] linux/arch/xtensa/kernel signal.c,1.6,1.7

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Update of /cvsroot/xtensa/linux/arch/xtensa/kernel
In directory sc8-pr-cvs1:/tmp/cvs-serv31547/arch/xtensa/kernel

Modified Files:
	signal.c 
Log Message:
Save and restore coprocessor state as needed when handling signals.


Index: signal.c
===================================================================
RCS file: /cvsroot/xtensa/linux/arch/xtensa/kernel/signal.c,v
retrieving revision 1.6
retrieving revision 1.7
diff -C2 -d -r1.6 -r1.7
*** signal.c	23 Apr 2003 00:36:27 -0000	1.6
--- signal.c	23 Apr 2003 23:19:55 -0000	1.7
***************
*** 34,37 ****
--- 34,39 ----
  asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
  
+ extern struct task_struct *coproc_owners[];
+ 
  int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from)
  {
***************
*** 171,178 ****
  {
  	struct sigcontext sc;
  	unsigned long extramask[_NSIG_WORDS-1];
  	unsigned char retcode[6];
- 	unsigned int window[4]; /* Window of 4 registers for initial context */
  	unsigned int reserved[4]; /* Reserved area for chaining */
  };
  
--- 173,181 ----
  {
  	struct sigcontext sc;
+ 	struct _cpstate cpstate;
  	unsigned long extramask[_NSIG_WORDS-1];
  	unsigned char retcode[6];
  	unsigned int reserved[4]; /* Reserved area for chaining */
+ 	unsigned int window[4]; /* Window of 4 registers for initial context */
  };
  
***************
*** 181,189 ****
  	struct siginfo info;
  	struct ucontext uc;
  	unsigned char retcode[6];
- 	unsigned int window[4]; /* Window of 4 registers for initial context */
  	unsigned int reserved[4]; /* Reserved area for chaining */
  };
  
  static int
  restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
--- 184,219 ----
  	struct siginfo info;
  	struct ucontext uc;
+ 	struct _cpstate cpstate;
  	unsigned char retcode[6];
  	unsigned int reserved[4]; /* Reserved area for chaining */
+ 	unsigned int window[4]; /* Window of 4 registers for initial context */
  };
  
+ static inline void
+ discard_my_cpstate(struct task_struct *tsk)
+ {
+ 	int i;
+ 	for (i = 0; i < XCHAL_CP_NUM; i++)
+ 		if (tsk == coproc_owners[i]) {
+ 			xthal_invalidate_cp(i);
+ 			coproc_owners[i] = 0;
+ 		}
+ }
+ 
+ static inline int
+ restore_cpextra (struct _cpstate *buf)
+ {
+ 	/* The signal handler may have used coprocessors in which
+ 	 * case they are still enabled.  We disable them to force a
+ 	 * reloading of the original task's CP state by the lazy
+ 	 * context-switching mechanisms of CP exception handling.
+ 	 * Also, we essentially discard any coprocessor state that the
+ 	 * signal handler created. */
+ 
+ 	struct task_struct *tsk = current;
+ 	discard_my_cpstate(tsk);
+ 	return __copy_from_user(tsk->thread.cpextra, buf, TOTAL_CPEXTRA_SIZE);
+ }
+ 
  static int
  restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc)
***************
*** 192,195 ****
--- 222,226 ----
  	unsigned int err = 0;
  	unsigned long ps;
+ 	struct _cpstate *buf;
  	int i;
  
***************
*** 249,278 ****
  		err |= __get_user(thread->regfile[i], &sc->sc_regfile[i]);
  	}
- #if (XCHAL_EXTRA_SA_SIZE > 0)
- 	err |= __copy_from_user(thread->cpextra,sc->sc_extra,XCHAL_EXTRA_SA_SIZE);
- #endif /* (XCHAL_EXTRA_SA_SIZE > 0) */
- 
- 	/* XTFIXME: cp[0-7]_regs? Yes, we should copy over these array
- 	 * contents, probably using the __copy_{to,from}_user() macros
- 	 * in uaccess.h.  For now, it doesn't affect development since
- 	 * LinuxBE/LinuxLE do not have coprocessors.  We should
- 	 * implement this section when we're ready to test it.
- 	 * Testing will be complex (Joe, keep your signaling test
- 	 * cases around.)
- 	 */
  
! 	/* thread->info is unused for now */
  
  	regs->syscall_nr = -1;		/* disable syscall checks */
  	return err;
  }
  
  static int
! setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs,
! 		 unsigned long mask)
  {
  	struct thread_struct *thread;
! 	int err = 0;
! 	int i;
  
  #define COPY(x)		err |= __put_user(regs->x, &sc->sc_##x)
--- 280,347 ----
  		err |= __get_user(thread->regfile[i], &sc->sc_regfile[i]);
  	}
  
! 	err |= __get_user(buf, &sc->sc_cpstate);
! 	if (buf) {
! 		if (verify_area(VERIFY_READ, buf, sizeof(*buf)))
! 			goto badframe;
! 		err |= restore_cpextra(buf);
! 	}
  
  	regs->syscall_nr = -1;		/* disable syscall checks */
  	return err;
+ 
+ badframe:
+ 	return 1;
  }
  
+ static inline void
+ flush_my_cpstate(struct task_struct *tsk)
+ {
+ 	int i;
+ 	for (i = 0; i < XCHAL_CP_NUM; i++) {
+ 		if (tsk == coproc_owners[i]) {
+ 			xthal_validate_cp(i);
+ 			xthal_save_cpregs(tsk->thread.cpregs_ptr[i], i);
+ 			xthal_invalidate_cp(i);
+ 			/* I think this is unnecessary; we're not switching owners. */
+ 			/* coproc_owners[i] = 0; */
+ 		}
+ 	}
+ }
+ 
+ /* Return codes:
+ 	0:  nothing saved
+ 	1:  stuff to save, successful
+        -1:  stuff to save, error happened
+ */
  static int
! save_cpextra (struct _cpstate *buf)
! {
! #if (XCHAL_EXTRA_SA_SIZE == 0) && (XCHAL_CP_NUM == 0)
! 	return 0;
! #else
! 
! 	/* XTFIXME: If a task has never used a coprocessor, there is
! 	   no need to save and restore anything.  Tracking this
! 	   information would allow us to optimize this section.
! 	   Perhaps we can use current->used_math or (current->flags &
! 	   PF_USEDFPU) or define a new field in the thread
! 	   structure. */
! 
! 	struct task_struct *tsk = current;
! 	flush_my_cpstate(tsk);
! 	/* Note that we just copy everything: 'extra' and 'cp' state together. */
! 	if (__copy_to_user(buf, tsk->thread.cpextra, TOTAL_CPEXTRA_SIZE))
! 		return -1;
! 	return 1;
! #endif
! }
! 
! static int
! setup_sigcontext(struct sigcontext *sc, struct _cpstate *cpstate,
! 		 struct pt_regs *regs, unsigned long mask)
  {
  	struct thread_struct *thread;
! 	int i, tmp, err = 0;
  
  #define COPY(x)		err |= __put_user(regs->x, &sc->sc_##x)
***************
*** 303,320 ****
  		err |= __put_user(thread->regfile[i], &sc->sc_regfile[i]);
  	}
- #if (XCHAL_EXTRA_SA_SIZE > 0)
- 	err |= __copy_to_user(sc->sc_extra, thread->cpextra, XCHAL_EXTRA_SA_SIZE);
- #endif /* (XCHAL_EXTRA_SA_SIZE > 0) */
- 
- 	/* XTFIXME: cp[0-7]_regs? Yes, we should copy over these array
- 	 * contents, probably using the __copy_{to,from}_user() macros
- 	 * in uaccess.h.  For now, it doesn't affect development since
- 	 * LinuxBE/LinuxLE do not have coprocessors.  We should
- 	 * implement this section when we're ready to test it.
- 	 * Testing will be complex (Joe, keep your signaling test
- 	 * cases around.)
- 	 */
  
! 	/* thread->info is unused for now */
  
  	/* non-iBCS2 extensions.. */
--- 372,381 ----
  		err |= __put_user(thread->regfile[i], &sc->sc_regfile[i]);
  	}
  
! 	tmp = save_cpextra(cpstate);
! 	if (tmp < 0)
! 	  err = 1;
! 	else
! 	  err |= __put_user(tmp ? cpstate : NULL, &sc->sc_cpstate);
  
  	/* non-iBCS2 extensions.. */
***************
*** 516,520 ****
  		: sig;
  
! 	err |= setup_sigcontext(&frame->sc, regs, set->sig[0]);
  
  	if (_NSIG_WORDS > 1) {
--- 577,581 ----
  		: sig;
  
! 	err |= setup_sigcontext(&frame->sc, &frame->cpstate, regs, set->sig[0]);
  
  	if (_NSIG_WORDS > 1) {
***************
*** 581,585 ****
  			  &frame->uc.uc_stack.ss_flags);
  	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
! 	err |= setup_sigcontext(&frame->uc.uc_mcontext,
  			        regs, set->sig[0]);
  	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
--- 642,646 ----
  			  &frame->uc.uc_stack.ss_flags);
  	err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
! 	err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->cpstate,
  			        regs, set->sig[0]);
  	err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));