From c658eac628aa8df040dfe614556d95e6da3a9ffb Mon Sep 17 00:00:00 2001 From: Chris Zankel Date: Tue, 12 Feb 2008 13:17:07 -0800 Subject: [XTENSA] Add support for configurable registers and coprocessors The Xtensa architecture allows to define custom instructions and registers. Registers that are bound to a coprocessor are only accessible if the corresponding enable bit is set, which allows to implement a 'lazy' context switch mechanism. Other registers needs to be saved and restore at the time of the context switch or during interrupt handling. This patch adds support for these additional states: - save and restore registers that are used by the compiler upon interrupt entry and exit. - context switch additional registers unbound to any coprocessor - 'lazy' context switch of registers bound to a coprocessor - ptrace interface to provide access to additional registers - update configuration files in include/asm-xtensa/variant-fsf Signed-off-by: Chris Zankel --- arch/xtensa/kernel/signal.c | 65 +++++++++++++++++++++++++++++---------------- 1 file changed, 42 insertions(+), 23 deletions(-) (limited to 'arch/xtensa/kernel/signal.c') diff --git a/arch/xtensa/kernel/signal.c b/arch/xtensa/kernel/signal.c index 42d9fd8a4225..299be42d116b 100644 --- a/arch/xtensa/kernel/signal.c +++ b/arch/xtensa/kernel/signal.c @@ -35,13 +35,17 @@ asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset); extern struct task_struct *coproc_owners[]; -extern void release_all_cp (struct task_struct *); - struct rt_sigframe { struct siginfo info; struct ucontext uc; - cp_state_t cpstate; + struct { + xtregs_opt_t opt; + xtregs_user_t user; +#if XTENSA_HAVE_COPROCESSORS + xtregs_coprocessor_t cp; +#endif + } xtregs; unsigned char retcode[6]; unsigned int window[4]; }; @@ -132,9 +136,10 @@ errout: */ static int -setup_sigcontext(struct sigcontext __user *sc, cp_state_t *cpstate, - struct pt_regs *regs) +setup_sigcontext(struct rt_sigframe __user *frame, struct pt_regs *regs) { + struct sigcontext __user *sc = &frame->uc.uc_mcontext; + struct thread_info *ti = current_thread_info(); int err = 0; #define COPY(x) err |= __put_user(regs->x, &sc->sc_##x) @@ -148,21 +153,32 @@ setup_sigcontext(struct sigcontext __user *sc, cp_state_t *cpstate, err |= flush_window_regs_user(regs); err |= __copy_to_user (sc->sc_a, regs->areg, 16 * 4); + err |= __put_user(0, &sc->sc_xtregs); - // err |= __copy_to_user (sc->sc_a, regs->areg, XCHAL_NUM_AREGS * 4) + if (err) + return err; -#if XCHAL_HAVE_CP -# error Coprocessors unsupported - err |= save_cpextra(cpstate); - err |= __put_user(err ? NULL : cpstate, &sc->sc_cpstate); +#if XTENSA_HAVE_COPROCESSORS + coprocessor_flush_all(ti); + coprocessor_release_all(ti); + err |= __copy_to_user(&frame->xtregs.cp, &ti->xtregs_cp, + sizeof (frame->xtregs.cp)); #endif + err |= __copy_to_user(&frame->xtregs.opt, ®s->xtregs_opt, + sizeof (xtregs_opt_t)); + err |= __copy_to_user(&frame->xtregs.user, &ti->xtregs_user, + sizeof (xtregs_user_t)); + + err |= __put_user(err ? NULL : &frame->xtregs, &sc->sc_xtregs); return err; } static int -restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) +restore_sigcontext(struct pt_regs *regs, struct rt_sigframe __user *frame) { + struct sigcontext __user *sc = &frame->uc.uc_mcontext; + struct thread_info *ti = current_thread_info(); unsigned int err = 0; unsigned long ps; @@ -180,6 +196,8 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) regs->windowbase = 0; regs->windowstart = 1; + regs->syscall = -1; /* disable syscall checks */ + /* For PS, restore only PS.CALLINC. * Assume that all other bits are either the same as for the signal * handler, or the user mode value doesn't matter (e.g. PS.OWB). @@ -195,8 +213,9 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) err |= __copy_from_user(regs->areg, sc->sc_a, 16 * 4); -#if XCHAL_HAVE_CP -# error Coprocessors unsupported + if (err) + return err; + /* 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 @@ -204,20 +223,20 @@ restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) * Also, we essentially discard any coprocessor state that the * signal handler created. */ - if (!err) { - struct task_struct *tsk = current; - release_all_cp(tsk); - err |= __copy_from_user(tsk->thread.cpextra, sc->sc_cpstate, - XTENSA_CP_EXTRA_SIZE); - } +#if XTENSA_HAVE_COPROCESSORS + coprocessor_release_all(ti); + err |= __copy_from_user(&ti->xtregs_cp, &frame->xtregs.cp, + sizeof (frame->xtregs.cp)); #endif + err |= __copy_from_user(&ti->xtregs_user, &frame->xtregs.user, + sizeof (xtregs_user_t)); + err |= __copy_from_user(®s->xtregs_opt, &frame->xtregs.opt, + sizeof (xtregs_opt_t)); - regs->syscall = -1; /* disable syscall checks */ return err; } - /* * Do a signal return; undo the signal stack. */ @@ -246,7 +265,7 @@ asmlinkage long xtensa_rt_sigreturn(long a0, long a1, long a2, long a3, recalc_sigpending(); spin_unlock_irq(¤t->sighand->siglock); - if (restore_sigcontext(regs, &frame->uc.uc_mcontext)) + if (restore_sigcontext(regs, frame)) goto badframe; ret = regs->areg[2]; @@ -359,7 +378,7 @@ static void setup_frame(int sig, struct k_sigaction *ka, siginfo_t *info, err |= __put_user(sas_ss_flags(regs->areg[1]), &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); + err |= setup_sigcontext(frame, regs); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); /* Create sys_rt_sigreturn syscall in stack frame */ -- cgit