blackfin architecture

This adds support for the Analog Devices Blackfin processor architecture, and
currently supports the BF533, BF532, BF531, BF537, BF536, BF534, and BF561
(Dual Core) devices, with a variety of development platforms including those
avaliable from Analog Devices (BF533-EZKit, BF533-STAMP, BF537-STAMP,
BF561-EZKIT), and Bluetechnix!  Tinyboards.

The Blackfin architecture was jointly developed by Intel and Analog Devices
Inc.  (ADI) as the Micro Signal Architecture (MSA) core and introduced it in
December of 2000.  Since then ADI has put this core into its Blackfin
processor family of devices.  The Blackfin core has the advantages of a clean,
orthogonal,RISC-like microprocessor instruction set.  It combines a dual-MAC
(Multiply/Accumulate), state-of-the-art signal processing engine and
single-instruction, multiple-data (SIMD) multimedia capabilities into a single
instruction-set architecture.

The Blackfin architecture, including the instruction set, is described by the
ADSP-BF53x/BF56x Blackfin Processor Programming Reference
http://blackfin.uclinux.org/gf/download/frsrelease/29/2549/Blackfin_PRM.pdf

The Blackfin processor is already supported by major releases of gcc, and
there are binary and source rpms/tarballs for many architectures at:
http://blackfin.uclinux.org/gf/project/toolchain/frs There is complete
documentation, including "getting started" guides available at:
http://docs.blackfin.uclinux.org/ which provides links to the sources and
patches you will need in order to set up a cross-compiling environment for
bfin-linux-uclibc

This patch, as well as the other patches (toolchain, distribution,
uClibc) are actively supported by Analog Devices Inc, at:
http://blackfin.uclinux.org/

We have tested this on LTP, and our test plan (including pass/fails) can
be found at:
http://docs.blackfin.uclinux.org/doku.php?id=testing_the_linux_kernel

[m.kozlowski@tuxland.pl: balance parenthesis in blackfin header files]
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Signed-off-by: Mariusz Kozlowski <m.kozlowski@tuxland.pl>
Signed-off-by: Aubrey Li <aubrey.li@analog.com>
Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 356 insertions, 0 deletions

diff --git a/arch/blackfin/kernel/signal.c b/arch/blackfin/kernel/signal.c
new file mode 100644
index 000000000000..316e65c3439d
--- /dev/null
+++ b/arch/blackfin/kernel/signal.c
@@ -0,0 +1,356 @@
+/*
+ * File:         arch/blackfin/kernel/signal.c
+ * Based on:
+ * Author:
+ *
+ * Created:
+ * Description:
+ *
+ * Modified:
+ *               Copyright 2004-2006 Analog Devices Inc.
+ *
+ * Bugs:         Enter bugs at http://blackfin.uclinux.org/
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see the file COPYING, or write
+ * to the Free Software Foundation, Inc.,
+ * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+#include <linux/signal.h>
+#include <linux/syscalls.h>
+#include <linux/ptrace.h>
+#include <linux/tty.h>
+#include <linux/personality.h>
+#include <linux/binfmts.h>
+#include <linux/freezer.h>
+
+#include <asm/uaccess.h>
+#include <asm/cacheflush.h>
+#include <asm/ucontext.h>
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+struct fdpic_func_descriptor {
+        unsigned long   text;
+        unsigned long   GOT;
+};
+
+struct rt_sigframe {
+        int sig;
+        struct siginfo *pinfo;
+        void *puc;
+        char retcode[8];
+        struct siginfo info;
+        struct ucontext uc;
+};
+
+asmlinkage int sys_sigaltstack(const stack_t * uss, stack_t * uoss)
+{
+        return do_sigaltstack(uss, uoss, rdusp());
+}
+
+static inline int
+rt_restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *pr0)
+{
+        unsigned long usp = 0;
+        int err = 0;
+
+#define RESTORE(x) err |= __get_user(regs->x, &sc->sc_##x)
+
+        /* restore passed registers */
+        RESTORE(r0); RESTORE(r1); RESTORE(r2); RESTORE(r3);
+        RESTORE(r4); RESTORE(r5); RESTORE(r6); RESTORE(r7);
+        RESTORE(p0); RESTORE(p1); RESTORE(p2); RESTORE(p3);
+        RESTORE(p4); RESTORE(p5);
+        err |= __get_user(usp, &sc->sc_usp);
+        wrusp(usp);
+        RESTORE(a0w); RESTORE(a1w);
+        RESTORE(a0x); RESTORE(a1x);
+        RESTORE(astat);
+        RESTORE(rets);
+        RESTORE(pc);
+        RESTORE(retx);
+        RESTORE(fp);
+        RESTORE(i0); RESTORE(i1); RESTORE(i2); RESTORE(i3);
+        RESTORE(m0); RESTORE(m1); RESTORE(m2); RESTORE(m3);
+        RESTORE(l0); RESTORE(l1); RESTORE(l2); RESTORE(l3);
+        RESTORE(b0); RESTORE(b1); RESTORE(b2); RESTORE(b3);
+        RESTORE(lc0); RESTORE(lc1);
+        RESTORE(lt0); RESTORE(lt1);
+        RESTORE(lb0); RESTORE(lb1);
+        RESTORE(seqstat);
+
+        regs->orig_p0 = -1;     /* disable syscall checks */
+
+        *pr0 = regs->r0;
+        return err;
+}
+
+asmlinkage int do_rt_sigreturn(unsigned long __unused)
+{
+        struct pt_regs *regs = (struct pt_regs *)__unused;
+        unsigned long usp = rdusp();
+        struct rt_sigframe *frame = (struct rt_sigframe *)(usp);
+        sigset_t set;
+        int r0;
+
+        if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
+                goto badframe;
+        if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
+                goto badframe;
+
+        sigdelsetmask(&set, ~_BLOCKABLE);
+        spin_lock_irq(&current->sighand->siglock);
+        current->blocked = set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        if (rt_restore_sigcontext(regs, &frame->uc.uc_mcontext, &r0))
+                goto badframe;
+
+        if (do_sigaltstack(&frame->uc.uc_stack, NULL, regs->usp) == -EFAULT)
+                goto badframe;
+
+        return r0;
+
+      badframe:
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+static inline int rt_setup_sigcontext(struct sigcontext *sc, struct pt_regs *regs)
+{
+        int err = 0;
+
+#define SETUP(x) err |= __put_user(regs->x, &sc->sc_##x)
+
+        SETUP(r0); SETUP(r1); SETUP(r2); SETUP(r3);
+        SETUP(r4); SETUP(r5); SETUP(r6); SETUP(r7);
+        SETUP(p0); SETUP(p1); SETUP(p2); SETUP(p3);
+        SETUP(p4); SETUP(p5);
+        err |= __put_user(rdusp(), &sc->sc_usp);
+        SETUP(a0w); SETUP(a1w);
+        SETUP(a0x); SETUP(a1x);
+        SETUP(astat);
+        SETUP(rets);
+        SETUP(pc);
+        SETUP(retx);
+        SETUP(fp);
+        SETUP(i0); SETUP(i1); SETUP(i2); SETUP(i3);
+        SETUP(m0); SETUP(m1); SETUP(m2); SETUP(m3);
+        SETUP(l0); SETUP(l1); SETUP(l2); SETUP(l3);
+        SETUP(b0); SETUP(b1); SETUP(b2); SETUP(b3);
+        SETUP(lc0); SETUP(lc1);
+        SETUP(lt0); SETUP(lt1);
+        SETUP(lb0); SETUP(lb1);
+        SETUP(seqstat);
+
+        return err;
+}
+
+static inline void push_cache(unsigned long vaddr, unsigned int len)
+{
+        flush_icache_range(vaddr, vaddr + len);
+}
+
+static inline void *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+                                 size_t frame_size)
+{
+        unsigned long usp;
+
+        /* Default to using normal stack.  */
+        usp = rdusp();
+
+        /* This is the X/Open sanctioned signal stack switching.  */
+        if (ka->sa.sa_flags & SA_ONSTACK) {
+                if (!on_sig_stack(usp))
+                        usp = current->sas_ss_sp + current->sas_ss_size;
+        }
+        return (void *)((usp - frame_size) & -8UL);
+}
+
+static int
+setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t * info,
+               sigset_t * set, struct pt_regs *regs)
+{
+        struct rt_sigframe *frame;
+        int err = 0;
+
+        frame = get_sigframe(ka, regs, sizeof(*frame));
+
+        err |= __put_user((current_thread_info()->exec_domain
+                           && current_thread_info()->exec_domain->signal_invmap
+                           && sig < 32
+                           ? current_thread_info()->exec_domain->
+                           signal_invmap[sig] : sig), &frame->sig);
+
+        err |= __put_user(&frame->info, &frame->pinfo);
+        err |= __put_user(&frame->uc, &frame->puc);
+        err |= copy_siginfo_to_user(&frame->info, info);
+
+        /* Create the ucontext.  */
+        err |= __put_user(0, &frame->uc.uc_flags);
+        err |= __put_user(0, &frame->uc.uc_link);
+        err |=
+            __put_user((void *)current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+        err |= __put_user(sas_ss_flags(rdusp()), &frame->uc.uc_stack.ss_flags);
+        err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size);
+        err |= rt_setup_sigcontext(&frame->uc.uc_mcontext, regs);
+        err |= copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+
+        /* Set up to return from userspace.  */
+        err |= __put_user(0x28, &(frame->retcode[0]));
+        err |= __put_user(0xe1, &(frame->retcode[1]));
+        err |= __put_user(0xad, &(frame->retcode[2]));
+        err |= __put_user(0x00, &(frame->retcode[3]));
+        err |= __put_user(0xa0, &(frame->retcode[4]));
+        err |= __put_user(0x00, &(frame->retcode[5]));
+
+        if (err)
+                goto give_sigsegv;
+
+        push_cache((unsigned long)&frame->retcode, sizeof(frame->retcode));
+
+        /* Set up registers for signal handler */
+        wrusp((unsigned long)frame);
+        if (get_personality & FDPIC_FUNCPTRS) {
+                struct fdpic_func_descriptor __user *funcptr =
+                        (struct fdpic_func_descriptor *) ka->sa.sa_handler;
+                __get_user(regs->pc, &funcptr->text);
+                __get_user(regs->p3, &funcptr->GOT);
+        } else
+                regs->pc = (unsigned long)ka->sa.sa_handler;
+        regs->rets = (unsigned long)(frame->retcode);
+
+        regs->r0 = frame->sig;
+        regs->r1 = (unsigned long)(&frame->info);
+        regs->r2 = (unsigned long)(&frame->uc);
+
+        return 0;
+
+      give_sigsegv:
+        if (sig == SIGSEGV)
+                ka->sa.sa_handler = SIG_DFL;
+        force_sig(SIGSEGV, current);
+        return -EFAULT;
+}
+
+static inline void
+handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
+{
+        switch (regs->r0) {
+        case -ERESTARTNOHAND:
+                if (!has_handler)
+                        goto do_restart;
+                regs->r0 = -EINTR;
+                break;
+
+        case -ERESTARTSYS:
+                if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
+                        regs->r0 = -EINTR;
+                        break;
+                }
+                /* fallthrough */
+        case -ERESTARTNOINTR:
+              do_restart:
+                regs->p0 = regs->orig_p0;
+                regs->r0 = regs->orig_r0;
+                regs->pc -= 2;
+                break;
+        }
+}
+
+/*
+ * OK, we're invoking a handler
+ */
+static int
+handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
+              sigset_t *oldset, struct pt_regs *regs)
+{
+        int ret;
+
+        /* are we from a system call? to see pt_regs->orig_p0 */
+        if (regs->orig_p0 >= 0)
+                /* If so, check system call restarting.. */
+                handle_restart(regs, ka, 1);
+
+        /* set up the stack frame */
+        ret = setup_rt_frame(sig, ka, info, oldset, regs);
+
+        if (ret == 0) {
+                spin_lock_irq(&current->sighand->siglock);
+                sigorsets(&current->blocked, &current->blocked,
+                          &ka->sa.sa_mask);
+                if (!(ka->sa.sa_flags & SA_NODEFER))
+                        sigaddset(&current->blocked, sig);
+                recalc_sigpending();
+                spin_unlock_irq(&current->sighand->siglock);
+        }
+        return ret;
+}
+
+/*
+ * Note that 'init' is a special process: it doesn't get signals it doesn't
+ * want to handle. Thus you cannot kill init even with a SIGKILL even by
+ * mistake.
+ *
+ * Note that we go through the signals twice: once to check the signals
+ * that the kernel can handle, and then we build all the user-level signal
+ * handling stack-frames in one go after that.
+ */
+asmlinkage void do_signal(struct pt_regs *regs)
+{
+        siginfo_t info;
+        int signr;
+        struct k_sigaction ka;
+        sigset_t *oldset;
+
+        current->thread.esp0 = (unsigned long)regs;
+
+        if (try_to_freeze())
+                goto no_signal;
+
+        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                oldset = &current->saved_sigmask;
+        else
+                oldset = &current->blocked;
+
+        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+        if (signr > 0) {
+                /* Whee!  Actually deliver the signal.  */
+                if (handle_signal(signr, &info, &ka, oldset, regs) == 0) {
+                        /* a signal was successfully delivered; the saved
+                         * sigmask will have been stored in the signal frame,
+                         * and will be restored by sigreturn, so we can simply
+                         * clear the TIF_RESTORE_SIGMASK flag */
+                        if (test_thread_flag(TIF_RESTORE_SIGMASK))
+                                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                }
+
+                return;
+        }
+
+no_signal:
+        /* Did we come from a system call? */
+        if (regs->orig_p0 >= 0)
+                /* Restart the system call - no handlers present */
+                handle_restart(regs, NULL, 0);
+
+        /* if there's no signal to deliver, we just put the saved sigmask
+         * back */
+        if (test_thread_flag(TIF_RESTORE_SIGMASK)) {
+                clear_thread_flag(TIF_RESTORE_SIGMASK);
+                sigprocmask(SIG_SETMASK, &current->saved_sigmask, NULL);
+        }
+}