[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 3

The attached patches provides part 3 of an architecture implementation for the
Tensilica Xtensa CPU series.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 407 insertions, 0 deletions

diff --git a/arch/xtensa/kernel/ptrace.c b/arch/xtensa/kernel/ptrace.c
new file mode 100644
index 000000000000..9ef07a4dd2a2
--- /dev/null
+++ b/arch/xtensa/kernel/ptrace.c
@@ -0,0 +1,407 @@
+// TODO some minor issues
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005  Tensilica Inc.
+ *
+ * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
+ * Chris Zankel <chris@zankel.net>
+ * Scott Foehner<sfoehner@yahoo.com>,
+ * Kevin Chea
+ * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/errno.h>
+#include <linux/ptrace.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/security.h>
+
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
+#include <asm/ptrace.h>
+#include <asm/elf.h>
+
+#define TEST_KERNEL     // verify kernel operations FIXME: remove
+
+
+/*
+ * Called by kernel/ptrace.c when detaching..
+ *
+ * Make sure single step bits etc are not set.
+ */
+
+void ptrace_disable(struct task_struct *child)
+{
+        /* Nothing to do.. */
+}
+
+int sys_ptrace(long request, long pid, long addr, long data)
+{
+        struct task_struct *child;
+        int ret = -EPERM;
+
+        lock_kernel();
+
+#if 0
+        if ((int)request != 1)
+        printk("ptrace(r=%d,pid=%d,addr=%08lx,data=%08lx)\n",
+               (int) request, (int) pid, (unsigned long) addr,
+               (unsigned long) data);
+#endif
+
+        if (request == PTRACE_TRACEME) {
+
+                /* Are we already being traced? */
+
+                if (current->ptrace & PT_PTRACED)
+                        goto out;
+
+                if ((ret = security_ptrace(current->parent, current)))
+                        goto out;
+
+                /* Set the ptrace bit in the process flags. */
+
+                current->ptrace |= PT_PTRACED;
+                ret = 0;
+                goto out;
+        }
+
+        ret = -ESRCH;
+        read_lock(&tasklist_lock);
+        child = find_task_by_pid(pid);
+        if (child)
+                get_task_struct(child);
+        read_unlock(&tasklist_lock);
+        if (!child)
+                goto out;
+
+        ret = -EPERM;
+        if (pid == 1)           /* you may not mess with init */
+                goto out;
+
+        if (request == PTRACE_ATTACH) {
+                ret = ptrace_attach(child);
+                goto out_tsk;
+        }
+
+        if ((ret = ptrace_check_attach(child, request == PTRACE_KILL)) < 0)
+                goto out_tsk;
+
+        switch (request) {
+        case PTRACE_PEEKTEXT: /* read word at location addr. */
+        case PTRACE_PEEKDATA:
+        {
+                unsigned long tmp;
+                int copied;
+
+                copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
+                ret = -EIO;
+                if (copied != sizeof(tmp))
+                        break;
+                ret = put_user(tmp,(unsigned long *) data);
+
+                goto out;
+        }
+
+        /* Read the word at location addr in the USER area.  */
+
+        case PTRACE_PEEKUSR:
+                {
+                struct pt_regs *regs;
+                unsigned long tmp;
+
+                regs = xtensa_pt_regs(child);
+                tmp = 0;  /* Default return value. */
+
+                switch(addr) {
+
+                case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
+                        {
+                        int ar = addr - REG_AR_BASE - regs->windowbase * 4;
+                        ar &= (XCHAL_NUM_AREGS - 1);
+                        if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
+                                tmp = regs->areg[ar];
+                        else
+                                ret = -EIO;
+                        break;
+                        }
+                case REG_A_BASE ... REG_A_BASE + 15:
+                        tmp = regs->areg[addr - REG_A_BASE];
+                        break;
+                case REG_PC:
+                        tmp = regs->pc;
+                        break;
+                case REG_PS:
+                        /* Note:  PS.EXCM is not set while user task is running;
+                         * its being set in regs is for exception handling
+                         * convenience.  */
+                        tmp = (regs->ps & ~XCHAL_PS_EXCM_MASK);
+                        break;
+                case REG_WB:
+                        tmp = regs->windowbase;
+                        break;
+                case REG_WS:
+                        tmp = regs->windowstart;
+                        break;
+                case REG_LBEG:
+                        tmp = regs->lbeg;
+                        break;
+                case REG_LEND:
+                        tmp = regs->lend;
+                        break;
+                case REG_LCOUNT:
+                        tmp = regs->lcount;
+                        break;
+                case REG_SAR:
+                        tmp = regs->sar;
+                        break;
+                case REG_DEPC:
+                        tmp = regs->depc;
+                        break;
+                case REG_EXCCAUSE:
+                        tmp = regs->exccause;
+                        break;
+                case REG_EXCVADDR:
+                        tmp = regs->excvaddr;
+                        break;
+                case SYSCALL_NR:
+                        tmp = regs->syscall;
+                        break;
+                default:
+                        tmp = 0;
+                        ret = -EIO;
+                        goto out;
+                }
+                ret = put_user(tmp, (unsigned long *) data);
+                goto out;
+                }
+
+        case PTRACE_POKETEXT: /* write the word at location addr. */
+        case PTRACE_POKEDATA:
+                if (access_process_vm(child, addr, &data, sizeof(data), 1)
+                    == sizeof(data))
+                        break;
+                ret = -EIO;
+                goto out;
+
+        case PTRACE_POKEUSR:
+                {
+                struct pt_regs *regs;
+                regs = xtensa_pt_regs(child);
+
+                switch (addr) {
+                case REG_AR_BASE ... REG_AR_BASE + XCHAL_NUM_AREGS - 1:
+                        {
+                        int ar = addr - REG_AR_BASE - regs->windowbase * 4;
+                        if (ar < 16 && ar + (regs->wmask >> 4) * 4 >= 0)
+                                regs->areg[ar & (XCHAL_NUM_AREGS - 1)] = data;
+                        else
+                                ret = -EIO;
+                        break;
+                        }
+                case REG_A_BASE ... REG_A_BASE + 15:
+                        regs->areg[addr - REG_A_BASE] = data;
+                        break;
+                case REG_PC:
+                        regs->pc = data;
+                        break;
+                case SYSCALL_NR:
+                        regs->syscall = data;
+                        break;
+#ifdef TEST_KERNEL
+                case REG_WB:
+                        regs->windowbase = data;
+                        break;
+                case REG_WS:
+                        regs->windowstart = data;
+                        break;
+#endif
+
+                default:
+                        /* The rest are not allowed. */
+                        ret = -EIO;
+                        break;
+                }
+                break;
+                }
+
+        /* continue and stop at next (return from) syscall */
+        case PTRACE_SYSCALL:
+        case PTRACE_CONT: /* restart after signal. */
+        {
+                ret = -EIO;
+                if ((unsigned long) data > _NSIG)
+                        break;
+                if (request == PTRACE_SYSCALL)
+                        set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+                else
+                        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+                child->exit_code = data;
+                /* Make sure the single step bit is not set. */
+                child->ptrace &= ~PT_SINGLESTEP;
+                wake_up_process(child);
+                ret = 0;
+                break;
+        }
+
+        /*
+         * make the child exit.  Best I can do is send it a sigkill.
+         * perhaps it should be put in the status that it wants to
+         * exit.
+         */
+        case PTRACE_KILL:
+                ret = 0;
+                if (child->state == EXIT_ZOMBIE)        /* already dead */
+                        break;
+                child->exit_code = SIGKILL;
+                child->ptrace &= ~PT_SINGLESTEP;
+                wake_up_process(child);
+                break;
+
+        case PTRACE_SINGLESTEP:
+                ret = -EIO;
+                if ((unsigned long) data > _NSIG)
+                        break;
+                clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
+                child->ptrace |= PT_SINGLESTEP;
+                child->exit_code = data;
+                wake_up_process(child);
+                ret = 0;
+                break;
+
+        case PTRACE_GETREGS:
+        {
+                /* 'data' points to user memory in which to write.
+                 * Mainly due to the non-live register values, we
+                 * reformat the register values into something more
+                 * standard.  For convenience, we use the handy
+                 * elf_gregset_t format. */
+
+                xtensa_gregset_t format;
+                struct pt_regs *regs = xtensa_pt_regs(child);
+
+                do_copy_regs (&format, regs, child);
+
+                /* Now, copy to user space nice and easy... */
+                ret = 0;
+                if (copy_to_user((void *)data, &format, sizeof(elf_gregset_t)))
+                        ret = -EFAULT;
+                break;
+        }
+
+        case PTRACE_SETREGS:
+        {
+                /* 'data' points to user memory that contains the new
+                 * values in the elf_gregset_t format. */
+
+                xtensa_gregset_t format;
+                struct pt_regs *regs = xtensa_pt_regs(child);
+
+                if (copy_from_user(&format,(void *)data,sizeof(elf_gregset_t))){
+                        ret = -EFAULT;
+                        break;
+                }
+
+                /* FIXME: Perhaps we want some sanity checks on
+                 * these user-space values?  See ARM version.  Are
+                 * debuggers a security concern? */
+
+                do_restore_regs (&format, regs, child);
+
+                ret = 0;
+                break;
+        }
+
+        case PTRACE_GETFPREGS:
+        {
+                /* 'data' points to user memory in which to write.
+                 * For convenience, we use the handy
+                 * elf_fpregset_t format. */
+
+                elf_fpregset_t fpregs;
+                struct pt_regs *regs = xtensa_pt_regs(child);
+
+                do_save_fpregs (&fpregs, regs, child);
+
+                /* Now, copy to user space nice and easy... */
+                ret = 0;
+                if (copy_to_user((void *)data, &fpregs, sizeof(elf_fpregset_t)))
+                        ret = -EFAULT;
+
+                break;
+        }
+
+        case PTRACE_SETFPREGS:
+        {
+                /* 'data' points to user memory that contains the new
+                 * values in the elf_fpregset_t format.
+                 */
+                elf_fpregset_t fpregs;
+                struct pt_regs *regs = xtensa_pt_regs(child);
+
+                ret = 0;
+                if (copy_from_user(&fpregs, (void *)data, sizeof(elf_fpregset_t))) {
+                        ret = -EFAULT;
+                        break;
+                }
+
+                if (do_restore_fpregs (&fpregs, regs, child))
+                        ret = -EIO;
+                break;
+        }
+
+        case PTRACE_GETFPREGSIZE:
+                /* 'data' points to 'unsigned long' set to the size
+                 * of elf_fpregset_t
+                 */
+                ret = put_user(sizeof(elf_fpregset_t), (unsigned long *) data);
+                break;
+
+        case PTRACE_DETACH: /* detach a process that was attached. */
+                ret = ptrace_detach(child, data);
+                break;
+
+        default:
+                ret = ptrace_request(child, request, addr, data);
+                goto out;
+        }
+out_tsk:
+        put_task_struct(child);
+out:
+        unlock_kernel();
+        return ret;
+}
+
+void do_syscall_trace(void)
+{
+        if (!test_thread_flag(TIF_SYSCALL_TRACE))
+                return;
+
+        if (!(current->ptrace & PT_PTRACED))
+                return;
+
+        /*
+         * The 0x80 provides a way for the tracing parent to distinguish
+         * between a syscall stop and SIGTRAP delivery
+         */
+        ptrace_notify(SIGTRAP|((current->ptrace & PT_TRACESYSGOOD) ? 0x80 : 0));
+
+        /*
+         * this isn't the same as continuing with a signal, but it will do
+         * for normal use.  strace only continues with a signal if the
+         * stopping signal is not SIGTRAP.  -brl
+         */
+        if (current->exit_code) {
+                send_sig(current->exit_code, current, 1);
+                current->exit_code = 0;
+        }
+}