powerpc: move ppc64/kernel/signal.c to arch/powerpc

Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>

1 files changed, 581 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
new file mode 100644
index 00000000000..ec9d0984b6a
--- /dev/null
+++ b/arch/powerpc/kernel/signal_64.c
@@ -0,0 +1,581 @@
+/*
+ *  linux/arch/ppc64/kernel/signal.c
+ *
+ *  PowerPC version 
+ *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
+ *
+ *  Derived from "arch/i386/kernel/signal.c"
+ *    Copyright (C) 1991, 1992 Linus Torvalds
+ *    1997-11-28  Modified for POSIX.1b signals by Richard Henderson
+ *
+ *  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.
+ */
+
+#include <linux/config.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/smp.h>
+#include <linux/smp_lock.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/errno.h>
+#include <linux/wait.h>
+#include <linux/unistd.h>
+#include <linux/stddef.h>
+#include <linux/elf.h>
+#include <linux/ptrace.h>
+#include <linux/module.h>
+
+#include <asm/sigcontext.h>
+#include <asm/ucontext.h>
+#include <asm/uaccess.h>
+#include <asm/pgtable.h>
+#include <asm/ppcdebug.h>
+#include <asm/unistd.h>
+#include <asm/cacheflush.h>
+#include <asm/vdso.h>
+
+#define DEBUG_SIG 0
+
+#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
+
+#define GP_REGS_SIZE    min(sizeof(elf_gregset_t), sizeof(struct pt_regs))
+#define FP_REGS_SIZE    sizeof(elf_fpregset_t)
+
+#define TRAMP_TRACEBACK 3
+#define TRAMP_SIZE      6
+
+/*
+ * When we have signals to deliver, we set up on the user stack,
+ * going down from the original stack pointer:
+ *      1) a rt_sigframe struct which contains the ucontext     
+ *      2) a gap of __SIGNAL_FRAMESIZE bytes which acts as a dummy caller
+ *         frame for the signal handler.
+ */
+
+struct rt_sigframe {
+        /* sys_rt_sigreturn requires the ucontext be the first field */
+        struct ucontext uc;
+        unsigned long _unused[2];
+        unsigned int tramp[TRAMP_SIZE];
+        struct siginfo *pinfo;
+        void *puc;
+        struct siginfo info;
+        /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
+        char abigap[288];
+} __attribute__ ((aligned (16)));
+
+
+/*
+ * Atomically swap in the new signal mask, and wait for a signal.
+ */
+long sys_rt_sigsuspend(sigset_t __user *unewset, size_t sigsetsize, int p3, int p4,
+                       int p6, int p7, struct pt_regs *regs)
+{
+        sigset_t saveset, newset;
+
+        /* XXX: Don't preclude handling different sized sigset_t's.  */
+        if (sigsetsize != sizeof(sigset_t))
+                return -EINVAL;
+
+        if (copy_from_user(&newset, unewset, sizeof(newset)))
+                return -EFAULT;
+        sigdelsetmask(&newset, ~_BLOCKABLE);
+
+        spin_lock_irq(&current->sighand->siglock);
+        saveset = current->blocked;
+        current->blocked = newset;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+
+        regs->result = -EINTR;
+        regs->gpr[3] = EINTR;
+        regs->ccr |= 0x10000000;
+        while (1) {
+                current->state = TASK_INTERRUPTIBLE;
+                schedule();
+                if (do_signal(&saveset, regs))
+                        return 0;
+        }
+}
+
+long sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss, unsigned long r5,
+                     unsigned long r6, unsigned long r7, unsigned long r8,
+                     struct pt_regs *regs)
+{
+        return do_sigaltstack(uss, uoss, regs->gpr[1]);
+}
+
+
+/*
+ * Set up the sigcontext for the signal frame.
+ */
+
+static long setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
+                 int signr, sigset_t *set, unsigned long handler)
+{
+        /* When CONFIG_ALTIVEC is set, we _always_ setup v_regs even if the
+         * process never used altivec yet (MSR_VEC is zero in pt_regs of
+         * the context). This is very important because we must ensure we
+         * don't lose the VRSAVE content that may have been set prior to
+         * the process doing its first vector operation
+         * Userland shall check AT_HWCAP to know wether it can rely on the
+         * v_regs pointer or not
+         */
+#ifdef CONFIG_ALTIVEC
+        elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
+#endif
+        long err = 0;
+
+        flush_fp_to_thread(current);
+
+        /* Make sure signal doesn't get spurrious FP exceptions */
+        current->thread.fpscr.val = 0;
+
+#ifdef CONFIG_ALTIVEC
+        err |= __put_user(v_regs, &sc->v_regs);
+
+        /* save altivec registers */
+        if (current->thread.used_vr) {
+                flush_altivec_to_thread(current);
+                /* Copy 33 vec registers (vr0..31 and vscr) to the stack */
+                err |= __copy_to_user(v_regs, current->thread.vr, 33 * sizeof(vector128));
+                /* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
+                 * contains valid data.
+                 */
+                regs->msr |= MSR_VEC;
+        }
+        /* We always copy to/from vrsave, it's 0 if we don't have or don't
+         * use altivec.
+         */
+        err |= __put_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+#else /* CONFIG_ALTIVEC */
+        err |= __put_user(0, &sc->v_regs);
+#endif /* CONFIG_ALTIVEC */
+        err |= __put_user(&sc->gp_regs, &sc->regs);
+        err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
+        err |= __copy_to_user(&sc->fp_regs, &current->thread.fpr, FP_REGS_SIZE);
+        err |= __put_user(signr, &sc->signal);
+        err |= __put_user(handler, &sc->handler);
+        if (set != NULL)
+                err |=  __put_user(set->sig[0], &sc->oldmask);
+
+        return err;
+}
+
+/*
+ * Restore the sigcontext from the signal frame.
+ */
+
+static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig,
+                              struct sigcontext __user *sc)
+{
+#ifdef CONFIG_ALTIVEC
+        elf_vrreg_t __user *v_regs;
+#endif
+        unsigned long err = 0;
+        unsigned long save_r13 = 0;
+        elf_greg_t *gregs = (elf_greg_t *)regs;
+#ifdef CONFIG_ALTIVEC
+        unsigned long msr;
+#endif
+        int i;
+
+        /* If this is not a signal return, we preserve the TLS in r13 */
+        if (!sig)
+                save_r13 = regs->gpr[13];
+
+        /* copy everything before MSR */
+        err |= __copy_from_user(regs, &sc->gp_regs,
+                                PT_MSR*sizeof(unsigned long));
+
+        /* skip MSR and SOFTE */
+        for (i = PT_MSR+1; i <= PT_RESULT; i++) {
+                if (i == PT_SOFTE)
+                        continue;
+                err |= __get_user(gregs[i], &sc->gp_regs[i]);
+        }
+
+        if (!sig)
+                regs->gpr[13] = save_r13;
+        err |= __copy_from_user(&current->thread.fpr, &sc->fp_regs, FP_REGS_SIZE);
+        if (set != NULL)
+                err |=  __get_user(set->sig[0], &sc->oldmask);
+
+#ifdef CONFIG_ALTIVEC
+        err |= __get_user(v_regs, &sc->v_regs);
+        err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
+        if (err)
+                return err;
+        /* Copy 33 vec registers (vr0..31 and vscr) from the stack */
+        if (v_regs != 0 && (msr & MSR_VEC) != 0)
+                err |= __copy_from_user(current->thread.vr, v_regs,
+                                        33 * sizeof(vector128));
+        else if (current->thread.used_vr)
+                memset(current->thread.vr, 0, 33 * sizeof(vector128));
+        /* Always get VRSAVE back */
+        if (v_regs != 0)
+                err |= __get_user(current->thread.vrsave, (u32 __user *)&v_regs[33]);
+        else
+                current->thread.vrsave = 0;
+#endif /* CONFIG_ALTIVEC */
+
+#ifndef CONFIG_SMP
+        preempt_disable();
+        if (last_task_used_math == current)
+                last_task_used_math = NULL;
+        if (last_task_used_altivec == current)
+                last_task_used_altivec = NULL;
+        preempt_enable();
+#endif
+        /* Force reload of FP/VEC */
+        regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC);
+
+        return err;
+}
+
+/*
+ * Allocate space for the signal frame
+ */
+static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
+                                  size_t frame_size)
+{
+        unsigned long newsp;
+
+        /* Default to using normal stack */
+        newsp = regs->gpr[1];
+
+        if (ka->sa.sa_flags & SA_ONSTACK) {
+                if (! on_sig_stack(regs->gpr[1]))
+                        newsp = (current->sas_ss_sp + current->sas_ss_size);
+        }
+
+        return (void __user *)((newsp - frame_size) & -16ul);
+}
+
+/*
+ * Setup the trampoline code on the stack
+ */
+static long setup_trampoline(unsigned int syscall, unsigned int __user *tramp)
+{
+        int i;
+        long err = 0;
+
+        /* addi r1, r1, __SIGNAL_FRAMESIZE  # Pop the dummy stackframe */
+        err |= __put_user(0x38210000UL | (__SIGNAL_FRAMESIZE & 0xffff), &tramp[0]);
+        /* li r0, __NR_[rt_]sigreturn| */
+        err |= __put_user(0x38000000UL | (syscall & 0xffff), &tramp[1]);
+        /* sc */
+        err |= __put_user(0x44000002UL, &tramp[2]);
+
+        /* Minimal traceback info */
+        for (i=TRAMP_TRACEBACK; i < TRAMP_SIZE ;i++)
+                err |= __put_user(0, &tramp[i]);
+
+        if (!err)
+                flush_icache_range((unsigned long) &tramp[0],
+                           (unsigned long) &tramp[TRAMP_SIZE]);
+
+        return err;
+}
+
+/*
+ * Restore the user process's signal mask (also used by signal32.c)
+ */
+void restore_sigmask(sigset_t *set)
+{
+        sigdelsetmask(set, ~_BLOCKABLE);
+        spin_lock_irq(&current->sighand->siglock);
+        current->blocked = *set;
+        recalc_sigpending();
+        spin_unlock_irq(&current->sighand->siglock);
+}
+
+
+/*
+ * Handle {get,set,swap}_context operations
+ */
+int sys_swapcontext(struct ucontext __user *old_ctx,
+                    struct ucontext __user *new_ctx,
+                    long ctx_size, long r6, long r7, long r8, struct pt_regs *regs)
+{
+        unsigned char tmp;
+        sigset_t set;
+
+        /* Context size is for future use. Right now, we only make sure
+         * we are passed something we understand
+         */
+        if (ctx_size < sizeof(struct ucontext))
+                return -EINVAL;
+
+        if (old_ctx != NULL) {
+                if (!access_ok(VERIFY_WRITE, old_ctx, sizeof(*old_ctx))
+                    || setup_sigcontext(&old_ctx->uc_mcontext, regs, 0, NULL, 0)
+                    || __copy_to_user(&old_ctx->uc_sigmask,
+                                      &current->blocked, sizeof(sigset_t)))
+                        return -EFAULT;
+        }
+        if (new_ctx == NULL)
+                return 0;
+        if (!access_ok(VERIFY_READ, new_ctx, sizeof(*new_ctx))
+            || __get_user(tmp, (u8 __user *) new_ctx)
+            || __get_user(tmp, (u8 __user *) (new_ctx + 1) - 1))
+                return -EFAULT;
+
+        /*
+         * If we get a fault copying the context into the kernel's
+         * image of the user's registers, we can't just return -EFAULT
+         * because the user's registers will be corrupted.  For instance
+         * the NIP value may have been updated but not some of the
+         * other registers.  Given that we have done the access_ok
+         * and successfully read the first and last bytes of the region
+         * above, this should only happen in an out-of-memory situation
+         * or if another thread unmaps the region containing the context.
+         * We kill the task with a SIGSEGV in this situation.
+         */
+
+        if (__copy_from_user(&set, &new_ctx->uc_sigmask, sizeof(set)))
+                do_exit(SIGSEGV);
+        restore_sigmask(&set);
+        if (restore_sigcontext(regs, NULL, 0, &new_ctx->uc_mcontext))
+                do_exit(SIGSEGV);
+
+        /* This returns like rt_sigreturn */
+        return 0;
+}
+
+
+/*
+ * Do a signal return; undo the signal stack.
+ */
+
+int sys_rt_sigreturn(unsigned long r3, unsigned long r4, unsigned long r5,
+                     unsigned long r6, unsigned long r7, unsigned long r8,
+                     struct pt_regs *regs)
+{
+        struct ucontext __user *uc = (struct ucontext __user *)regs->gpr[1];
+        sigset_t set;
+
+        /* Always make any pending restarted system calls return -EINTR */
+        current_thread_info()->restart_block.fn = do_no_restart_syscall;
+
+        if (!access_ok(VERIFY_READ, uc, sizeof(*uc)))
+                goto badframe;
+
+        if (__copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
+                goto badframe;
+        restore_sigmask(&set);
+        if (restore_sigcontext(regs, NULL, 1, &uc->uc_mcontext))
+                goto badframe;
+
+        /* do_sigaltstack expects a __user pointer and won't modify
+         * what's in there anyway
+         */
+        do_sigaltstack(&uc->uc_stack, NULL, regs->gpr[1]);
+
+        return regs->result;
+
+badframe:
+#if DEBUG_SIG
+        printk("badframe in sys_rt_sigreturn, regs=%p uc=%p &uc->uc_mcontext=%p\n",
+               regs, uc, &uc->uc_mcontext);
+#endif
+        force_sig(SIGSEGV, current);
+        return 0;
+}
+
+static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
+                sigset_t *set, struct pt_regs *regs)
+{
+        /* Handler is *really* a pointer to the function descriptor for
+         * the signal routine.  The first entry in the function
+         * descriptor is the entry address of signal and the second
+         * entry is the TOC value we need to use.
+         */
+        func_descr_t __user *funct_desc_ptr;
+        struct rt_sigframe __user *frame;
+        unsigned long newsp = 0;
+        long err = 0;
+
+        frame = get_sigframe(ka, regs, sizeof(*frame));
+
+        if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
+                goto badframe;
+
+        err |= __put_user(&frame->info, &frame->pinfo);
+        err |= __put_user(&frame->uc, &frame->puc);
+        err |= copy_siginfo_to_user(&frame->info, info);
+        if (err)
+                goto badframe;
+
+        /* Create the ucontext.  */
+        err |= __put_user(0, &frame->uc.uc_flags);
+        err |= __put_user(0, &frame->uc.uc_link);
+        err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
+        err |= __put_user(sas_ss_flags(regs->gpr[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, regs, signr, NULL,
+                                (unsigned long)ka->sa.sa_handler);
+        err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
+        if (err)
+                goto badframe;
+
+        /* Set up to return from userspace. */
+        if (vdso64_rt_sigtramp && current->thread.vdso_base) {
+                regs->link = current->thread.vdso_base + vdso64_rt_sigtramp;
+        } else {
+                err |= setup_trampoline(__NR_rt_sigreturn, &frame->tramp[0]);
+                if (err)
+                        goto badframe;
+                regs->link = (unsigned long) &frame->tramp[0];
+        }
+        funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;
+
+        /* Allocate a dummy caller frame for the signal handler. */
+        newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;
+        err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);
+
+        /* Set up "regs" so we "return" to the signal handler. */
+        err |= get_user(regs->nip, &funct_desc_ptr->entry);
+        regs->gpr[1] = newsp;
+        err |= get_user(regs->gpr[2], &funct_desc_ptr->toc);
+        regs->gpr[3] = signr;
+        regs->result = 0;
+        if (ka->sa.sa_flags & SA_SIGINFO) {
+                err |= get_user(regs->gpr[4], (unsigned long __user *)&frame->pinfo);
+                err |= get_user(regs->gpr[5], (unsigned long __user *)&frame->puc);
+                regs->gpr[6] = (unsigned long) frame;
+        } else {
+                regs->gpr[4] = (unsigned long)&frame->uc.uc_mcontext;
+        }
+        if (err)
+                goto badframe;
+
+        if (test_thread_flag(TIF_SINGLESTEP))
+                ptrace_notify(SIGTRAP);
+
+        return 1;
+
+badframe:
+#if DEBUG_SIG
+        printk("badframe in setup_rt_frame, regs=%p frame=%p newsp=%lx\n",
+               regs, frame, newsp);
+#endif
+        force_sigsegv(signr, current);
+        return 0;
+}
+
+
+/*
+ * OK, we're invoking a handler
+ */
+static int handle_signal(unsigned long sig, struct k_sigaction *ka,
+                         siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)
+{
+        int ret;
+
+        /* Set up Signal Frame */
+        ret = setup_rt_frame(sig, ka, info, oldset, regs);
+
+        if (ret) {
+                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;
+}
+
+static inline void syscall_restart(struct pt_regs *regs, struct k_sigaction *ka)
+{
+        switch ((int)regs->result) {
+        case -ERESTART_RESTARTBLOCK:
+        case -ERESTARTNOHAND:
+                /* ERESTARTNOHAND means that the syscall should only be
+                 * restarted if there was no handler for the signal, and since
+                 * we only get here if there is a handler, we dont restart.
+                 */
+                regs->result = -EINTR;
+                break;
+        case -ERESTARTSYS:
+                /* ERESTARTSYS means to restart the syscall if there is no
+                 * handler or the handler was registered with SA_RESTART
+                 */
+                if (!(ka->sa.sa_flags & SA_RESTART)) {
+                        regs->result = -EINTR;
+                        break;
+                }
+                /* fallthrough */
+        case -ERESTARTNOINTR:
+                /* ERESTARTNOINTR means that the syscall should be
+                 * called again after the signal handler returns.
+                 */
+                regs->gpr[3] = regs->orig_gpr3;
+                regs->nip -= 4;
+                regs->result = 0;
+                break;
+        }
+}
+
+/*
+ * 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.
+ */
+int do_signal(sigset_t *oldset, struct pt_regs *regs)
+{
+        siginfo_t info;
+        int signr;
+        struct k_sigaction ka;
+
+        /*
+         * If the current thread is 32 bit - invoke the
+         * 32 bit signal handling code
+         */
+        if (test_thread_flag(TIF_32BIT))
+                return do_signal32(oldset, regs);
+
+        if (!oldset)
+                oldset = &current->blocked;
+
+        signr = get_signal_to_deliver(&info, &ka, regs, NULL);
+        if (signr > 0) {
+                /* Whee!  Actually deliver the signal.  */
+                if (TRAP(regs) == 0x0C00)
+                        syscall_restart(regs, &ka);
+
+                /*
+                 * Reenable the DABR before delivering the signal to
+                 * user space. The DABR will have been cleared if it
+                 * triggered inside the kernel.
+                 */
+                if (current->thread.dabr)
+                        set_dabr(current->thread.dabr);
+
+                return handle_signal(signr, &ka, &info, oldset, regs);
+        }
+
+        if (TRAP(regs) == 0x0C00) {     /* System Call! */
+                if ((int)regs->result == -ERESTARTNOHAND ||
+                    (int)regs->result == -ERESTARTSYS ||
+                    (int)regs->result == -ERESTARTNOINTR) {
+                        regs->gpr[3] = regs->orig_gpr3;
+                        regs->nip -= 4; /* Back up & retry system call */
+                        regs->result = 0;
+                } else if ((int)regs->result == -ERESTART_RESTARTBLOCK) {
+                        regs->gpr[0] = __NR_restart_syscall;
+                        regs->nip -= 4;
+                        regs->result = 0;
+                }
+        }
+
+        return 0;
+}
+EXPORT_SYMBOL(do_signal);