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    Subject[PATCH v5 14/36] Hexagon: Add signal functions
    Signed-off-by: Richard Kuo <rkuo@codeaurora.org>
    Signed-off-by: Linas Vepstas <linas@codeaurora.org>
    Acked-by: Arnd Bergmann <arnd@arndb.de>
    ---
    arch/hexagon/include/asm/sigcontext.h | 33 +++
    arch/hexagon/include/asm/signal.h | 26 +++
    arch/hexagon/include/asm/vdso.h | 31 +++
    arch/hexagon/kernel/signal.c | 345 +++++++++++++++++++++++++++++++++
    arch/hexagon/kernel/trampoline.S | 35 ++++
    arch/hexagon/kernel/vdso.c | 101 ++++++++++
    6 files changed, 571 insertions(+), 0 deletions(-)
    create mode 100644 arch/hexagon/include/asm/sigcontext.h
    create mode 100644 arch/hexagon/include/asm/signal.h
    create mode 100644 arch/hexagon/include/asm/vdso.h
    create mode 100644 arch/hexagon/kernel/signal.c
    create mode 100644 arch/hexagon/kernel/trampoline.S
    create mode 100644 arch/hexagon/kernel/vdso.c

    diff --git a/arch/hexagon/include/asm/sigcontext.h b/arch/hexagon/include/asm/sigcontext.h
    new file mode 100644
    index 0000000..ce6dcd9
    --- /dev/null
    +++ b/arch/hexagon/include/asm/sigcontext.h
    @@ -0,0 +1,33 @@
    +/*
    + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +#ifndef _ASM_SIGCONTEXT_H
    +#define _ASM_SIGCONTEXT_H
    +
    +#include <asm/user.h>
    +
    +/*
    + * Signal context structure - contains all info to do with the state
    + * before the signal handler was invoked. Note: only add new entries
    + * to the end of the structure.
    + */
    +struct sigcontext {
    + struct user_regs_struct sc_regs;
    +} __aligned(8);
    +
    +#endif
    diff --git a/arch/hexagon/include/asm/signal.h b/arch/hexagon/include/asm/signal.h
    new file mode 100644
    index 0000000..471c056
    --- /dev/null
    +++ b/arch/hexagon/include/asm/signal.h
    @@ -0,0 +1,26 @@
    +/*
    + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +#ifndef _ASM_SIGNAL_H
    +#define _ASM_SIGNAL_H
    +
    +extern unsigned long __rt_sigtramp_template[2];
    +
    +#include <asm-generic/signal.h>
    +
    +#endif
    diff --git a/arch/hexagon/include/asm/vdso.h b/arch/hexagon/include/asm/vdso.h
    new file mode 100644
    index 0000000..2e429a3
    --- /dev/null
    +++ b/arch/hexagon/include/asm/vdso.h
    @@ -0,0 +1,31 @@
    +/*
    + * vDSO implementation for Hexagon
    + *
    + * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +#ifndef __ASM_VDSO_H
    +#define __ASM_VDSO_H
    +
    +#include <linux/types.h>
    +
    +struct hexagon_vdso {
    + u32 rt_signal_trampoline[2];
    +};
    +
    +#endif /* __ASM_VDSO_H */
    +
    diff --git a/arch/hexagon/kernel/signal.c b/arch/hexagon/kernel/signal.c
    new file mode 100644
    index 0000000..b45be31
    --- /dev/null
    +++ b/arch/hexagon/kernel/signal.c
    @@ -0,0 +1,345 @@
    +/*
    + * Signal support for Hexagon processor
    + *
    + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +#include <linux/linkage.h>
    +#include <linux/syscalls.h>
    +#include <linux/freezer.h>
    +#include <linux/tracehook.h>
    +#include <asm/registers.h>
    +#include <asm/thread_info.h>
    +#include <asm/unistd.h>
    +#include <asm/uaccess.h>
    +#include <asm/ucontext.h>
    +#include <asm/cacheflush.h>
    +#include <asm/signal.h>
    +#include <asm/vdso.h>
    +
    +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
    +
    +struct rt_sigframe {
    + unsigned long tramp[2];
    + struct siginfo info;
    + struct ucontext uc;
    +};
    +
    +static void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
    + size_t frame_size)
    +{
    + unsigned long sp = regs->r29;
    +
    + /* Switch to signal stack if appropriate */
    + if ((ka->sa.sa_flags & SA_ONSTACK) && (sas_ss_flags(sp) == 0))
    + sp = current->sas_ss_sp + current->sas_ss_size;
    +
    + return (void __user *)((sp - frame_size) & ~(sizeof(long long) - 1));
    +}
    +
    +static int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
    +{
    + unsigned long tmp;
    + int err = 0;
    +
    + err |= copy_to_user(&sc->sc_regs.r0, &regs->r00,
    + 32*sizeof(unsigned long));
    +
    + err |= __put_user(regs->sa0, &sc->sc_regs.sa0);
    + err |= __put_user(regs->lc0, &sc->sc_regs.lc0);
    + err |= __put_user(regs->sa1, &sc->sc_regs.sa1);
    + err |= __put_user(regs->lc1, &sc->sc_regs.lc1);
    + err |= __put_user(regs->m0, &sc->sc_regs.m0);
    + err |= __put_user(regs->m1, &sc->sc_regs.m1);
    + err |= __put_user(regs->usr, &sc->sc_regs.usr);
    + err |= __put_user(regs->preds, &sc->sc_regs.p3_0);
    + err |= __put_user(regs->gp, &sc->sc_regs.gp);
    + err |= __put_user(regs->ugp, &sc->sc_regs.ugp);
    +
    + tmp = pt_elr(regs); err |= __put_user(tmp, &sc->sc_regs.pc);
    + tmp = pt_cause(regs); err |= __put_user(tmp, &sc->sc_regs.cause);
    + tmp = pt_badva(regs); err |= __put_user(tmp, &sc->sc_regs.badva);
    +
    + return err;
    +}
    +
    +static int restore_sigcontext(struct pt_regs *regs,
    + struct sigcontext __user *sc)
    +{
    + unsigned long tmp;
    + int err = 0;
    +
    + err |= copy_from_user(&regs->r00, &sc->sc_regs.r0,
    + 32 * sizeof(unsigned long));
    +
    + err |= __get_user(regs->sa0, &sc->sc_regs.sa0);
    + err |= __get_user(regs->lc0, &sc->sc_regs.lc0);
    + err |= __get_user(regs->sa1, &sc->sc_regs.sa1);
    + err |= __get_user(regs->lc1, &sc->sc_regs.lc1);
    + err |= __get_user(regs->m0, &sc->sc_regs.m0);
    + err |= __get_user(regs->m1, &sc->sc_regs.m1);
    + err |= __get_user(regs->usr, &sc->sc_regs.usr);
    + err |= __get_user(regs->preds, &sc->sc_regs.p3_0);
    + err |= __get_user(regs->gp, &sc->sc_regs.gp);
    + err |= __get_user(regs->ugp, &sc->sc_regs.ugp);
    +
    + err |= __get_user(tmp, &sc->sc_regs.pc); pt_set_elr(regs, tmp);
    +
    + return err;
    +}
    +
    +/*
    + * Setup signal stack frame with siginfo structure
    + */
    +static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
    + sigset_t *set, struct pt_regs *regs)
    +{
    + int err = 0;
    + struct rt_sigframe __user *frame;
    + struct hexagon_vdso *vdso = current->mm->context.vdso;
    +
    + frame = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
    +
    + if (!access_ok(VERIFY_WRITE, frame, sizeof(struct rt_sigframe)))
    + goto sigsegv;
    +
    + if (copy_siginfo_to_user(&frame->info, info))
    + goto sigsegv;
    +
    + /* The on-stack signal trampoline is no longer executed;
    + * however, the libgcc signal frame unwinding code checks for
    + * the presence of these two numeric magic values.
    + */
    + err |= __put_user(0x7800d166, &frame->tramp[0]);
    + err |= __put_user(0x5400c004, &frame->tramp[1]);
    + err |= setup_sigcontext(regs, &frame->uc.uc_mcontext);
    + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
    + if (err)
    + goto sigsegv;
    +
    + /* Load r0/r1 pair with signumber/siginfo pointer... */
    + regs->r0100 = ((unsigned long long)((unsigned long)&frame->info) << 32)
    + | (unsigned long long)signr;
    + regs->r02 = (unsigned long) &frame->uc;
    + regs->r31 = (unsigned long) vdso->rt_signal_trampoline;
    + pt_psp(regs) = (unsigned long) frame;
    + pt_set_elr(regs, (unsigned long)ka->sa.sa_handler);
    +
    + return 0;
    +
    +sigsegv:
    + force_sigsegv(signr, current);
    + return -EFAULT;
    +}
    +
    +/*
    + * Setup invocation of signal handler
    + */
    +static int handle_signal(int sig, siginfo_t *info, struct k_sigaction *ka,
    + sigset_t *oldset, struct pt_regs *regs)
    +{
    + int rc;
    +
    + /*
    + * If we're handling a signal that aborted a system call,
    + * set up the error return value before adding the signal
    + * frame to the stack.
    + */
    +
    + if (regs->syscall_nr >= 0) {
    + switch (regs->r00) {
    + case -ERESTART_RESTARTBLOCK:
    + case -ERESTARTNOHAND:
    + regs->r00 = -EINTR;
    + break;
    + case -ERESTARTSYS:
    + if (!(ka->sa.sa_flags & SA_RESTART)) {
    + regs->r00 = -EINTR;
    + break;
    + }
    + /* Fall through */
    + case -ERESTARTNOINTR:
    + regs->r06 = regs->syscall_nr;
    + pt_set_elr(regs, pt_elr(regs) - 4);
    + regs->r00 = regs->restart_r0;
    + break;
    + default:
    + break;
    + }
    + }
    +
    + /*
    + * Set up the stack frame; not doing the SA_SIGINFO thing. We
    + * only set up the rt_frame flavor.
    + */
    + rc = setup_rt_frame(sig, ka, info, oldset, regs);
    +
    + /* If there was an error on setup, no signal was delivered. */
    + if (rc)
    + return rc;
    +
    + 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 0;
    +}
    +
    +/*
    + * Called from return-from-event code.
    + */
    +static void do_signal(struct pt_regs *regs)
    +{
    + struct k_sigaction sigact;
    + siginfo_t info;
    + int signo;
    +
    + if (!user_mode(regs))
    + return;
    +
    + if (try_to_freeze())
    + goto no_signal;
    +
    + signo = get_signal_to_deliver(&info, &sigact, regs, NULL);
    +
    + if (signo > 0) {
    + sigset_t *oldset;
    +
    + if (test_thread_flag(TIF_RESTORE_SIGMASK))
    + oldset = &current->saved_sigmask;
    + else
    + oldset = &current->blocked;
    +
    + if (handle_signal(signo, &info, &sigact, oldset, regs) == 0) {
    + /*
    + * Successful delivery case. The saved sigmask is
    + * stored in the signal frame, and will be restored
    + * by sigreturn. We can clear the TIF flag.
    + */
    + clear_thread_flag(TIF_RESTORE_SIGMASK);
    +
    + tracehook_signal_handler(signo, &info, &sigact, regs,
    + test_thread_flag(TIF_SINGLESTEP));
    + }
    + return;
    + }
    +
    +no_signal:
    + /*
    + * If we came from a system call, handle the restart.
    + */
    + if (regs->syscall_nr >= 0) {
    + switch (regs->r00) {
    + case -ERESTARTNOHAND:
    + case -ERESTARTSYS:
    + case -ERESTARTNOINTR:
    + regs->r06 = regs->syscall_nr;
    + break;
    + case -ERESTART_RESTARTBLOCK:
    + regs->r06 = __NR_restart_syscall;
    + break;
    + default:
    + goto no_restart;
    + }
    + pt_set_elr(regs, pt_elr(regs) - 4);
    + regs->r00 = regs->restart_r0;
    + }
    +
    +no_restart:
    + /* If there's no signal to deliver, 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);
    + }
    +}
    +
    +void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
    +{
    + if (thread_info_flags & _TIF_SIGPENDING)
    + do_signal(regs);
    +
    + if (thread_info_flags & _TIF_NOTIFY_RESUME) {
    + clear_thread_flag(TIF_NOTIFY_RESUME);
    + if (current->replacement_session_keyring)
    + key_replace_session_keyring();
    + }
    +}
    +
    +/*
    + * Architecture-specific wrappers for signal-related system calls
    + */
    +asmlinkage int sys_sigaltstack(const stack_t __user *uss, stack_t __user *uoss)
    +{
    + struct pt_regs *regs = current_thread_info()->regs;
    +
    + return do_sigaltstack(uss, uoss, regs->r29);
    +}
    +
    +asmlinkage int sys_rt_sigreturn(void)
    +{
    + struct pt_regs *regs = current_thread_info()->regs;
    + struct rt_sigframe __user *frame;
    + sigset_t blocked;
    +
    + frame = (struct rt_sigframe __user *)pt_psp(regs);
    + if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
    + goto badframe;
    + if (__copy_from_user(&blocked, &frame->uc.uc_sigmask, sizeof(blocked)))
    + goto badframe;
    +
    + sigdelsetmask(&blocked, ~_BLOCKABLE);
    + spin_lock_irq(&current->sighand->siglock);
    + current->blocked = blocked;
    + recalc_sigpending();
    + spin_unlock_irq(&current->sighand->siglock);
    +
    + if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
    + goto badframe;
    +
    + /* Restore the user's stack as well */
    + pt_psp(regs) = regs->r29;
    +
    + /*
    + * Leave a trace in the stack frame that this was a sigreturn.
    + * If the system call is to replay, we've already restored the
    + * number in the GPR slot and it will be regenerated on the
    + * new system call trap entry. Note that if restore_sigcontext()
    + * did something other than a bulk copy of the pt_regs struct,
    + * we could avoid this assignment by simply not overwriting
    + * regs->syscall_nr.
    + */
    + regs->syscall_nr = __NR_rt_sigreturn;
    +
    + /*
    + * If we were meticulous, we'd only call this if we knew that
    + * we were actually going to use an alternate stack, and we'd
    + * consider any error to be fatal. What we do here, in common
    + * with many other architectures, is call it blindly and only
    + * consider the -EFAULT return case to be proof of a problem.
    + */
    + if (do_sigaltstack(&frame->uc.uc_stack, NULL, pt_psp(regs)) == -EFAULT)
    + goto badframe;
    +
    + return 0;
    +
    +badframe:
    + force_sig(SIGSEGV, current);
    + return 0;
    +}
    diff --git a/arch/hexagon/kernel/trampoline.S b/arch/hexagon/kernel/trampoline.S
    new file mode 100644
    index 0000000..06c36c0
    --- /dev/null
    +++ b/arch/hexagon/kernel/trampoline.S
    @@ -0,0 +1,35 @@
    +/*
    + * Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +/*
    + * Trampoline sequences to be copied onto user stack.
    + * This consumes a little more space than hand-assembling
    + * immediate constants for use in C, but is more portable
    + * to future tweaks to the Hexagon instruction set.
    + */
    +
    +#include <asm/unistd.h>
    +
    +/* Sig trampolines - call sys_sigreturn or sys_rt_sigreturn as appropriate */
    +
    +/* plain sigreturn is gone. */
    +
    + .globl __rt_sigtramp_template
    +__rt_sigtramp_template:
    + r6 = #__NR_rt_sigreturn;
    + trap0(#1);
    diff --git a/arch/hexagon/kernel/vdso.c b/arch/hexagon/kernel/vdso.c
    new file mode 100644
    index 0000000..5ae4134
    --- /dev/null
    +++ b/arch/hexagon/kernel/vdso.c
    @@ -0,0 +1,101 @@
    +/*
    + * vDSO implementation for Hexagon
    + *
    + * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 and
    + * only version 2 as published by the Free Software Foundation.
    + *
    + * 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, write to the Free Software
    + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
    + * 02110-1301, USA.
    + */
    +
    +#include <linux/err.h>
    +#include <linux/mm.h>
    +#include <linux/vmalloc.h>
    +
    +#include <asm/vdso.h>
    +
    +static struct page *vdso_page;
    +
    +/* Create a vDSO page holding the signal trampoline.
    + * We want this for a non-executable stack.
    + */
    +static int __init vdso_init(void)
    +{
    + struct hexagon_vdso *vdso;
    +
    + vdso_page = alloc_page(GFP_KERNEL);
    + if (!vdso_page)
    + panic("Cannot allocate vdso");
    +
    + vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL);
    + if (!vdso)
    + panic("Cannot map vdso");
    + clear_page(vdso);
    +
    + /* Install the signal trampoline; currently looks like this:
    + * r6 = #__NR_rt_sigreturn;
    + * trap0(#1);
    + */
    + vdso->rt_signal_trampoline[0] = __rt_sigtramp_template[0];
    + vdso->rt_signal_trampoline[1] = __rt_sigtramp_template[1];
    +
    + vunmap(vdso);
    +
    + return 0;
    +}
    +arch_initcall(vdso_init);
    +
    +/*
    + * Called from binfmt_elf. Create a VMA for the vDSO page.
    + */
    +int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
    +{
    + int ret;
    + unsigned long vdso_base;
    + struct mm_struct *mm = current->mm;
    +
    + down_write(&mm->mmap_sem);
    +
    + /* Try to get it loaded right near ld.so/glibc. */
    + vdso_base = STACK_TOP;
    +
    + vdso_base = get_unmapped_area(NULL, vdso_base, PAGE_SIZE, 0, 0);
    + if (IS_ERR_VALUE(vdso_base)) {
    + ret = vdso_base;
    + goto up_fail;
    + }
    +
    + /* MAYWRITE to allow gdb to COW and set breakpoints. */
    + ret = install_special_mapping(mm, vdso_base, PAGE_SIZE,
    + VM_READ|VM_EXEC|
    + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC|
    + VM_ALWAYSDUMP,
    + &vdso_page);
    +
    + if (ret)
    + goto up_fail;
    +
    + mm->context.vdso = (void *)vdso_base;
    +
    +up_fail:
    + up_write(&mm->mmap_sem);
    + return ret;
    +}
    +
    +const char *arch_vma_name(struct vm_area_struct *vma)
    +{
    + if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
    + return "[vdso]";
    + return NULL;
    +}
    +
    --
    1.7.1

    --

    Sent by an employee of the Qualcomm Innovation Center, Inc.
    The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum.


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