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    Subject[PATCHv2 11/11] unicore32 core architecture: signals handling
    Date
    This patch implements signals.

    Signed-off-by: Guan Xuetao <gxt@mprc.pku.edu.cn>
    ---
    arch/unicore32/include/asm/sigcontext.h | 29 ++
    arch/unicore32/kernel/signal.c | 494 +++++++++++++++++++++++++++++++
    2 files changed, 523 insertions(+), 0 deletions(-)
    create mode 100644 arch/unicore32/include/asm/sigcontext.h
    create mode 100644 arch/unicore32/kernel/signal.c

    diff --git a/arch/unicore32/include/asm/sigcontext.h b/arch/unicore32/include/asm/sigcontext.h
    new file mode 100644
    index 0000000..6a2d767
    --- /dev/null
    +++ b/arch/unicore32/include/asm/sigcontext.h
    @@ -0,0 +1,29 @@
    +/*
    + * linux/arch/unicore32/include/asm/sigcontext.h
    + *
    + * Code specific to PKUnity SoC and UniCore ISA
    + *
    + * Copyright (C) 2001-2010 GUAN Xue-tao
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + */
    +#ifndef __UNICORE_SIGCONTEXT_H__
    +#define __UNICORE_SIGCONTEXT_H__
    +
    +#include <asm/ptrace.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 {
    + unsigned long trap_no;
    + unsigned long error_code;
    + unsigned long oldmask;
    + unsigned long fault_address;
    + struct pt_regs regs;
    +};
    +
    +#endif
    diff --git a/arch/unicore32/kernel/signal.c b/arch/unicore32/kernel/signal.c
    new file mode 100644
    index 0000000..b163fca
    --- /dev/null
    +++ b/arch/unicore32/kernel/signal.c
    @@ -0,0 +1,494 @@
    +/*
    + * linux/arch/unicore32/kernel/signal.c
    + *
    + * Code specific to PKUnity SoC and UniCore ISA
    + *
    + * Copyright (C) 2001-2010 GUAN Xue-tao
    + *
    + * This program is free software; you can redistribute it and/or modify
    + * it under the terms of the GNU General Public License version 2 as
    + * published by the Free Software Foundation.
    + */
    +#include <linux/errno.h>
    +#include <linux/signal.h>
    +#include <linux/personality.h>
    +#include <linux/freezer.h>
    +#include <linux/uaccess.h>
    +#include <linux/tracehook.h>
    +#include <linux/elf.h>
    +#include <linux/unistd.h>
    +
    +#include <asm/cacheflush.h>
    +#include <asm/ucontext.h>
    +
    +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
    +
    +/*
    + * For UniCore syscalls, we encode the syscall number into the instruction.
    + */
    +#define SWI_SYS_SIGRETURN (0xff000000) /* error number for new abi */
    +#define SWI_SYS_RT_SIGRETURN (0xff000000 | (__NR_rt_sigreturn))
    +#define SWI_SYS_RESTART (0xff000000 | (__NR_restart_syscall))
    +
    +#define KERN_SIGRETURN_CODE (KUSER_VECPAGE_BASE + 0x00000500)
    +#define KERN_RESTART_CODE (KERN_SIGRETURN_CODE + sizeof(sigreturn_codes))
    +
    +const unsigned long sigreturn_codes[3] = {
    + SWI_SYS_SIGRETURN, SWI_SYS_RT_SIGRETURN,
    +};
    +
    +const unsigned long syscall_restart_code[2] = {
    + SWI_SYS_RESTART, /* swi __NR_restart_syscall */
    + 0x69efc004, /* ldr pc, [sp], #4 */
    +};
    +
    +/*
    + * Do a signal return; undo the signal stack. These are aligned to 64-bit.
    + */
    +struct sigframe {
    + struct ucontext uc;
    + unsigned long retcode[2];
    +};
    +
    +struct rt_sigframe {
    + struct siginfo info;
    + struct sigframe sig;
    +};
    +
    +static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
    +{
    + sigset_t set;
    + int err;
    +
    + err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
    + if (err == 0) {
    + sigdelsetmask(&set, ~_BLOCKABLE);
    + spin_lock_irq(&current->sighand->siglock);
    + current->blocked = set;
    + recalc_sigpending();
    + spin_unlock_irq(&current->sighand->siglock);
    + }
    +
    + err |= __get_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00);
    + err |= __get_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01);
    + err |= __get_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02);
    + err |= __get_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03);
    + err |= __get_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04);
    + err |= __get_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05);
    + err |= __get_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06);
    + err |= __get_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07);
    + err |= __get_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08);
    + err |= __get_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09);
    + err |= __get_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10);
    + err |= __get_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11);
    + err |= __get_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12);
    + err |= __get_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13);
    + err |= __get_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14);
    + err |= __get_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15);
    + err |= __get_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16);
    + err |= __get_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17);
    + err |= __get_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18);
    + err |= __get_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19);
    + err |= __get_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20);
    + err |= __get_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21);
    + err |= __get_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22);
    + err |= __get_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23);
    + err |= __get_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24);
    + err |= __get_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25);
    + err |= __get_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26);
    + err |= __get_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp);
    + err |= __get_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip);
    + err |= __get_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp);
    + err |= __get_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr);
    + err |= __get_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc);
    + err |= __get_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr);
    +
    + err |= !valid_user_regs(regs);
    +
    + return err;
    +}
    +
    +asmlinkage int __sys_rt_sigreturn(struct pt_regs *regs)
    +{
    + struct rt_sigframe __user *frame;
    +
    + /* Always make any pending restarted system calls return -EINTR */
    + current_thread_info()->restart_block.fn = do_no_restart_syscall;
    +
    + /*
    + * Since we stacked the signal on a 64-bit boundary,
    + * then 'sp' should be word aligned here. If it's
    + * not, then the user is trying to mess with us.
    + */
    + if (regs->UCreg_sp & 7)
    + goto badframe;
    +
    + frame = (struct rt_sigframe __user *)regs->UCreg_sp;
    +
    + if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
    + goto badframe;
    +
    + if (restore_sigframe(regs, &frame->sig))
    + goto badframe;
    +
    + if (do_sigaltstack(&frame->sig.uc.uc_stack, NULL, regs->UCreg_sp)
    + == -EFAULT)
    + goto badframe;
    +
    + return regs->UCreg_00;
    +
    +badframe:
    + force_sig(SIGSEGV, current);
    + return 0;
    +}
    +
    +static int setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs,
    + sigset_t *set)
    +{
    + int err = 0;
    +
    + err |= __put_user(regs->UCreg_00, &sf->uc.uc_mcontext.regs.UCreg_00);
    + err |= __put_user(regs->UCreg_01, &sf->uc.uc_mcontext.regs.UCreg_01);
    + err |= __put_user(regs->UCreg_02, &sf->uc.uc_mcontext.regs.UCreg_02);
    + err |= __put_user(regs->UCreg_03, &sf->uc.uc_mcontext.regs.UCreg_03);
    + err |= __put_user(regs->UCreg_04, &sf->uc.uc_mcontext.regs.UCreg_04);
    + err |= __put_user(regs->UCreg_05, &sf->uc.uc_mcontext.regs.UCreg_05);
    + err |= __put_user(regs->UCreg_06, &sf->uc.uc_mcontext.regs.UCreg_06);
    + err |= __put_user(regs->UCreg_07, &sf->uc.uc_mcontext.regs.UCreg_07);
    + err |= __put_user(regs->UCreg_08, &sf->uc.uc_mcontext.regs.UCreg_08);
    + err |= __put_user(regs->UCreg_09, &sf->uc.uc_mcontext.regs.UCreg_09);
    + err |= __put_user(regs->UCreg_10, &sf->uc.uc_mcontext.regs.UCreg_10);
    + err |= __put_user(regs->UCreg_11, &sf->uc.uc_mcontext.regs.UCreg_11);
    + err |= __put_user(regs->UCreg_12, &sf->uc.uc_mcontext.regs.UCreg_12);
    + err |= __put_user(regs->UCreg_13, &sf->uc.uc_mcontext.regs.UCreg_13);
    + err |= __put_user(regs->UCreg_14, &sf->uc.uc_mcontext.regs.UCreg_14);
    + err |= __put_user(regs->UCreg_15, &sf->uc.uc_mcontext.regs.UCreg_15);
    + err |= __put_user(regs->UCreg_16, &sf->uc.uc_mcontext.regs.UCreg_16);
    + err |= __put_user(regs->UCreg_17, &sf->uc.uc_mcontext.regs.UCreg_17);
    + err |= __put_user(regs->UCreg_18, &sf->uc.uc_mcontext.regs.UCreg_18);
    + err |= __put_user(regs->UCreg_19, &sf->uc.uc_mcontext.regs.UCreg_19);
    + err |= __put_user(regs->UCreg_20, &sf->uc.uc_mcontext.regs.UCreg_20);
    + err |= __put_user(regs->UCreg_21, &sf->uc.uc_mcontext.regs.UCreg_21);
    + err |= __put_user(regs->UCreg_22, &sf->uc.uc_mcontext.regs.UCreg_22);
    + err |= __put_user(regs->UCreg_23, &sf->uc.uc_mcontext.regs.UCreg_23);
    + err |= __put_user(regs->UCreg_24, &sf->uc.uc_mcontext.regs.UCreg_24);
    + err |= __put_user(regs->UCreg_25, &sf->uc.uc_mcontext.regs.UCreg_25);
    + err |= __put_user(regs->UCreg_26, &sf->uc.uc_mcontext.regs.UCreg_26);
    + err |= __put_user(regs->UCreg_fp, &sf->uc.uc_mcontext.regs.UCreg_fp);
    + err |= __put_user(regs->UCreg_ip, &sf->uc.uc_mcontext.regs.UCreg_ip);
    + err |= __put_user(regs->UCreg_sp, &sf->uc.uc_mcontext.regs.UCreg_sp);
    + err |= __put_user(regs->UCreg_lr, &sf->uc.uc_mcontext.regs.UCreg_lr);
    + err |= __put_user(regs->UCreg_pc, &sf->uc.uc_mcontext.regs.UCreg_pc);
    + err |= __put_user(regs->UCreg_asr, &sf->uc.uc_mcontext.regs.UCreg_asr);
    +
    + err |= __put_user(current->thread.trap_no,
    + &sf->uc.uc_mcontext.trap_no);
    + err |= __put_user(current->thread.error_code,
    + &sf->uc.uc_mcontext.error_code);
    + err |= __put_user(current->thread.address,
    + &sf->uc.uc_mcontext.fault_address);
    + err |= __put_user(set->sig[0], &sf->uc.uc_mcontext.oldmask);
    +
    + err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
    +
    + return err;
    +}
    +
    +static inline void __user *get_sigframe(struct k_sigaction *ka,
    + struct pt_regs *regs, int framesize)
    +{
    + unsigned long sp = regs->UCreg_sp;
    + void __user *frame;
    +
    + /*
    + * This is the X/Open sanctioned signal stack switching.
    + */
    + if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
    + sp = current->sas_ss_sp + current->sas_ss_size;
    +
    + /*
    + * ATPCS B01 mandates 8-byte alignment
    + */
    + frame = (void __user *)((sp - framesize) & ~7);
    +
    + /*
    + * Check that we can actually write to the signal frame.
    + */
    + if (!access_ok(VERIFY_WRITE, frame, framesize))
    + frame = NULL;
    +
    + return frame;
    +}
    +
    +static int setup_return(struct pt_regs *regs, struct k_sigaction *ka,
    + unsigned long __user *rc, void __user *frame, int usig)
    +{
    + unsigned long handler = (unsigned long)ka->sa.sa_handler;
    + unsigned long retcode;
    + unsigned long asr = regs->UCreg_asr & ~PSR_f;
    +
    + unsigned int idx = 0;
    +
    + if (ka->sa.sa_flags & SA_SIGINFO)
    + idx += 1;
    +
    + if (__put_user(sigreturn_codes[idx], rc) ||
    + __put_user(sigreturn_codes[idx+1], rc+1))
    + return 1;
    +
    + retcode = KERN_SIGRETURN_CODE + (idx << 2);
    +
    + regs->UCreg_00 = usig;
    + regs->UCreg_sp = (unsigned long)frame;
    + regs->UCreg_lr = retcode;
    + regs->UCreg_pc = handler;
    + regs->UCreg_asr = asr;
    +
    + return 0;
    +}
    +
    +static int setup_frame(int usig, struct k_sigaction *ka,
    + sigset_t *set, struct pt_regs *regs)
    +{
    + struct sigframe __user *frame = get_sigframe(ka, regs, sizeof(*frame));
    + int err = 0;
    +
    + if (!frame)
    + return 1;
    +
    + /*
    + * Set uc.uc_flags to a value which sc.trap_no would never have.
    + */
    + err |= __put_user(0x5ac3c35a, &frame->uc.uc_flags);
    +
    + err |= setup_sigframe(frame, regs, set);
    + if (err == 0)
    + err |= setup_return(regs, ka, frame->retcode, frame, usig);
    +
    + return err;
    +}
    +
    +static int setup_rt_frame(int usig, struct k_sigaction *ka, siginfo_t *info,
    + sigset_t *set, struct pt_regs *regs)
    +{
    + struct rt_sigframe __user *frame =
    + get_sigframe(ka, regs, sizeof(*frame));
    + stack_t stack;
    + int err = 0;
    +
    + if (!frame)
    + return 1;
    +
    + err |= copy_siginfo_to_user(&frame->info, info);
    +
    + err |= __put_user(0, &frame->sig.uc.uc_flags);
    + err |= __put_user(NULL, &frame->sig.uc.uc_link);
    +
    + memset(&stack, 0, sizeof(stack));
    + stack.ss_sp = (void __user *)current->sas_ss_sp;
    + stack.ss_flags = sas_ss_flags(regs->UCreg_sp);
    + stack.ss_size = current->sas_ss_size;
    + err |= __copy_to_user(&frame->sig.uc.uc_stack, &stack, sizeof(stack));
    +
    + err |= setup_sigframe(&frame->sig, regs, set);
    + if (err == 0)
    + err |= setup_return(regs, ka, frame->sig.retcode, frame, usig);
    +
    + if (err == 0) {
    + /*
    + * For realtime signals we must also set the second and third
    + * arguments for the signal handler.
    + */
    + regs->UCreg_01 = (unsigned long)&frame->info;
    + regs->UCreg_02 = (unsigned long)&frame->sig.uc;
    + }
    +
    + return err;
    +}
    +
    +static inline void setup_syscall_restart(struct pt_regs *regs)
    +{
    + regs->UCreg_00 = regs->UCreg_ORIG_00;
    + regs->UCreg_pc -= 4;
    +}
    +
    +/*
    + * 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 syscall)
    +{
    + struct thread_info *thread = current_thread_info();
    + struct task_struct *tsk = current;
    + int usig = sig;
    + int ret;
    +
    + /*
    + * If we were from a system call, check for system call restarting...
    + */
    + if (syscall) {
    + switch (regs->UCreg_00) {
    + case -ERESTART_RESTARTBLOCK:
    + case -ERESTARTNOHAND:
    + regs->UCreg_00 = -EINTR;
    + break;
    + case -ERESTARTSYS:
    + if (!(ka->sa.sa_flags & SA_RESTART)) {
    + regs->UCreg_00 = -EINTR;
    + break;
    + }
    + /* fallthrough */
    + case -ERESTARTNOINTR:
    + setup_syscall_restart(regs);
    + }
    + }
    +
    + /*
    + * translate the signal
    + */
    + if (usig < 32 && thread->exec_domain
    + && thread->exec_domain->signal_invmap)
    + usig = thread->exec_domain->signal_invmap[usig];
    +
    + /*
    + * Set up the stack frame
    + */
    + if (ka->sa.sa_flags & SA_SIGINFO)
    + ret = setup_rt_frame(usig, ka, info, oldset, regs);
    + else
    + ret = setup_frame(usig, ka, oldset, regs);
    +
    + /*
    + * Check that the resulting registers are actually sane.
    + */
    + ret |= !valid_user_regs(regs);
    +
    + if (ret != 0) {
    + force_sigsegv(sig, tsk);
    + return ret;
    + }
    +
    + /*
    + * Block the signal if we were successful.
    + */
    + spin_lock_irq(&tsk->sighand->siglock);
    + sigorsets(&tsk->blocked, &tsk->blocked,
    + &ka->sa.sa_mask);
    + if (!(ka->sa.sa_flags & SA_NODEFER))
    + sigaddset(&tsk->blocked, sig);
    + recalc_sigpending();
    + spin_unlock_irq(&tsk->sighand->siglock);
    +
    + return 0;
    +}
    +
    +/*
    + * 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.
    + */
    +static void do_signal(struct pt_regs *regs, int syscall)
    +{
    + struct k_sigaction ka;
    + siginfo_t info;
    + int signr;
    +
    + /*
    + * We want the common case to go fast, which
    + * is why we may in certain cases get here from
    + * kernel mode. Just return without doing anything
    + * if so.
    + */
    + if (!user_mode(regs))
    + return;
    +
    + if (try_to_freeze())
    + goto no_signal;
    +
    + signr = get_signal_to_deliver(&info, &ka, regs, NULL);
    + if (signr > 0) {
    + sigset_t *oldset;
    +
    + if (test_thread_flag(TIF_RESTORE_SIGMASK))
    + oldset = &current->saved_sigmask;
    + else
    + oldset = &current->blocked;
    + if (handle_signal(signr, &ka, &info, oldset, regs, syscall)
    + == 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:
    + /*
    + * No signal to deliver to the process - restart the syscall.
    + */
    + if (syscall) {
    + if (regs->UCreg_00 == -ERESTART_RESTARTBLOCK) {
    + u32 __user *usp;
    +
    + regs->UCreg_sp -= 4;
    + usp = (u32 __user *)regs->UCreg_sp;
    +
    + if (put_user(regs->UCreg_pc, usp) == 0) {
    + regs->UCreg_pc = KERN_RESTART_CODE;
    + } else {
    + regs->UCreg_sp += 4;
    + force_sigsegv(0, current);
    + }
    + }
    + if (regs->UCreg_00 == -ERESTARTNOHAND ||
    + regs->UCreg_00 == -ERESTARTSYS ||
    + regs->UCreg_00 == -ERESTARTNOINTR) {
    + setup_syscall_restart(regs);
    + }
    +
    + /* 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);
    + }
    + }
    +}
    +
    +asmlinkage void do_notify_resume(struct pt_regs *regs,
    + unsigned int thread_flags, int syscall)
    +{
    + if (thread_flags & _TIF_SIGPENDING)
    + do_signal(regs, syscall);
    +
    + if (thread_flags & _TIF_NOTIFY_RESUME) {
    + clear_thread_flag(TIF_NOTIFY_RESUME);
    + tracehook_notify_resume(regs);
    + if (current->replacement_session_keyring)
    + key_replace_session_keyring();
    + }
    +}
    +
    +/*
    + * Copy signal return handlers into the vector page, and
    + * set sigreturn to be a pointer to these.
    + */
    +void __init early_signal_init(void)
    +{
    + memcpy((void *)kuser_vecpage_to_vectors(KERN_SIGRETURN_CODE),
    + sigreturn_codes, sizeof(sigreturn_codes));
    + memcpy((void *)kuser_vecpage_to_vectors(KERN_RESTART_CODE),
    + syscall_restart_code, sizeof(syscall_restart_code));
    + /* Need not to flush icache, since early_trap_init will do it last. */
    +}
    --
    1.7.0.4



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