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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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