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    Subject[PATCH 09/24] C6X: signal management
    Date
    Signed-off-by: Mark Salter <msalter@redhat.com>
    ---
    arch/c6x/include/asm/sigcontext.h | 80 ++++++++
    arch/c6x/include/asm/signal.h | 17 ++
    arch/c6x/kernel/signal.c | 377 +++++++++++++++++++++++++++++++++++++
    3 files changed, 474 insertions(+), 0 deletions(-)
    create mode 100644 arch/c6x/include/asm/sigcontext.h
    create mode 100644 arch/c6x/include/asm/signal.h
    create mode 100644 arch/c6x/kernel/signal.c

    diff --git a/arch/c6x/include/asm/sigcontext.h b/arch/c6x/include/asm/sigcontext.h
    new file mode 100644
    index 0000000..eb702f3
    --- /dev/null
    +++ b/arch/c6x/include/asm/sigcontext.h
    @@ -0,0 +1,80 @@
    +/*
    + * Port on Texas Instruments TMS320C6x architecture
    + *
    + * Copyright (C) 2004, 2009 Texas Instruments Incorporated
    + * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
    + *
    + * 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 _ASM_C6X_SIGCONTEXT_H
    +#define _ASM_C6X_SIGCONTEXT_H
    +
    +
    +struct sigcontext {
    + unsigned long sc_mask; /* old sigmask */
    + unsigned long sc_sp; /* old user stack pointer */
    +
    + unsigned long sc_a4;
    + unsigned long sc_b4;
    + unsigned long sc_a6;
    + unsigned long sc_b6;
    + unsigned long sc_a8;
    + unsigned long sc_b8;
    +
    + unsigned long sc_a0;
    + unsigned long sc_a1;
    + unsigned long sc_a2;
    + unsigned long sc_a3;
    + unsigned long sc_a5;
    + unsigned long sc_a7;
    + unsigned long sc_a9;
    +
    + unsigned long sc_b0;
    + unsigned long sc_b1;
    + unsigned long sc_b2;
    + unsigned long sc_b3;
    + unsigned long sc_b5;
    + unsigned long sc_b7;
    + unsigned long sc_b9;
    +
    + unsigned long sc_a16;
    + unsigned long sc_a17;
    + unsigned long sc_a18;
    + unsigned long sc_a19;
    + unsigned long sc_a20;
    + unsigned long sc_a21;
    + unsigned long sc_a22;
    + unsigned long sc_a23;
    + unsigned long sc_a24;
    + unsigned long sc_a25;
    + unsigned long sc_a26;
    + unsigned long sc_a27;
    + unsigned long sc_a28;
    + unsigned long sc_a29;
    + unsigned long sc_a30;
    + unsigned long sc_a31;
    +
    + unsigned long sc_b16;
    + unsigned long sc_b17;
    + unsigned long sc_b18;
    + unsigned long sc_b19;
    + unsigned long sc_b20;
    + unsigned long sc_b21;
    + unsigned long sc_b22;
    + unsigned long sc_b23;
    + unsigned long sc_b24;
    + unsigned long sc_b25;
    + unsigned long sc_b26;
    + unsigned long sc_b27;
    + unsigned long sc_b28;
    + unsigned long sc_b29;
    + unsigned long sc_b30;
    + unsigned long sc_b31;
    +
    + unsigned long sc_csr;
    + unsigned long sc_pc;
    +};
    +
    +#endif /* _ASM_C6X_SIGCONTEXT_H */
    diff --git a/arch/c6x/include/asm/signal.h b/arch/c6x/include/asm/signal.h
    new file mode 100644
    index 0000000..f1cd870
    --- /dev/null
    +++ b/arch/c6x/include/asm/signal.h
    @@ -0,0 +1,17 @@
    +#ifndef _ASM_C6X_SIGNAL_H
    +#define _ASM_C6X_SIGNAL_H
    +
    +#include <asm-generic/signal.h>
    +
    +#ifndef __ASSEMBLY__
    +#include <linux/linkage.h>
    +
    +struct pt_regs;
    +
    +extern asmlinkage int do_rt_sigreturn(struct pt_regs *regs);
    +extern asmlinkage void do_notify_resume(struct pt_regs *regs,
    + u32 thread_info_flags,
    + int syscall);
    +#endif
    +
    +#endif /* _ASM_C6X_SIGNAL_H */
    diff --git a/arch/c6x/kernel/signal.c b/arch/c6x/kernel/signal.c
    new file mode 100644
    index 0000000..89cfabd
    --- /dev/null
    +++ b/arch/c6x/kernel/signal.c
    @@ -0,0 +1,377 @@
    +/*
    + * Port on Texas Instruments TMS320C6x architecture
    + *
    + * Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
    + * Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
    + *
    + * Updated for 2.6.34: Mark Salter <msalter@redhat.com>
    + *
    + * 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/kernel.h>
    +#include <linux/uaccess.h>
    +#include <linux/syscalls.h>
    +#include <linux/tracehook.h>
    +
    +#include <asm/ucontext.h>
    +#include <asm/cacheflush.h>
    +
    +
    +#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
    +
    +/*
    + * Do a signal return, undo the signal stack.
    + */
    +
    +#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
    +
    +struct rt_sigframe {
    + struct siginfo __user *pinfo;
    + void __user *puc;
    + struct siginfo info;
    + struct ucontext uc;
    + unsigned long retcode[RETCODE_SIZE >> 2];
    +};
    +
    +static int restore_sigcontext(struct pt_regs *regs,
    + struct sigcontext __user *sc)
    +{
    + int err = 0;
    +
    + /* The access_ok check was done by caller, so use __get_user here */
    +#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
    +
    + COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
    + COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
    + COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
    +
    + COPY(a16); COPY(a17); COPY(a18); COPY(a19);
    + COPY(a20); COPY(a21); COPY(a22); COPY(a23);
    + COPY(a24); COPY(a25); COPY(a26); COPY(a27);
    + COPY(a28); COPY(a29); COPY(a30); COPY(a31);
    + COPY(b16); COPY(b17); COPY(b18); COPY(b19);
    + COPY(b20); COPY(b21); COPY(b22); COPY(b23);
    + COPY(b24); COPY(b25); COPY(b26); COPY(b27);
    + COPY(b28); COPY(b29); COPY(b30); COPY(b31);
    +
    + COPY(csr); COPY(pc);
    +
    +#undef COPY
    +
    + return err;
    +}
    +
    +asmlinkage int do_rt_sigreturn(struct pt_regs *regs)
    +{
    + struct rt_sigframe __user *frame;
    + sigset_t set;
    +
    + /*
    + * Since we stacked the signal on a dword boundary,
    + * 'sp' should be dword aligned here. If it's
    + * not, then the user is trying to mess with us.
    + */
    + if (regs->sp & 7)
    + goto badframe;
    +
    + frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
    +
    + if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
    + goto badframe;
    + if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
    + goto badframe;
    +
    + sigdelsetmask(&set, ~_BLOCKABLE);
    + spin_lock_irq(&current->sighand->siglock);
    + current->blocked = set;
    + recalc_sigpending();
    + spin_unlock_irq(&current->sighand->siglock);
    +
    + if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
    + goto badframe;
    +
    + return regs->a4;
    +
    +badframe:
    + force_sig(SIGSEGV, current);
    + return 0;
    +}
    +
    +static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
    + unsigned long mask)
    +{
    + int err = 0;
    +
    + err |= __put_user(mask, &sc->sc_mask);
    +
    + /* The access_ok check was done by caller, so use __put_user here */
    +#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
    +
    + COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
    + COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
    + COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
    +
    + COPY(a16); COPY(a17); COPY(a18); COPY(a19);
    + COPY(a20); COPY(a21); COPY(a22); COPY(a23);
    + COPY(a24); COPY(a25); COPY(a26); COPY(a27);
    + COPY(a28); COPY(a29); COPY(a30); COPY(a31);
    + COPY(b16); COPY(b17); COPY(b18); COPY(b19);
    + COPY(b20); COPY(b21); COPY(b22); COPY(b23);
    + COPY(b24); COPY(b25); COPY(b26); COPY(b27);
    + COPY(b28); COPY(b29); COPY(b30); COPY(b31);
    +
    + COPY(csr); COPY(pc);
    +
    +#undef COPY
    +
    + return err;
    +}
    +
    +static inline void __user *get_sigframe(struct k_sigaction *ka,
    + struct pt_regs *regs,
    + unsigned long framesize)
    +{
    + unsigned long sp = regs->sp;
    +
    + /*
    + * This is the X/Open sanctioned signal stack switching.
    + */
    + if ((ka->sa.sa_flags & SA_ONSTACK) && sas_ss_flags(sp) == 0)
    + sp = current->sas_ss_sp + current->sas_ss_size;
    +
    + /*
    + * No matter what happens, 'sp' must be dword
    + * aligned. Otherwise, nasty things will happen
    + */
    + return (void __user *)((sp - framesize) & ~7);
    +}
    +
    +static int setup_rt_frame(int signr, struct k_sigaction *ka, siginfo_t *info,
    + sigset_t *set, struct pt_regs *regs)
    +{
    + struct rt_sigframe __user *frame;
    + unsigned long __user *retcode;
    + int err = 0;
    +
    + frame = get_sigframe(ka, regs, sizeof(*frame));
    +
    + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
    + goto segv_and_exit;
    +
    + err |= __put_user(&frame->info, &frame->pinfo);
    + err |= __put_user(&frame->uc, &frame->puc);
    + err |= copy_siginfo_to_user(&frame->info, info);
    +
    + /* Clear all the bits of the ucontext we don't use. */
    + err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
    +
    + err |= setup_sigcontext(&frame->uc.uc_mcontext, regs, set->sig[0]);
    + err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
    +
    + /* Set up to return from userspace */
    + retcode = (unsigned long __user *) &frame->retcode;
    +
    + /* The access_ok check was done above, so use __put_user here */
    +#define COPY(x) (err |= __put_user(x, retcode++))
    +
    + COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
    + /* MVK __NR_rt_sigreturn,B0 */
    + COPY(0x10000000UL); /* SWE */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    + COPY(0x00006000UL); /* NOP 4 */
    +
    +#undef COPY
    +
    + if (err)
    + goto segv_and_exit;
    +
    + flush_icache_range((unsigned long) &frame->retcode,
    + (unsigned long) &frame->retcode + RETCODE_SIZE);
    +
    + retcode = (unsigned long __user *) &frame->retcode;
    +
    + /* Change user context to branch to signal handler */
    + regs->sp = (unsigned long) frame - 8;
    + regs->b3 = (unsigned long) retcode;
    + regs->pc = (unsigned long) ka->sa.sa_handler;
    +
    + /* Give the signal number to the handler */
    + regs->a4 = signr;
    +
    + /*
    + * For realtime signals we must also set the second and third
    + * arguments for the signal handler.
    + * -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
    + */
    + regs->b4 = (unsigned long)&frame->info;
    + regs->a6 = (unsigned long)&frame->uc;
    +
    + return 0;
    +
    +segv_and_exit:
    + force_sig(SIGSEGV, current);
    + return -EFAULT;
    +}
    +
    +static inline void
    +handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
    +{
    + switch (regs->a4) {
    + case -ERESTARTNOHAND:
    + if (!has_handler)
    + goto do_restart;
    + regs->a4 = -EINTR;
    + break;
    +
    + case -ERESTARTSYS:
    + if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
    + regs->a4 = -EINTR;
    + break;
    + }
    + /* fallthrough */
    + case -ERESTARTNOINTR:
    +do_restart:
    + regs->a4 = regs->orig_a4;
    + regs->pc -= 4;
    + break;
    + }
    +}
    +
    +/*
    + * handle the actual delivery of a signal to userspace
    + */
    +static int handle_signal(int sig,
    + siginfo_t *info, struct k_sigaction *ka,
    + sigset_t *oldset, struct pt_regs *regs,
    + int syscall)
    +{
    + int ret;
    +
    + /* Are we from a system call? */
    + if (syscall) {
    + /* If so, check system call restarting.. */
    + switch (regs->a4) {
    + case -ERESTART_RESTARTBLOCK:
    + case -ERESTARTNOHAND:
    + regs->a4 = -EINTR;
    + break;
    +
    + case -ERESTARTSYS:
    + if (!(ka->sa.sa_flags & SA_RESTART)) {
    + regs->a4 = -EINTR;
    + break;
    + }
    +
    + /* fallthrough */
    + case -ERESTARTNOINTR:
    + regs->a4 = regs->orig_a4;
    + regs->pc -= 4;
    + }
    + }
    +
    + /* Set up the stack frame */
    + ret = setup_rt_frame(sig, ka, info, oldset, regs);
    + if (ret == 0) {
    + 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;
    +}
    +
    +/*
    + * handle a potential signal
    + */
    +static void do_signal(struct pt_regs *regs, int syscall)
    +{
    + struct k_sigaction ka;
    + siginfo_t info;
    + sigset_t *oldset;
    + int signr;
    +
    + /* we want the common case to go fast, which is why we may in certain
    + * cases get here from kernel mode */
    + if (!user_mode(regs))
    + return;
    +
    + if (test_thread_flag(TIF_RESTORE_SIGMASK))
    + oldset = &current->saved_sigmask;
    + else
    + oldset = &current->blocked;
    +
    + signr = get_signal_to_deliver(&info, &ka, regs, NULL);
    + if (signr > 0) {
    + if (handle_signal(signr, &info, &ka, 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);
    +
    + tracehook_signal_handler(signr, &info, &ka, regs, 0);
    + }
    +
    + return;
    + }
    +
    + /* did we come from a system call? */
    + if (syscall) {
    + /* restart the system call - no handlers present */
    + switch (regs->a4) {
    + case -ERESTARTNOHAND:
    + case -ERESTARTSYS:
    + case -ERESTARTNOINTR:
    + regs->a4 = regs->orig_a4;
    + regs->pc -= 4;
    + break;
    +
    + case -ERESTART_RESTARTBLOCK:
    + regs->a4 = regs->orig_a4;
    + regs->b0 = __NR_restart_syscall;
    + regs->pc -= 4;
    + break;
    + }
    + }
    +
    + /* 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);
    + }
    +}
    +
    +/*
    + * notification of userspace execution resumption
    + * - triggered by current->work.notify_resume
    + */
    +asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
    + int syscall)
    +{
    + /* deal with pending signal delivery */
    + if (thread_info_flags & ((1 << TIF_SIGPENDING) |
    + (1 << TIF_RESTORE_SIGMASK)))
    + do_signal(regs, syscall);
    +
    + if (thread_info_flags & (1 << TIF_NOTIFY_RESUME)) {
    + clear_thread_flag(TIF_NOTIFY_RESUME);
    + tracehook_notify_resume(regs);
    + if (current->replacement_session_keyring)
    + key_replace_session_keyring();
    + }
    +}
    --
    1.7.6


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