[PATCH v3 10/24] C6X: signal management

From: Mark Salter
Date: Tue Sep 27 2011 - 16:35:35 EST

Signed-off-by: Mark Salter <msalter@xxxxxxxxxx>
---
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@xxxxxxxxxx)
+ *
+ * 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..304f675
--- /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@xxxxxxxxxx)
+ *
+ * Updated for 2.6.34: Mark Salter <msalter@xxxxxxxxxx>
+ *
+ * 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@xxxxxxxxxxxxxxxxxxxxxx> 2000-12-06
+ */
+ regs->b4 = (unsigned long)&frame->info;
+ regs->a6 = (unsigned long)&frame->uc;
+
+ return 0;
+
+segv_and_exit:
+ force_sigsegv(signr, 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();
+ }
+}
--
1.7.6.2

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