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-rw-r--r--arch/powerpc/kernel/signal.c381
1 files changed, 381 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
new file mode 100644
index 000000000..a8bb0aca1
--- /dev/null
+++ b/arch/powerpc/kernel/signal.c
@@ -0,0 +1,381 @@
+/*
+ * Common signal handling code for both 32 and 64 bits
+ *
+ * Copyright (c) 2007 Benjamin Herrenschmidt, IBM Corporation
+ * Extracted from signal_32.c and signal_64.c
+ *
+ * This file is subject to the terms and conditions of the GNU General
+ * Public License. See the file README.legal in the main directory of
+ * this archive for more details.
+ */
+
+#include <linux/tracehook.h>
+#include <linux/signal.h>
+#include <linux/uprobes.h>
+#include <linux/key.h>
+#include <linux/context_tracking.h>
+#include <linux/livepatch.h>
+#include <linux/syscalls.h>
+#include <asm/hw_breakpoint.h>
+#include <linux/uaccess.h>
+#include <asm/switch_to.h>
+#include <asm/unistd.h>
+#include <asm/debug.h>
+#include <asm/tm.h>
+
+#include "signal.h"
+
+#ifdef CONFIG_VSX
+unsigned long copy_fpr_to_user(void __user *to,
+ struct task_struct *task)
+{
+ u64 buf[ELF_NFPREG];
+ int i;
+
+ /* save FPR copy to local buffer then write to the thread_struct */
+ for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+ buf[i] = task->thread.TS_FPR(i);
+ buf[i] = task->thread.fp_state.fpscr;
+ return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
+}
+
+unsigned long copy_fpr_from_user(struct task_struct *task,
+ void __user *from)
+{
+ u64 buf[ELF_NFPREG];
+ int i;
+
+ if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
+ return 1;
+ for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+ task->thread.TS_FPR(i) = buf[i];
+ task->thread.fp_state.fpscr = buf[i];
+
+ return 0;
+}
+
+unsigned long copy_vsx_to_user(void __user *to,
+ struct task_struct *task)
+{
+ u64 buf[ELF_NVSRHALFREG];
+ int i;
+
+ /* save FPR copy to local buffer then write to the thread_struct */
+ for (i = 0; i < ELF_NVSRHALFREG; i++)
+ buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
+ return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
+}
+
+unsigned long copy_vsx_from_user(struct task_struct *task,
+ void __user *from)
+{
+ u64 buf[ELF_NVSRHALFREG];
+ int i;
+
+ if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
+ return 1;
+ for (i = 0; i < ELF_NVSRHALFREG ; i++)
+ task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+ return 0;
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+unsigned long copy_ckfpr_to_user(void __user *to,
+ struct task_struct *task)
+{
+ u64 buf[ELF_NFPREG];
+ int i;
+
+ /* save FPR copy to local buffer then write to the thread_struct */
+ for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+ buf[i] = task->thread.TS_CKFPR(i);
+ buf[i] = task->thread.ckfp_state.fpscr;
+ return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
+}
+
+unsigned long copy_ckfpr_from_user(struct task_struct *task,
+ void __user *from)
+{
+ u64 buf[ELF_NFPREG];
+ int i;
+
+ if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
+ return 1;
+ for (i = 0; i < (ELF_NFPREG - 1) ; i++)
+ task->thread.TS_CKFPR(i) = buf[i];
+ task->thread.ckfp_state.fpscr = buf[i];
+
+ return 0;
+}
+
+unsigned long copy_ckvsx_to_user(void __user *to,
+ struct task_struct *task)
+{
+ u64 buf[ELF_NVSRHALFREG];
+ int i;
+
+ /* save FPR copy to local buffer then write to the thread_struct */
+ for (i = 0; i < ELF_NVSRHALFREG; i++)
+ buf[i] = task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET];
+ return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
+}
+
+unsigned long copy_ckvsx_from_user(struct task_struct *task,
+ void __user *from)
+{
+ u64 buf[ELF_NVSRHALFREG];
+ int i;
+
+ if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
+ return 1;
+ for (i = 0; i < ELF_NVSRHALFREG ; i++)
+ task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
+ return 0;
+}
+#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+#else
+inline unsigned long copy_fpr_to_user(void __user *to,
+ struct task_struct *task)
+{
+ return __copy_to_user(to, task->thread.fp_state.fpr,
+ ELF_NFPREG * sizeof(double));
+}
+
+inline unsigned long copy_fpr_from_user(struct task_struct *task,
+ void __user *from)
+{
+ return __copy_from_user(task->thread.fp_state.fpr, from,
+ ELF_NFPREG * sizeof(double));
+}
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+inline unsigned long copy_ckfpr_to_user(void __user *to,
+ struct task_struct *task)
+{
+ return __copy_to_user(to, task->thread.ckfp_state.fpr,
+ ELF_NFPREG * sizeof(double));
+}
+
+inline unsigned long copy_ckfpr_from_user(struct task_struct *task,
+ void __user *from)
+{
+ return __copy_from_user(task->thread.ckfp_state.fpr, from,
+ ELF_NFPREG * sizeof(double));
+}
+#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
+#endif
+
+/* Log an error when sending an unhandled signal to a process. Controlled
+ * through debug.exception-trace sysctl.
+ */
+
+int show_unhandled_signals = 1;
+
+/*
+ * Allocate space for the signal frame
+ */
+void __user *get_sigframe(struct ksignal *ksig, unsigned long sp,
+ size_t frame_size, int is_32)
+{
+ unsigned long oldsp, newsp;
+
+ /* Default to using normal stack */
+ oldsp = get_clean_sp(sp, is_32);
+ oldsp = sigsp(oldsp, ksig);
+ newsp = (oldsp - frame_size) & ~0xFUL;
+
+ /* Check access */
+ if (!access_ok((void __user *)newsp, oldsp - newsp))
+ return NULL;
+
+ return (void __user *)newsp;
+}
+
+static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
+ int has_handler)
+{
+ unsigned long ret = regs->gpr[3];
+ int restart = 1;
+
+ /* syscall ? */
+ if (!trap_is_syscall(regs))
+ return;
+
+ if (trap_norestart(regs))
+ return;
+
+ /* error signalled ? */
+ if (trap_is_scv(regs)) {
+ /* 32-bit compat mode sign extend? */
+ if (!IS_ERR_VALUE(ret))
+ return;
+ ret = -ret;
+ } else if (!(regs->ccr & 0x10000000)) {
+ return;
+ }
+
+ switch (ret) {
+ case ERESTART_RESTARTBLOCK:
+ case ERESTARTNOHAND:
+ /* ERESTARTNOHAND means that the syscall should only be
+ * restarted if there was no handler for the signal, and since
+ * we only get here if there is a handler, we dont restart.
+ */
+ restart = !has_handler;
+ break;
+ case ERESTARTSYS:
+ /* ERESTARTSYS means to restart the syscall if there is no
+ * handler or the handler was registered with SA_RESTART
+ */
+ restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
+ break;
+ case ERESTARTNOINTR:
+ /* ERESTARTNOINTR means that the syscall should be
+ * called again after the signal handler returns.
+ */
+ break;
+ default:
+ return;
+ }
+ if (restart) {
+ if (ret == ERESTART_RESTARTBLOCK)
+ regs->gpr[0] = __NR_restart_syscall;
+ else
+ regs->gpr[3] = regs->orig_gpr3;
+ regs->nip -= 4;
+ regs->result = 0;
+ } else {
+ if (trap_is_scv(regs)) {
+ regs->result = -EINTR;
+ regs->gpr[3] = -EINTR;
+ } else {
+ regs->result = -EINTR;
+ regs->gpr[3] = EINTR;
+ regs->ccr |= 0x10000000;
+ }
+ }
+}
+
+static void do_signal(struct task_struct *tsk)
+{
+ sigset_t *oldset = sigmask_to_save();
+ struct ksignal ksig = { .sig = 0 };
+ int ret;
+
+ BUG_ON(tsk != current);
+
+ get_signal(&ksig);
+
+ /* Is there any syscall restart business here ? */
+ check_syscall_restart(tsk->thread.regs, &ksig.ka, ksig.sig > 0);
+
+ if (ksig.sig <= 0) {
+ /* No signal to deliver -- put the saved sigmask back */
+ restore_saved_sigmask();
+ set_trap_norestart(tsk->thread.regs);
+ return; /* no signals delivered */
+ }
+
+ /*
+ * Reenable the DABR before delivering the signal to
+ * user space. The DABR will have been cleared if it
+ * triggered inside the kernel.
+ */
+ if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {
+ int i;
+
+ for (i = 0; i < nr_wp_slots(); i++) {
+ if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type)
+ __set_breakpoint(i, &tsk->thread.hw_brk[i]);
+ }
+ }
+
+ /* Re-enable the breakpoints for the signal stack */
+ thread_change_pc(tsk, tsk->thread.regs);
+
+ rseq_signal_deliver(&ksig, tsk->thread.regs);
+
+ if (is_32bit_task()) {
+ if (ksig.ka.sa.sa_flags & SA_SIGINFO)
+ ret = handle_rt_signal32(&ksig, oldset, tsk);
+ else
+ ret = handle_signal32(&ksig, oldset, tsk);
+ } else {
+ ret = handle_rt_signal64(&ksig, oldset, tsk);
+ }
+
+ set_trap_norestart(tsk->thread.regs);
+ signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP));
+}
+
+void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
+{
+ user_exit();
+
+ if (thread_info_flags & _TIF_UPROBE)
+ uprobe_notify_resume(regs);
+
+ if (thread_info_flags & _TIF_PATCH_PENDING)
+ klp_update_patch_state(current);
+
+ if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
+ BUG_ON(regs != current->thread.regs);
+ do_signal(current);
+ }
+
+ if (thread_info_flags & _TIF_NOTIFY_RESUME) {
+ tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(NULL, regs);
+ }
+
+ user_enter();
+}
+
+unsigned long get_tm_stackpointer(struct task_struct *tsk)
+{
+ /* When in an active transaction that takes a signal, we need to be
+ * careful with the stack. It's possible that the stack has moved back
+ * up after the tbegin. The obvious case here is when the tbegin is
+ * called inside a function that returns before a tend. In this case,
+ * the stack is part of the checkpointed transactional memory state.
+ * If we write over this non transactionally or in suspend, we are in
+ * trouble because if we get a tm abort, the program counter and stack
+ * pointer will be back at the tbegin but our in memory stack won't be
+ * valid anymore.
+ *
+ * To avoid this, when taking a signal in an active transaction, we
+ * need to use the stack pointer from the checkpointed state, rather
+ * than the speculated state. This ensures that the signal context
+ * (written tm suspended) will be written below the stack required for
+ * the rollback. The transaction is aborted because of the treclaim,
+ * so any memory written between the tbegin and the signal will be
+ * rolled back anyway.
+ *
+ * For signals taken in non-TM or suspended mode, we use the
+ * normal/non-checkpointed stack pointer.
+ */
+
+ unsigned long ret = tsk->thread.regs->gpr[1];
+
+#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
+ BUG_ON(tsk != current);
+
+ if (MSR_TM_ACTIVE(tsk->thread.regs->msr)) {
+ preempt_disable();
+ tm_reclaim_current(TM_CAUSE_SIGNAL);
+ if (MSR_TM_TRANSACTIONAL(tsk->thread.regs->msr))
+ ret = tsk->thread.ckpt_regs.gpr[1];
+
+ /*
+ * If we treclaim, we must clear the current thread's TM bits
+ * before re-enabling preemption. Otherwise we might be
+ * preempted and have the live MSR[TS] changed behind our back
+ * (tm_recheckpoint_new_task() would recheckpoint). Besides, we
+ * enter the signal handler in non-transactional state.
+ */
+ tsk->thread.regs->msr &= ~MSR_TS_MASK;
+ preempt_enable();
+ }
+#endif
+ return ret;
+}
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