Orange Pi5 kernel

/*
 * 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) {
<------><------>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;
}