Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
 
#include <linux/signal.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
 
#include <asm/traps.h>
#include <asm/ucontext.h>
#include <asm/vdso.h>
 
#include <abi/regdef.h>
 
#ifdef CONFIG_CPU_HAS_FPU
#include <abi/fpu.h>
static int restore_fpu_state(struct sigcontext __user *sc)
{
<------>int err = 0;
<------>struct user_fp user_fp;
 
<------>err = __copy_from_user(&user_fp, &sc->sc_user_fp, sizeof(user_fp));
 
<------>restore_from_user_fp(&user_fp);
 
<------>return err;
}
 
static int save_fpu_state(struct sigcontext __user *sc)
{
<------>struct user_fp user_fp;
 
<------>save_to_user_fp(&user_fp);
 
<------>return __copy_to_user(&sc->sc_user_fp, &user_fp, sizeof(user_fp));
}
#else
#define restore_fpu_state(sigcontext)	(0)
#define save_fpu_state(sigcontext)	(0)
#endif
 
struct rt_sigframe {
<------>/*
<------> * pad[3] is compatible with the same struct defined in
<------> * gcc/libgcc/config/csky/linux-unwind.h
<------> */
<------>int pad[3];
<------>struct siginfo info;
<------>struct ucontext uc;
};
 
static long restore_sigcontext(struct pt_regs *regs,
<------>struct sigcontext __user *sc)
{
<------>int err = 0;
<------>unsigned long sr = regs->sr;
 
<------>/* sc_pt_regs is structured the same as the start of pt_regs */
<------>err |= __copy_from_user(regs, &sc->sc_pt_regs, sizeof(struct pt_regs));
 
<------>/* BIT(0) of regs->sr is Condition Code/Carry bit */
<------>regs->sr = (sr & ~1) | (regs->sr & 1);
 
<------>/* Restore the floating-point state. */
<------>err |= restore_fpu_state(sc);
 
<------>return err;
}
 
SYSCALL_DEFINE0(rt_sigreturn)
{
<------>struct pt_regs *regs = current_pt_regs();
<------>struct rt_sigframe __user *frame;
<------>sigset_t set;
 
<------>/* Always make any pending restarted system calls return -EINTR */
<------>current->restart_block.fn = do_no_restart_syscall;
 
<------>frame = (struct rt_sigframe __user *)regs->usp;
 
<------>if (!access_ok(frame, sizeof(*frame)))
<------><------>goto badframe;
 
<------>if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set)))
<------><------>goto badframe;
 
<------>set_current_blocked(&set);
 
<------>if (restore_sigcontext(regs, &frame->uc.uc_mcontext))
<------><------>goto badframe;
 
<------>if (restore_altstack(&frame->uc.uc_stack))
<------><------>goto badframe;
 
<------>return regs->a0;
 
badframe:
<------>force_sig(SIGSEGV);
<------>return 0;
}
 
static int setup_sigcontext(struct rt_sigframe __user *frame,
<------>struct pt_regs *regs)
{
<------>struct sigcontext __user *sc = &frame->uc.uc_mcontext;
<------>int err = 0;
 
<------>err |= __copy_to_user(&sc->sc_pt_regs, regs, sizeof(struct pt_regs));
<------>err |= save_fpu_state(sc);
 
<------>return err;
}
 
static inline void __user *get_sigframe(struct ksignal *ksig,
<------>struct pt_regs *regs, size_t framesize)
{
<------>unsigned long sp;
<------>/* Default to using normal stack */
<------>sp = regs->usp;
 
<------>/*
<------> * If we are on the alternate signal stack and would overflow it, don't.
<------> * Return an always-bogus address instead so we will die with SIGSEGV.
<------> */
<------>if (on_sig_stack(sp) && !likely(on_sig_stack(sp - framesize)))
<------><------>return (void __user __force *)(-1UL);
 
<------>/* This is the X/Open sanctioned signal stack switching. */
<------>sp = sigsp(sp, ksig) - framesize;
 
<------>/* Align the stack frame. */
<------>sp &= -8UL;
 
<------>return (void __user *)sp;
}
 
static int
setup_rt_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
{
<------>struct rt_sigframe __user *frame;
<------>int err = 0;
<------>struct csky_vdso *vdso = current->mm->context.vdso;
 
<------>frame = get_sigframe(ksig, regs, sizeof(*frame));
<------>if (!access_ok(frame, sizeof(*frame)))
<------><------>return -EFAULT;
 
<------>err |= copy_siginfo_to_user(&frame->info, &ksig->info);
 
<------>/* Create the ucontext. */
<------>err |= __put_user(0, &frame->uc.uc_flags);
<------>err |= __put_user(NULL, &frame->uc.uc_link);
<------>err |= __save_altstack(&frame->uc.uc_stack, regs->usp);
<------>err |= setup_sigcontext(frame, regs);
<------>err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set));
<------>if (err)
<------><------>return -EFAULT;
 
<------>/* Set up to return from userspace. */
<------>regs->lr = (unsigned long)(vdso->rt_signal_retcode);
 
<------>/*
<------> * Set up registers for signal handler.
<------> * Registers that we don't modify keep the value they had from
<------> * user-space at the time we took the signal.
<------> * We always pass siginfo and mcontext, regardless of SA_SIGINFO,
<------> * since some things rely on this (e.g. glibc's debug/segfault.c).
<------> */
<------>regs->pc  = (unsigned long)ksig->ka.sa.sa_handler;
<------>regs->usp = (unsigned long)frame;
<------>regs->a0  = ksig->sig;				/* a0: signal number */
<------>regs->a1  = (unsigned long)(&(frame->info));	/* a1: siginfo pointer */
<------>regs->a2  = (unsigned long)(&(frame->uc));	/* a2: ucontext pointer */
 
<------>return 0;
}
 
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
<------>sigset_t *oldset = sigmask_to_save();
<------>int ret;
 
<------>rseq_signal_deliver(ksig, regs);
 
<------>/* Are we from a system call? */
<------>if (in_syscall(regs)) {
<------><------>/* Avoid additional syscall restarting via ret_from_exception */
<------><------>forget_syscall(regs);
 
<------><------>/* If so, check system call restarting.. */
<------><------>switch (regs->a0) {
<------><------>case -ERESTART_RESTARTBLOCK:
<------><------>case -ERESTARTNOHAND:
<------><------><------>regs->a0 = -EINTR;
<------><------><------>break;
 
<------><------>case -ERESTARTSYS:
<------><------><------>if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
<------><------><------><------>regs->a0 = -EINTR;
<------><------><------><------>break;
<------><------><------>}
<------><------><------>fallthrough;
<------><------>case -ERESTARTNOINTR:
<------><------><------>regs->a0 = regs->orig_a0;
<------><------><------>regs->pc -= TRAP0_SIZE;
<------><------><------>break;
<------><------>}
<------>}
 
<------>/* Set up the stack frame */
<------>ret = setup_rt_frame(ksig, oldset, regs);
 
<------>signal_setup_done(ret, ksig, 0);
}
 
static void do_signal(struct pt_regs *regs)
{
<------>struct ksignal ksig;
 
<------>if (get_signal(&ksig)) {
<------><------>/* Actually deliver the signal */
<------><------>handle_signal(&ksig, regs);
<------><------>return;
<------>}
 
<------>/* Did we come from a system call? */
<------>if (in_syscall(regs)) {
<------><------>/* Avoid additional syscall restarting via ret_from_exception */
<------><------>forget_syscall(regs);
 
<------><------>/* Restart the system call - no handlers present */
<------><------>switch (regs->a0) {
<------><------>case -ERESTARTNOHAND:
<------><------>case -ERESTARTSYS:
<------><------>case -ERESTARTNOINTR:
<------><------><------>regs->a0 = regs->orig_a0;
<------><------><------>regs->pc -= TRAP0_SIZE;
<------><------><------>break;
<------><------>case -ERESTART_RESTARTBLOCK:
<------><------><------>regs->a0 = regs->orig_a0;
<------><------><------>regs_syscallid(regs) = __NR_restart_syscall;
<------><------><------>regs->pc -= TRAP0_SIZE;
<------><------><------>break;
<------><------>}
<------>}
 
<------>/*
<------> * If there is no signal to deliver, we just put the saved
<------> * sigmask back.
<------> */
<------>restore_saved_sigmask();
}
 
/*
 * notification of userspace execution resumption
 * - triggered by the _TIF_WORK_MASK flags
 */
asmlinkage void do_notify_resume(struct pt_regs *regs,
<------>unsigned long thread_info_flags)
{
<------>if (thread_info_flags & _TIF_UPROBE)
<------><------>uprobe_notify_resume(regs);
 
<------>/* Handle pending signal delivery */
<------>if (thread_info_flags & _TIF_SIGPENDING)
<------><------>do_signal(regs);
 
<------>if (thread_info_flags & _TIF_NOTIFY_RESUME) {
<------><------>tracehook_notify_resume(regs);
<------><------>rseq_handle_notify_resume(NULL, regs);
<------>}
}