OpenCloudOS-Kernel/arch/csky/kernel/signal.c

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// 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;
/* 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));
/* 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;
Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-04 10:57:57 +08:00
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 *frame;
int err = 0;
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_SYMBOL(
current->mm->context.vdso, rt_sigreturn);
/*
* 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 | _TIF_NOTIFY_SIGNAL))
do_signal(regs);
if (thread_info_flags & _TIF_NOTIFY_RESUME)
tracehook_notify_resume(regs);
}