swh:1:snp:173f8deb0c56c557784b4fd217e7608ac6197844
Tip revision: 62fb9874f5da54fdb243003b386128037319b219 authored by Linus Torvalds on 27 June 2021, 22:21:11 UTC
Linux 5.13
Linux 5.13
Tip revision: 62fb987
signal.c
/*
* Signal handling
*
* Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
* Copyright (C) 2008-2009 PetaLogix
* Copyright (C) 2003,2004 John Williams <jwilliams@itee.uq.edu.au>
* Copyright (C) 2001 NEC Corporation
* Copyright (C) 2001 Miles Bader <miles@gnu.org>
* Copyright (C) 1999,2000 Niibe Yutaka & Kaz Kojima
* Copyright (C) 1991,1992 Linus Torvalds
*
* 1997-11-28 Modified for POSIX.1b signals by Richard Henderson
*
* This file was was derived from the sh version, arch/sh/kernel/signal.c
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file COPYING in the main directory of this
* archive for more details.
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/percpu.h>
#include <linux/linkage.h>
#include <linux/tracehook.h>
#include <asm/entry.h>
#include <asm/ucontext.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <asm/cacheflush.h>
#include <asm/syscalls.h>
/*
* Do a signal return; undo the signal stack.
*/
struct sigframe {
struct sigcontext sc;
unsigned long extramask[_NSIG_WORDS-1];
unsigned long tramp[2]; /* signal trampoline */
};
struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
unsigned long tramp[2]; /* signal trampoline */
};
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc, int *rval_p)
{
unsigned int err = 0;
#define COPY(x) {err |= __get_user(regs->x, &sc->regs.x); }
COPY(r0);
COPY(r1);
COPY(r2); COPY(r3); COPY(r4); COPY(r5);
COPY(r6); COPY(r7); COPY(r8); COPY(r9);
COPY(r10); COPY(r11); COPY(r12); COPY(r13);
COPY(r14); COPY(r15); COPY(r16); COPY(r17);
COPY(r18); COPY(r19); COPY(r20); COPY(r21);
COPY(r22); COPY(r23); COPY(r24); COPY(r25);
COPY(r26); COPY(r27); COPY(r28); COPY(r29);
COPY(r30); COPY(r31);
COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
#undef COPY
*rval_p = regs->r3;
return err;
}
asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(regs->r1);
sigset_t set;
int rval;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
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, &rval))
goto badframe;
if (restore_altstack(&frame->uc.uc_stack))
goto badframe;
return rval;
badframe:
force_sig(SIGSEGV);
return 0;
}
/*
* Set up a signal frame.
*/
static int
setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
#define COPY(x) {err |= __put_user(regs->x, &sc->regs.x); }
COPY(r0);
COPY(r1);
COPY(r2); COPY(r3); COPY(r4); COPY(r5);
COPY(r6); COPY(r7); COPY(r8); COPY(r9);
COPY(r10); COPY(r11); COPY(r12); COPY(r13);
COPY(r14); COPY(r15); COPY(r16); COPY(r17);
COPY(r18); COPY(r19); COPY(r20); COPY(r21);
COPY(r22); COPY(r23); COPY(r24); COPY(r25);
COPY(r26); COPY(r27); COPY(r28); COPY(r29);
COPY(r30); COPY(r31);
COPY(pc); COPY(ear); COPY(esr); COPY(fsr);
#undef COPY
err |= __put_user(mask, &sc->oldmask);
return err;
}
/*
* Determine which stack to use..
*/
static inline void __user *
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size)
{
/* Default to using normal stack */
unsigned long sp = sigsp(regs->r1, ksig);
return (void __user *)((sp - frame_size) & -8UL);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
int err = 0, sig = ksig->sig;
unsigned long address = 0;
pmd_t *pmdp;
pte_t *ptep;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
return -EFAULT;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
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->r1);
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. If provided, use a stub
already in userspace. */
/* minus 8 is offset to cater for "rtsd r15,8" */
/* addi r12, r0, __NR_sigreturn */
err |= __put_user(0x31800000 | __NR_rt_sigreturn ,
frame->tramp + 0);
/* brki r14, 0x8 */
err |= __put_user(0xb9cc0008, frame->tramp + 1);
/* Return from sighandler will jump to the tramp.
Negative 8 offset because return is rtsd r15, 8 */
regs->r15 = ((unsigned long)frame->tramp)-8;
address = ((unsigned long)frame->tramp);
pmdp = pmd_off(current->mm, address);
preempt_disable();
ptep = pte_offset_map(pmdp, address);
if (pte_present(*ptep)) {
address = (unsigned long) page_address(pte_page(*ptep));
/* MS: I need add offset in page */
address += ((unsigned long)frame->tramp) & ~PAGE_MASK;
/* MS address is virtual */
address = __virt_to_phys(address);
invalidate_icache_range(address, address + 8);
flush_dcache_range(address, address + 8);
}
pte_unmap(ptep);
preempt_enable();
if (err)
return -EFAULT;
/* Set up registers for signal handler */
regs->r1 = (unsigned long) frame;
/* Signal handler args: */
regs->r5 = sig; /* arg 0: signum */
regs->r6 = (unsigned long) &frame->info; /* arg 1: siginfo */
regs->r7 = (unsigned long) &frame->uc; /* arg2: ucontext */
/* Offset to handle microblaze rtid r14, 0 */
regs->pc = (unsigned long)ksig->ka.sa.sa_handler;
#ifdef DEBUG_SIG
pr_info("SIG deliver (%s:%d): sp=%p pc=%08lx\n",
current->comm, current->pid, frame, regs->pc);
#endif
return 0;
}
/* Handle restarting system calls */
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->r3) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->r3 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->r3 = -EINTR;
break;
}
fallthrough;
case -ERESTARTNOINTR:
do_restart:
/* offset of 4 bytes to re-execute trap (brki) instruction */
regs->pc -= 4;
break;
}
}
/*
* OK, we're invoking a handler
*/
static void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int ret;
/* Set up the stack frame */
ret = setup_rt_frame(ksig, oldset, regs);
signal_setup_done(ret, ksig, test_thread_flag(TIF_SINGLESTEP));
}
/*
* Note that 'init' is a special process: it doesn't get signals it doesn't
* want to handle. Thus you cannot kill init even with a SIGKILL even by
* mistake.
*
* Note that we go through the signals twice: once to check the signals that
* the kernel can handle, and then we build all the user-level signal handling
* stack-frames in one go after that.
*/
static void do_signal(struct pt_regs *regs, int in_syscall)
{
struct ksignal ksig;
#ifdef DEBUG_SIG
pr_info("do signal: %p %d\n", regs, in_syscall);
pr_info("do signal2: %lx %lx %ld [%lx]\n", regs->pc, regs->r1,
regs->r12, current_thread_info()->flags);
#endif
if (get_signal(&ksig)) {
/* Whee! Actually deliver the signal. */
if (in_syscall)
handle_restart(regs, &ksig.ka, 1);
handle_signal(&ksig, regs);
return;
}
if (in_syscall)
handle_restart(regs, NULL, 0);
/*
* If there's no signal to deliver, we just put the saved sigmask
* back.
*/
restore_saved_sigmask();
}
asmlinkage void do_notify_resume(struct pt_regs *regs, int in_syscall)
{
if (test_thread_flag(TIF_SIGPENDING) ||
test_thread_flag(TIF_NOTIFY_SIGNAL))
do_signal(regs, in_syscall);
if (test_thread_flag(TIF_NOTIFY_RESUME))
tracehook_notify_resume(regs);
}