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// SPDX-License-Identifier: GPL-2.0-only
/*
* Port on Texas Instruments TMS320C6x architecture
*
* Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
* Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
*
* Updated for 2.6.34: Mark Salter <msalter@redhat.com>
*/
#include <linux/kernel.h>
#include <linux/uaccess.h>
#include <linux/syscalls.h>
#include <linux/tracehook.h>
#include <asm/asm-offsets.h>
#include <asm/ucontext.h>
#include <asm/cacheflush.h>
/*
* Do a signal return, undo the signal stack.
*/
#define RETCODE_SIZE (9 << 2) /* 9 instructions = 36 bytes */
struct rt_sigframe {
struct siginfo __user *pinfo;
void __user *puc;
struct siginfo info;
struct ucontext uc;
unsigned long retcode[RETCODE_SIZE >> 2];
};
static int restore_sigcontext(struct pt_regs *regs,
struct sigcontext __user *sc)
{
int err = 0;
/* The access_ok check was done by caller, so use __get_user here */
#define COPY(x) (err |= __get_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
asmlinkage int do_rt_sigreturn(struct pt_regs *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;
/*
* Since we stacked the signal on a dword boundary,
* 'sp' should be dword aligned here. If it's
* not, then the user is trying to mess with us.
*/
if (regs->sp & 7)
goto badframe;
frame = (struct rt_sigframe __user *) ((unsigned long) regs->sp + 8);
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;
return regs->a4;
badframe:
force_sig(SIGSEGV);
return 0;
}
static int setup_sigcontext(struct sigcontext __user *sc, struct pt_regs *regs,
unsigned long mask)
{
int err = 0;
err |= __put_user(mask, &sc->sc_mask);
/* The access_ok check was done by caller, so use __put_user here */
#define COPY(x) (err |= __put_user(regs->x, &sc->sc_##x))
COPY(sp); COPY(a4); COPY(b4); COPY(a6); COPY(b6); COPY(a8); COPY(b8);
COPY(a0); COPY(a1); COPY(a2); COPY(a3); COPY(a5); COPY(a7); COPY(a9);
COPY(b0); COPY(b1); COPY(b2); COPY(b3); COPY(b5); COPY(b7); COPY(b9);
COPY(a16); COPY(a17); COPY(a18); COPY(a19);
COPY(a20); COPY(a21); COPY(a22); COPY(a23);
COPY(a24); COPY(a25); COPY(a26); COPY(a27);
COPY(a28); COPY(a29); COPY(a30); COPY(a31);
COPY(b16); COPY(b17); COPY(b18); COPY(b19);
COPY(b20); COPY(b21); COPY(b22); COPY(b23);
COPY(b24); COPY(b25); COPY(b26); COPY(b27);
COPY(b28); COPY(b29); COPY(b30); COPY(b31);
COPY(csr); COPY(pc);
#undef COPY
return err;
}
static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs,
unsigned long framesize)
{
unsigned long sp = sigsp(regs->sp, ksig);
/*
* No matter what happens, 'sp' must be dword
* aligned. Otherwise, nasty things will happen
*/
return (void __user *)((sp - framesize) & ~7);
}
static int setup_rt_frame(struct ksignal *ksig, sigset_t *set,
struct pt_regs *regs)
{
struct rt_sigframe __user *frame;
unsigned long __user *retcode;
int err = 0;
frame = get_sigframe(ksig, regs, sizeof(*frame));
if (!access_ok(frame, sizeof(*frame)))
return -EFAULT;
err |= __put_user(&frame->info, &frame->pinfo);
err |= __put_user(&frame->uc, &frame->puc);
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
/* Clear all the bits of the ucontext we don't use. */
err |= __clear_user(&frame->uc, offsetof(struct ucontext, uc_mcontext));
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 */
retcode = (unsigned long __user *) &frame->retcode;
/* The access_ok check was done above, so use __put_user here */
#define COPY(x) (err |= __put_user(x, retcode++))
COPY(0x0000002AUL | (__NR_rt_sigreturn << 7));
/* MVK __NR_rt_sigreturn,B0 */
COPY(0x10000000UL); /* SWE */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
COPY(0x00006000UL); /* NOP 4 */
#undef COPY
if (err)
return -EFAULT;
flush_icache_range((unsigned long) &frame->retcode,
(unsigned long) &frame->retcode + RETCODE_SIZE);
retcode = (unsigned long __user *) &frame->retcode;
/* Change user context to branch to signal handler */
regs->sp = (unsigned long) frame - 8;
regs->b3 = (unsigned long) retcode;
regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
/* Give the signal number to the handler */
regs->a4 = ksig->sig;
/*
* For realtime signals we must also set the second and third
* arguments for the signal handler.
* -- Peter Maydell <pmaydell@chiark.greenend.org.uk> 2000-12-06
*/
regs->b4 = (unsigned long)&frame->info;
regs->a6 = (unsigned long)&frame->uc;
return 0;
}
static inline void
handle_restart(struct pt_regs *regs, struct k_sigaction *ka, int has_handler)
{
switch (regs->a4) {
case -ERESTARTNOHAND:
if (!has_handler)
goto do_restart;
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (has_handler && !(ka->sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
fallthrough;
case -ERESTARTNOINTR:
do_restart:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
}
}
/*
* handle the actual delivery of a signal to userspace
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs,
int syscall)
{
int ret;
/* Are we from a system call? */
if (syscall) {
/* If so, check system call restarting.. */
switch (regs->a4) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->a4 = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->a4 = -EINTR;
break;
}
fallthrough;
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
}
}
/* Set up the stack frame */
ret = setup_rt_frame(ksig, sigmask_to_save(), regs);
signal_setup_done(ret, ksig, 0);
}
/*
* handle a potential signal
*/
static void do_signal(struct pt_regs *regs, int syscall)
{
struct ksignal ksig;
/* we want the common case to go fast, which is why we may in certain
* cases get here from kernel mode */
if (!user_mode(regs))
return;
if (get_signal(&ksig)) {
handle_signal(&ksig, regs, syscall);
return;
}
/* did we come from a system call? */
if (syscall) {
/* restart the system call - no handlers present */
switch (regs->a4) {
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->a4 = regs->orig_a4;
regs->pc -= 4;
break;
case -ERESTART_RESTARTBLOCK:
regs->a4 = regs->orig_a4;
regs->b0 = __NR_restart_syscall;
regs->pc -= 4;
break;
}
}
/* if there's no signal to deliver, we just put the saved sigmask
* back */
restore_saved_sigmask();
}
/*
* notification of userspace execution resumption
* - triggered by current->work.notify_resume
*/
asmlinkage void do_notify_resume(struct pt_regs *regs, u32 thread_info_flags,
int syscall)
{
/* deal with pending signal delivery */
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL))
do_signal(regs, syscall);
if (thread_info_flags & (1 << TIF_NOTIFY_RESUME))
tracehook_notify_resume(regs);
}
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