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nds32: Signal handling support
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This patch adds support for signal handling.

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
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Greentime Hu committed Feb 22, 2018
1 parent eefacd1 commit 7ecbac7
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60 changes: 60 additions & 0 deletions arch/nds32/include/uapi/asm/sigcontext.h
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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation

#ifndef _ASMNDS32_SIGCONTEXT_H
#define _ASMNDS32_SIGCONTEXT_H

/*
* Signal context structure - contains all info to do with the state
* before the signal handler was invoked. Note: only add new entries
* to the end of the structure.
*/

struct zol_struct {
unsigned long nds32_lc; /* $LC */
unsigned long nds32_le; /* $LE */
unsigned long nds32_lb; /* $LB */
};

struct sigcontext {
unsigned long trap_no;
unsigned long error_code;
unsigned long oldmask;
unsigned long nds32_r0;
unsigned long nds32_r1;
unsigned long nds32_r2;
unsigned long nds32_r3;
unsigned long nds32_r4;
unsigned long nds32_r5;
unsigned long nds32_r6;
unsigned long nds32_r7;
unsigned long nds32_r8;
unsigned long nds32_r9;
unsigned long nds32_r10;
unsigned long nds32_r11;
unsigned long nds32_r12;
unsigned long nds32_r13;
unsigned long nds32_r14;
unsigned long nds32_r15;
unsigned long nds32_r16;
unsigned long nds32_r17;
unsigned long nds32_r18;
unsigned long nds32_r19;
unsigned long nds32_r20;
unsigned long nds32_r21;
unsigned long nds32_r22;
unsigned long nds32_r23;
unsigned long nds32_r24;
unsigned long nds32_r25;
unsigned long nds32_fp; /* $r28 */
unsigned long nds32_gp; /* $r29 */
unsigned long nds32_lp; /* $r30 */
unsigned long nds32_sp; /* $r31 */
unsigned long nds32_ipc;
unsigned long fault_address;
unsigned long used_math_flag;
/* FPU Registers */
struct zol_struct zol;
};

#endif
324 changes: 324 additions & 0 deletions arch/nds32/kernel/signal.c
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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation

#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/ptrace.h>
#include <linux/personality.h>
#include <linux/freezer.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>

#include <asm/cacheflush.h>
#include <asm/ucontext.h>
#include <asm/unistd.h>

#include <asm/ptrace.h>
#include <asm/vdso.h>

struct rt_sigframe {
struct siginfo info;
struct ucontext uc;
};

static int restore_sigframe(struct pt_regs *regs,
struct rt_sigframe __user * sf)
{
sigset_t set;
int err;

err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
if (err == 0) {
set_current_blocked(&set);
}

__get_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
__get_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
__get_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
__get_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
__get_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
__get_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
__get_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
__get_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
__get_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
__get_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
__get_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
__get_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
__get_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
__get_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
__get_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
__get_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
__get_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
__get_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
__get_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
__get_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
__get_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);
__get_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
__get_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
__get_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
__get_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
__get_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);

__get_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
__get_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
__get_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
__get_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
__get_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
#if defined(CONFIG_HWZOL)
__get_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
__get_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
__get_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
#endif

/*
* Avoid sys_rt_sigreturn() restarting.
*/
forget_syscall(regs);
return err;
}

asmlinkage long sys_rt_sigreturn(struct pt_regs *regs)
{
struct rt_sigframe __user *frame;

/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;

/*
* Since we stacked the signal on a 64-bit boundary,
* then 'sp' should be two-word 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 *)regs->sp;

if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
goto badframe;

if (restore_sigframe(regs, frame))
goto badframe;

if (restore_altstack(&frame->uc.uc_stack))
goto badframe;

return regs->uregs[0];

badframe:
force_sig(SIGSEGV, current);
return 0;
}

static int
setup_sigframe(struct rt_sigframe __user * sf, struct pt_regs *regs,
sigset_t * set)
{
int err = 0;

__put_user_error(regs->uregs[0], &sf->uc.uc_mcontext.nds32_r0, err);
__put_user_error(regs->uregs[1], &sf->uc.uc_mcontext.nds32_r1, err);
__put_user_error(regs->uregs[2], &sf->uc.uc_mcontext.nds32_r2, err);
__put_user_error(regs->uregs[3], &sf->uc.uc_mcontext.nds32_r3, err);
__put_user_error(regs->uregs[4], &sf->uc.uc_mcontext.nds32_r4, err);
__put_user_error(regs->uregs[5], &sf->uc.uc_mcontext.nds32_r5, err);
__put_user_error(regs->uregs[6], &sf->uc.uc_mcontext.nds32_r6, err);
__put_user_error(regs->uregs[7], &sf->uc.uc_mcontext.nds32_r7, err);
__put_user_error(regs->uregs[8], &sf->uc.uc_mcontext.nds32_r8, err);
__put_user_error(regs->uregs[9], &sf->uc.uc_mcontext.nds32_r9, err);
__put_user_error(regs->uregs[10], &sf->uc.uc_mcontext.nds32_r10, err);
__put_user_error(regs->uregs[11], &sf->uc.uc_mcontext.nds32_r11, err);
__put_user_error(regs->uregs[12], &sf->uc.uc_mcontext.nds32_r12, err);
__put_user_error(regs->uregs[13], &sf->uc.uc_mcontext.nds32_r13, err);
__put_user_error(regs->uregs[14], &sf->uc.uc_mcontext.nds32_r14, err);
__put_user_error(regs->uregs[15], &sf->uc.uc_mcontext.nds32_r15, err);
__put_user_error(regs->uregs[16], &sf->uc.uc_mcontext.nds32_r16, err);
__put_user_error(regs->uregs[17], &sf->uc.uc_mcontext.nds32_r17, err);
__put_user_error(regs->uregs[18], &sf->uc.uc_mcontext.nds32_r18, err);
__put_user_error(regs->uregs[19], &sf->uc.uc_mcontext.nds32_r19, err);
__put_user_error(regs->uregs[20], &sf->uc.uc_mcontext.nds32_r20, err);

__put_user_error(regs->uregs[21], &sf->uc.uc_mcontext.nds32_r21, err);
__put_user_error(regs->uregs[22], &sf->uc.uc_mcontext.nds32_r22, err);
__put_user_error(regs->uregs[23], &sf->uc.uc_mcontext.nds32_r23, err);
__put_user_error(regs->uregs[24], &sf->uc.uc_mcontext.nds32_r24, err);
__put_user_error(regs->uregs[25], &sf->uc.uc_mcontext.nds32_r25, err);
__put_user_error(regs->fp, &sf->uc.uc_mcontext.nds32_fp, err);
__put_user_error(regs->gp, &sf->uc.uc_mcontext.nds32_gp, err);
__put_user_error(regs->lp, &sf->uc.uc_mcontext.nds32_lp, err);
__put_user_error(regs->sp, &sf->uc.uc_mcontext.nds32_sp, err);
__put_user_error(regs->ipc, &sf->uc.uc_mcontext.nds32_ipc, err);
#if defined(CONFIG_HWZOL)
__put_user_error(regs->lc, &sf->uc.uc_mcontext.zol.nds32_lc, err);
__put_user_error(regs->le, &sf->uc.uc_mcontext.zol.nds32_le, err);
__put_user_error(regs->lb, &sf->uc.uc_mcontext.zol.nds32_lb, err);
#endif

__put_user_error(current->thread.trap_no, &sf->uc.uc_mcontext.trap_no,
err);
__put_user_error(current->thread.error_code,
&sf->uc.uc_mcontext.error_code, err);
__put_user_error(current->thread.address,
&sf->uc.uc_mcontext.fault_address, err);
__put_user_error(set->sig[0], &sf->uc.uc_mcontext.oldmask, err);

err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));

return err;
}

static inline void __user *get_sigframe(struct ksignal *ksig,
struct pt_regs *regs, int framesize)
{
unsigned long sp;

/* Default to using normal stack */
sp = regs->sp;

/*
* 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);

/*
* nds32 mandates 8-byte alignment
*/
sp &= ~0x7UL;

return (void __user *)sp;
}

static int
setup_return(struct pt_regs *regs, struct ksignal *ksig, void __user * frame)
{
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
unsigned long retcode;

retcode = VDSO_SYMBOL(current->mm->context.vdso, rt_sigtramp);
regs->uregs[0] = ksig->sig;
regs->sp = (unsigned long)frame;
regs->lp = retcode;
regs->ipc = handler;

return 0;
}

static int
setup_rt_frame(struct ksignal *ksig, sigset_t * set, struct pt_regs *regs)
{
struct rt_sigframe __user *frame =
get_sigframe(ksig, regs, sizeof(*frame));
int err = 0;

if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
return -EFAULT;

__put_user_error(0, &frame->uc.uc_flags, err);
__put_user_error(NULL, &frame->uc.uc_link, err);

err |= __save_altstack(&frame->uc.uc_stack, regs->sp);
err |= setup_sigframe(frame, regs, set);
if (err == 0) {
setup_return(regs, ksig, frame);
if (ksig->ka.sa.sa_flags & SA_SIGINFO) {
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
regs->uregs[1] = (unsigned long)&frame->info;
regs->uregs[2] = (unsigned long)&frame->uc;
}
}
return err;
}

/*
* OK, we're invoking a handler
*/
static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
int ret;
sigset_t *oldset = sigmask_to_save();

if (in_syscall(regs)) {
/* Avoid additional syscall restarting via ret_slow_syscall. */
forget_syscall(regs);

switch (regs->uregs[0]) {
case -ERESTART_RESTARTBLOCK:
case -ERESTARTNOHAND:
regs->uregs[0] = -EINTR;
break;
case -ERESTARTSYS:
if (!(ksig->ka.sa.sa_flags & SA_RESTART)) {
regs->uregs[0] = -EINTR;
break;
}
case -ERESTARTNOINTR:
regs->uregs[0] = regs->orig_r0;
regs->ipc -= 4;
break;
}
}
/*
* Set up the stack frame
*/
ret = setup_rt_frame(ksig, oldset, regs);

signal_setup_done(ret, ksig, 0);
}

/*
* 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)
{
struct ksignal ksig;

if (get_signal(&ksig)) {
handle_signal(&ksig, regs);
return;
}

/*
* If we were from a system call, check for system call restarting...
*/
if (in_syscall(regs)) {
/* Restart the system call - no handlers present */

/* Avoid additional syscall restarting via ret_slow_syscall. */
forget_syscall(regs);

switch (regs->uregs[0]) {
case -ERESTART_RESTARTBLOCK:
regs->uregs[15] = __NR_restart_syscall;
case -ERESTARTNOHAND:
case -ERESTARTSYS:
case -ERESTARTNOINTR:
regs->uregs[0] = regs->orig_r0;
regs->ipc -= 0x4;
break;
}
}
restore_saved_sigmask();
}

asmlinkage void
do_notify_resume(struct pt_regs *regs, unsigned int thread_flags)
{
if (thread_flags & _TIF_SIGPENDING)
do_signal(regs);

if (thread_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}

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