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linux-sg2042/arch/sparc/kernel/signal_32.c

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// SPDX-License-Identifier: GPL-2.0
/* linux/arch/sparc/kernel/signal.c
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 1996 Miguel de Icaza (miguel@nuclecu.unam.mx)
* Copyright (C) 1997 Eddie C. Dost (ecd@skynet.be)
*/
#include <linux/sched.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/mm.h>
#include <linux/tty.h>
#include <linux/smp.h>
#include <linux/binfmts.h> /* do_coredum */
#include <linux/bitops.h>
#include <linux/tracehook.h>
#include <linux/uaccess.h>
#include <asm/ptrace.h>
#include <asm/pgalloc.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h> /* flush_sig_insns */
#include <asm/switch_to.h>
#include "sigutil.h"
#include "kernel.h"
extern void fpsave(unsigned long *fpregs, unsigned long *fsr,
void *fpqueue, unsigned long *fpqdepth);
extern void fpload(unsigned long *fpregs, unsigned long *fsr);
struct signal_frame {
struct sparc_stackf ss;
__siginfo32_t info;
__siginfo_fpu_t __user *fpu_save;
unsigned long insns[2] __attribute__ ((aligned (8)));
unsigned int extramask[_NSIG_WORDS - 1];
unsigned int extra_size; /* Should be 0 */
__siginfo_rwin_t __user *rwin_save;
} __attribute__((aligned(8)));
struct rt_signal_frame {
struct sparc_stackf ss;
siginfo_t info;
struct pt_regs regs;
sigset_t mask;
__siginfo_fpu_t __user *fpu_save;
unsigned int insns[2];
stack_t stack;
unsigned int extra_size; /* Should be 0 */
__siginfo_rwin_t __user *rwin_save;
} __attribute__((aligned(8)));
/* Align macros */
#define SF_ALIGNEDSZ (((sizeof(struct signal_frame) + 7) & (~7)))
#define RT_ALIGNEDSZ (((sizeof(struct rt_signal_frame) + 7) & (~7)))
/* Checks if the fp is valid. We always build signal frames which are
* 16-byte aligned, therefore we can always enforce that the restore
* frame has that property as well.
*/
static inline bool invalid_frame_pointer(void __user *fp, int fplen)
{
if ((((unsigned long) fp) & 15) || !__access_ok((unsigned long)fp, fplen))
return true;
return false;
}
asmlinkage void do_sigreturn(struct pt_regs *regs)
{
unsigned long up_psr, pc, npc, ufp;
struct signal_frame __user *sf;
sigset_t set;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
int err;
/* Always make any pending restarted system calls return -EINTR */
current->restart_block.fn = do_no_restart_syscall;
synchronize_user_stack();
sf = (struct signal_frame __user *) regs->u_regs[UREG_FP];
/* 1. Make sure we are not getting garbage from the user */
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv_and_exit;
if (get_user(ufp, &sf->info.si_regs.u_regs[UREG_FP]))
goto segv_and_exit;
if (ufp & 0x7)
goto segv_and_exit;
err = __get_user(pc, &sf->info.si_regs.pc);
err |= __get_user(npc, &sf->info.si_regs.npc);
if ((pc | npc) & 3)
goto segv_and_exit;
/* 2. Restore the state */
up_psr = regs->psr;
err |= __copy_from_user(regs, &sf->info.si_regs, sizeof(struct pt_regs));
/* User can only change condition codes and FPU enabling in %psr. */
regs->psr = (up_psr & ~(PSR_ICC | PSR_EF))
| (regs->psr & (PSR_ICC | PSR_EF));
/* Prevent syscall restart. */
pt_regs_clear_syscall(regs);
err |= __get_user(fpu_save, &sf->fpu_save);
if (fpu_save)
err |= restore_fpu_state(regs, fpu_save);
err |= __get_user(rwin_save, &sf->rwin_save);
if (rwin_save)
err |= restore_rwin_state(rwin_save);
/* This is pretty much atomic, no amount locking would prevent
* the races which exist anyways.
*/
err |= __get_user(set.sig[0], &sf->info.si_mask);
err |= __copy_from_user(&set.sig[1], &sf->extramask,
(_NSIG_WORDS-1) * sizeof(unsigned int));
if (err)
goto segv_and_exit;
set_current_blocked(&set);
return;
segv_and_exit:
force_sig(SIGSEGV, current);
}
asmlinkage void do_rt_sigreturn(struct pt_regs *regs)
{
struct rt_signal_frame __user *sf;
unsigned int psr, pc, npc, ufp;
__siginfo_fpu_t __user *fpu_save;
__siginfo_rwin_t __user *rwin_save;
sigset_t set;
int err;
synchronize_user_stack();
sf = (struct rt_signal_frame __user *) regs->u_regs[UREG_FP];
if (invalid_frame_pointer(sf, sizeof(*sf)))
goto segv;
if (get_user(ufp, &sf->regs.u_regs[UREG_FP]))
goto segv;
if (ufp & 0x7)
goto segv;
err = __get_user(pc, &sf->regs.pc);
err |= __get_user(npc, &sf->regs.npc);
err |= ((pc | npc) & 0x03);
err |= __get_user(regs->y, &sf->regs.y);
err |= __get_user(psr, &sf->regs.psr);
err |= __copy_from_user(&regs->u_regs[UREG_G1],
&sf->regs.u_regs[UREG_G1], 15 * sizeof(u32));
regs->psr = (regs->psr & ~PSR_ICC) | (psr & PSR_ICC);
/* Prevent syscall restart. */
pt_regs_clear_syscall(regs);
err |= __get_user(fpu_save, &sf->fpu_save);
if (!err && fpu_save)
err |= restore_fpu_state(regs, fpu_save);
err |= __copy_from_user(&set, &sf->mask, sizeof(sigset_t));
err |= restore_altstack(&sf->stack);
if (err)
goto segv;
regs->pc = pc;
regs->npc = npc;
err |= __get_user(rwin_save, &sf->rwin_save);
if (!err && rwin_save) {
if (restore_rwin_state(rwin_save))
goto segv;
}
set_current_blocked(&set);
return;
segv:
force_sig(SIGSEGV, current);
}
static inline void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, unsigned long framesize)
{
unsigned long sp = regs->u_regs[UREG_FP];
/*
* 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 *) -1L;
/* This is the X/Open sanctioned signal stack switching. */
sp = sigsp(sp, ksig) - framesize;
/* Always align the stack frame. This handles two cases. First,
* sigaltstack need not be mindful of platform specific stack
* alignment. Second, if we took this signal because the stack
* is not aligned properly, we'd like to take the signal cleanly
* and report that.
*/
sp &= ~15UL;
return (void __user *) sp;
}
static int setup_frame(struct ksignal *ksig, struct pt_regs *regs,
sigset_t *oldset)
{
struct signal_frame __user *sf;
int sigframe_size, err, wsaved;
void __user *tail;
/* 1. Make sure everything is clean */
synchronize_user_stack();
wsaved = current_thread_info()->w_saved;
sigframe_size = sizeof(*sf);
if (used_math())
sigframe_size += sizeof(__siginfo_fpu_t);
if (wsaved)
sigframe_size += sizeof(__siginfo_rwin_t);
sf = (struct signal_frame __user *)
get_sigframe(ksig, regs, sigframe_size);
if (invalid_frame_pointer(sf, sigframe_size)) {
do_exit(SIGILL);
return -EINVAL;
}
tail = sf + 1;
/* 2. Save the current process state */
err = __copy_to_user(&sf->info.si_regs, regs, sizeof(struct pt_regs));
err |= __put_user(0, &sf->extra_size);
if (used_math()) {
__siginfo_fpu_t __user *fp = tail;
tail += sizeof(*fp);
err |= save_fpu_state(regs, fp);
err |= __put_user(fp, &sf->fpu_save);
} else {
err |= __put_user(0, &sf->fpu_save);
}
if (wsaved) {
__siginfo_rwin_t __user *rwp = tail;
tail += sizeof(*rwp);
err |= save_rwin_state(wsaved, rwp);
err |= __put_user(rwp, &sf->rwin_save);
} else {
err |= __put_user(0, &sf->rwin_save);
}
err |= __put_user(oldset->sig[0], &sf->info.si_mask);
err |= __copy_to_user(sf->extramask, &oldset->sig[1],
(_NSIG_WORDS - 1) * sizeof(unsigned int));
if (!wsaved) {
err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
sizeof(struct reg_window32));
} else {
struct reg_window32 *rp;
rp = &current_thread_info()->reg_window[wsaved - 1];
err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
}
if (err)
return err;
/* 3. signal handler back-trampoline and parameters */
regs->u_regs[UREG_FP] = (unsigned long) sf;
regs->u_regs[UREG_I0] = ksig->sig;
regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
regs->u_regs[UREG_I2] = (unsigned long) &sf->info;
/* 4. signal handler */
regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
regs->npc = (regs->pc + 4);
/* 5. return to kernel instructions */
if (ksig->ka.ka_restorer)
regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
else {
regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
/* mov __NR_sigreturn, %g1 */
err |= __put_user(0x821020d8, &sf->insns[0]);
/* t 0x10 */
err |= __put_user(0x91d02010, &sf->insns[1]);
if (err)
return err;
/* Flush instruction space. */
flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
}
return 0;
}
static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs,
sigset_t *oldset)
{
struct rt_signal_frame __user *sf;
int sigframe_size, wsaved;
void __user *tail;
unsigned int psr;
int err;
synchronize_user_stack();
wsaved = current_thread_info()->w_saved;
sigframe_size = sizeof(*sf);
if (used_math())
sigframe_size += sizeof(__siginfo_fpu_t);
if (wsaved)
sigframe_size += sizeof(__siginfo_rwin_t);
sf = (struct rt_signal_frame __user *)
get_sigframe(ksig, regs, sigframe_size);
if (invalid_frame_pointer(sf, sigframe_size)) {
do_exit(SIGILL);
return -EINVAL;
}
tail = sf + 1;
err = __put_user(regs->pc, &sf->regs.pc);
err |= __put_user(regs->npc, &sf->regs.npc);
err |= __put_user(regs->y, &sf->regs.y);
psr = regs->psr;
if (used_math())
psr |= PSR_EF;
err |= __put_user(psr, &sf->regs.psr);
err |= __copy_to_user(&sf->regs.u_regs, regs->u_regs, sizeof(regs->u_regs));
err |= __put_user(0, &sf->extra_size);
if (psr & PSR_EF) {
__siginfo_fpu_t __user *fp = tail;
tail += sizeof(*fp);
err |= save_fpu_state(regs, fp);
err |= __put_user(fp, &sf->fpu_save);
} else {
err |= __put_user(0, &sf->fpu_save);
}
if (wsaved) {
__siginfo_rwin_t __user *rwp = tail;
tail += sizeof(*rwp);
err |= save_rwin_state(wsaved, rwp);
err |= __put_user(rwp, &sf->rwin_save);
} else {
err |= __put_user(0, &sf->rwin_save);
}
err |= __copy_to_user(&sf->mask, &oldset->sig[0], sizeof(sigset_t));
/* Setup sigaltstack */
err |= __save_altstack(&sf->stack, regs->u_regs[UREG_FP]);
if (!wsaved) {
err |= __copy_to_user(sf, (char *) regs->u_regs[UREG_FP],
sizeof(struct reg_window32));
} else {
struct reg_window32 *rp;
rp = &current_thread_info()->reg_window[wsaved - 1];
err |= __copy_to_user(sf, rp, sizeof(struct reg_window32));
}
err |= copy_siginfo_to_user(&sf->info, &ksig->info);
if (err)
return err;
regs->u_regs[UREG_FP] = (unsigned long) sf;
regs->u_regs[UREG_I0] = ksig->sig;
regs->u_regs[UREG_I1] = (unsigned long) &sf->info;
regs->u_regs[UREG_I2] = (unsigned long) &sf->regs;
regs->pc = (unsigned long) ksig->ka.sa.sa_handler;
regs->npc = (regs->pc + 4);
if (ksig->ka.ka_restorer)
regs->u_regs[UREG_I7] = (unsigned long)ksig->ka.ka_restorer;
else {
regs->u_regs[UREG_I7] = (unsigned long)(&(sf->insns[0]) - 2);
/* mov __NR_sigreturn, %g1 */
err |= __put_user(0x821020d8, &sf->insns[0]);
/* t 0x10 */
err |= __put_user(0x91d02010, &sf->insns[1]);
if (err)
return err;
/* Flush instruction space. */
flush_sig_insns(current->mm, (unsigned long) &(sf->insns[0]));
}
return 0;
}
static inline void
handle_signal(struct ksignal *ksig, struct pt_regs *regs)
{
sigset_t *oldset = sigmask_to_save();
int err;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
err = setup_rt_frame(ksig, regs, oldset);
else
err = setup_frame(ksig, regs, oldset);
signal_setup_done(err, ksig, 0);
}
static inline void syscall_restart(unsigned long orig_i0, struct pt_regs *regs,
struct sigaction *sa)
{
switch(regs->u_regs[UREG_I0]) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
no_system_call_restart:
regs->u_regs[UREG_I0] = EINTR;
regs->psr |= PSR_C;
break;
case ERESTARTSYS:
if (!(sa->sa_flags & SA_RESTART))
goto no_system_call_restart;
/* fallthrough */
case ERESTARTNOINTR:
regs->u_regs[UREG_I0] = orig_i0;
regs->pc -= 4;
regs->npc -= 4;
}
}
/* 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.
*/
static void do_signal(struct pt_regs *regs, unsigned long orig_i0)
{
struct ksignal ksig;
int restart_syscall;
bool has_handler;
/* It's a lot of work and synchronization to add a new ptrace
* register for GDB to save and restore in order to get
* orig_i0 correct for syscall restarts when debugging.
*
* Although it should be the case that most of the global
* registers are volatile across a system call, glibc already
* depends upon that fact that we preserve them. So we can't
* just use any global register to save away the orig_i0 value.
*
* In particular %g2, %g3, %g4, and %g5 are all assumed to be
* preserved across a system call trap by various pieces of
* code in glibc.
*
* %g7 is used as the "thread register". %g6 is not used in
* any fixed manner. %g6 is used as a scratch register and
* a compiler temporary, but it's value is never used across
* a system call. Therefore %g6 is usable for orig_i0 storage.
*/
if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C))
regs->u_regs[UREG_G6] = orig_i0;
has_handler = get_signal(&ksig);
/* If the debugger messes with the program counter, it clears
* the software "in syscall" bit, directing us to not perform
* a syscall restart.
*/
restart_syscall = 0;
if (pt_regs_is_syscall(regs) && (regs->psr & PSR_C)) {
restart_syscall = 1;
orig_i0 = regs->u_regs[UREG_G6];
}
if (has_handler) {
if (restart_syscall)
syscall_restart(orig_i0, regs, &ksig.ka.sa);
handle_signal(&ksig, regs);
} else {
if (restart_syscall) {
switch (regs->u_regs[UREG_I0]) {
case ERESTARTNOHAND:
case ERESTARTSYS:
case ERESTARTNOINTR:
/* replay the system call when we are done */
regs->u_regs[UREG_I0] = orig_i0;
regs->pc -= 4;
regs->npc -= 4;
pt_regs_clear_syscall(regs);
/* fall through */
case ERESTART_RESTARTBLOCK:
regs->u_regs[UREG_G1] = __NR_restart_syscall;
regs->pc -= 4;
regs->npc -= 4;
pt_regs_clear_syscall(regs);
}
}
restore_saved_sigmask();
}
}
void do_notify_resume(struct pt_regs *regs, unsigned long orig_i0,
unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_SIGPENDING)
do_signal(regs, orig_i0);
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
}
}
asmlinkage int do_sys_sigstack(struct sigstack __user *ssptr,
struct sigstack __user *ossptr,
unsigned long sp)
{
int ret = -EFAULT;
/* First see if old state is wanted. */
if (ossptr) {
if (put_user(current->sas_ss_sp + current->sas_ss_size,
&ossptr->the_stack) ||
__put_user(on_sig_stack(sp), &ossptr->cur_status))
goto out;
}
/* Now see if we want to update the new state. */
if (ssptr) {
char *ss_sp;
if (get_user(ss_sp, &ssptr->the_stack))
goto out;
/* If the current stack was set with sigaltstack, don't
swap stacks while we are on it. */
ret = -EPERM;
if (current->sas_ss_sp && on_sig_stack(sp))
goto out;
/* Since we don't know the extent of the stack, and we don't
track onstack-ness, but rather calculate it, we must
presume a size. Ho hum this interface is lossy. */
current->sas_ss_sp = (unsigned long)ss_sp - SIGSTKSZ;
current->sas_ss_size = SIGSTKSZ;
}
ret = 0;
out:
return ret;
}
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