// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Common signal handling code for both 32 and 64 bits
*
* Copyright (c) 2007 Benjamin Herrenschmidt, IBM Corporation
* Extracted from signal_32.c and signal_64.c
*/
#include <linux/resume_user_mode.h>
#include <linux/signal.h>
#include <linux/uprobes.h>
#include <linux/key.h>
#include <linux/context_tracking.h>
#include <linux/livepatch.h>
#include <linux/syscalls.h>
#include <asm/hw_breakpoint.h>
#include <linux/uaccess.h>
#include <asm/switch_to.h>
#include <asm/unistd.h>
#include <asm/debug.h>
#include <asm/tm.h>
#include "signal.h"
#ifdef CONFIG_VSX
unsigned long copy_fpr_to_user(void __user *to,
struct task_struct *task)
{
u64 buf[ELF_NFPREG];
int i;
/* save FPR copy to local buffer then write to the thread_struct */
for (i = 0; i < (ELF_NFPREG - 1) ; i++)
buf[i] = task->thread.TS_FPR(i);
buf[i] = task->thread.fp_state.fpscr;
return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
}
unsigned long copy_fpr_from_user(struct task_struct *task,
void __user *from)
{
u64 buf[ELF_NFPREG];
int i;
if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
return 1;
for (i = 0; i < (ELF_NFPREG - 1) ; i++)
task->thread.TS_FPR(i) = buf[i];
task->thread.fp_state.fpscr = buf[i];
return 0;
}
unsigned long copy_vsx_to_user(void __user *to,
struct task_struct *task)
{
u64 buf[ELF_NVSRHALFREG];
int i;
/* save FPR copy to local buffer then write to the thread_struct */
for (i = 0; i < ELF_NVSRHALFREG; i++)
buf[i] = task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET];
return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
}
unsigned long copy_vsx_from_user(struct task_struct *task,
void __user *from)
{
u64 buf[ELF_NVSRHALFREG];
int i;
if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
return 1;
for (i = 0; i < ELF_NVSRHALFREG ; i++)
task->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
return 0;
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
unsigned long copy_ckfpr_to_user(void __user *to,
struct task_struct *task)
{
u64 buf[ELF_NFPREG];
int i;
/* save FPR copy to local buffer then write to the thread_struct */
for (i = 0; i < (ELF_NFPREG - 1) ; i++)
buf[i] = task->thread.TS_CKFPR(i);
buf[i] = task->thread.ckfp_state.fpscr;
return __copy_to_user(to, buf, ELF_NFPREG * sizeof(double));
}
unsigned long copy_ckfpr_from_user(struct task_struct *task,
void __user *from)
{
u64 buf[ELF_NFPREG];
int i;
if (__copy_from_user(buf, from, ELF_NFPREG * sizeof(double)))
return 1;
for (i = 0; i < (ELF_NFPREG - 1) ; i++)
task->thread.TS_CKFPR(i) = buf[i];
task->thread.ckfp_state.fpscr = buf[i];
return 0;
}
unsigned long copy_ckvsx_to_user(void __user *to,
struct task_struct *task)
{
u64 buf[ELF_NVSRHALFREG];
int i;
/* save FPR copy to local buffer then write to the thread_struct */
for (i = 0; i < ELF_NVSRHALFREG; i++)
buf[i] = task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET];
return __copy_to_user(to, buf, ELF_NVSRHALFREG * sizeof(double));
}
unsigned long copy_ckvsx_from_user(struct task_struct *task,
void __user *from)
{
u64 buf[ELF_NVSRHALFREG];
int i;
if (__copy_from_user(buf, from, ELF_NVSRHALFREG * sizeof(double)))
return 1;
for (i = 0; i < ELF_NVSRHALFREG ; i++)
task->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = buf[i];
return 0;
}
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
#endif
/* Log an error when sending an unhandled signal to a process. Controlled
* through debug.exception-trace sysctl.
*/
int show_unhandled_signals = 1;
unsigned long get_min_sigframe_size(void)
{
if (IS_ENABLED(CONFIG_PPC64))
return get_min_sigframe_size_64();
else
return get_min_sigframe_size_32();
}
#ifdef CONFIG_COMPAT
unsigned long get_min_sigframe_size_compat(void)
{
return get_min_sigframe_size_32();
}
#endif
/*
* Allocate space for the signal frame
*/
static unsigned long get_tm_stackpointer(struct task_struct *tsk);
void __user *get_sigframe(struct ksignal *ksig, struct task_struct *tsk,
size_t frame_size, int is_32)
{
unsigned long oldsp, newsp;
unsigned long sp = get_tm_stackpointer(tsk);
/* Default to using normal stack */
if (is_32)
oldsp = sp & 0x0ffffffffUL;
else
oldsp = sp;
oldsp = sigsp(oldsp, ksig);
newsp = (oldsp - frame_size) & ~0xFUL;
return (void __user *)newsp;
}
static void check_syscall_restart(struct pt_regs *regs, struct k_sigaction *ka,
int has_handler)
{
unsigned long ret = regs->gpr[3];
int restart = 1;
/* syscall ? */
if (!trap_is_syscall(regs))
return;
if (trap_norestart(regs))
return;
/* error signalled ? */
if (trap_is_scv(regs)) {
/* 32-bit compat mode sign extend? */
if (!IS_ERR_VALUE(ret))
return;
ret = -ret;
} else if (!(regs->ccr & 0x10000000)) {
return;
}
switch (ret) {
case ERESTART_RESTARTBLOCK:
case ERESTARTNOHAND:
/* ERESTARTNOHAND means that the syscall should only be
* restarted if there was no handler for the signal, and since
* we only get here if there is a handler, we dont restart.
*/
restart = !has_handler;
break;
case ERESTARTSYS:
/* ERESTARTSYS means to restart the syscall if there is no
* handler or the handler was registered with SA_RESTART
*/
restart = !has_handler || (ka->sa.sa_flags & SA_RESTART) != 0;
break;
case ERESTARTNOINTR:
/* ERESTARTNOINTR means that the syscall should be
* called again after the signal handler returns.
*/
break;
default:
return;
}
if (restart) {
if (ret == ERESTART_RESTARTBLOCK)
regs->gpr[0] = __NR_restart_syscall;
else
regs->gpr[3] = regs->orig_gpr3;
regs_add_return_ip(regs, -4);
regs->result = 0;
} else {
if (trap_is_scv(regs)) {
regs->result = -EINTR;
regs->gpr[3] = -EINTR;
} else {
regs->result = -EINTR;
regs->gpr[3] = EINTR;
regs->ccr |= 0x10000000;
}
}
}
static void do_signal(struct task_struct *tsk)
{
sigset_t *oldset = sigmask_to_save();
struct ksignal ksig = { .sig = 0 };
int ret;
BUG_ON(tsk != current);
get_signal(&ksig);
/* Is there any syscall restart business here ? */
check_syscall_restart(tsk->thread.regs, &ksig.ka, ksig.sig > 0);
if (ksig.sig <= 0) {
/* No signal to deliver -- put the saved sigmask back */
restore_saved_sigmask();
set_trap_norestart(tsk->thread.regs);
return; /* no signals delivered */
}
/*
* Reenable the DABR before delivering the signal to
* user space. The DABR will have been cleared if it
* triggered inside the kernel.
*/
if (!IS_ENABLED(CONFIG_PPC_ADV_DEBUG_REGS)) {
int i;
for (i = 0; i < nr_wp_slots(); i++) {
if (tsk->thread.hw_brk[i].address && tsk->thread.hw_brk[i].type)
__set_breakpoint(i, &tsk->thread.hw_brk[i]);
}
}
/* Re-enable the breakpoints for the signal stack */
thread_change_pc(tsk, tsk->thread.regs);
rseq_signal_deliver(&ksig, tsk->thread.regs);
if (is_32bit_task()) {
if (ksig.ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(&ksig, oldset, tsk);
else
ret = handle_signal32(&ksig, oldset, tsk);
} else {
ret = handle_rt_signal64(&ksig, oldset, tsk);
}
set_trap_norestart(tsk->thread.regs);
signal_setup_done(ret, &ksig, test_thread_flag(TIF_SINGLESTEP));
}
void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
{
if (thread_info_flags & _TIF_UPROBE)
uprobe_notify_resume(regs);
if (thread_info_flags & _TIF_PATCH_PENDING)
klp_update_patch_state(current);
if (thread_info_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
BUG_ON(regs != current->thread.regs);
do_signal(current);
}
if (thread_info_flags & _TIF_NOTIFY_RESUME)
resume_user_mode_work(regs);
}
static unsigned long get_tm_stackpointer(struct task_struct *tsk)
{
/* When in an active transaction that takes a signal, we need to be
* careful with the stack. It's possible that the stack has moved back
* up after the tbegin. The obvious case here is when the tbegin is
* called inside a function that returns before a tend. In this case,
* the stack is part of the checkpointed transactional memory state.
* If we write over this non transactionally or in suspend, we are in
* trouble because if we get a tm abort, the program counter and stack
* pointer will be back at the tbegin but our in memory stack won't be
* valid anymore.
*
* To avoid this, when taking a signal in an active transaction, we
* need to use the stack pointer from the checkpointed state, rather
* than the speculated state. This ensures that the signal context
* (written tm suspended) will be written below the stack required for
* the rollback. The transaction is aborted because of the treclaim,
* so any memory written between the tbegin and the signal will be
* rolled back anyway.
*
* For signals taken in non-TM or suspended mode, we use the
* normal/non-checkpointed stack pointer.
*/
struct pt_regs *regs = tsk->thread.regs;
unsigned long ret = regs->gpr[1];
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
BUG_ON(tsk != current);
if (MSR_TM_ACTIVE(regs->msr)) {
preempt_disable();
tm_reclaim_current(TM_CAUSE_SIGNAL);
if (MSR_TM_TRANSACTIONAL(regs->msr))
ret = tsk->thread.ckpt_regs.gpr[1];
/*
* If we treclaim, we must clear the current thread's TM bits
* before re-enabling preemption. Otherwise we might be
* preempted and have the live MSR[TS] changed behind our back
* (tm_recheckpoint_new_task() would recheckpoint). Besides, we
* enter the signal handler in non-transactional state.
*/
regs_set_return_msr(regs, regs->msr & ~MSR_TS_MASK);
preempt_enable();
}
#endif
return ret;
}
static const char fm32[] = KERN_INFO "%s[%d]: bad frame in %s: %p nip %08lx lr %08lx\n";
static const char fm64[] = KERN_INFO "%s[%d]: bad frame in %s: %p nip %016lx lr %016lx\n";
void signal_fault(struct task_struct *tsk, struct pt_regs *regs,
const char *where, void __user *ptr)
{
if (show_unhandled_signals)
printk_ratelimited(regs->msr & MSR_64BIT ? fm64 : fm32, tsk->comm,
task_pid_nr(tsk), where, ptr, regs->nip, regs->link);
}
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