717 lines
18 KiB
C
717 lines
18 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* linux/arch/arm/kernel/signal.c
|
|
*
|
|
* Copyright (C) 1995-2009 Russell King
|
|
*/
|
|
#include <linux/errno.h>
|
|
#include <linux/random.h>
|
|
#include <linux/signal.h>
|
|
#include <linux/personality.h>
|
|
#include <linux/uaccess.h>
|
|
#include <linux/resume_user_mode.h>
|
|
#include <linux/uprobes.h>
|
|
#include <linux/syscalls.h>
|
|
|
|
#include <asm/elf.h>
|
|
#include <asm/cacheflush.h>
|
|
#include <asm/traps.h>
|
|
#include <asm/unistd.h>
|
|
#include <asm/vfp.h>
|
|
|
|
#include "signal.h"
|
|
|
|
extern const unsigned long sigreturn_codes[17];
|
|
|
|
static unsigned long signal_return_offset;
|
|
|
|
#ifdef CONFIG_IWMMXT
|
|
|
|
static int preserve_iwmmxt_context(struct iwmmxt_sigframe __user *frame)
|
|
{
|
|
char kbuf[sizeof(*frame) + 8];
|
|
struct iwmmxt_sigframe *kframe;
|
|
int err = 0;
|
|
|
|
/* the iWMMXt context must be 64 bit aligned */
|
|
kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
|
|
|
|
if (test_thread_flag(TIF_USING_IWMMXT)) {
|
|
kframe->magic = IWMMXT_MAGIC;
|
|
kframe->size = IWMMXT_STORAGE_SIZE;
|
|
iwmmxt_task_copy(current_thread_info(), &kframe->storage);
|
|
} else {
|
|
/*
|
|
* For bug-compatibility with older kernels, some space
|
|
* has to be reserved for iWMMXt even if it's not used.
|
|
* Set the magic and size appropriately so that properly
|
|
* written userspace can skip it reliably:
|
|
*/
|
|
*kframe = (struct iwmmxt_sigframe) {
|
|
.magic = DUMMY_MAGIC,
|
|
.size = IWMMXT_STORAGE_SIZE,
|
|
};
|
|
}
|
|
|
|
err = __copy_to_user(frame, kframe, sizeof(*kframe));
|
|
|
|
return err;
|
|
}
|
|
|
|
static int restore_iwmmxt_context(char __user **auxp)
|
|
{
|
|
struct iwmmxt_sigframe __user *frame =
|
|
(struct iwmmxt_sigframe __user *)*auxp;
|
|
char kbuf[sizeof(*frame) + 8];
|
|
struct iwmmxt_sigframe *kframe;
|
|
|
|
/* the iWMMXt context must be 64 bit aligned */
|
|
kframe = (struct iwmmxt_sigframe *)((unsigned long)(kbuf + 8) & ~7);
|
|
if (__copy_from_user(kframe, frame, sizeof(*frame)))
|
|
return -1;
|
|
|
|
/*
|
|
* For non-iWMMXt threads: a single iwmmxt_sigframe-sized dummy
|
|
* block is discarded for compatibility with setup_sigframe() if
|
|
* present, but we don't mandate its presence. If some other
|
|
* magic is here, it's not for us:
|
|
*/
|
|
if (!test_thread_flag(TIF_USING_IWMMXT) &&
|
|
kframe->magic != DUMMY_MAGIC)
|
|
return 0;
|
|
|
|
if (kframe->size != IWMMXT_STORAGE_SIZE)
|
|
return -1;
|
|
|
|
if (test_thread_flag(TIF_USING_IWMMXT)) {
|
|
if (kframe->magic != IWMMXT_MAGIC)
|
|
return -1;
|
|
|
|
iwmmxt_task_restore(current_thread_info(), &kframe->storage);
|
|
}
|
|
|
|
*auxp += IWMMXT_STORAGE_SIZE;
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
#ifdef CONFIG_VFP
|
|
|
|
static int preserve_vfp_context(struct vfp_sigframe __user *frame)
|
|
{
|
|
struct vfp_sigframe kframe;
|
|
int err = 0;
|
|
|
|
memset(&kframe, 0, sizeof(kframe));
|
|
kframe.magic = VFP_MAGIC;
|
|
kframe.size = VFP_STORAGE_SIZE;
|
|
|
|
err = vfp_preserve_user_clear_hwstate(&kframe.ufp, &kframe.ufp_exc);
|
|
if (err)
|
|
return err;
|
|
|
|
return __copy_to_user(frame, &kframe, sizeof(kframe));
|
|
}
|
|
|
|
static int restore_vfp_context(char __user **auxp)
|
|
{
|
|
struct vfp_sigframe frame;
|
|
int err;
|
|
|
|
err = __copy_from_user(&frame, *auxp, sizeof(frame));
|
|
if (err)
|
|
return err;
|
|
|
|
if (frame.magic != VFP_MAGIC || frame.size != VFP_STORAGE_SIZE)
|
|
return -EINVAL;
|
|
|
|
*auxp += sizeof(frame);
|
|
return vfp_restore_user_hwstate(&frame.ufp, &frame.ufp_exc);
|
|
}
|
|
|
|
#endif
|
|
|
|
/*
|
|
* Do a signal return; undo the signal stack. These are aligned to 64-bit.
|
|
*/
|
|
|
|
static int restore_sigframe(struct pt_regs *regs, struct sigframe __user *sf)
|
|
{
|
|
struct sigcontext context;
|
|
char __user *aux;
|
|
sigset_t set;
|
|
int err;
|
|
|
|
err = __copy_from_user(&set, &sf->uc.uc_sigmask, sizeof(set));
|
|
if (err == 0)
|
|
set_current_blocked(&set);
|
|
|
|
err |= __copy_from_user(&context, &sf->uc.uc_mcontext, sizeof(context));
|
|
if (err == 0) {
|
|
regs->ARM_r0 = context.arm_r0;
|
|
regs->ARM_r1 = context.arm_r1;
|
|
regs->ARM_r2 = context.arm_r2;
|
|
regs->ARM_r3 = context.arm_r3;
|
|
regs->ARM_r4 = context.arm_r4;
|
|
regs->ARM_r5 = context.arm_r5;
|
|
regs->ARM_r6 = context.arm_r6;
|
|
regs->ARM_r7 = context.arm_r7;
|
|
regs->ARM_r8 = context.arm_r8;
|
|
regs->ARM_r9 = context.arm_r9;
|
|
regs->ARM_r10 = context.arm_r10;
|
|
regs->ARM_fp = context.arm_fp;
|
|
regs->ARM_ip = context.arm_ip;
|
|
regs->ARM_sp = context.arm_sp;
|
|
regs->ARM_lr = context.arm_lr;
|
|
regs->ARM_pc = context.arm_pc;
|
|
regs->ARM_cpsr = context.arm_cpsr;
|
|
}
|
|
|
|
err |= !valid_user_regs(regs);
|
|
|
|
aux = (char __user *) sf->uc.uc_regspace;
|
|
#ifdef CONFIG_IWMMXT
|
|
if (err == 0)
|
|
err |= restore_iwmmxt_context(&aux);
|
|
#endif
|
|
#ifdef CONFIG_VFP
|
|
if (err == 0)
|
|
err |= restore_vfp_context(&aux);
|
|
#endif
|
|
|
|
return err;
|
|
}
|
|
|
|
asmlinkage int sys_sigreturn(struct pt_regs *regs)
|
|
{
|
|
struct 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 word aligned here. If it's
|
|
* not, then the user is trying to mess with us.
|
|
*/
|
|
if (regs->ARM_sp & 7)
|
|
goto badframe;
|
|
|
|
frame = (struct sigframe __user *)regs->ARM_sp;
|
|
|
|
if (!access_ok(frame, sizeof (*frame)))
|
|
goto badframe;
|
|
|
|
if (restore_sigframe(regs, frame))
|
|
goto badframe;
|
|
|
|
return regs->ARM_r0;
|
|
|
|
badframe:
|
|
force_sig(SIGSEGV);
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage int 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 word aligned here. If it's
|
|
* not, then the user is trying to mess with us.
|
|
*/
|
|
if (regs->ARM_sp & 7)
|
|
goto badframe;
|
|
|
|
frame = (struct rt_sigframe __user *)regs->ARM_sp;
|
|
|
|
if (!access_ok(frame, sizeof (*frame)))
|
|
goto badframe;
|
|
|
|
if (restore_sigframe(regs, &frame->sig))
|
|
goto badframe;
|
|
|
|
if (restore_altstack(&frame->sig.uc.uc_stack))
|
|
goto badframe;
|
|
|
|
return regs->ARM_r0;
|
|
|
|
badframe:
|
|
force_sig(SIGSEGV);
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
setup_sigframe(struct sigframe __user *sf, struct pt_regs *regs, sigset_t *set)
|
|
{
|
|
struct aux_sigframe __user *aux;
|
|
struct sigcontext context;
|
|
int err = 0;
|
|
|
|
context = (struct sigcontext) {
|
|
.arm_r0 = regs->ARM_r0,
|
|
.arm_r1 = regs->ARM_r1,
|
|
.arm_r2 = regs->ARM_r2,
|
|
.arm_r3 = regs->ARM_r3,
|
|
.arm_r4 = regs->ARM_r4,
|
|
.arm_r5 = regs->ARM_r5,
|
|
.arm_r6 = regs->ARM_r6,
|
|
.arm_r7 = regs->ARM_r7,
|
|
.arm_r8 = regs->ARM_r8,
|
|
.arm_r9 = regs->ARM_r9,
|
|
.arm_r10 = regs->ARM_r10,
|
|
.arm_fp = regs->ARM_fp,
|
|
.arm_ip = regs->ARM_ip,
|
|
.arm_sp = regs->ARM_sp,
|
|
.arm_lr = regs->ARM_lr,
|
|
.arm_pc = regs->ARM_pc,
|
|
.arm_cpsr = regs->ARM_cpsr,
|
|
|
|
.trap_no = current->thread.trap_no,
|
|
.error_code = current->thread.error_code,
|
|
.fault_address = current->thread.address,
|
|
.oldmask = set->sig[0],
|
|
};
|
|
|
|
err |= __copy_to_user(&sf->uc.uc_mcontext, &context, sizeof(context));
|
|
|
|
err |= __copy_to_user(&sf->uc.uc_sigmask, set, sizeof(*set));
|
|
|
|
aux = (struct aux_sigframe __user *) sf->uc.uc_regspace;
|
|
#ifdef CONFIG_IWMMXT
|
|
if (err == 0)
|
|
err |= preserve_iwmmxt_context(&aux->iwmmxt);
|
|
#endif
|
|
#ifdef CONFIG_VFP
|
|
if (err == 0)
|
|
err |= preserve_vfp_context(&aux->vfp);
|
|
#endif
|
|
err |= __put_user(0, &aux->end_magic);
|
|
|
|
return err;
|
|
}
|
|
|
|
static inline void __user *
|
|
get_sigframe(struct ksignal *ksig, struct pt_regs *regs, int framesize)
|
|
{
|
|
unsigned long sp = sigsp(regs->ARM_sp, ksig);
|
|
void __user *frame;
|
|
|
|
/*
|
|
* ATPCS B01 mandates 8-byte alignment
|
|
*/
|
|
frame = (void __user *)((sp - framesize) & ~7);
|
|
|
|
/*
|
|
* Check that we can actually write to the signal frame.
|
|
*/
|
|
if (!access_ok(frame, framesize))
|
|
frame = NULL;
|
|
|
|
return frame;
|
|
}
|
|
|
|
static int
|
|
setup_return(struct pt_regs *regs, struct ksignal *ksig,
|
|
unsigned long __user *rc, void __user *frame)
|
|
{
|
|
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
|
|
unsigned long handler_fdpic_GOT = 0;
|
|
unsigned long retcode;
|
|
unsigned int idx, thumb = 0;
|
|
unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
|
|
bool fdpic = IS_ENABLED(CONFIG_BINFMT_ELF_FDPIC) &&
|
|
(current->personality & FDPIC_FUNCPTRS);
|
|
|
|
if (fdpic) {
|
|
unsigned long __user *fdpic_func_desc =
|
|
(unsigned long __user *)handler;
|
|
if (__get_user(handler, &fdpic_func_desc[0]) ||
|
|
__get_user(handler_fdpic_GOT, &fdpic_func_desc[1]))
|
|
return 1;
|
|
}
|
|
|
|
cpsr |= PSR_ENDSTATE;
|
|
|
|
/*
|
|
* Maybe we need to deliver a 32-bit signal to a 26-bit task.
|
|
*/
|
|
if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
|
|
cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
|
|
|
|
#ifdef CONFIG_ARM_THUMB
|
|
if (elf_hwcap & HWCAP_THUMB) {
|
|
/*
|
|
* The LSB of the handler determines if we're going to
|
|
* be using THUMB or ARM mode for this signal handler.
|
|
*/
|
|
thumb = handler & 1;
|
|
|
|
/*
|
|
* Clear the If-Then Thumb-2 execution state. ARM spec
|
|
* requires this to be all 000s in ARM mode. Snapdragon
|
|
* S4/Krait misbehaves on a Thumb=>ARM signal transition
|
|
* without this.
|
|
*
|
|
* We must do this whenever we are running on a Thumb-2
|
|
* capable CPU, which includes ARMv6T2. However, we elect
|
|
* to always do this to simplify the code; this field is
|
|
* marked UNK/SBZP for older architectures.
|
|
*/
|
|
cpsr &= ~PSR_IT_MASK;
|
|
|
|
if (thumb) {
|
|
cpsr |= PSR_T_BIT;
|
|
} else
|
|
cpsr &= ~PSR_T_BIT;
|
|
}
|
|
#endif
|
|
|
|
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
|
|
retcode = (unsigned long)ksig->ka.sa.sa_restorer;
|
|
if (fdpic) {
|
|
/*
|
|
* We need code to load the function descriptor.
|
|
* That code follows the standard sigreturn code
|
|
* (6 words), and is made of 3 + 2 words for each
|
|
* variant. The 4th copied word is the actual FD
|
|
* address that the assembly code expects.
|
|
*/
|
|
idx = 6 + thumb * 3;
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
|
|
idx += 5;
|
|
if (__put_user(sigreturn_codes[idx], rc ) ||
|
|
__put_user(sigreturn_codes[idx+1], rc+1) ||
|
|
__put_user(sigreturn_codes[idx+2], rc+2) ||
|
|
__put_user(retcode, rc+3))
|
|
return 1;
|
|
goto rc_finish;
|
|
}
|
|
} else {
|
|
idx = thumb << 1;
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
|
|
idx += 3;
|
|
|
|
/*
|
|
* Put the sigreturn code on the stack no matter which return
|
|
* mechanism we use in order to remain ABI compliant
|
|
*/
|
|
if (__put_user(sigreturn_codes[idx], rc) ||
|
|
__put_user(sigreturn_codes[idx+1], rc+1))
|
|
return 1;
|
|
|
|
rc_finish:
|
|
#ifdef CONFIG_MMU
|
|
if (cpsr & MODE32_BIT) {
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
/*
|
|
* 32-bit code can use the signal return page
|
|
* except when the MPU has protected the vectors
|
|
* page from PL0
|
|
*/
|
|
retcode = mm->context.sigpage + signal_return_offset +
|
|
(idx << 2) + thumb;
|
|
} else
|
|
#endif
|
|
{
|
|
/*
|
|
* Ensure that the instruction cache sees
|
|
* the return code written onto the stack.
|
|
*/
|
|
flush_icache_range((unsigned long)rc,
|
|
(unsigned long)(rc + 3));
|
|
|
|
retcode = ((unsigned long)rc) + thumb;
|
|
}
|
|
}
|
|
|
|
regs->ARM_r0 = ksig->sig;
|
|
regs->ARM_sp = (unsigned long)frame;
|
|
regs->ARM_lr = retcode;
|
|
regs->ARM_pc = handler;
|
|
if (fdpic)
|
|
regs->ARM_r9 = handler_fdpic_GOT;
|
|
regs->ARM_cpsr = cpsr;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int
|
|
setup_frame(struct ksignal *ksig, sigset_t *set, struct pt_regs *regs)
|
|
{
|
|
struct sigframe __user *frame = get_sigframe(ksig, regs, sizeof(*frame));
|
|
int err = 0;
|
|
|
|
if (!frame)
|
|
return 1;
|
|
|
|
/*
|
|
* Set uc.uc_flags to a value which sc.trap_no would never have.
|
|
*/
|
|
err = __put_user(0x5ac3c35a, &frame->uc.uc_flags);
|
|
|
|
err |= setup_sigframe(frame, regs, set);
|
|
if (err == 0)
|
|
err = setup_return(regs, ksig, frame->retcode, frame);
|
|
|
|
return err;
|
|
}
|
|
|
|
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 (!frame)
|
|
return 1;
|
|
|
|
err |= copy_siginfo_to_user(&frame->info, &ksig->info);
|
|
|
|
err |= __put_user(0, &frame->sig.uc.uc_flags);
|
|
err |= __put_user(NULL, &frame->sig.uc.uc_link);
|
|
|
|
err |= __save_altstack(&frame->sig.uc.uc_stack, regs->ARM_sp);
|
|
err |= setup_sigframe(&frame->sig, regs, set);
|
|
if (err == 0)
|
|
err = setup_return(regs, ksig, frame->sig.retcode, frame);
|
|
|
|
if (err == 0) {
|
|
/*
|
|
* 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->ARM_r1 = (unsigned long)&frame->info;
|
|
regs->ARM_r2 = (unsigned long)&frame->sig.uc;
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
/*
|
|
* Perform fixup for the pre-signal frame.
|
|
*/
|
|
rseq_signal_deliver(ksig, regs);
|
|
|
|
/*
|
|
* Set up the stack frame
|
|
*/
|
|
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
|
|
ret = setup_rt_frame(ksig, oldset, regs);
|
|
else
|
|
ret = setup_frame(ksig, oldset, regs);
|
|
|
|
/*
|
|
* Check that the resulting registers are actually sane.
|
|
*/
|
|
ret |= !valid_user_regs(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 int do_signal(struct pt_regs *regs, int syscall)
|
|
{
|
|
unsigned int retval = 0, continue_addr = 0, restart_addr = 0;
|
|
struct ksignal ksig;
|
|
int restart = 0;
|
|
|
|
/*
|
|
* If we were from a system call, check for system call restarting...
|
|
*/
|
|
if (syscall) {
|
|
continue_addr = regs->ARM_pc;
|
|
restart_addr = continue_addr - (thumb_mode(regs) ? 2 : 4);
|
|
retval = regs->ARM_r0;
|
|
|
|
/*
|
|
* Prepare for system call restart. We do this here so that a
|
|
* debugger will see the already changed PSW.
|
|
*/
|
|
switch (retval) {
|
|
case -ERESTART_RESTARTBLOCK:
|
|
restart -= 2;
|
|
fallthrough;
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
restart++;
|
|
regs->ARM_r0 = regs->ARM_ORIG_r0;
|
|
regs->ARM_pc = restart_addr;
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get the signal to deliver. When running under ptrace, at this
|
|
* point the debugger may change all our registers ...
|
|
*/
|
|
/*
|
|
* Depending on the signal settings we may need to revert the
|
|
* decision to restart the system call. But skip this if a
|
|
* debugger has chosen to restart at a different PC.
|
|
*/
|
|
if (get_signal(&ksig)) {
|
|
/* handler */
|
|
if (unlikely(restart) && regs->ARM_pc == restart_addr) {
|
|
if (retval == -ERESTARTNOHAND ||
|
|
retval == -ERESTART_RESTARTBLOCK
|
|
|| (retval == -ERESTARTSYS
|
|
&& !(ksig.ka.sa.sa_flags & SA_RESTART))) {
|
|
regs->ARM_r0 = -EINTR;
|
|
regs->ARM_pc = continue_addr;
|
|
}
|
|
}
|
|
handle_signal(&ksig, regs);
|
|
} else {
|
|
/* no handler */
|
|
restore_saved_sigmask();
|
|
if (unlikely(restart) && regs->ARM_pc == restart_addr) {
|
|
regs->ARM_pc = continue_addr;
|
|
return restart;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
asmlinkage int
|
|
do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
|
|
{
|
|
/*
|
|
* The assembly code enters us with IRQs off, but it hasn't
|
|
* informed the tracing code of that for efficiency reasons.
|
|
* Update the trace code with the current status.
|
|
*/
|
|
trace_hardirqs_off();
|
|
do {
|
|
if (likely(thread_flags & _TIF_NEED_RESCHED)) {
|
|
schedule();
|
|
} else {
|
|
if (unlikely(!user_mode(regs)))
|
|
return 0;
|
|
local_irq_enable();
|
|
if (thread_flags & (_TIF_SIGPENDING | _TIF_NOTIFY_SIGNAL)) {
|
|
int restart = do_signal(regs, syscall);
|
|
if (unlikely(restart)) {
|
|
/*
|
|
* Restart without handlers.
|
|
* Deal with it without leaving
|
|
* the kernel space.
|
|
*/
|
|
return restart;
|
|
}
|
|
syscall = 0;
|
|
} else if (thread_flags & _TIF_UPROBE) {
|
|
uprobe_notify_resume(regs);
|
|
} else {
|
|
resume_user_mode_work(regs);
|
|
}
|
|
}
|
|
local_irq_disable();
|
|
thread_flags = read_thread_flags();
|
|
} while (thread_flags & _TIF_WORK_MASK);
|
|
return 0;
|
|
}
|
|
|
|
struct page *get_signal_page(void)
|
|
{
|
|
unsigned long ptr;
|
|
unsigned offset;
|
|
struct page *page;
|
|
void *addr;
|
|
|
|
page = alloc_pages(GFP_KERNEL, 0);
|
|
|
|
if (!page)
|
|
return NULL;
|
|
|
|
addr = page_address(page);
|
|
|
|
/* Poison the entire page */
|
|
memset32(addr, __opcode_to_mem_arm(0xe7fddef1),
|
|
PAGE_SIZE / sizeof(u32));
|
|
|
|
/* Give the signal return code some randomness */
|
|
offset = 0x200 + (get_random_int() & 0x7fc);
|
|
signal_return_offset = offset;
|
|
|
|
/* Copy signal return handlers into the page */
|
|
memcpy(addr + offset, sigreturn_codes, sizeof(sigreturn_codes));
|
|
|
|
/* Flush out all instructions in this page */
|
|
ptr = (unsigned long)addr;
|
|
flush_icache_range(ptr, ptr + PAGE_SIZE);
|
|
|
|
return page;
|
|
}
|
|
|
|
#ifdef CONFIG_DEBUG_RSEQ
|
|
asmlinkage void do_rseq_syscall(struct pt_regs *regs)
|
|
{
|
|
rseq_syscall(regs);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* Compile-time assertions for siginfo_t offsets. Check NSIG* as well, as
|
|
* changes likely come with new fields that should be added below.
|
|
*/
|
|
static_assert(NSIGILL == 11);
|
|
static_assert(NSIGFPE == 15);
|
|
static_assert(NSIGSEGV == 9);
|
|
static_assert(NSIGBUS == 5);
|
|
static_assert(NSIGTRAP == 6);
|
|
static_assert(NSIGCHLD == 6);
|
|
static_assert(NSIGSYS == 2);
|
|
static_assert(sizeof(siginfo_t) == 128);
|
|
static_assert(__alignof__(siginfo_t) == 4);
|
|
static_assert(offsetof(siginfo_t, si_signo) == 0x00);
|
|
static_assert(offsetof(siginfo_t, si_errno) == 0x04);
|
|
static_assert(offsetof(siginfo_t, si_code) == 0x08);
|
|
static_assert(offsetof(siginfo_t, si_pid) == 0x0c);
|
|
static_assert(offsetof(siginfo_t, si_uid) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_tid) == 0x0c);
|
|
static_assert(offsetof(siginfo_t, si_overrun) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_status) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_utime) == 0x18);
|
|
static_assert(offsetof(siginfo_t, si_stime) == 0x1c);
|
|
static_assert(offsetof(siginfo_t, si_value) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_int) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_ptr) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_addr) == 0x0c);
|
|
static_assert(offsetof(siginfo_t, si_addr_lsb) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_lower) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_upper) == 0x18);
|
|
static_assert(offsetof(siginfo_t, si_pkey) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_perf_data) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_perf_type) == 0x14);
|
|
static_assert(offsetof(siginfo_t, si_perf_flags) == 0x18);
|
|
static_assert(offsetof(siginfo_t, si_band) == 0x0c);
|
|
static_assert(offsetof(siginfo_t, si_fd) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_call_addr) == 0x0c);
|
|
static_assert(offsetof(siginfo_t, si_syscall) == 0x10);
|
|
static_assert(offsetof(siginfo_t, si_arch) == 0x14);
|