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/*
* Copyright (C) 2003 PathScale, Inc.
* Copyright (C) 2003 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/kernel.h>
#include <asm/unistd.h>
#include <asm/uaccess.h>
#include <asm/ucontext.h>
#include "frame_kern.h"
#include "skas.h"
static int copy_sc_from_user(struct pt_regs *regs,
struct sigcontext __user *from)
{
struct sigcontext sc;
struct user_i387_struct fp;
void __user *buf;
int err;
err = copy_from_user(&sc, from, sizeof(sc));
if (err)
return err;
#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname
GETREG(R8, r8);
GETREG(R9, r9);
GETREG(R10, r10);
GETREG(R11, r11);
GETREG(R12, r12);
GETREG(R13, r13);
GETREG(R14, r14);
GETREG(R15, r15);
GETREG(RDI, di);
GETREG(RSI, si);
GETREG(RBP, bp);
GETREG(RBX, bx);
GETREG(RDX, dx);
GETREG(RAX, ax);
GETREG(RCX, cx);
GETREG(SP, sp);
GETREG(IP, ip);
GETREG(EFLAGS, flags);
GETREG(CS, cs);
#undef GETREG
buf = sc.fpstate;
err = copy_from_user(&fp, buf, sizeof(struct user_i387_struct));
if (err)
return 1;
err = restore_fp_registers(userspace_pid[current_thread_info()->cpu],
(unsigned long *) &fp);
if (err < 0) {
printk(KERN_ERR "copy_sc_from_user - "
"restore_fp_registers failed, errno = %d\n",
-err);
return 1;
}
return 0;
}
static int copy_sc_to_user(struct sigcontext __user *to,
struct _fpstate __user *to_fp, struct pt_regs *regs,
unsigned long mask, unsigned long sp)
{
struct faultinfo * fi = ¤t->thread.arch.faultinfo;
struct sigcontext sc;
struct user_i387_struct fp;
int err = 0;
memset(&sc, 0, sizeof(struct sigcontext));
#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno]
PUTREG(RDI, di);
PUTREG(RSI, si);
PUTREG(RBP, bp);
/*
* Must use original RSP, which is passed in, rather than what's in
* signal frame.
*/
sc.sp = sp;
PUTREG(RBX, bx);
PUTREG(RDX, dx);
PUTREG(RCX, cx);
PUTREG(RAX, ax);
PUTREG(R8, r8);
PUTREG(R9, r9);
PUTREG(R10, r10);
PUTREG(R11, r11);
PUTREG(R12, r12);
PUTREG(R13, r13);
PUTREG(R14, r14);
PUTREG(R15, r15);
PUTREG(CS, cs); /* XXX x86_64 doesn't do this */
sc.cr2 = fi->cr2;
sc.err = fi->error_code;
sc.trapno = fi->trap_no;
PUTREG(IP, ip);
PUTREG(EFLAGS, flags);
#undef PUTREG
sc.oldmask = mask;
err = copy_to_user(to, &sc, sizeof(struct sigcontext));
if (err)
return 1;
err = save_fp_registers(userspace_pid[current_thread_info()->cpu],
(unsigned long *) &fp);
if (err < 0) {
printk(KERN_ERR "copy_sc_from_user - restore_fp_registers "
"failed, errno = %d\n", -err);
return 1;
}
if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct)))
return 1;
return err;
}
struct rt_sigframe
{
char __user *pretcode;
struct ucontext uc;
struct siginfo info;
struct _fpstate fpstate;
};
int setup_signal_stack_si(unsigned long stack_top, int sig,
struct k_sigaction *ka, struct pt_regs * regs,
siginfo_t *info, sigset_t *set)
{
struct rt_sigframe __user *frame;
unsigned long save_sp = PT_REGS_RSP(regs);
int err = 0;
struct task_struct *me = current;
frame = (struct rt_sigframe __user *)
round_down(stack_top - sizeof(struct rt_sigframe), 16);
/* Subtract 128 for a red zone and 8 for proper alignment */
frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8);
if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))
goto out;
if (ka->sa.sa_flags & SA_SIGINFO) {
err |= copy_siginfo_to_user(&frame->info, info);
if (err)
goto out;
}
/*
* Update SP now because the page fault handler refuses to extend
* the stack if the faulting address is too far below the current
* SP, which frame now certainly is. If there's an error, the original
* value is restored on the way out.
* When writing the sigcontext to the stack, we have to write the
* original value, so that's passed to copy_sc_to_user, which does
* the right thing with it.
*/
PT_REGS_RSP(regs) = (unsigned long) frame;
/* Create the ucontext. */
err |= __put_user(0, &frame->uc.uc_flags);
err |= __put_user(0, &frame->uc.uc_link);
err |= __put_user(me->sas_ss_sp, &frame->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(save_sp),
&frame->uc.uc_stack.ss_flags);
err |= __put_user(me->sas_ss_size, &frame->uc.uc_stack.ss_size);
err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs,
set->sig[0], save_sp);
err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate);
if (sizeof(*set) == 16) {
__put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]);
__put_user(set->sig[1], &frame->uc.uc_sigmask.sig[1]);
}
else
err |= __copy_to_user(&frame->uc.uc_sigmask, set,
sizeof(*set));
/*
* Set up to return from userspace. If provided, use a stub
* already in userspace.
*/
/* x86-64 should always use SA_RESTORER. */
if (ka->sa.sa_flags & SA_RESTORER)
err |= __put_user(ka->sa.sa_restorer, &frame->pretcode);
else
/* could use a vstub here */
goto restore_sp;
if (err)
goto restore_sp;
/* Set up registers for signal handler */
{
struct exec_domain *ed = current_thread_info()->exec_domain;
if (unlikely(ed && ed->signal_invmap && sig < 32))
sig = ed->signal_invmap[sig];
}
PT_REGS_RDI(regs) = sig;
/* In case the signal handler was declared without prototypes */
PT_REGS_RAX(regs) = 0;
/*
* This also works for non SA_SIGINFO handlers because they expect the
* next argument after the signal number on the stack.
*/
PT_REGS_RSI(regs) = (unsigned long) &frame->info;
PT_REGS_RDX(regs) = (unsigned long) &frame->uc;
PT_REGS_RIP(regs) = (unsigned long) ka->sa.sa_handler;
out:
return err;
restore_sp:
PT_REGS_RSP(regs) = save_sp;
return err;
}
long sys_rt_sigreturn(struct pt_regs *regs)
{
unsigned long sp = PT_REGS_SP(¤t->thread.regs);
struct rt_sigframe __user *frame =
(struct rt_sigframe __user *)(sp - 8);
struct ucontext __user *uc = &frame->uc;
sigset_t set;
if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set)))
goto segfault;
sigdelsetmask(&set, ~_BLOCKABLE);
set_current_blocked(&set);
if (copy_sc_from_user(¤t->thread.regs, &uc->uc_mcontext))
goto segfault;
/* Avoid ERESTART handling */
PT_REGS_SYSCALL_NR(¤t->thread.regs) = -1;
return PT_REGS_SYSCALL_RET(¤t->thread.regs);
segfault:
force_sig(SIGSEGV, current);
return 0;
}
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