diff options
Diffstat (limited to 'arch/x86/um/signal.c')
| -rw-r--r-- | arch/x86/um/signal.c | 602 |
1 files changed, 602 insertions, 0 deletions
diff --git a/arch/x86/um/signal.c b/arch/x86/um/signal.c new file mode 100644 index 00000000000..5e04a1c899f --- /dev/null +++ b/arch/x86/um/signal.c @@ -0,0 +1,602 @@ +/* + * 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> + +#ifdef CONFIG_X86_32 + +/* + * FPU tag word conversions. + */ + +static inline unsigned short twd_i387_to_fxsr(unsigned short twd) +{ + unsigned int tmp; /* to avoid 16 bit prefixes in the code */ + + /* Transform each pair of bits into 01 (valid) or 00 (empty) */ + tmp = ~twd; + tmp = (tmp | (tmp>>1)) & 0x5555; /* 0V0V0V0V0V0V0V0V */ + /* and move the valid bits to the lower byte. */ + tmp = (tmp | (tmp >> 1)) & 0x3333; /* 00VV00VV00VV00VV */ + tmp = (tmp | (tmp >> 2)) & 0x0f0f; /* 0000VVVV0000VVVV */ + tmp = (tmp | (tmp >> 4)) & 0x00ff; /* 00000000VVVVVVVV */ + return tmp; +} + +static inline unsigned long twd_fxsr_to_i387(struct user_fxsr_struct *fxsave) +{ + struct _fpxreg *st = NULL; + unsigned long twd = (unsigned long) fxsave->twd; + unsigned long tag; + unsigned long ret = 0xffff0000; + int i; + +#define FPREG_ADDR(f, n) ((char *)&(f)->st_space + (n) * 16) + + for (i = 0; i < 8; i++) { + if (twd & 0x1) { + st = (struct _fpxreg *) FPREG_ADDR(fxsave, i); + + switch (st->exponent & 0x7fff) { + case 0x7fff: + tag = 2; /* Special */ + break; + case 0x0000: + if ( !st->significand[0] && + !st->significand[1] && + !st->significand[2] && + !st->significand[3] ) { + tag = 1; /* Zero */ + } else { + tag = 2; /* Special */ + } + break; + default: + if (st->significand[3] & 0x8000) { + tag = 0; /* Valid */ + } else { + tag = 2; /* Special */ + } + break; + } + } else { + tag = 3; /* Empty */ + } + ret |= (tag << (2 * i)); + twd = twd >> 1; + } + return ret; +} + +static int convert_fxsr_to_user(struct _fpstate __user *buf, + struct user_fxsr_struct *fxsave) +{ + unsigned long env[7]; + struct _fpreg __user *to; + struct _fpxreg *from; + int i; + + env[0] = (unsigned long)fxsave->cwd | 0xffff0000ul; + env[1] = (unsigned long)fxsave->swd | 0xffff0000ul; + env[2] = twd_fxsr_to_i387(fxsave); + env[3] = fxsave->fip; + env[4] = fxsave->fcs | ((unsigned long)fxsave->fop << 16); + env[5] = fxsave->foo; + env[6] = fxsave->fos; + + if (__copy_to_user(buf, env, 7 * sizeof(unsigned long))) + return 1; + + to = &buf->_st[0]; + from = (struct _fpxreg *) &fxsave->st_space[0]; + for (i = 0; i < 8; i++, to++, from++) { + unsigned long __user *t = (unsigned long __user *)to; + unsigned long *f = (unsigned long *)from; + + if (__put_user(*f, t) || + __put_user(*(f + 1), t + 1) || + __put_user(from->exponent, &to->exponent)) + return 1; + } + return 0; +} + +static int convert_fxsr_from_user(struct user_fxsr_struct *fxsave, + struct _fpstate __user *buf) +{ + unsigned long env[7]; + struct _fpxreg *to; + struct _fpreg __user *from; + int i; + + if (copy_from_user( env, buf, 7 * sizeof(long))) + return 1; + + fxsave->cwd = (unsigned short)(env[0] & 0xffff); + fxsave->swd = (unsigned short)(env[1] & 0xffff); + fxsave->twd = twd_i387_to_fxsr((unsigned short)(env[2] & 0xffff)); + fxsave->fip = env[3]; + fxsave->fop = (unsigned short)((env[4] & 0xffff0000ul) >> 16); + fxsave->fcs = (env[4] & 0xffff); + fxsave->foo = env[5]; + fxsave->fos = env[6]; + + to = (struct _fpxreg *) &fxsave->st_space[0]; + from = &buf->_st[0]; + for (i = 0; i < 8; i++, to++, from++) { + unsigned long *t = (unsigned long *)to; + unsigned long __user *f = (unsigned long __user *)from; + + if (__get_user(*t, f) || + __get_user(*(t + 1), f + 1) || + __get_user(to->exponent, &from->exponent)) + return 1; + } + return 0; +} + +extern int have_fpx_regs; + +#endif + +static int copy_sc_from_user(struct pt_regs *regs, + struct sigcontext __user *from) +{ + struct sigcontext sc; + int err, pid; + + /* Always make any pending restarted system calls return -EINTR */ + current_thread_info()->restart_block.fn = do_no_restart_syscall; + + err = copy_from_user(&sc, from, sizeof(sc)); + if (err) + return err; + +#define GETREG(regno, regname) regs->regs.gp[HOST_##regno] = sc.regname + +#ifdef CONFIG_X86_32 + GETREG(GS, gs); + GETREG(FS, fs); + GETREG(ES, es); + GETREG(DS, ds); +#endif + GETREG(DI, di); + GETREG(SI, si); + GETREG(BP, bp); + GETREG(SP, sp); + GETREG(BX, bx); + GETREG(DX, dx); + GETREG(CX, cx); + GETREG(AX, ax); + GETREG(IP, ip); + +#ifdef CONFIG_X86_64 + GETREG(R8, r8); + GETREG(R9, r9); + GETREG(R10, r10); + GETREG(R11, r11); + GETREG(R12, r12); + GETREG(R13, r13); + GETREG(R14, r14); + GETREG(R15, r15); +#endif + + GETREG(CS, cs); + GETREG(EFLAGS, flags); +#ifdef CONFIG_X86_32 + GETREG(SS, ss); +#endif + +#undef GETREG + + pid = userspace_pid[current_thread_info()->cpu]; +#ifdef CONFIG_X86_32 + if (have_fpx_regs) { + struct user_fxsr_struct fpx; + + err = copy_from_user(&fpx, + &((struct _fpstate __user *)sc.fpstate)->_fxsr_env[0], + sizeof(struct user_fxsr_struct)); + if (err) + return 1; + + err = convert_fxsr_from_user(&fpx, sc.fpstate); + if (err) + return 1; + + err = restore_fpx_registers(pid, (unsigned long *) &fpx); + if (err < 0) { + printk(KERN_ERR "copy_sc_from_user - " + "restore_fpx_registers failed, errno = %d\n", + -err); + return 1; + } + } else +#endif + { + struct user_i387_struct fp; + + err = copy_from_user(&fp, sc.fpstate, + sizeof(struct user_i387_struct)); + if (err) + return 1; + + err = restore_fp_registers(pid, (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) +{ + struct sigcontext sc; + struct faultinfo * fi = ¤t->thread.arch.faultinfo; + int err, pid; + memset(&sc, 0, sizeof(struct sigcontext)); + +#define PUTREG(regno, regname) sc.regname = regs->regs.gp[HOST_##regno] + +#ifdef CONFIG_X86_32 + PUTREG(GS, gs); + PUTREG(FS, fs); + PUTREG(ES, es); + PUTREG(DS, ds); +#endif + PUTREG(DI, di); + PUTREG(SI, si); + PUTREG(BP, bp); + PUTREG(SP, sp); + PUTREG(BX, bx); + PUTREG(DX, dx); + PUTREG(CX, cx); + PUTREG(AX, ax); +#ifdef CONFIG_X86_64 + PUTREG(R8, r8); + PUTREG(R9, r9); + PUTREG(R10, r10); + PUTREG(R11, r11); + PUTREG(R12, r12); + PUTREG(R13, r13); + PUTREG(R14, r14); + PUTREG(R15, r15); +#endif + + sc.cr2 = fi->cr2; + sc.err = fi->error_code; + sc.trapno = fi->trap_no; + PUTREG(IP, ip); + PUTREG(CS, cs); + PUTREG(EFLAGS, flags); +#ifdef CONFIG_X86_32 + PUTREG(SP, sp_at_signal); + PUTREG(SS, ss); +#endif +#undef PUTREG + sc.oldmask = mask; + sc.fpstate = to_fp; + + err = copy_to_user(to, &sc, sizeof(struct sigcontext)); + if (err) + return 1; + + pid = userspace_pid[current_thread_info()->cpu]; + +#ifdef CONFIG_X86_32 + if (have_fpx_regs) { + struct user_fxsr_struct fpx; + + err = save_fpx_registers(pid, (unsigned long *) &fpx); + if (err < 0){ + printk(KERN_ERR "copy_sc_to_user - save_fpx_registers " + "failed, errno = %d\n", err); + return 1; + } + + err = convert_fxsr_to_user(to_fp, &fpx); + if (err) + return 1; + + err |= __put_user(fpx.swd, &to_fp->status); + err |= __put_user(X86_FXSR_MAGIC, &to_fp->magic); + if (err) + return 1; + + if (copy_to_user(&to_fp->_fxsr_env[0], &fpx, + sizeof(struct user_fxsr_struct))) + return 1; + } else +#endif + { + struct user_i387_struct fp; + + err = save_fp_registers(pid, (unsigned long *) &fp); + if (copy_to_user(to_fp, &fp, sizeof(struct user_i387_struct))) + return 1; + } + + return 0; +} + +#ifdef CONFIG_X86_32 +static int copy_ucontext_to_user(struct ucontext __user *uc, + struct _fpstate __user *fp, sigset_t *set, + unsigned long sp) +{ + int err = 0; + + err |= __save_altstack(&uc->uc_stack, sp); + err |= copy_sc_to_user(&uc->uc_mcontext, fp, ¤t->thread.regs, 0); + err |= copy_to_user(&uc->uc_sigmask, set, sizeof(*set)); + return err; +} + +struct sigframe +{ + char __user *pretcode; + int sig; + struct sigcontext sc; + struct _fpstate fpstate; + unsigned long extramask[_NSIG_WORDS-1]; + char retcode[8]; +}; + +struct rt_sigframe +{ + char __user *pretcode; + int sig; + struct siginfo __user *pinfo; + void __user *puc; + struct siginfo info; + struct ucontext uc; + struct _fpstate fpstate; + char retcode[8]; +}; + +int setup_signal_stack_sc(unsigned long stack_top, int sig, + struct k_sigaction *ka, struct pt_regs *regs, + sigset_t *mask) +{ + struct sigframe __user *frame; + void __user *restorer; + int err = 0; + + /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */ + stack_top = ((stack_top + 4) & -16UL) - 4; + frame = (struct sigframe __user *) stack_top - 1; + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + return 1; + + restorer = frame->retcode; + if (ka->sa.sa_flags & SA_RESTORER) + restorer = ka->sa.sa_restorer; + + err |= __put_user(restorer, &frame->pretcode); + err |= __put_user(sig, &frame->sig); + err |= copy_sc_to_user(&frame->sc, &frame->fpstate, regs, mask->sig[0]); + if (_NSIG_WORDS > 1) + err |= __copy_to_user(&frame->extramask, &mask->sig[1], + sizeof(frame->extramask)); + + /* + * This is popl %eax ; movl $,%eax ; int $0x80 + * + * WE DO NOT USE IT ANY MORE! It's only left here for historical + * reasons and because gdb uses it as a signature to notice + * signal handler stack frames. + */ + err |= __put_user(0xb858, (short __user *)(frame->retcode+0)); + err |= __put_user(__NR_sigreturn, (int __user *)(frame->retcode+2)); + err |= __put_user(0x80cd, (short __user *)(frame->retcode+6)); + + if (err) + return err; + + PT_REGS_SP(regs) = (unsigned long) frame; + PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; + PT_REGS_AX(regs) = (unsigned long) sig; + PT_REGS_DX(regs) = (unsigned long) 0; + PT_REGS_CX(regs) = (unsigned long) 0; + return 0; +} + +int setup_signal_stack_si(unsigned long stack_top, int sig, + struct k_sigaction *ka, struct pt_regs *regs, + siginfo_t *info, sigset_t *mask) +{ + struct rt_sigframe __user *frame; + void __user *restorer; + int err = 0; + + stack_top &= -8UL; + frame = (struct rt_sigframe __user *) stack_top - 1; + if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) + return 1; + + restorer = frame->retcode; + if (ka->sa.sa_flags & SA_RESTORER) + restorer = ka->sa.sa_restorer; + + err |= __put_user(restorer, &frame->pretcode); + err |= __put_user(sig, &frame->sig); + err |= __put_user(&frame->info, &frame->pinfo); + err |= __put_user(&frame->uc, &frame->puc); + err |= copy_siginfo_to_user(&frame->info, info); + err |= copy_ucontext_to_user(&frame->uc, &frame->fpstate, mask, + PT_REGS_SP(regs)); + + /* + * This is movl $,%eax ; int $0x80 + * + * WE DO NOT USE IT ANY MORE! It's only left here for historical + * reasons and because gdb uses it as a signature to notice + * signal handler stack frames. + */ + err |= __put_user(0xb8, (char __user *)(frame->retcode+0)); + err |= __put_user(__NR_rt_sigreturn, (int __user *)(frame->retcode+1)); + err |= __put_user(0x80cd, (short __user *)(frame->retcode+5)); + + if (err) + return err; + + PT_REGS_SP(regs) = (unsigned long) frame; + PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; + PT_REGS_AX(regs) = (unsigned long) sig; + PT_REGS_DX(regs) = (unsigned long) &frame->info; + PT_REGS_CX(regs) = (unsigned long) &frame->uc; + return 0; +} + +long sys_sigreturn(void) +{ + unsigned long sp = PT_REGS_SP(¤t->thread.regs); + struct sigframe __user *frame = (struct sigframe __user *)(sp - 8); + sigset_t set; + struct sigcontext __user *sc = &frame->sc; + unsigned long __user *oldmask = &sc->oldmask; + unsigned long __user *extramask = frame->extramask; + int sig_size = (_NSIG_WORDS - 1) * sizeof(unsigned long); + + if (copy_from_user(&set.sig[0], oldmask, sizeof(set.sig[0])) || + copy_from_user(&set.sig[1], extramask, sig_size)) + goto segfault; + + set_current_blocked(&set); + + if (copy_sc_from_user(¤t->thread.regs, sc)) + 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; +} + +#else + +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; + int err = 0; + + 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; + } + + /* Create the ucontext. */ + err |= __put_user(0, &frame->uc.uc_flags); + err |= __put_user(0, &frame->uc.uc_link); + err |= __save_altstack(&frame->uc.uc_stack, PT_REGS_SP(regs)); + err |= copy_sc_to_user(&frame->uc.uc_mcontext, &frame->fpstate, regs, + set->sig[0]); + err |= __put_user(&frame->fpstate, &frame->uc.uc_mcontext.fpstate); + if (sizeof(*set) == 16) { + err |= __put_user(set->sig[0], &frame->uc.uc_sigmask.sig[0]); + err |= __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 */ + return err; + + if (err) + return err; + + /* 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_SP(regs) = (unsigned long) frame; + PT_REGS_DI(regs) = sig; + /* In case the signal handler was declared without prototypes */ + PT_REGS_AX(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_SI(regs) = (unsigned long) &frame->info; + PT_REGS_DX(regs) = (unsigned long) &frame->uc; + PT_REGS_IP(regs) = (unsigned long) ka->sa.sa_handler; + out: + return err; +} +#endif + +long sys_rt_sigreturn(void) +{ + unsigned long sp = PT_REGS_SP(¤t->thread.regs); + struct rt_sigframe __user *frame = + (struct rt_sigframe __user *)(sp - sizeof(long)); + struct ucontext __user *uc = &frame->uc; + sigset_t set; + + if (copy_from_user(&set, &uc->uc_sigmask, sizeof(set))) + goto segfault; + + 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; +} |