ia32_signal.c

一个2.4.21版本的嵌入式linux内核

/*
 * IA32 Architecture-specific signal handling support.
 *
 * Copyright (C) 1999, 2001 Hewlett-Packard Co
 *	David Mosberger-Tang <[e-mail]>
 * Copyright (C) 1999 Arun Sharma <[e-mail]>
 * Copyright (C) 2000 VA Linux Co
 * Copyright (C) 2000 Don Dugger <[e-mail]>
 *
 * Derived from i386 and Alpha versions.
 */

#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/personality.h>
#include <linux/ptrace.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/wait.h>

#include <asm/uaccess.h>
#include <asm/rse.h>
#include <asm/sigcontext.h>
#include <asm/segment.h>
#include <asm/ia32.h>

#include "../kernel/sigframe.h"

#define A(__x)		((unsigned long)(__x))

#define DEBUG_SIG	0
#define _BLOCKABLE	(~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

#define __IA32_NR_sigreturn            119
#define __IA32_NR_rt_sigreturn         173

register double f16 asm ("f16"); register double f17 asm ("f17");
register double f18 asm ("f18"); register double f19 asm ("f19");
register double f20 asm ("f20"); register double f21 asm ("f21");
register double f22 asm ("f22"); register double f23 asm ("f23");

register double f24 asm ("f24"); register double f25 asm ("f25");
register double f26 asm ("f26"); register double f27 asm ("f27");
register double f28 asm ("f28"); register double f29 asm ("f29");
register double f30 asm ("f30"); register double f31 asm ("f31");

struct sigframe_ia32
{
       int pretcode;
       int sig;
       struct sigcontext_ia32 sc;
       struct _fpstate_ia32 fpstate;
       unsigned int extramask[_IA32_NSIG_WORDS-1];
       char retcode[8];
};

struct rt_sigframe_ia32
{
       int pretcode;
       int sig;
       int pinfo;
       int puc;
       siginfo_t32 info;
       struct ucontext_ia32 uc;
       struct _fpstate_ia32 fpstate;
       char retcode[8];
};

int
copy_siginfo_from_user32 (siginfo_t *to, siginfo_t32 *from)
{
	unsigned long tmp;
	int err;

	if (!access_ok(VERIFY_READ, from, sizeof(siginfo_t32)))
		return -EFAULT;

	err = __get_user(to->si_signo, &from->si_signo);
	err |= __get_user(to->si_errno, &from->si_errno);
	err |= __get_user(to->si_code, &from->si_code);

	if (from->si_code < 0)
		err |= __copy_from_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
	else {
		switch (from->si_code >> 16) {
		      case __SI_CHLD >> 16:
			err |= __get_user(to->si_utime, &from->si_utime);
			err |= __get_user(to->si_stime, &from->si_stime);
			err |= __get_user(to->si_status, &from->si_status);
		      default:
			err |= __get_user(to->si_pid, &from->si_pid);
			err |= __get_user(to->si_uid, &from->si_uid);
			break;
		      case __SI_FAULT >> 16:
			err |= __get_user(tmp, &from->si_addr);
			to->si_addr = (void *) tmp;
			break;
		      case __SI_POLL >> 16:
			err |= __get_user(to->si_band, &from->si_band);
			err |= __get_user(to->si_fd, &from->si_fd);
			break;
			/* case __SI_RT: This is not generated by the kernel as of now.  */
		}
	}
	return err;
}

int
copy_siginfo_to_user32 (siginfo_t32 *to, siginfo_t *from)
{
	int err;

	if (!access_ok(VERIFY_WRITE, to, sizeof(siginfo_t32)))
		return -EFAULT;

	/* If you change siginfo_t structure, please be sure
	   this code is fixed accordingly.
	   It should never copy any pad contained in the structure
	   to avoid security leaks, but must copy the generic
	   3 ints plus the relevant union member.
	   This routine must convert siginfo from 64bit to 32bit as well
	   at the same time.  */
	err = __put_user(from->si_signo, &to->si_signo);
	err |= __put_user(from->si_errno, &to->si_errno);
	err |= __put_user((short)from->si_code, &to->si_code);
	if (from->si_code < 0)
		err |= __copy_to_user(&to->_sifields._pad, &from->_sifields._pad, SI_PAD_SIZE);
	else {
		switch (from->si_code >> 16) {
		case __SI_CHLD >> 16:
			err |= __put_user(from->si_utime, &to->si_utime);
			err |= __put_user(from->si_stime, &to->si_stime);
			err |= __put_user(from->si_status, &to->si_status);
		default:
			err |= __put_user(from->si_pid, &to->si_pid);
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		case __SI_FAULT >> 16:
			err |= __put_user((long)from->si_addr, &to->si_addr);
			break;
		case __SI_POLL >> 16:
			err |= __put_user(from->si_band, &to->si_band);
			err |= __put_user(from->si_fd, &to->si_fd);
			break;
		/* case __SI_RT: This is not generated by the kernel as of now.  */
		}
	}
	return err;
}


/*
 *  SAVE and RESTORE of ia32 fpstate info, from ia64 current state
 *  Used in exception handler to pass the fpstate to the user, and restore
 *  the fpstate while returning from the exception handler.
 *
 *    fpstate info and their mapping to IA64 regs:
 *    fpstate    REG(BITS)      Attribute    Comments
 *    cw         ar.fcr(0:12)                with bits 7 and 6 not used
 *    sw         ar.fsr(0:15)
 *    tag        ar.fsr(16:31)               with odd numbered bits not used
 *                                           (read returns 0, writes ignored)
 *    ipoff      ar.fir(0:31)
 *    cssel      ar.fir(32:47)
 *    dataoff    ar.fdr(0:31)
 *    datasel    ar.fdr(32:47)
 *
 *    _st[(0+TOS)%8]   f8
 *    _st[(1+TOS)%8]   f9                    (f8, f9 from ptregs)
 *      : :            :                     (f10..f15 from live reg)
 *      : :            :
 *    _st[(7+TOS)%8]   f15                   TOS=sw.top(bits11:13)
 *
 *    status     Same as sw     RO
 *    magic      0                           as X86_FXSR_MAGIC in ia32
 *    mxcsr      Bits(7:15)=ar.fcr(39:47)
 *               Bits(0:5) =ar.fsr(32:37)    with bit 6 reserved
 *    _xmm[0..7] f16..f31                    (live registers)
 *                                           with _xmm[0]
 *                                             Bit(64:127)=f17(0:63)
 *                                             Bit(0:63)=f16(0:63)
 *    All other fields unused...
 */

#define __ldfe(regnum, x)						\
({									\
 	register double __f__ asm ("f"#regnum);				\
	__asm__ __volatile__ ("ldfe %0=[%1] ;;" :"=f"(__f__): "r"(x));	\
})

#define __ldf8(regnum, x)						\
({									\
 	register double __f__ asm ("f"#regnum);				\
	__asm__ __volatile__ ("ldf8 %0=[%1] ;;" :"=f"(__f__): "r"(x));	\
})

#define __stfe(x, regnum)							\
({										\
 	register double __f__ asm ("f"#regnum);					\
	__asm__ __volatile__ ("stfe [%0]=%1" :: "r"(x), "f"(__f__) : "memory");	\
})

#define __stf8(x, regnum)							\
({										\
 	register double __f__ asm ("f"#regnum);					\
	__asm__ __volatile__ ("stf8 [%0]=%1" :: "r"(x), "f"(__f__) : "memory");	\
})

static int
save_ia32_fpstate_live (struct _fpstate_ia32 *save)
{
	struct task_struct *tsk = current;
	struct pt_regs *ptp;
	struct _fpreg_ia32 *fpregp;
	char buf[32];
	unsigned long fsr, fcr, fir, fdr;
	unsigned long new_fsr;
	unsigned long num128[2];
	unsigned long mxcsr=0;
	int fp_tos, fr8_st_map;

	if (!access_ok(VERIFY_WRITE, save, sizeof(*save)))
		return -EFAULT;

	/* Readin fsr, fcr, fir, fdr and copy onto fpstate */
	asm volatile ( "mov %0=ar.fsr;" : "=r"(fsr));
	asm volatile ( "mov %0=ar.fcr;" : "=r"(fcr));
	asm volatile ( "mov %0=ar.fir;" : "=r"(fir));
	asm volatile ( "mov %0=ar.fdr;" : "=r"(fdr));
	/*
	 * We need to clear the exception state before calling the signal handler. Clear
	 * the bits 15, bits 0-7 in fp status word. Similar to the functionality of fnclex
	 * instruction.
	 */
	new_fsr = fsr & ~0x80ff;
	asm volatile ( "mov ar.fsr=%0;" :: "r"(new_fsr));

	__put_user(fcr & 0xffff, &save->cw);
	__put_user(fsr & 0xffff, &save->sw);
	__put_user((fsr>>16) & 0xffff, &save->tag);
	__put_user(fir, &save->ipoff);
	__put_user((fir>>32) & 0xffff, &save->cssel);
	__put_user(fdr, &save->dataoff);
	__put_user((fdr>>32) & 0xffff, &save->datasel);
	__put_user(fsr & 0xffff, &save->status);

	mxcsr = ((fcr>>32) & 0xff80) | ((fsr>>32) & 0x3f);
	__put_user(mxcsr & 0xffff, &save->mxcsr);
	__put_user( 0, &save->magic); //#define X86_FXSR_MAGIC   0x0000

	/*
	 * save f8 and f9  from pt_regs
	 * save f10..f15 from live register set
	 */
	/*
	 *  Find the location where f8 has to go in fp reg stack.  This depends on
	 *  TOP(11:13) field of sw. Other f reg continue sequentially from where f8 maps
	 *  to.
	 */
	fp_tos = (fsr>>11)&0x7;
	fr8_st_map = (8-fp_tos)&0x7;
	ptp = ia64_task_regs(tsk);
	fpregp = (struct _fpreg_ia32 *)(((unsigned long)buf + 15) & ~15);
	ia64f2ia32f(fpregp, &ptp->f8);
	copy_to_user(&save->_st[(0+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	ia64f2ia32f(fpregp, &ptp->f9);
	copy_to_user(&save->_st[(1+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));

	__stfe(fpregp, 10);
	copy_to_user(&save->_st[(2+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	__stfe(fpregp, 11);
	copy_to_user(&save->_st[(3+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	__stfe(fpregp, 12);
	copy_to_user(&save->_st[(4+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	__stfe(fpregp, 13);
	copy_to_user(&save->_st[(5+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	__stfe(fpregp, 14);
	copy_to_user(&save->_st[(6+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));
	__stfe(fpregp, 15);
	copy_to_user(&save->_st[(7+fr8_st_map)&0x7], fpregp, sizeof(struct _fpreg_ia32));

	__stf8(&num128[0], 16);
	__stf8(&num128[1], 17);
	copy_to_user(&save->_xmm[0], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 18);
	__stf8(&num128[1], 19);
	copy_to_user(&save->_xmm[1], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 20);
	__stf8(&num128[1], 21);
	copy_to_user(&save->_xmm[2], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 22);
	__stf8(&num128[1], 23);
	copy_to_user(&save->_xmm[3], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 24);
	__stf8(&num128[1], 25);
	copy_to_user(&save->_xmm[4], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 26);
	__stf8(&num128[1], 27);
	copy_to_user(&save->_xmm[5], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 28);
	__stf8(&num128[1], 29);
	copy_to_user(&save->_xmm[6], num128, sizeof(struct _xmmreg_ia32));

	__stf8(&num128[0], 30);
	__stf8(&num128[1], 31);
	copy_to_user(&save->_xmm[7], num128, sizeof(struct _xmmreg_ia32));
	return 0;
}

static int
restore_ia32_fpstate_live (struct _fpstate_ia32 *save)
{
	struct task_struct *tsk = current;
	struct pt_regs *ptp;
	unsigned int lo, hi;
	unsigned long num128[2];
	unsigned long num64, mxcsr;
	struct _fpreg_ia32 *fpregp;
	char buf[32];
	unsigned long fsr, fcr, fir, fdr;
	int fp_tos, fr8_st_map;

	if (!access_ok(VERIFY_READ, save, sizeof(*save)))
		return(-EFAULT);

	/*
	 * Updating fsr, fcr, fir, fdr.
	 * Just a bit more complicated than save.
	 * - Need to make sure that we dont write any value other than the
	 *   specific fpstate info
	 * - Need to make sure that the untouched part of frs, fdr, fir, fcr
	 *   should remain same while writing.
	 * So, we do a read, change specific fields and write.
	 */
	asm volatile ( "mov %0=ar.fsr;" : "=r"(fsr));
	asm volatile ( "mov %0=ar.fcr;" : "=r"(fcr));
	asm volatile ( "mov %0=ar.fir;" : "=r"(fir));
	asm volatile ( "mov %0=ar.fdr;" : "=r"(fdr));

	__get_user(mxcsr, (unsigned int *)&save->mxcsr);
	/* setting bits 0..5 8..12 with cw and 39..47 from mxcsr */
	__get_user(lo, (unsigned int *)&save->cw);
	num64 = mxcsr & 0xff10;
	num64 = (num64 << 32) | (lo & 0x1f3f);
	fcr = (fcr & (~0xff1000001f3f)) | num64;