/*
Copyright (c) 2003-2006 Hewlett-Packard Development Company, L.P.
Permission is hereby granted, free of charge, to any person
obtaining a copy of this software and associated documentation
files (the "Software"), to deal in the Software without
restriction, including without limitation the rights to use,
copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following
conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.
*/

#include "uwx_env.h"
#include "uwx_utable.h"
#include "uwx_swap.h"
#include "uwx_trace.h"

/*
 *  uwx_utable.c
 *
 *  This file contains the routines for searching an unwind table.
 *  The main entry point, uwx_search_utable(), gets the
 *  necessary information from the lookup ip callback's result
 *  vector, determines whether the table is 32-bit or 64-bit,
 *  then invokes the binary search routine for that format.
 */


/* Forward declarations */

int uwx_search_utable32(
    struct uwx_env *env,
    uint32_t ip,
    uint32_t text_base,
    uint32_t unwind_start,
    uint32_t unwind_end,
    struct uwx_utable_entry *uentry);

int uwx_search_utable64(
    struct uwx_env *env,
    uint64_t ip,
    uint64_t text_base,
    uint64_t unwind_start,
    uint64_t unwind_end,
    struct uwx_utable_entry *uentry);


/* uwx_search_utable: Searches an unwind table for IP in current context */

int uwx_search_utable(
    struct uwx_env *env,
    uint64_t ip,
    uint64_t *uvec,
    struct uwx_utable_entry *uentry)
{
    uint64_t text_base;
    uint64_t unwind_flags;
    uint64_t unwind_start;
    uint64_t unwind_end;
    int keys;
    int status;

    /* Get unwind table information from the result vector. */
    /* Make sure all three required values are given. */

    keys = 0;
    text_base = 0;
    unwind_flags = 0;
    unwind_start = 0;
    unwind_end = 0;
    while (*uvec != 0) {
	switch ((int)*uvec++) {
	    case UWX_KEY_TBASE:
		keys |= 1;
		env->text_base = text_base = *uvec++;
		break;
	    case UWX_KEY_UFLAGS:
		unwind_flags = *uvec++;
		break;
	    case UWX_KEY_USTART:
		keys |= 2;
		unwind_start = *uvec++;
		break;
	    case UWX_KEY_UEND:
		keys |= 4;
		unwind_end = *uvec++;
		break;
	    case UWX_KEY_GP:
		uwx_set_reg(env, UWX_REG_GP, *uvec++);
		break;
	    default:
		return UWX_ERR_BADKEY;
	}
    }
    if (keys != 7)
	return UWX_ERR_BADKEY;

    /* Copy the unwind flags into the unwind entry. */
    /* (uwx_decode_uinfo needs to know whether it's 32-bit or 64-bit.) */

    uentry->unwind_flags = unwind_flags;

    /* Call the appropriate binary search routine. */

    if (unwind_flags & UNWIND_TBL_32BIT)
	status = uwx_search_utable32(env,
			(uint32_t) ip,
			(uint32_t) text_base,
			(uint32_t) unwind_start,
			(uint32_t) unwind_end,
			uentry);
    else
	status = uwx_search_utable64(env,
			ip, text_base, unwind_start, unwind_end, uentry);

    return status;
}


/* uwx_search_utable32: Binary search of 32-bit unwind table */

#define COPYIN_UINFO_4(dest, src) \
    (env->remote? \
	(*env->copyin)(UWX_COPYIN_UINFO, (dest), (src), \
						WORDSZ, env->cb_token) : \
	(*(uint32_t *)(dest) = *(uint32_t *)(src), WORDSZ) )

#define SWIZZLE(x) (((uint64_t)((x) & 0xc0000000) << 31) | (x))

int uwx_search_utable32(
    struct uwx_env *env,
    uint32_t ip,
    uint32_t text_base,
    uint32_t unwind_start,
    uint32_t unwind_end,
    struct uwx_utable_entry *uentry)
{
    int lb;
    int ub;
    int mid;
    int len;
    uint32_t code_start;
    uint32_t code_end;
    uint32_t unwind_info;

    /* Since the unwind table uses segment-relative offsets, convert */
    /* the IP in the current context to a segment-relative offset. */

    ip -= text_base;

    TRACE_T_SEARCH32(ip)

    /* Standard binary search. */
    /* Might modify this to do interpolation in the future. */

    lb = 0;
    ub = (unwind_end - unwind_start) / (3 * WORDSZ);
    mid = 0;
    while (ub > lb) {
	mid = (lb + ub) / 2;
	len = COPYIN_UINFO_4((char *)&code_start,
	    (uintptr_t)(unwind_start+mid*3*WORDSZ));
	len += COPYIN_UINFO_4((char *)&code_end,
	    (uintptr_t)(unwind_start+mid*3*WORDSZ+WORDSZ));
	if (len != 2 * WORDSZ)
	    return UWX_ERR_COPYIN_UTBL;
	if (env->byte_swap) {
	    uwx_swap4(&code_start);
	    uwx_swap4(&code_end);
	}
	TRACE_T_BINSEARCH32(lb, ub, mid, code_start, code_end)
	if (ip >= code_end)
	    lb = mid + 1;
	else if (ip < code_start)
	    ub = mid;
	else
	    break;
    }
    if (ub <= lb)
	return UWX_ERR_NOUENTRY;
    len = COPYIN_UINFO_4((char *)&unwind_info,
	(uintptr_t)(unwind_start+mid*3*WORDSZ+2*WORDSZ));
    if (len != WORDSZ)
	return UWX_ERR_COPYIN_UTBL;
    if (env->byte_swap)
	uwx_swap4(&unwind_info);
    uentry->ptr_size = WORDSZ;
    uentry->code_start = SWIZZLE(text_base + code_start);
    uentry->code_end = SWIZZLE(text_base + code_end);
    uentry->unwind_info = SWIZZLE(text_base + unwind_info);
    return UWX_OK;
}


/* uwx_search_utable64: Binary search of 64-bit unwind table */

#define COPYIN_UINFO_8(dest, src) \
    (env->remote? \
      (*env->copyin)(UWX_COPYIN_UINFO, (dest), (src), \
						DWORDSZ, env->cb_token) : \
      (*(uint64_t *)(intptr_t)(dest) = *(uint64_t *)(intptr_t)(src), DWORDSZ) )

int uwx_search_utable64(
    struct uwx_env *env,
    uint64_t ip,
    uint64_t text_base,
    uint64_t unwind_start,
    uint64_t unwind_end,
    struct uwx_utable_entry *uentry)
{
    int lb;
    int ub;
    int mid;
    int len;
    uint64_t code_start;
    uint64_t code_end;
    uint64_t unwind_info;

    /* Since the unwind table uses segment-relative offsets, convert */
    /* the IP in the current context to a segment-relative offset. */

    ip -= text_base;

    /* Standard binary search. */
    /* Might modify this to do interpolation in the future. */

    lb = 0;
    ub = (unwind_end - unwind_start) / (3 * DWORDSZ);
    mid = 0;
    while (ub > lb) {
	mid = (lb + ub) / 2;
	len = COPYIN_UINFO_8((char *)&code_start, unwind_start+mid*3*DWORDSZ);
	len += COPYIN_UINFO_8((char *)&code_end,
				unwind_start+mid*3*DWORDSZ+DWORDSZ);
	if (len != 2 * DWORDSZ)
	    return UWX_ERR_COPYIN_UTBL;
	if (env->byte_swap) {
	    uwx_swap8(&code_start);
	    uwx_swap8(&code_end);
	}
	if (ip >= code_end)
	    lb = mid + 1;
	else if (ip < code_start)
	    ub = mid;
	else
	    break;
    }
    if (ub <= lb)
	return UWX_ERR_NOUENTRY;
    len = COPYIN_UINFO_8((char *)&unwind_info,
			unwind_start+mid*3*DWORDSZ+2*DWORDSZ);
    if (len != DWORDSZ)
	return UWX_ERR_COPYIN_UTBL;
    if (env->byte_swap)
	uwx_swap8(&unwind_info);
    uentry->ptr_size = DWORDSZ;
    uentry->code_start = text_base + code_start;
    uentry->code_end = text_base + code_end;
    uentry->unwind_info = text_base + unwind_info;
    return UWX_OK;
}