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/* addr-trans.h - Address translation functions.
Copyright (C) 2007, 2008 Free Software Foundation, Inc.
Written by Neal H. Walfield <neal@gnu.org>.
This file is part of the GNU Hurd.
GNU Hurd is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation, either version 3 of the
License, or (at your option) any later version.
GNU Hurd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with GNU Hurd. If not, see
<http://www.gnu.org/licenses/>. */
#ifndef _HURD_ADDR_TRANS_H
#define _HURD_ADDR_TRANS_H
#include <l4/types.h>
#include <hurd/stddef.h>
/* Capabilities have two primary functions: they designate objects and
they participate in address translation. This structure controls
how the page table walker translates bits when passing through this
capability. */
#define CAP_ADDR_TRANS_GUARD_SUBPAGE_BITS 22
#define CAP_ADDR_TRANS_SUBPAGES_BITS 4
#define CAP_ADDR_TRANS_GDEPTH_BITS 6
struct cap_addr_trans
{
union
{
struct
{
/* The value of the guard and the subpage to use.
A capability page is partitioned into 2^SUBPAGES_LOG2 subpages.
This value determines the number of subpage index bits and
maximum number of guard bits. The number of subpage index bits
is SUBPAGES_LOG2 and the number of guard bits is the remainder
(the guard lies in the upper bits; the subpage in the lower).
If SUBPAGES_LOG2 is 0, there is a single subpage (covering the
entire page). This implies that there are no subpage bits (the
only valid offset is 0) and 21 possible guard bits. If
SUBPAGES_LOG2 is 0, there are 256 subpages, 8 subpage bits and a
maximum of 21-8=15 guard bits. */
l4_uint32_t guard_subpage: CAP_ADDR_TRANS_GUARD_SUBPAGE_BITS;
/* The log2 of the subpages. The size of a subpage is thus 2^(8 -
SUBPAGES_LOG2). Values of SUBPAGES_LOG2 other than 0 are only
allowed for cap pages. */
l4_uint32_t subpages_log2: CAP_ADDR_TRANS_SUBPAGES_BITS;
/* Number of significant guard bits. The value of the GUARD is zero
extended if GDEPTH is greater than the number of available guard
bits. */
l4_uint32_t gdepth: CAP_ADDR_TRANS_GDEPTH_BITS;
};
l4_uint32_t raw;
};
};
#define CAP_ADDR_TRANS_INIT { { .raw = 0 } }
#define CAP_ADDR_TRANS_VOID (struct cap_addr_trans) { { .raw = 0 } }
/* The log2 number of subpages. */
#define CAP_ADDR_TRANS_SUBPAGES_LOG2(cap_addr_trans_) \
((cap_addr_trans_).subpages_log2)
/* The number of subpages. */
#define CAP_ADDR_TRANS_SUBPAGES(cap_addr_trans_) \
(1 << CAP_ADDR_TRANS_SUBPAGES_LOG2((cap_addr_trans_)))
/* The designated subpage. */
#define CAP_ADDR_TRANS_SUBPAGE(cap_addr_trans_) \
((cap_addr_trans_).guard_subpage \
& (CAP_ADDR_TRANS_SUBPAGES ((cap_addr_trans_)) - 1))
/* The log2 of the size of the named subpage (in capability
units). */
#define CAP_ADDR_TRANS_SUBPAGE_SIZE_LOG2(cap_addr_trans_) \
(8 - (cap_addr_trans_).subpages_log2)
/* The number of caps addressed by this capability. */
#define CAP_ADDR_TRANS_SUBPAGE_SIZE(cap_addr_trans_) \
(1 << CAP_ADDR_TRANS_SUBPAGE_SIZE_LOG2 ((cap_addr_trans_)))
/* The offset in capability units (with respect to the start of the
capability page) of the first capability in the designated
sub-page. */
#define CAP_ADDR_TRANS_SUBPAGE_OFFSET(cap_addr_trans_) \
(CAP_ADDR_TRANS_SUBPAGE ((cap_addr_trans_)) \
* CAP_ADDR_TRANS_SUBPAGE_SIZE ((cap_addr_trans_)))
/* The number of guard bits. */
#define CAP_ADDR_TRANS_GUARD_BITS(cap_addr_trans_) ((cap_addr_trans_).gdepth)
/* The value of the guard. */
#define CAP_ADDR_TRANS_GUARD(cap_addr_trans_) \
((l4_uint64_t) ((cap_addr_trans_).guard_subpage \
>> (cap_addr_trans_).subpages_log2))
#define CATSGST_(test_, format, args...) \
if (! (test_)) \
{ \
r_ = false; \
debug (1, format, ##args); \
}
/* Set CAP_ADDR_TRANS_P_'s guard and the subpage. Returns true on success
(parameters valid), false otherwise. */
#define CAP_ADDR_TRANS_SET_GUARD_SUBPAGE(cap_addr_trans_p_, guard_, gdepth_, \
subpage_, subpages_) \
({ bool r_ = true; \
/* There must be at least 1 subpage. */ \
CATSGST_ (((subpages_) > 0), \
"subpages_ (%d) must be at least 1\n", (subpages_)); \
CATSGST_ (((subpages_) & ((subpages_) - 1)) == 0, \
"SUBPAGES_ (%d) must be a power of 2\n", (subpages_)); \
int subpages_log2_ = l4_msb ((subpages_)) - 1; \
CATSGST_ (subpages_log2_ <= 8, \
"maximum subpages is 256 (%d)\n", (subpages_)); \
CATSGST_ (0 <= (subpage_) && (subpage_) < (subpages_), \
"subpage (%d) must be between 0 and SUBPAGES_ (%d) - 1\n", \
(subpage_), (subpages_)); \
\
/* The number of required guard bits. */ \
int gbits_ = l4_msb64 ((guard_)); \
CATSGST_ (gbits_ <= (gdepth_), \
"Significant guard bits (%d) must be less than depth (%d)\n", \
gbits_, (gdepth_)); \
CATSGST_ (gbits_ + subpages_log2_ <= CAP_ADDR_TRANS_GUARD_SUBPAGE_BITS, \
"Significant guard bits (%d) plus subpage bits (%d) > %d\n", \
gbits_, subpages_log2_, CAP_ADDR_TRANS_GUARD_SUBPAGE_BITS); \
\
if (r_) \
{ \
(cap_addr_trans_p_)->subpages_log2 = subpages_log2_; \
(cap_addr_trans_p_)->gdepth = (gdepth_); \
(cap_addr_trans_p_)->guard_subpage \
= ((guard_) << subpages_log2_) | (subpage_); \
} \
r_; \
})
/* Set *CAP_ADDR_TRANS_P_'s guard. Returns true on success (parameters
valid), false otherwise. */
#define CAP_ADDR_TRANS_SET_GUARD(cap_addr_trans_p_, guard_, gdepth_) \
({ int subpage_ = CAP_ADDR_TRANS_SUBPAGE (*(cap_addr_trans_p_)); \
int subpages_ = CAP_ADDR_TRANS_SUBPAGES (*(cap_addr_trans_p_)); \
CAP_ADDR_TRANS_SET_GUARD_SUBPAGE ((cap_addr_trans_p_), \
(guard_), (gdepth_), \
(subpage_), (subpages_)); \
})
/* Set *CAP_ADDR_TRANS_P_'s subpage. Returns true on success (parameters
valid), false otherwise. */
#define CAP_ADDR_TRANS_SET_SUBPAGE(cap_addr_trans_p_, subpage_, subpages_) \
({ int gdepth_ = CAP_ADDR_TRANS_GUARD_BITS (*(cap_addr_trans_p_)); \
int guard_ = CAP_ADDR_TRANS_GUARD (*(cap_addr_trans_p_)); \
CAP_ADDR_TRANS_SET_GUARD_SUBPAGE ((cap_addr_trans_p_), \
(guard_), (gdepth_), \
(subpage_), (subpages_)); \
})
/* Returns whether the capability address CAP_ADDR_TRANS is well-formed. */
#define CAP_ADDR_TRANS_VALID(cap_addr_trans) \
({ bool r_ = true; \
CATSGST_ (CAP_ADDR_TRANS_GUARD_BITS (cap_addr_trans) <= L4_WORDSIZE, \
"Invalid guard depth (%d)", \
CAP_ADDR_TRANS_GUARD_BITS (cap_addr_trans)); \
CATSGST_ (CAP_ADDR_TRANS_SUBPAGES_LOG2 (cap_addr_trans) <= 8, \
"Invalid number of subpages (%d)", \
CAP_ADDR_TRANS_SUBPAGES (cap_addr_trans)); \
CATSGST_ (l4_msb (CAP_ADDR_TRANS_GUARD (cap_addr_trans)) \
<= CAP_ADDR_TRANS_GUARD_BITS (cap_addr_trans), \
"Significant guard bits (%d) exceeds guard depth (%d)", \
l4_msb (CAP_ADDR_TRANS_GUARD (cap_addr_trans)), \
CAP_ADDR_TRANS_GUARD_BITS (cap_addr_trans)); \
r_; \
})
#endif
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