-/* Caching code. Typically used by remote back ends for
- caching remote memory.
+/* Caching code for GDB, the GNU debugger.
- Copyright 1992-1993, 1995, 1998-1999 Free Software Foundation, Inc.
+ Copyright (C) 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001, 2003, 2007,
+ 2008, 2009 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 2 of the License, or
+ the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#include "defs.h"
#include "dcache.h"
#include "gdbcmd.h"
#include "gdb_string.h"
#include "gdbcore.h"
+#include "target.h"
-/*
- The data cache could lead to incorrect results because it doesn't know
- about volatile variables, thus making it impossible to debug
- functions which use memory mapped I/O devices.
-
- set remotecache 0
-
- In those cases.
+/* The data cache could lead to incorrect results because it doesn't
+ know about volatile variables, thus making it impossible to debug
+ functions which use memory mapped I/O devices. Set the nocache
+ memory region attribute in those cases.
In general the dcache speeds up performance, some speed improvement
comes from the actual caching mechanism, but the major gain is in
multiple of the LINE_SIZE) and a vector of bytes over the range.
There's another vector which contains the state of the bytes.
- ENTRY_BAD means that the byte is just plain wrong, and has no
+ ENTRY_INVALID means that the byte is just plain wrong, and has no
correspondence with anything else (as it would when the cache is
- turned on, but nothing has been done to it.
+ turned on, but nothing has been done to it).
ENTRY_DIRTY means that the byte has some data in it which should be
written out to the remote target one day, but contains correct
- data. ENTRY_OK means that the data is the same in the cache as it
- is in remote memory.
+ data.
+
+ ENTRY_VALID means that the data is the same in the cache as it is in
+ remote memory.
The ENTRY_DIRTY state is necessary because GDB likes to write large
protocol overhead. This way, all those little writes are bundled
up into an entire cache line write in one go, without having to
read the cache line in the first place.
+ */
+/* NOTE: Interaction of dcache and memory region attributes
- */
+ As there is no requirement that memory region attributes be aligned
+ to or be a multiple of the dcache page size, dcache_read_line() and
+ dcache_write_line() must break up the page by memory region. If a
+ chunk does not have the cache attribute set, an invalid memory type
+ is set, etc., then the chunk is skipped. Those chunks are handled
+ in target_xfer_memory() (or target_xfer_memory_partial()).
+ This doesn't occur very often. The most common occurance is when
+ the last bit of the .text segment and the first bit of the .data
+ segment fall within the same dcache page with a ro/cacheable memory
+ region defined for the .text segment and a rw/non-cacheable memory
+ region defined for the .data segment. */
/* This value regulates the number of cache blocks stored.
Smaller values reduce the time spent searching for a cache
#define MASK(x) ((x) & ~LINE_SIZE_MASK)
-#define ENTRY_BAD 0 /* data at this byte is wrong */
-#define ENTRY_DIRTY 1 /* data at this byte needs to be written back */
-#define ENTRY_OK 2 /* data at this byte is same as in memory */
+#define ENTRY_INVALID 0 /* data at this byte is wrong */
+#define ENTRY_DIRTY 1 /* data at this byte needs to be written back */
+#define ENTRY_VALID 2 /* data at this byte is same as in memory */
+/* For cache state display by "info dcache".
+ The letters I,D,V map to
+ I = ENTRY_INVALID
+ D = ENTRY_DIRTY
+ V = ENTRY_VALID */
+static const char state_chars[3] = { 'I', 'D', 'V' };
struct dcache_block
{
struct dcache_block *p; /* next in list */
CORE_ADDR addr; /* Address for which data is recorded. */
- char data[LINE_SIZE]; /* bytes at given address */
+ gdb_byte data[LINE_SIZE]; /* bytes at given address */
unsigned char state[LINE_SIZE]; /* what state the data is in */
/* whether anything in state is dirty - used to speed up the
};
-struct dcache_struct
- {
- /* Function to actually read the target memory. */
- memxferfunc read_memory;
+/* FIXME: dcache_struct used to have a cache_has_stuff field that was
+ used to record whether the cache had been accessed. This was used
+ to invalidate the cache whenever caching was (re-)enabled (if the
+ cache was disabled and later re-enabled, it could contain stale
+ data). This was not needed because the cache is write through and
+ the code that enables, disables, and deletes memory region all
+ invalidate the cache.
- /* Function to actually write the target memory */
- memxferfunc write_memory;
+ This is overkill, since it also invalidates cache lines from
+ unrelated regions. One way this could be addressed by adding a
+ new function that takes an address and a length and invalidates
+ only those cache lines that match. */
+struct dcache_struct
+ {
/* free list */
struct dcache_block *free_head;
struct dcache_block *free_tail;
/* The cache itself. */
struct dcache_block *the_cache;
-
- /* potentially, if the cache was enabled, and then turned off, and
- then turned on again, the stuff in it could be stale, so this is
- used to mark it */
- int cache_has_stuff;
};
-static int dcache_poke_byte (DCACHE * dcache, CORE_ADDR addr, char *ptr);
+static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr);
-static int dcache_peek_byte (DCACHE * dcache, CORE_ADDR addr, char *ptr);
+static int dcache_write_line (DCACHE *dcache, struct dcache_block *db);
-static struct dcache_block *dcache_hit (DCACHE * dcache, CORE_ADDR addr);
+static int dcache_read_line (DCACHE *dcache, struct dcache_block *db);
-static int dcache_write_line (DCACHE * dcache, struct dcache_block *db);
+static struct dcache_block *dcache_alloc (DCACHE *dcache, CORE_ADDR addr);
-static struct dcache_block *dcache_alloc (DCACHE * dcache, CORE_ADDR addr);
-
-static int dcache_writeback (DCACHE * dcache);
+static int dcache_writeback (DCACHE *dcache);
static void dcache_info (char *exp, int tty);
static int dcache_enabled_p = 0;
+static void
+show_dcache_enabled_p (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file, _("Cache use for remote targets is %s.\n"), value);
+}
+
+
DCACHE *last_cache; /* Used by info dcache */
/* Free all the data cache blocks, thus discarding all cached data. */
void
-dcache_flush (DCACHE *dcache)
+dcache_invalidate (DCACHE *dcache)
{
int i;
dcache->valid_head = 0;
db->p = 0;
}
- dcache->cache_has_stuff = 0;
-
return;
}
static struct dcache_block *
dcache_hit (DCACHE *dcache, CORE_ADDR addr)
{
- register struct dcache_block *db;
+ struct dcache_block *db;
/* Search all cache blocks for one that is at this address. */
db = dcache->valid_head;
be written is. */
static int
-dcache_write_line (DCACHE *dcache, register struct dcache_block *db)
+dcache_write_line (DCACHE *dcache, struct dcache_block *db)
{
- int s;
- int e;
- s = 0;
- if (db->anydirty)
+ CORE_ADDR memaddr;
+ gdb_byte *myaddr;
+ int len;
+ int res;
+ int reg_len;
+ struct mem_region *region;
+
+ if (!db->anydirty)
+ return 1;
+
+ len = LINE_SIZE;
+ memaddr = db->addr;
+ myaddr = db->data;
+
+ while (len > 0)
{
- for (s = 0; s < LINE_SIZE; s++)
+ int s;
+ int e;
+ int dirty_len;
+
+ region = lookup_mem_region(memaddr);
+ if (memaddr + len < region->hi)
+ reg_len = len;
+ else
+ reg_len = region->hi - memaddr;
+
+ if (!region->attrib.cache || region->attrib.mode == MEM_RO)
{
- if (db->state[s] == ENTRY_DIRTY)
- {
- int len = 0;
- for (e = s; e < LINE_SIZE; e++, len++)
- if (db->state[e] != ENTRY_DIRTY)
- break;
- {
- /* all bytes from s..s+len-1 need to
- be written out */
- int done = 0;
- while (done < len)
- {
- int t = dcache->write_memory (db->addr + s + done,
- db->data + s + done,
- len - done);
- if (t == 0)
- return 0;
- done += t;
- }
- memset (db->state + s, ENTRY_OK, len);
- s = e;
- }
- }
+ memaddr += reg_len;
+ myaddr += reg_len;
+ len -= reg_len;
+ continue;
+ }
+
+ while (reg_len > 0)
+ {
+ s = XFORM(memaddr);
+ while (reg_len > 0) {
+ if (db->state[s] == ENTRY_DIRTY)
+ break;
+ s++;
+ reg_len--;
+
+ memaddr++;
+ myaddr++;
+ len--;
+ }
+
+ e = s;
+ while (reg_len > 0) {
+ if (db->state[e] != ENTRY_DIRTY)
+ break;
+ e++;
+ reg_len--;
+ }
+
+ dirty_len = e - s;
+ res = target_write (¤t_target, TARGET_OBJECT_RAW_MEMORY,
+ NULL, myaddr, memaddr, dirty_len);
+ if (res < dirty_len)
+ return 0;
+
+ memset (&db->state[XFORM(memaddr)], ENTRY_VALID, res);
+ memaddr += res;
+ myaddr += res;
+ len -= res;
}
- db->anydirty = 0;
}
+
+ db->anydirty = 0;
return 1;
}
+/* Read cache line */
+static int
+dcache_read_line (DCACHE *dcache, struct dcache_block *db)
+{
+ CORE_ADDR memaddr;
+ gdb_byte *myaddr;
+ int len;
+ int res;
+ int reg_len;
+ struct mem_region *region;
+
+ /* If there are any dirty bytes in the line, it must be written
+ before a new line can be read */
+ if (db->anydirty)
+ {
+ if (!dcache_write_line (dcache, db))
+ return 0;
+ }
+
+ len = LINE_SIZE;
+ memaddr = db->addr;
+ myaddr = db->data;
+
+ while (len > 0)
+ {
+ region = lookup_mem_region(memaddr);
+ if (memaddr + len < region->hi)
+ reg_len = len;
+ else
+ reg_len = region->hi - memaddr;
+
+ if (!region->attrib.cache || region->attrib.mode == MEM_WO)
+ {
+ memaddr += reg_len;
+ myaddr += reg_len;
+ len -= reg_len;
+ continue;
+ }
+
+ res = target_read (¤t_target, TARGET_OBJECT_RAW_MEMORY,
+ NULL, myaddr, memaddr, reg_len);
+ if (res < reg_len)
+ return 0;
+
+ memaddr += res;
+ myaddr += res;
+ len -= res;
+ }
+
+ memset (db->state, ENTRY_VALID, sizeof (db->data));
+ db->anydirty = 0;
+
+ return 1;
+}
/* Get a free cache block, put or keep it on the valid list,
and return its address. */
static struct dcache_block *
dcache_alloc (DCACHE *dcache, CORE_ADDR addr)
{
- register struct dcache_block *db;
-
- if (dcache_enabled_p == 0)
- abort ();
+ struct dcache_block *db;
/* Take something from the free list */
db = dcache->free_head;
{
/* Nothing left on free list, so grab one from the valid list */
db = dcache->valid_head;
- dcache->valid_head = db->p;
- dcache_write_line (dcache, db);
+ if (!dcache_write_line (dcache, db))
+ return NULL;
+
+ dcache->valid_head = db->p;
}
db->addr = MASK(addr);
db->refs = 0;
db->anydirty = 0;
- memset (db->state, ENTRY_BAD, sizeof (db->data));
+ memset (db->state, ENTRY_INVALID, sizeof (db->data));
/* append this line to end of valid list */
if (!dcache->valid_head)
return db;
}
-/* Using the data cache DCACHE return the contents of the byte at
- address ADDR in the remote machine.
-
- Returns 0 on error. */
-
-static int
-dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr)
-{
- register struct dcache_block *db = dcache_hit (dcache, addr);
- int ok = 1;
- int done = 0;
- if (db == 0
- || db->state[XFORM (addr)] == ENTRY_BAD)
- {
- if (db)
- {
- dcache_write_line (dcache, db);
- }
- else
- db = dcache_alloc (dcache, addr);
-
- immediate_quit++;
- while (done < LINE_SIZE)
- {
- int try =
- (*dcache->read_memory)
- (db->addr + done,
- db->data + done,
- LINE_SIZE - done);
- if (try == 0)
- return 0;
- done += try;
- }
- immediate_quit--;
-
- memset (db->state, ENTRY_OK, sizeof (db->data));
- db->anydirty = 0;
- }
- *ptr = db->data[XFORM (addr)];
- return ok;
-}
-
-/* Writeback any dirty lines to the remote. */
+/* Writeback any dirty lines. */
static int
dcache_writeback (DCACHE *dcache)
{
}
+/* Using the data cache DCACHE return the contents of the byte at
+ address ADDR in the remote machine.
+
+ Returns 0 on error. */
+
+static int
+dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
+{
+ struct dcache_block *db = dcache_hit (dcache, addr);
+
+ if (!db)
+ {
+ db = dcache_alloc (dcache, addr);
+ if (!db)
+ return 0;
+ }
+
+ if (db->state[XFORM (addr)] == ENTRY_INVALID)
+ {
+ if (!dcache_read_line(dcache, db))
+ return 0;
+ }
+
+ *ptr = db->data[XFORM (addr)];
+ return 1;
+}
+
+
/* Write the byte at PTR into ADDR in the data cache.
Return zero on write error.
*/
static int
-dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr)
+dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
{
- register struct dcache_block *db = dcache_hit (dcache, addr);
+ struct dcache_block *db = dcache_hit (dcache, addr);
if (!db)
{
db = dcache_alloc (dcache, addr);
+ if (!db)
+ return 0;
}
db->data[XFORM (addr)] = *ptr;
/* Initialize the data cache. */
DCACHE *
-dcache_init (memxferfunc reading, memxferfunc writing)
+dcache_init (void)
{
int csize = sizeof (struct dcache_block) * DCACHE_SIZE;
DCACHE *dcache;
dcache = (DCACHE *) xmalloc (sizeof (*dcache));
- dcache->read_memory = reading;
- dcache->write_memory = writing;
dcache->the_cache = (struct dcache_block *) xmalloc (csize);
memset (dcache->the_cache, 0, csize);
- dcache_flush (dcache);
+ dcache_invalidate (dcache);
last_cache = dcache;
return dcache;
}
+/* Free a data cache */
+void
+dcache_free (DCACHE *dcache)
+{
+ if (last_cache == dcache)
+ last_cache = NULL;
+
+ xfree (dcache->the_cache);
+ xfree (dcache);
+}
+
/* Read or write LEN bytes from inferior memory at MEMADDR, transferring
to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is
nonzero.
This routine is indended to be called by remote_xfer_ functions. */
int
-dcache_xfer_memory (DCACHE *dcache, CORE_ADDR memaddr, char *myaddr, int len,
- int should_write)
+dcache_xfer_memory (DCACHE *dcache, CORE_ADDR memaddr, gdb_byte *myaddr,
+ int len, int should_write)
{
int i;
+ int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr);
+ xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
- if (dcache_enabled_p)
+ for (i = 0; i < len; i++)
{
- int (*xfunc) (DCACHE * dcache, CORE_ADDR addr, char *ptr);
- xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
-
- for (i = 0; i < len; i++)
- {
- if (!xfunc (dcache, memaddr + i, myaddr + i))
- return 0;
- }
- dcache->cache_has_stuff = 1;
- dcache_writeback (dcache);
+ if (!xfunc (dcache, memaddr + i, myaddr + i))
+ return 0;
}
- else
- {
- memxferfunc xfunc;
- xfunc = should_write ? dcache->write_memory : dcache->read_memory;
-
- if (dcache->cache_has_stuff)
- dcache_flush (dcache);
- len = xfunc (memaddr, myaddr, len);
- }
+ /* FIXME: There may be some benefit from moving the cache writeback
+ to a higher layer, as it could occur after a sequence of smaller
+ writes have been completed (as when a stack frame is constructed
+ for an inferior function call). Note that only moving it up one
+ level to target_xfer_memory() (also target_xfer_memory_partial())
+ is not sufficent, since we want to coalesce memory transfers that
+ are "logically" connected but not actually a single call to one
+ of the memory transfer functions. */
+
+ if (should_write)
+ dcache_writeback (dcache);
+
return len;
}
{
struct dcache_block *p;
- if (!dcache_enabled_p)
- {
- printf_filtered ("Dcache not enabled\n");
- return;
- }
- printf_filtered ("Dcache enabled, line width %d, depth %d\n",
+ printf_filtered (_("Dcache line width %d, depth %d\n"),
LINE_SIZE, DCACHE_SIZE);
if (last_cache)
{
- printf_filtered ("Cache state:\n");
+ printf_filtered (_("Cache state:\n"));
for (p = last_cache->valid_head; p; p = p->p)
{
int j;
- printf_filtered ("Line at %s, referenced %d times\n",
+ printf_filtered (_("Line at %s, referenced %d times\n"),
paddr (p->addr), p->refs);
for (j = 0; j < LINE_SIZE; j++)
printf_filtered ("%02x", p->data[j] & 0xFF);
- printf_filtered ("\n");
+ printf_filtered (("\n"));
for (j = 0; j < LINE_SIZE; j++)
- printf_filtered (" %2x", p->state[j]);
+ printf_filtered (" %c", state_chars[p->state[j]]);
printf_filtered ("\n");
}
}
}
-/* Turn dcache on or off. */
-void
-set_dcache_state (int what)
-{
- dcache_enabled_p = !!what;
-}
-
void
_initialize_dcache (void)
{
- add_show_from_set
- (add_set_cmd ("remotecache", class_support, var_boolean,
- (char *) &dcache_enabled_p,
- "\
-Set cache use for remote targets.\n\
+ add_setshow_boolean_cmd ("remotecache", class_support,
+ &dcache_enabled_p, _("\
+Set cache use for remote targets."), _("\
+Show cache use for remote targets."), _("\
When on, use data caching for remote targets. For many remote targets\n\
this option can offer better throughput for reading target memory.\n\
Unfortunately, gdb does not currently know anything about volatile\n\
registers and thus data caching will produce incorrect results with\n\
-volatile registers are in use. By default, this option is off.",
- &setlist),
- &showlist);
+volatile registers are in use. By default, this option is off."),
+ NULL,
+ show_dcache_enabled_p,
+ &setlist, &showlist);
add_info ("dcache", dcache_info,
- "Print information on the dcache performance.");
-
+ _("\
+Print information on the dcache performance.\n\
+The state of each cached byte is represented by a letter:\n\
+ I = invalid\n\
+ D = dirty\n\
+ V = valid"));
}
projects / external / binutils.git / blobdiff