/* Caching code for GDB, the GNU debugger.
- Copyright 1992, 1993, 1995, 1996, 1998, 1999, 2000, 2001, 2003 Free
- Software Foundation, Inc.
+ Copyright (C) 1992-2013 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 "gdb_string.h"
#include "gdbcore.h"
#include "target.h"
+#include "inferior.h"
+#include "splay-tree.h"
+
+/* Commands with a prefix of `{set,show} dcache'. */
+static struct cmd_list_element *dcache_set_list = NULL;
+static struct cmd_list_element *dcache_show_list = NULL;
/* 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
+ In general the dcache speeds up performance. Some speed improvement
comes from the actual caching mechanism, but the major gain is in
the reduction of the remote protocol overhead; instead of reading
or writing a large area of memory in 4 byte requests, the cache
- bundles up the requests into 32 byte (actually LINE_SIZE) chunks.
- Reducing the overhead to an eighth of what it was. This is very
- obvious when displaying a large amount of data,
-
- eg, x/200x 0
-
- caching | no yes
- ----------------------------
- first time | 4 sec 2 sec improvement due to chunking
- second time | 4 sec 0 sec improvement due to caching
-
- The cache structure is unusual, we keep a number of cache blocks
- (DCACHE_SIZE) and each one caches a LINE_SIZEed area of memory.
- Within each line we remember the address of the line (always a
- 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
- correspondence with anything else (as it would when the cache is
- 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.
-
-
- The ENTRY_DIRTY state is necessary because GDB likes to write large
- lumps of memory in small bits. If the caching mechanism didn't
- maintain the DIRTY information, then something like a two byte
- write would mean that the entire cache line would have to be read,
- the two bytes modified and then written out again. The alternative
- would be to not read in the cache line in the first place, and just
- write the two bytes directly into target memory. The trouble with
- that is that it really nails performance, because of the remote
- 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.
- */
+ bundles up the requests into LINE_SIZE chunks, reducing overhead
+ significantly. This is most useful when accessing a large amount
+ of data, such as when performing a backtrace.
+
+ The cache is a splay tree along with a linked list for replacement.
+ Each block caches a LINE_SIZE area of memory. Within each line we
+ remember the address of the line (which must be a multiple of
+ LINE_SIZE) and the actual data block.
+
+ Lines are only allocated as needed, so DCACHE_SIZE really specifies the
+ *maximum* number of lines in the cache.
+
+ At present, the cache is write-through rather than writeback: as soon
+ as data is written to the cache, it is also immediately written to
+ the target. Therefore, cache lines are never "dirty". Whether a given
+ line is valid or not depends on where it is stored in the dcache_struct;
+ there is no per-block valid flag. */
/* NOTE: Interaction of dcache and memory region attributes
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. */
+ 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
- line, and reduce memory requirements, but increase the risk
- of a line not being in memory */
+/* The maximum number of lines stored. The total size of the cache is
+ equal to DCACHE_SIZE times LINE_SIZE. */
+#define DCACHE_DEFAULT_SIZE 4096
+static unsigned dcache_size = DCACHE_DEFAULT_SIZE;
-#define DCACHE_SIZE 64
-
-/* This value regulates the size of a cache line. Smaller values
- reduce the time taken to read a single byte, but reduce overall
- throughput. */
-
-#define LINE_SIZE_POWER (5)
-#define LINE_SIZE (1 << LINE_SIZE_POWER)
+/* The default size of a cache line. Smaller values reduce the time taken to
+ read a single byte and make the cache more granular, but increase
+ overhead and reduce the effectiveness of the cache as a prefetcher. */
+#define DCACHE_DEFAULT_LINE_SIZE 64
+static unsigned dcache_line_size = DCACHE_DEFAULT_LINE_SIZE;
/* Each cache block holds LINE_SIZE bytes of data
starting at a multiple-of-LINE_SIZE address. */
-#define LINE_SIZE_MASK ((LINE_SIZE - 1))
-#define XFORM(x) ((x) & LINE_SIZE_MASK)
-#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 LINE_SIZE_MASK(dcache) ((dcache->line_size - 1))
+#define XFORM(dcache, x) ((x) & LINE_SIZE_MASK (dcache))
+#define MASK(dcache, x) ((x) & ~LINE_SIZE_MASK (dcache))
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 */
- unsigned char state[LINE_SIZE]; /* what state the data is in */
-
- /* whether anything in state is dirty - used to speed up the
- dirty scan. */
- int anydirty;
-
- int refs;
- };
-
-
-/* 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.
+{
+ /* For least-recently-allocated and free lists. */
+ struct dcache_block *prev;
+ struct dcache_block *next;
- 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. */
+ CORE_ADDR addr; /* address of data */
+ int refs; /* # hits */
+ gdb_byte data[1]; /* line_size bytes at given address */
+};
struct dcache_struct
- {
- /* free list */
- struct dcache_block *free_head;
- struct dcache_block *free_tail;
+{
+ splay_tree tree;
+ struct dcache_block *oldest; /* least-recently-allocated list. */
- /* in use list */
- struct dcache_block *valid_head;
- struct dcache_block *valid_tail;
+ /* The free list is maintained identically to OLDEST to simplify
+ the code: we only need one set of accessors. */
+ struct dcache_block *freelist;
- /* The cache itself. */
- struct dcache_block *the_cache;
- };
+ /* The number of in-use lines in the cache. */
+ int size;
+ CORE_ADDR line_size; /* current line_size. */
-static int dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr);
+ /* The ptid of last inferior to use cache or null_ptid. */
+ ptid_t ptid;
+};
-static int dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr);
+typedef void (block_func) (struct dcache_block *block, void *param);
static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr);
-static int dcache_write_line (DCACHE *dcache, struct dcache_block *db);
-
static int dcache_read_line (DCACHE *dcache, struct dcache_block *db);
static struct dcache_block *dcache_alloc (DCACHE *dcache, CORE_ADDR addr);
-static int dcache_writeback (DCACHE *dcache);
-
static void dcache_info (char *exp, int tty);
void _initialize_dcache (void);
-static int dcache_enabled_p = 0;
+static int dcache_enabled_p = 0; /* OBSOLETE */
-DCACHE *last_cache; /* Used by info dcache */
+static void
+show_dcache_enabled_p (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
+{
+ fprintf_filtered (file, _("Deprecated remotecache flag is %s.\n"), value);
+}
+static DCACHE *last_cache; /* Used by info dcache. */
-/* Free all the data cache blocks, thus discarding all cached data. */
+/* Add BLOCK to circular block list BLIST, behind the block at *BLIST.
+ *BLIST is not updated (unless it was previously NULL of course).
+ This is for the least-recently-allocated list's sake:
+ BLIST points to the oldest block.
+ ??? This makes for poor cache usage of the free list,
+ but is it measurable? */
-void
-dcache_invalidate (DCACHE *dcache)
+static void
+append_block (struct dcache_block **blist, struct dcache_block *block)
{
- int i;
- dcache->valid_head = 0;
- dcache->valid_tail = 0;
+ if (*blist)
+ {
+ block->next = *blist;
+ block->prev = (*blist)->prev;
+ block->prev->next = block;
+ (*blist)->prev = block;
+ /* We don't update *BLIST here to maintain the invariant that for the
+ least-recently-allocated list *BLIST points to the oldest block. */
+ }
+ else
+ {
+ block->next = block;
+ block->prev = block;
+ *blist = block;
+ }
+}
- dcache->free_head = 0;
- dcache->free_tail = 0;
+/* Remove BLOCK from circular block list BLIST. */
- for (i = 0; i < DCACHE_SIZE; i++)
+static void
+remove_block (struct dcache_block **blist, struct dcache_block *block)
+{
+ if (block->next == block)
{
- struct dcache_block *db = dcache->the_cache + i;
-
- if (!dcache->free_head)
- dcache->free_head = db;
- else
- dcache->free_tail->p = db;
- dcache->free_tail = db;
- db->p = 0;
+ *blist = NULL;
+ }
+ else
+ {
+ block->next->prev = block->prev;
+ block->prev->next = block->next;
+ /* If we removed the block *BLIST points to, shift it to the next block
+ to maintain the invariant that for the least-recently-allocated list
+ *BLIST points to the oldest block. */
+ if (*blist == block)
+ *blist = block->next;
}
-
- return;
}
-/* If addr is present in the dcache, return the address of the block
- containing it. */
+/* Iterate over all elements in BLIST, calling FUNC.
+ PARAM is passed to FUNC.
+ FUNC may remove the block it's passed, but only that block. */
-static struct dcache_block *
-dcache_hit (DCACHE *dcache, CORE_ADDR addr)
+static void
+for_each_block (struct dcache_block **blist, block_func *func, void *param)
{
struct dcache_block *db;
- /* Search all cache blocks for one that is at this address. */
- db = dcache->valid_head;
+ if (*blist == NULL)
+ return;
- while (db)
+ db = *blist;
+ do
{
- if (MASK (addr) == db->addr)
- {
- db->refs++;
- return db;
- }
- db = db->p;
+ struct dcache_block *next = db->next;
+
+ func (db, param);
+ db = next;
}
+ while (*blist && db != *blist);
+}
+
+/* BLOCK_FUNC routine for dcache_free. */
- return NULL;
+static void
+free_block (struct dcache_block *block, void *param)
+{
+ xfree (block);
}
-/* Make sure that anything in this line which needs to
- be written is. */
+/* Free a data cache. */
-static int
-dcache_write_line (DCACHE *dcache, struct dcache_block *db)
+void
+dcache_free (DCACHE *dcache)
{
- CORE_ADDR memaddr;
- char *myaddr;
- int len;
- int res;
- int reg_len;
- struct mem_region *region;
+ if (last_cache == dcache)
+ last_cache = NULL;
- if (!db->anydirty)
- return 1;
+ splay_tree_delete (dcache->tree);
+ for_each_block (&dcache->oldest, free_block, NULL);
+ for_each_block (&dcache->freelist, free_block, NULL);
+ xfree (dcache);
+}
- len = LINE_SIZE;
- memaddr = db->addr;
- myaddr = db->data;
- while (len > 0)
+/* BLOCK_FUNC function for dcache_invalidate.
+ This doesn't remove the block from the oldest list on purpose.
+ dcache_invalidate will do it later. */
+
+static void
+invalidate_block (struct dcache_block *block, void *param)
+{
+ DCACHE *dcache = (DCACHE *) param;
+
+ splay_tree_remove (dcache->tree, (splay_tree_key) block->addr);
+ append_block (&dcache->freelist, block);
+}
+
+/* Free all the data cache blocks, thus discarding all cached data. */
+
+void
+dcache_invalidate (DCACHE *dcache)
+{
+ for_each_block (&dcache->oldest, invalidate_block, dcache);
+
+ dcache->oldest = NULL;
+ dcache->size = 0;
+ dcache->ptid = null_ptid;
+
+ if (dcache->line_size != dcache_line_size)
{
- 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;
+ /* We've been asked to use a different line size.
+ All of our freelist blocks are now the wrong size, so free them. */
- if (!region->attrib.cache || region->attrib.mode == MEM_RO)
- {
- memaddr += reg_len;
- myaddr += reg_len;
- len -= reg_len;
- continue;
- }
+ for_each_block (&dcache->freelist, free_block, dcache);
+ dcache->freelist = NULL;
+ dcache->line_size = dcache_line_size;
+ }
+}
- 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;
- while (dirty_len > 0)
- {
- res = do_xfer_memory(memaddr, myaddr, dirty_len, 1,
- ®ion->attrib);
- if (res <= 0)
- return 0;
-
- memset (&db->state[XFORM(memaddr)], ENTRY_OK, res);
- memaddr += res;
- myaddr += res;
- len -= res;
- dirty_len -= res;
- }
- }
+/* Invalidate the line associated with ADDR. */
+
+static void
+dcache_invalidate_line (DCACHE *dcache, CORE_ADDR addr)
+{
+ struct dcache_block *db = dcache_hit (dcache, addr);
+
+ if (db)
+ {
+ splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
+ remove_block (&dcache->oldest, db);
+ append_block (&dcache->freelist, db);
+ --dcache->size;
}
+}
- db->anydirty = 0;
- return 1;
+/* If addr is present in the dcache, return the address of the block
+ containing it. Otherwise return NULL. */
+
+static struct dcache_block *
+dcache_hit (DCACHE *dcache, CORE_ADDR addr)
+{
+ struct dcache_block *db;
+
+ splay_tree_node node = splay_tree_lookup (dcache->tree,
+ (splay_tree_key) MASK (dcache, addr));
+
+ if (!node)
+ return NULL;
+
+ db = (struct dcache_block *) node->value;
+ db->refs++;
+ return db;
}
-/* Read cache line */
+/* Fill a cache line from target memory.
+ The result is 1 for success, 0 if the (entire) cache line
+ wasn't readable. */
+
static int
dcache_read_line (DCACHE *dcache, struct dcache_block *db)
{
CORE_ADDR memaddr;
- char *myaddr;
+ 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;
+ len = dcache->line_size;
memaddr = db->addr;
myaddr = db->data;
while (len > 0)
{
- region = lookup_mem_region(memaddr);
- if (memaddr + len < region->hi)
+ /* Don't overrun if this block is right at the end of the region. */
+ region = lookup_mem_region (memaddr);
+ if (region->hi == 0 || memaddr + len < region->hi)
reg_len = len;
else
reg_len = region->hi - memaddr;
- if (!region->attrib.cache || region->attrib.mode == MEM_WO)
+ /* Skip non-readable regions. The cache attribute can be ignored,
+ since we may be loading this for a stack access. */
+ if (region->attrib.mode == MEM_WO)
{
memaddr += reg_len;
myaddr += reg_len;
continue;
}
- while (reg_len > 0)
- {
- res = do_xfer_memory (memaddr, myaddr, reg_len, 0,
- ®ion->attrib);
- if (res <= 0)
- return 0;
-
- memaddr += res;
- myaddr += res;
- len -= res;
- reg_len -= res;
- }
+ 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_OK, sizeof (db->data));
- db->anydirty = 0;
-
return 1;
}
{
struct dcache_block *db;
- /* Take something from the free list */
- db = dcache->free_head;
- if (db)
+ if (dcache->size >= dcache_size)
{
- dcache->free_head = db->p;
+ /* Evict the least recently allocated line. */
+ db = dcache->oldest;
+ remove_block (&dcache->oldest, db);
+
+ splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
}
else
{
- /* Nothing left on free list, so grab one from the valid list */
- db = dcache->valid_head;
+ db = dcache->freelist;
+ if (db)
+ remove_block (&dcache->freelist, db);
+ else
+ db = xmalloc (offsetof (struct dcache_block, data) +
+ dcache->line_size);
- if (!dcache_write_line (dcache, db))
- return NULL;
-
- dcache->valid_head = db->p;
+ dcache->size++;
}
- db->addr = MASK(addr);
+ db->addr = MASK (dcache, addr);
db->refs = 0;
- db->anydirty = 0;
- memset (db->state, ENTRY_BAD, sizeof (db->data));
-
- /* append this line to end of valid list */
- if (!dcache->valid_head)
- dcache->valid_head = db;
- else
- dcache->valid_tail->p = db;
- dcache->valid_tail = db;
- db->p = 0;
-
- return db;
-}
-/* Writeback any dirty lines. */
-static int
-dcache_writeback (DCACHE *dcache)
-{
- struct dcache_block *db;
+ /* Put DB at the end of the list, it's the newest. */
+ append_block (&dcache->oldest, db);
- db = dcache->valid_head;
+ splay_tree_insert (dcache->tree, (splay_tree_key) db->addr,
+ (splay_tree_value) db);
- while (db)
- {
- if (!dcache_write_line (dcache, db))
- return 0;
- db = db->p;
- }
- return 1;
+ return db;
}
-
-/* Using the data cache DCACHE return the contents of the byte at
+/* Using the data cache DCACHE, store in *PTR the contents of the byte at
address ADDR in the remote machine.
- Returns 0 on error. */
+ Returns 1 for success, 0 for error. */
static int
-dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr)
+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_BAD)
- {
- if (!dcache_read_line(dcache, db))
+
+ if (!dcache_read_line (dcache, db))
return 0;
}
- *ptr = db->data[XFORM (addr)];
+ *ptr = db->data[XFORM (dcache, addr)];
return 1;
}
-
/* Write the byte at PTR into ADDR in the data cache.
- Return zero on write error.
- */
+
+ The caller is responsible for also promptly writing the data
+ through to target memory.
+
+ If addr is not in cache, this function does nothing; writing to
+ an area of memory which wasn't present in the cache doesn't cause
+ it to be loaded in.
+
+ Always return 1 (meaning success) to simplify dcache_xfer_memory. */
static int
-dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr)
+dcache_poke_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)
+ db->data[XFORM (dcache, addr)] = *ptr;
- db->data[XFORM (addr)] = *ptr;
- db->state[XFORM (addr)] = ENTRY_DIRTY;
- db->anydirty = 1;
return 1;
}
-/* Initialize the data cache. */
+static int
+dcache_splay_tree_compare (splay_tree_key a, splay_tree_key b)
+{
+ if (a > b)
+ return 1;
+ else if (a == b)
+ return 0;
+ else
+ return -1;
+}
+
+/* Allocate and initialize a data cache. */
+
DCACHE *
dcache_init (void)
{
- int csize = sizeof (struct dcache_block) * DCACHE_SIZE;
DCACHE *dcache;
dcache = (DCACHE *) xmalloc (sizeof (*dcache));
- dcache->the_cache = (struct dcache_block *) xmalloc (csize);
- memset (dcache->the_cache, 0, csize);
-
- dcache_invalidate (dcache);
+ dcache->tree = splay_tree_new (dcache_splay_tree_compare,
+ NULL,
+ NULL);
+ dcache->oldest = NULL;
+ dcache->freelist = NULL;
+ dcache->size = 0;
+ dcache->line_size = dcache_line_size;
+ dcache->ptid = null_ptid;
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.
- Returns length of data written or read; 0 for error.
-
- This routine is indended to be called by remote_xfer_ functions. */
+ Return the number of bytes actually transfered, or -1 if the
+ transfer is not supported or otherwise fails. Return of a non-negative
+ value less than LEN indicates that no further transfer is possible.
+ NOTE: This is different than the to_xfer_partial interface, in which
+ positive values less than LEN mean further transfers may be possible. */
int
-dcache_xfer_memory (DCACHE *dcache, CORE_ADDR memaddr, char *myaddr, int len,
- int should_write)
+dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
+ CORE_ADDR memaddr, gdb_byte *myaddr,
+ int len, int should_write)
{
int i;
- int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, char *ptr);
+ int res;
+ int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr);
+
xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
- for (i = 0; i < len; i++)
+ /* If this is a different inferior from what we've recorded,
+ flush the cache. */
+
+ if (! ptid_equal (inferior_ptid, dcache->ptid))
{
- if (!xfunc (dcache, memaddr + i, myaddr + i))
- return 0;
+ dcache_invalidate (dcache);
+ dcache->ptid = inferior_ptid;
}
- /* 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. */
+ /* Do write-through first, so that if it fails, we don't write to
+ the cache at all. */
if (should_write)
- dcache_writeback (dcache);
+ {
+ res = target_write (ops, TARGET_OBJECT_RAW_MEMORY,
+ NULL, myaddr, memaddr, len);
+ if (res <= 0)
+ return res;
+ /* Update LEN to what was actually written. */
+ len = res;
+ }
+
+ for (i = 0; i < len; i++)
+ {
+ if (!xfunc (dcache, memaddr + i, myaddr + i))
+ {
+ /* That failed. Discard its cache line so we don't have a
+ partially read line. */
+ dcache_invalidate_line (dcache, memaddr + i);
+ /* If we're writing, we still wrote LEN bytes. */
+ if (should_write)
+ return len;
+ else
+ return i;
+ }
+ }
return len;
}
+/* FIXME: There would be some benefit to making the cache write-back and
+ moving the writeback operation 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[_partial]() is not
+ sufficient since we want to coalesce memory transfers that are
+ "logically" connected but not actually a single call to one of the
+ memory transfer functions. */
+
+/* Just update any cache lines which are already present. This is called
+ by memory_xfer_partial in cases where the access would otherwise not go
+ through the cache. */
+
+void
+dcache_update (DCACHE *dcache, CORE_ADDR memaddr, gdb_byte *myaddr, int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ dcache_poke_byte (dcache, memaddr + i, myaddr + i);
+}
+
static void
-dcache_info (char *exp, int tty)
+dcache_print_line (int index)
{
- struct dcache_block *p;
+ splay_tree_node n;
+ struct dcache_block *db;
+ int i, j;
- printf_filtered (_("Dcache line width %d, depth %d\n"),
- LINE_SIZE, DCACHE_SIZE);
+ if (!last_cache)
+ {
+ printf_filtered (_("No data cache available.\n"));
+ return;
+ }
- if (last_cache)
+ n = splay_tree_min (last_cache->tree);
+
+ for (i = index; i > 0; --i)
{
- printf_filtered (_("Cache state:\n"));
+ if (!n)
+ break;
+ n = splay_tree_successor (last_cache->tree, n->key);
+ }
- for (p = last_cache->valid_head; p; p = p->p)
- {
- int j;
- printf_filtered (_("Line at %s, referenced %d times\n"),
- paddr (p->addr), p->refs);
+ if (!n)
+ {
+ printf_filtered (_("No such cache line exists.\n"));
+ return;
+ }
+
+ db = (struct dcache_block *) n->value;
+
+ printf_filtered (_("Line %d: address %s [%d hits]\n"),
+ index, paddress (target_gdbarch (), db->addr), db->refs);
+
+ for (j = 0; j < last_cache->line_size; j++)
+ {
+ printf_filtered ("%02x ", db->data[j]);
+
+ /* Print a newline every 16 bytes (48 characters). */
+ if ((j % 16 == 15) && (j != last_cache->line_size - 1))
+ printf_filtered ("\n");
+ }
+ printf_filtered ("\n");
+}
+
+static void
+dcache_info (char *exp, int tty)
+{
+ splay_tree_node n;
+ int i, refcount;
- for (j = 0; j < LINE_SIZE; j++)
- printf_filtered ("%02x", p->data[j] & 0xFF);
- printf_filtered (("\n"));
+ if (exp)
+ {
+ char *linestart;
- for (j = 0; j < LINE_SIZE; j++)
- printf_filtered ("%2x", p->state[j]);
- printf_filtered ("\n");
+ i = strtol (exp, &linestart, 10);
+ if (linestart == exp || i < 0)
+ {
+ printf_filtered (_("Usage: info dcache [linenumber]\n"));
+ return;
}
+
+ dcache_print_line (i);
+ return;
+ }
+
+ printf_filtered (_("Dcache %u lines of %u bytes each.\n"),
+ dcache_size,
+ last_cache ? (unsigned) last_cache->line_size
+ : dcache_line_size);
+
+ if (!last_cache || ptid_equal (last_cache->ptid, null_ptid))
+ {
+ printf_filtered (_("No data cache available.\n"));
+ return;
}
+
+ printf_filtered (_("Contains data for %s\n"),
+ target_pid_to_str (last_cache->ptid));
+
+ refcount = 0;
+
+ n = splay_tree_min (last_cache->tree);
+ i = 0;
+
+ while (n)
+ {
+ struct dcache_block *db = (struct dcache_block *) n->value;
+
+ printf_filtered (_("Line %d: address %s [%d hits]\n"),
+ i, paddress (target_gdbarch (), db->addr), db->refs);
+ i++;
+ refcount += db->refs;
+
+ n = splay_tree_successor (last_cache->tree, n->key);
+ }
+
+ printf_filtered (_("Cache state: %d active lines, %d hits\n"), i, refcount);
+}
+
+static void
+set_dcache_size (char *args, int from_tty,
+ struct cmd_list_element *c)
+{
+ if (dcache_size == 0)
+ {
+ dcache_size = DCACHE_DEFAULT_SIZE;
+ error (_("Dcache size must be greater than 0."));
+ }
+ if (last_cache)
+ dcache_invalidate (last_cache);
+}
+
+static void
+set_dcache_line_size (char *args, int from_tty,
+ struct cmd_list_element *c)
+{
+ if (dcache_line_size < 2
+ || (dcache_line_size & (dcache_line_size - 1)) != 0)
+ {
+ unsigned d = dcache_line_size;
+ dcache_line_size = DCACHE_DEFAULT_LINE_SIZE;
+ error (_("Invalid dcache line size: %u (must be power of 2)."), d);
+ }
+ if (last_cache)
+ dcache_invalidate (last_cache);
+}
+
+static void
+set_dcache_command (char *arg, int from_tty)
+{
+ printf_unfiltered (
+ "\"set dcache\" must be followed by the name of a subcommand.\n");
+ help_list (dcache_set_list, "set dcache ", -1, gdb_stdout);
+}
+
+static void
+show_dcache_command (char *args, int from_tty)
+{
+ cmd_show_list (dcache_show_list, from_tty, "");
}
void
&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."),
+This used to enable the data cache for remote targets. The cache\n\
+functionality is now controlled by the memory region system and the\n\
+\"stack-cache\" flag; \"remotecache\" now does nothing and\n\
+exists only for compatibility reasons."),
NULL,
- NULL, /* FIXME: i18n: */
+ show_dcache_enabled_p,
&setlist, &showlist);
add_info ("dcache", dcache_info,
- _("Print information on the dcache performance."));
-
+ _("\
+Print information on the dcache performance.\n\
+With no arguments, this command prints the cache configuration and a\n\
+summary of each line in the cache. Use \"info dcache <lineno> to dump\"\n\
+the contents of a given line."));
+
+ add_prefix_cmd ("dcache", class_obscure, set_dcache_command, _("\
+Use this command to set number of lines in dcache and line-size."),
+ &dcache_set_list, "set dcache ", /*allow_unknown*/0, &setlist);
+ add_prefix_cmd ("dcache", class_obscure, show_dcache_command, _("\
+Show dcachesettings."),
+ &dcache_show_list, "show dcache ", /*allow_unknown*/0, &showlist);
+
+ add_setshow_uinteger_cmd ("line-size", class_obscure,
+ &dcache_line_size, _("\
+Set dcache line size in bytes (must be power of 2)."), _("\
+Show dcache line size."),
+ NULL,
+ set_dcache_line_size,
+ NULL,
+ &dcache_set_list, &dcache_show_list);
+ add_setshow_uinteger_cmd ("size", class_obscure,
+ &dcache_size, _("\
+Set number of dcache lines."), _("\
+Show number of dcache lines."),
+ NULL,
+ set_dcache_size,
+ NULL,
+ &dcache_set_list, &dcache_show_list);
}
projects / external / binutils.git / blobdiff