-/* Caching code. Typically used by remote back ends for
- caching remote memory.
+/* Caching code for GDB, the GNU debugger.
- Copyright 1992, 1993, 1995, 1998 Free Software Foundation, Inc.
+ Copyright (C) 1992-2020 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-dcache.h"
+#include "inferior.h"
+#include "splay-tree.h"
+#include "gdbarch.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.
+/* 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;
- set remotecache 0
+/* 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 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.
+ 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
+
+ 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 occurrence 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. */
+
+/* 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;
+
+/* 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. */
- 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.
-
+#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
+{
+ /* For least-recently-allocated and free lists. */
+ struct dcache_block *prev;
+ struct dcache_block *next;
+ CORE_ADDR addr; /* address of data */
+ int refs; /* # hits */
+ gdb_byte data[1]; /* line_size bytes at given address */
+};
-/* 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 */
+struct dcache_struct
+{
+ splay_tree tree;
+ struct dcache_block *oldest; /* least-recently-allocated list. */
-#define DCACHE_SIZE 64
+ /* The free list is maintained identically to OLDEST to simplify
+ the code: we only need one set of accessors. */
+ struct dcache_block *freelist;
-/* This value regulates the size of a cache line. Smaller values
- reduce the time taken to read a single byte, but reduce overall
- throughput. */
+ /* The number of in-use lines in the cache. */
+ int size;
+ CORE_ADDR line_size; /* current line_size. */
-#define LINE_SIZE_POWER (5)
-#define LINE_SIZE (1 << LINE_SIZE_POWER)
+ /* The ptid of last inferior to use cache or null_ptid. */
+ ptid_t ptid;
+};
-/* Each cache block holds LINE_SIZE bytes of data
- starting at a multiple-of-LINE_SIZE address. */
+typedef void (block_func) (struct dcache_block *block, void *param);
-#define LINE_SIZE_MASK ((LINE_SIZE - 1))
-#define XFORM(x) ((x) & LINE_SIZE_MASK)
-#define MASK(x) ((x) & ~LINE_SIZE_MASK)
+static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr);
+static int dcache_read_line (DCACHE *dcache, struct dcache_block *db);
-#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 */
+static struct dcache_block *dcache_alloc (DCACHE *dcache, CORE_ADDR addr);
+static bool dcache_enabled_p = false; /* OBSOLETE */
-struct dcache_block
+static void
+show_dcache_enabled_p (struct ui_file *file, int from_tty,
+ struct cmd_list_element *c, const char *value)
{
- 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;
-};
+ fprintf_filtered (file, _("Deprecated remotecache flag is %s.\n"), value);
+}
+/* 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? */
-struct dcache_struct
+static void
+append_block (struct dcache_block **blist, struct dcache_block *block)
{
- /* Function to actually read the target memory. */
- memxferfunc read_memory;
-
- /* Function to actually write the target memory */
- memxferfunc write_memory;
+ 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;
+ }
+}
- /* free list */
- struct dcache_block *free_head;
- struct dcache_block *free_tail;
+/* Remove BLOCK from circular block list BLIST. */
- /* in use list */
- struct dcache_block *valid_head;
- struct dcache_block *valid_tail;
+static void
+remove_block (struct dcache_block **blist, struct dcache_block *block)
+{
+ if (block->next == block)
+ {
+ *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;
+ }
+}
- /* The cache itself. */
- struct dcache_block *the_cache;
+/* 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. */
- /* 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 void
+for_each_block (struct dcache_block **blist, block_func *func, void *param)
+{
+ struct dcache_block *db;
-static int dcache_poke_byte PARAMS ((DCACHE *dcache, CORE_ADDR addr,
- char *ptr));
+ if (*blist == NULL)
+ return;
-static int dcache_peek_byte PARAMS ((DCACHE *dcache, CORE_ADDR addr,
- char *ptr));
+ db = *blist;
+ do
+ {
+ struct dcache_block *next = db->next;
-static struct dcache_block *dcache_hit PARAMS ((DCACHE *dcache,
- CORE_ADDR addr));
+ func (db, param);
+ db = next;
+ }
+ while (*blist && db != *blist);
+}
-static int dcache_write_line PARAMS ((DCACHE *dcache,struct dcache_block *db));
+/* BLOCK_FUNC routine for dcache_free. */
-static struct dcache_block *dcache_alloc PARAMS ((DCACHE *dcache));
+static void
+free_block (struct dcache_block *block, void *param)
+{
+ xfree (block);
+}
-static int dcache_writeback PARAMS ((DCACHE *dcache));
+/* Free a data cache. */
-static void dcache_info PARAMS ((char *exp, int tty));
+void
+dcache_free (DCACHE *dcache)
+{
+ splay_tree_delete (dcache->tree);
+ for_each_block (&dcache->oldest, free_block, NULL);
+ for_each_block (&dcache->freelist, free_block, NULL);
+ xfree (dcache);
+}
-void _initialize_dcache PARAMS ((void));
-int remote_dcache = 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. */
-DCACHE *last_cache; /* Used by info dcache */
+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_flush (dcache)
- DCACHE *dcache;
+dcache_invalidate (DCACHE *dcache)
{
- int i;
- dcache->valid_head = 0;
- dcache->valid_tail = 0;
+ for_each_block (&dcache->oldest, invalidate_block, dcache);
- dcache->free_head = 0;
- dcache->free_tail = 0;
+ dcache->oldest = NULL;
+ dcache->size = 0;
+ dcache->ptid = null_ptid;
- for (i = 0; i < DCACHE_SIZE; i++)
+ if (dcache->line_size != dcache_line_size)
{
- struct dcache_block *db = dcache->the_cache + i;
+ /* We've been asked to use a different line size.
+ All of our freelist blocks are now the wrong size, so free them. */
- if (!dcache->free_head)
- dcache->free_head = db;
- else
- dcache->free_tail->p = db;
- dcache->free_tail = db;
- db->p = 0;
+ for_each_block (&dcache->freelist, free_block, dcache);
+ dcache->freelist = NULL;
+ dcache->line_size = dcache_line_size;
}
+}
+
+/* Invalidate the line associated with ADDR. */
- dcache->cache_has_stuff = 0;
+static void
+dcache_invalidate_line (DCACHE *dcache, CORE_ADDR addr)
+{
+ struct dcache_block *db = dcache_hit (dcache, addr);
- return;
+ if (db)
+ {
+ splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
+ remove_block (&dcache->oldest, db);
+ append_block (&dcache->freelist, db);
+ --dcache->size;
+ }
}
/* If addr is present in the dcache, return the address of the block
- containing it. */
+ containing it. Otherwise return NULL. */
static struct dcache_block *
-dcache_hit (dcache, addr)
- DCACHE *dcache;
- CORE_ADDR addr;
+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;
+ splay_tree_node node = splay_tree_lookup (dcache->tree,
+ (splay_tree_key) MASK (dcache, addr));
- while (db)
- {
- if (MASK(addr) == db->addr)
- {
- db->refs++;
- return db;
- }
- db = db->p;
- }
+ if (!node)
+ return NULL;
- return NULL;
+ db = (struct dcache_block *) node->value;
+ db->refs++;
+ return db;
}
-/* Make sure that anything in this line which needs to
- be written is. */
+/* 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_write_line (dcache, db)
- DCACHE *dcache;
- register struct dcache_block *db;
+dcache_read_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;
+
+ len = dcache->line_size;
+ memaddr = db->addr;
+ myaddr = db->data;
+
+ while (len > 0)
{
- for (s = 0; s < LINE_SIZE; s++)
+ /* 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;
+
+ /* 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)
{
- 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;
}
- db->anydirty = 0;
+
+ res = target_read_raw_memory (memaddr, myaddr, reg_len);
+ if (res != 0)
+ return 0;
+
+ memaddr += reg_len;
+ myaddr += reg_len;
+ len -= reg_len;
}
+
return 1;
}
-
/* Get a free cache block, put or keep it on the valid list,
- and return its address. The caller should store into the block
- the address and data that it describes, then remque it from the
- free list and insert it into the valid list. This procedure
- prevents errors from creeping in if a memory retrieval is
- interrupted (which used to put garbage blocks in the valid
- list...). */
+ and return its address. */
static struct dcache_block *
-dcache_alloc (dcache)
- DCACHE *dcache;
+dcache_alloc (DCACHE *dcache, CORE_ADDR addr)
{
- register struct dcache_block *db;
-
- if (remote_dcache == 0)
- abort ();
+ 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;
- dcache->valid_head = db->p;
+ db = dcache->freelist;
+ if (db)
+ remove_block (&dcache->freelist, db);
+ else
+ db = ((struct dcache_block *)
+ xmalloc (offsetof (struct dcache_block, data)
+ + dcache->line_size));
- dcache_write_line (dcache, db);
+ dcache->size++;
}
- /* 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;
+ db->addr = MASK (dcache, addr);
+ db->refs = 0;
+
+ /* Put DB at the end of the list, it's the newest. */
+ append_block (&dcache->oldest, db);
+
+ splay_tree_insert (dcache->tree, (splay_tree_key) db->addr,
+ (splay_tree_value) db);
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, addr, ptr)
- DCACHE *dcache;
- CORE_ADDR addr;
- char *ptr;
+dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *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)
+ struct dcache_block *db = dcache_hit (dcache, addr);
+
+ if (!db)
{
- if (db)
- {
- dcache_write_line (dcache, db);
- }
- else
- db = dcache_alloc (dcache);
- immediate_quit++;
- db->addr = MASK (addr);
- 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;
+ db = dcache_alloc (dcache, addr);
+
+ if (!dcache_read_line (dcache, db))
+ return 0;
}
- *ptr = db->data[XFORM (addr)];
- return ok;
+
+ *ptr = db->data[XFORM (dcache, addr)];
+ return 1;
}
-/* Writeback any dirty lines to the remote. */
-static int
-dcache_writeback (dcache)
- DCACHE *dcache;
+/* Write the byte at PTR into ADDR in the data cache.
+
+ The caller should have written the data through to target memory
+ already.
+
+ 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. */
+
+static void
+dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, const gdb_byte *ptr)
{
- struct dcache_block *db;
+ struct dcache_block *db = dcache_hit (dcache, addr);
- db = dcache->valid_head;
+ if (db)
+ db->data[XFORM (dcache, addr)] = *ptr;
+}
- while (db)
- {
- if (!dcache_write_line (dcache, db))
- return 0;
- db = db->p;
- }
- return 1;
+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. */
-/* Using the data cache DCACHE return the contents of the word at
- address ADDR in the remote machine. */
-int
-dcache_fetch (dcache, addr)
- DCACHE *dcache;
- CORE_ADDR addr;
+DCACHE *
+dcache_init (void)
{
- int res;
+ DCACHE *dcache = XNEW (DCACHE);
+
+ dcache->tree = splay_tree_new (dcache_splay_tree_compare,
+ NULL,
+ NULL);
- if (dcache_xfer_memory (dcache, addr, (char *)&res, sizeof res, 0) != sizeof res)
- memory_error (EIO, addr);
+ dcache->oldest = NULL;
+ dcache->freelist = NULL;
+ dcache->size = 0;
+ dcache->line_size = dcache_line_size;
+ dcache->ptid = null_ptid;
- return res;
+ return dcache;
}
-/* Write the byte at PTR into ADDR in the data cache.
- Return zero on write error.
- */
+/* Read LEN bytes from dcache memory at MEMADDR, transferring to
+ debugger address MYADDR. If the data is presently cached, this
+ fills the cache. Arguments/return are like the target_xfer_partial
+ interface. */
-static int
-dcache_poke_byte (dcache, addr, ptr)
- DCACHE *dcache;
- CORE_ADDR addr;
- char *ptr;
+enum target_xfer_status
+dcache_read_memory_partial (struct target_ops *ops, DCACHE *dcache,
+ CORE_ADDR memaddr, gdb_byte *myaddr,
+ ULONGEST len, ULONGEST *xfered_len)
{
- register struct dcache_block *db = dcache_hit (dcache, addr);
+ ULONGEST i;
- if (!db)
+ /* If this is a different inferior from what we've recorded,
+ flush the cache. */
+
+ if (inferior_ptid != dcache->ptid)
{
- db = dcache_alloc (dcache);
- db->addr = MASK (addr);
- memset (db->state, ENTRY_BAD, sizeof (db->data));
+ dcache_invalidate (dcache);
+ dcache->ptid = inferior_ptid;
}
- db->data[XFORM (addr)] = *ptr;
- db->state[XFORM (addr)] = ENTRY_DIRTY;
- db->anydirty = 1;
- return 1;
+ for (i = 0; i < len; i++)
+ {
+ if (!dcache_peek_byte (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);
+ break;
+ }
+ }
+
+ if (i == 0)
+ {
+ /* Even though reading the whole line failed, we may be able to
+ read a piece starting where the caller wanted. */
+ return raw_memory_xfer_partial (ops, myaddr, NULL, memaddr, len,
+ xfered_len);
+ }
+ else
+ {
+ *xfered_len = i;
+ return TARGET_XFER_OK;
+ }
}
-/* Write the word at ADDR both in the data cache and in the remote machine.
- Return zero on write error.
- */
+/* 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. */
-int
-dcache_poke (dcache, addr, data)
- DCACHE *dcache;
- CORE_ADDR addr;
- int data;
+/* Just update any cache lines which are already present. This is
+ called by the target_xfer_partial machinery when writing raw
+ memory. */
+
+void
+dcache_update (DCACHE *dcache, enum target_xfer_status status,
+ CORE_ADDR memaddr, const gdb_byte *myaddr,
+ ULONGEST len)
{
- if (dcache_xfer_memory (dcache, addr, (char *)&data, sizeof data, 1) != sizeof data)
- return 0;
+ ULONGEST i;
- return dcache_writeback (dcache);
+ for (i = 0; i < len; i++)
+ if (status == TARGET_XFER_OK)
+ dcache_poke_byte (dcache, memaddr + i, myaddr + i);
+ else
+ {
+ /* Discard the whole cache line so we don't have a partially
+ valid line. */
+ dcache_invalidate_line (dcache, memaddr + i);
+ }
}
+/* Print DCACHE line INDEX. */
-/* Initialize the data cache. */
-DCACHE *
-dcache_init (reading, writing)
- memxferfunc reading;
- memxferfunc writing;
+static void
+dcache_print_line (DCACHE *dcache, int index)
{
- int csize = sizeof (struct dcache_block) * DCACHE_SIZE;
- DCACHE *dcache;
+ splay_tree_node n;
+ struct dcache_block *db;
+ int i, j;
- dcache = (DCACHE *) xmalloc (sizeof (*dcache));
- dcache->read_memory = reading;
- dcache->write_memory = writing;
+ if (dcache == NULL)
+ {
+ printf_filtered (_("No data cache available.\n"));
+ return;
+ }
- dcache->the_cache = (struct dcache_block *) xmalloc (csize);
- memset (dcache->the_cache, 0, csize);
+ n = splay_tree_min (dcache->tree);
- dcache_flush (dcache);
+ for (i = index; i > 0; --i)
+ {
+ if (!n)
+ break;
+ n = splay_tree_successor (dcache->tree, n->key);
+ }
- last_cache = dcache;
- return dcache;
-}
+ if (!n)
+ {
+ printf_filtered (_("No such cache line exists.\n"));
+ return;
+ }
+
+ db = (struct dcache_block *) n->value;
-/* 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.
+ printf_filtered (_("Line %d: address %s [%d hits]\n"),
+ index, paddress (target_gdbarch (), db->addr), db->refs);
- Returns length of data written or read; 0 for error.
+ for (j = 0; j < dcache->line_size; j++)
+ {
+ printf_filtered ("%02x ", db->data[j]);
- This routine is indended to be called by remote_xfer_ functions. */
+ /* Print a newline every 16 bytes (48 characters). */
+ if ((j % 16 == 15) && (j != dcache->line_size - 1))
+ printf_filtered ("\n");
+ }
+ printf_filtered ("\n");
+}
-int
-dcache_xfer_memory (dcache, memaddr, myaddr, len, should_write)
- DCACHE *dcache;
- CORE_ADDR memaddr;
- char *myaddr;
- int len;
- int should_write;
+/* Parse EXP and show the info about DCACHE. */
+
+static void
+dcache_info_1 (DCACHE *dcache, const char *exp)
{
- int i;
+ splay_tree_node n;
+ int i, refcount;
- if (remote_dcache)
+ if (exp)
{
- int (*xfunc) PARAMS ((DCACHE *dcache, CORE_ADDR addr, char *ptr));
- xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
+ char *linestart;
- for (i = 0; i < len; i++)
+ i = strtol (exp, &linestart, 10);
+ if (linestart == exp || i < 0)
{
- if (!xfunc (dcache, memaddr + i, myaddr + i))
- return 0;
+ printf_filtered (_("Usage: info dcache [LINENUMBER]\n"));
+ return;
}
- dcache->cache_has_stuff = 1;
- dcache_writeback (dcache);
+
+ dcache_print_line (dcache, i);
+ return;
+ }
+
+ printf_filtered (_("Dcache %u lines of %u bytes each.\n"),
+ dcache_size,
+ dcache ? (unsigned) dcache->line_size
+ : dcache_line_size);
+
+ if (dcache == NULL || dcache->ptid == null_ptid)
+ {
+ printf_filtered (_("No data cache available.\n"));
+ return;
}
- else
+
+ printf_filtered (_("Contains data for %s\n"),
+ target_pid_to_str (dcache->ptid).c_str ());
+
+ refcount = 0;
+
+ n = splay_tree_min (dcache->tree);
+ i = 0;
+
+ while (n)
{
- memxferfunc xfunc;
- xfunc = should_write ? dcache->write_memory : dcache->read_memory;
+ struct dcache_block *db = (struct dcache_block *) n->value;
- if (dcache->cache_has_stuff)
- dcache_flush (dcache);
+ printf_filtered (_("Line %d: address %s [%d hits]\n"),
+ i, paddress (target_gdbarch (), db->addr), db->refs);
+ i++;
+ refcount += db->refs;
- len = xfunc (memaddr, myaddr, len);
+ n = splay_tree_successor (dcache->tree, n->key);
}
- return len;
+
+ printf_filtered (_("Cache state: %d active lines, %d hits\n"), i, refcount);
}
-static void
-dcache_info (exp, tty)
- char *exp;
- int tty;
+static void
+info_dcache_command (const char *exp, int tty)
{
- struct dcache_block *p;
+ dcache_info_1 (target_dcache_get (), exp);
+}
- if (!remote_dcache)
+static void
+set_dcache_size (const char *args, int from_tty,
+ struct cmd_list_element *c)
+{
+ if (dcache_size == 0)
{
- printf_filtered ("Dcache not enabled\n");
- return;
+ dcache_size = DCACHE_DEFAULT_SIZE;
+ error (_("Dcache size must be greater than 0."));
}
- printf_filtered ("Dcache enabled, line width %d, depth %d\n",
- LINE_SIZE, DCACHE_SIZE);
-
- printf_filtered ("Cache state:\n");
+ target_dcache_invalidate ();
+}
- for (p = last_cache->valid_head; p; p = p->p)
+static void
+set_dcache_line_size (const char *args, int from_tty,
+ struct cmd_list_element *c)
+{
+ if (dcache_line_size < 2
+ || (dcache_line_size & (dcache_line_size - 1)) != 0)
{
- int j;
- printf_filtered ("Line at %08xd, referenced %d times\n",
- p->addr, p->refs);
-
- for (j = 0; j < LINE_SIZE; j++)
- printf_filtered ("%02x", p->data[j] & 0xFF);
- printf_filtered ("\n");
-
- for (j = 0; j < LINE_SIZE; j++)
- printf_filtered (" %2x", p->state[j]);
- printf_filtered ("\n");
+ unsigned d = dcache_line_size;
+ dcache_line_size = DCACHE_DEFAULT_LINE_SIZE;
+ error (_("Invalid dcache line size: %u (must be power of 2)."), d);
}
+ target_dcache_invalidate ();
}
+void _initialize_dcache ();
void
_initialize_dcache ()
{
- add_show_from_set
- (add_set_cmd ("remotecache", class_support, var_boolean,
- (char *) &remote_dcache,
- "\
-Set cache use for remote targets.\n\
-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 on.",
- &setlist),
- &showlist);
-
- add_info ("dcache", dcache_info,
- "Print information on the dcache performance.");
-
+ add_setshow_boolean_cmd ("remotecache", class_support,
+ &dcache_enabled_p, _("\
+Set cache use for remote targets."), _("\
+Show cache use for remote targets."), _("\
+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,
+ show_dcache_enabled_p,
+ &setlist, &showlist);
+
+ add_info ("dcache", info_dcache_command,
+ _("\
+Print information on the dcache performance.\n\
+Usage: info dcache [LINENUMBER]\n\
+With no arguments, this command prints the cache configuration and a\n\
+summary of each line in the cache. With an argument, dump\"\n\
+the contents of the given line."));
+
+ add_basic_prefix_cmd ("dcache", class_obscure, _("\
+Use this command to set number of lines in dcache and line-size."),
+ &dcache_set_list, "set dcache ", /*allow_unknown*/0,
+ &setlist);
+ add_show_prefix_cmd ("dcache", class_obscure, _("\
+Show dcachesettings."),
+ &dcache_show_list, "show dcache ", /*allow_unknown*/0,
+ &showlist);
+
+ add_setshow_zuinteger_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_zuinteger_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 / deliverable / binutils-gdb.git / blobdiff