From 4b5752d02f5e21329ae17790fd766b5f2df0d362 Mon Sep 17 00:00:00 2001 From: Vladimir Prus Date: Tue, 21 Nov 2006 16:50:16 +0000 Subject: [PATCH] gdb/ * memattr.h (enum mem_access_mode): New value MEM_NONE. * memattr.c (unknown_mem_attrib): New. (inaccessible_by_default): New. (show_inaccessible_by_default): New. (lookup_mem_region): Check inaccessible_by_default. (dummy_cmd): New. (mem_set_cmdlist, mem_show_cmdlist): New. (_initialize_mem): Register new "set" and "show" commands. * target.c (memory_xfer_partial): If memory type is MEM_NONE, return an error. Clip to region size when calling to_xfer_partial. If upper limit of memory range is 0, don't clip anything. gdb/doc/ * gdb.texinfo (Memory Access Checking): New. --- gdb/ChangeLog | 18 +++++++++++ gdb/doc/ChangeLog | 4 +++ gdb/doc/gdb.texinfo | 21 +++++++++++++ gdb/memattr.c | 75 +++++++++++++++++++++++++++++++++++++++++++-- gdb/memattr.h | 4 +++ gdb/target.c | 8 +++-- 6 files changed, 126 insertions(+), 4 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index 4726e265f8..2f6ef8d0cd 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,21 @@ +2006-11-21 Vladimir Prus + + * memattr.h (enum mem_access_mode): New value + MEM_NONE. + * memattr.c (unknown_mem_attrib): New. + (inaccessible_by_default): New. + (show_inaccessible_by_default): New. + (lookup_mem_region): Check inaccessible_by_default. + (dummy_cmd): New. + (mem_set_cmdlist, mem_show_cmdlist): New. + (_initialize_mem): Register new "set" and "show" + commands. + * target.c (memory_xfer_partial): If memory type + is MEM_NONE, return an error. + Clip to region size when calling to_xfer_partial. + If upper limit of memory range is 0, don't clip + anything. + 2006-11-20 Joel Brobecker * README: Remove obsolete information. diff --git a/gdb/doc/ChangeLog b/gdb/doc/ChangeLog index ecf7a8ccc1..71f30c1e73 100644 --- a/gdb/doc/ChangeLog +++ b/gdb/doc/ChangeLog @@ -1,3 +1,7 @@ +2006-11-21 Vladimir Prus + + * gdb.texinfo (Memory Access Checking): New. + 2006-11-16 Daniel Jacobowitz * gdb.texinfo (Remote configuration): Mention diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo index f0b5f87e10..f89cc09781 100644 --- a/gdb/doc/gdb.texinfo +++ b/gdb/doc/gdb.texinfo @@ -6894,6 +6894,27 @@ Enable @value{GDBN} to cache target memory. Disable @value{GDBN} from caching target memory. This is the default. @end table +@subsection Memory Access Checking +@value{GDBN} can be instructed to refuse accesses to memory that is +not explicitly described. This can be useful if accessing such +regions has undesired effects for a specific target, or to provide +better error checking. The following commands control this behaviour. + +@table @code +@kindex set mem inaccessible-by-default +@item set mem inaccessible-by-default [on|off] +If @code{on} is specified, make @value{GDBN} treat memory not +explicitly described by the memory ranges as non-existent and refuse accesses +to such memory. The checks are only performed if there's at least one +memory range defined. If @code{off} is specified, make @value{GDBN} +treat the memory not explicitly described by the memory ranges as RAM. +The default value is @code{off}. +@kindex show mem inaccessible-by-default +@item show mem inaccessible-by-default +Show the current handling of accesses to unknown memory. +@end table + + @c @subsubsection Memory Write Verification @c The memory write verification attributes set whether @value{GDBN} @c will re-reads data after each write to verify the write was successful. diff --git a/gdb/memattr.c b/gdb/memattr.c index 889d03ac8f..a114dc1ff8 100644 --- a/gdb/memattr.c +++ b/gdb/memattr.c @@ -40,6 +40,17 @@ const struct mem_attrib default_mem_attrib = -1 /* Flash blocksize not specified. */ }; +const struct mem_attrib unknown_mem_attrib = +{ + MEM_NONE, /* mode */ + MEM_WIDTH_UNSPECIFIED, + 0, /* hwbreak */ + 0, /* cache */ + 0, /* verify */ + -1 /* Flash blocksize not specified. */ +}; + + VEC(mem_region_s) *mem_region_list, *target_mem_region_list; static int mem_number = 0; @@ -53,6 +64,25 @@ static int mem_use_target = 1; empty, then the target can't supply memory regions. */ static int target_mem_regions_valid; +/* If this flag is set, gdb will assume that memory ranges not + specified by the memory map have type MEM_NONE, and will + emit errors on all accesses to that memory. */ +static int inaccessible_by_default = 0; + +static void +show_inaccessible_by_default (struct ui_file *file, int from_tty, + struct cmd_list_element *c, + const char *value) +{ + if (inaccessible_by_default) + fprintf_filtered (file, _("\ +Unknown memory addresses will be treated as inaccessible.\n")); + else + fprintf_filtered (file, _("\ +Unknown memory addresses will be treated as RAM.\n")); +} + + /* Predicate function which returns true if LHS should sort before RHS in a list of memory regions, useful for VEC_lower_bound. */ @@ -215,13 +245,17 @@ lookup_mem_region (CORE_ADDR addr) lo = 0; hi = 0; - /* If we ever want to support a huge list of memory regions, this + /* Either find memory range containing ADDRESS, or set LO and HI + to the nearest boundaries of an existing memory range. + + If we ever want to support a huge list of memory regions, this check should be replaced with a binary search (probably using VEC_lower_bound). */ for (ix = 0; VEC_iterate (mem_region_s, mem_region_list, ix, m); ix++) { if (m->enabled_p == 1) { + /* If the address is in the memory region, return that memory range. */ if (addr >= m->lo && (addr < m->hi || m->hi == 0)) return m; @@ -243,7 +277,15 @@ lookup_mem_region (CORE_ADDR addr) was learned above. */ region.lo = lo; region.hi = hi; - region.attrib = default_mem_attrib; + + /* When no memory map is defined at all, we always return + 'default_mem_attrib', so that we do not make all memory + inaccessible for targets that don't provide a memory map. */ + if (inaccessible_by_default && !VEC_empty (mem_region_s, mem_region_list)) + region.attrib = unknown_mem_attrib; + else + region.attrib = default_mem_attrib; + return ®ion; } @@ -674,9 +716,17 @@ mem_delete_command (char *args, int from_tty) dont_repeat (); } + +static void +dummy_cmd (char *args, int from_tty) +{ +} extern initialize_file_ftype _initialize_mem; /* -Wmissing-prototype */ +static struct cmd_list_element *mem_set_cmdlist; +static struct cmd_list_element *mem_show_cmdlist; + void _initialize_mem (void) { @@ -709,4 +759,25 @@ Do \"info mem\" to see current list of code numbers."), &deletelist); add_info ("mem", mem_info_command, _("Memory region attributes")); + + add_prefix_cmd ("mem", class_vars, dummy_cmd, _("\ +Memory regions settings"), + &mem_set_cmdlist, "set mem ", + 0/* allow-unknown */, &setlist); + add_prefix_cmd ("mem", class_vars, dummy_cmd, _("\ +Memory regions settings"), + &mem_show_cmdlist, "show mem ", + 0/* allow-unknown */, &showlist); + + add_setshow_boolean_cmd ("inaccessible-by-default", no_class, + &inaccessible_by_default, _("\ +Set handling of unknown memory regions."), _("\ +Show handling of unknown memory regions."), _("\ +If on, and some memory map is defined, debugger will emit errors on\n\ +accesses to memory not defined in the memory map. If off, accesses to all\n\ +memory addresses will be allowed."), + NULL, + show_inaccessible_by_default, + &mem_set_cmdlist, + &mem_show_cmdlist); } diff --git a/gdb/memattr.h b/gdb/memattr.h index 046af68963..077ccee86c 100644 --- a/gdb/memattr.h +++ b/gdb/memattr.h @@ -26,6 +26,7 @@ enum mem_access_mode { + MEM_NONE, /* Memory that is not physically present. */ MEM_RW, /* read/write */ MEM_RO, /* read only */ MEM_WO, /* write only */ @@ -76,7 +77,10 @@ struct mem_attrib struct mem_region { + /* Lowest address in the region. */ CORE_ADDR lo; + /* Address past the highest address of the region. + If 0, upper bound is "infinity". */ CORE_ADDR hi; /* Item number of this memory region. */ diff --git a/gdb/target.c b/gdb/target.c index 2ff882cf91..2062733037 100644 --- a/gdb/target.c +++ b/gdb/target.c @@ -1015,7 +1015,8 @@ memory_xfer_partial (struct target_ops *ops, void *readbuf, const void *writebuf /* Try GDB's internal data cache. */ region = lookup_mem_region (memaddr); - if (memaddr + len < region->hi) + /* region->hi == 0 means there's no upper bound. */ + if (memaddr + len < region->hi || region->hi == 0) reg_len = len; else reg_len = region->hi - memaddr; @@ -1037,6 +1038,9 @@ memory_xfer_partial (struct target_ops *ops, void *readbuf, const void *writebuf if (writebuf != NULL) error (_("Writing to flash memory forbidden in this context")); break; + + case MEM_NONE: + return -1; } if (region->attrib.cache) @@ -1072,7 +1076,7 @@ memory_xfer_partial (struct target_ops *ops, void *readbuf, const void *writebuf do { res = ops->to_xfer_partial (ops, TARGET_OBJECT_MEMORY, NULL, - readbuf, writebuf, memaddr, len); + readbuf, writebuf, memaddr, reg_len); if (res > 0) return res; -- 2.34.1