#define BUNDLE_LEN 16
+/* See the saved memory layout comment for ia64_memory_insert_breakpoint. */
+
+#if BREAKPOINT_MAX < BUNDLE_LEN - 2
+# error "BREAKPOINT_MAX < BUNDLE_LEN - 2"
+#endif
+
static gdbarch_init_ftype ia64_gdbarch_init;
static gdbarch_register_name_ftype ia64_register_name;
replace_bit_field (bundle, instr, 5+41*slotnum, 41);
}
-static enum instruction_type template_encoding_table[32][3] =
+static const enum instruction_type template_encoding_table[32][3] =
{
{ M, I, I }, /* 00 */
{ M, I, I }, /* 01 */
simulators. So I changed the pattern slightly to do "break.i 0x080001"
instead. But that didn't work either (I later found out that this
pattern was used by the simulator that I was using.) So I ended up
- using the pattern seen below. */
+ using the pattern seen below.
+
+ SHADOW_CONTENTS has byte-based addressing (PLACED_ADDRESS and SHADOW_LEN)
+ while we need bit-based addressing as the instructions length is 41 bits and
+ we must not modify/corrupt the adjacent slots in the same bundle.
+ Fortunately we may store larger memory incl. the adjacent bits with the
+ original memory content (not the possibly already stored breakpoints there).
+ We need to be careful in ia64_memory_remove_breakpoint to always restore
+ only the specific bits of this instruction ignoring any adjacent stored
+ bits.
+
+ We use the original addressing with the low nibble in the range <0..2> which
+ gets incorrectly interpreted by generic non-ia64 breakpoint_restore_shadows
+ as the direct byte offset of SHADOW_CONTENTS. We store whole BUNDLE_LEN
+ bytes just without these two possibly skipped bytes to not to exceed to the
+ next bundle.
+
+ If we would like to store the whole bundle to SHADOW_CONTENTS we would have
+ to store already the base address (`address & ~0x0f') into PLACED_ADDRESS.
+ In such case there is no other place where to store
+ SLOTNUM (`adress & 0x0f', value in the range <0..2>). We need to know
+ SLOTNUM in ia64_memory_remove_breakpoint.
+
+ ia64 16-byte bundle layout:
+ | 5 bits | slot 0 with 41 bits | slot 1 with 41 bits | slot 2 with 41 bits |
+
+ The current addressing used by the code below:
+ original PC placed_address placed_size required covered
+ == bp_tgt->shadow_len reqd \subset covered
+ 0xABCDE0 0xABCDE0 0xE <0x0...0x5> <0x0..0xD>
+ 0xABCDE1 0xABCDE1 0xE <0x5...0xA> <0x1..0xE>
+ 0xABCDE2 0xABCDE2 0xE <0xA...0xF> <0x2..0xF>
+
+ `objdump -d' and some other tools show a bit unjustified offsets:
+ original PC byte where starts the instruction objdump offset
+ 0xABCDE0 0xABCDE0 0xABCDE0
+ 0xABCDE1 0xABCDE5 0xABCDE6
+ 0xABCDE2 0xABCDEA 0xABCDEC
+ */
#define IA64_BREAKPOINT 0x00003333300LL
struct bp_target_info *bp_tgt)
{
CORE_ADDR addr = bp_tgt->placed_address;
- char bundle[BUNDLE_LEN];
+ gdb_byte bundle[BUNDLE_LEN];
int slotnum = (int) (addr & 0x0f) / SLOT_MULTIPLIER;
- long long instr;
+ long long instr_breakpoint;
int val;
int template;
+ struct cleanup *cleanup;
if (slotnum > 2)
error (_("Can't insert breakpoint for slot numbers greater than 2."));
addr &= ~0x0f;
+ /* Disable the automatic memory restoration from breakpoints while
+ we read our instruction bundle. Otherwise, the general restoration
+ mechanism kicks in and we would possibly remove parts of the adjacent
+ placed breakpoints. It is due to our SHADOW_CONTENTS overlapping the real
+ breakpoint instruction bits region. */
+ cleanup = make_show_memory_breakpoints_cleanup (1);
val = target_read_memory (addr, bundle, BUNDLE_LEN);
- /* Check for L type instruction in 2nd slot, if present then
- bump up the slot number to the 3rd slot */
+ /* Check for L type instruction in slot 1, if present then bump up the slot
+ number to the slot 2. */
template = extract_bit_field (bundle, 0, 5);
- if (slotnum == 1 && template_encoding_table[template][1] == L)
- {
- slotnum = 2;
- }
-
- instr = slotN_contents (bundle, slotnum);
- memcpy (bp_tgt->shadow_contents, &instr, sizeof (instr));
- bp_tgt->placed_size = bp_tgt->shadow_len = sizeof (instr);
+ if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
+ slotnum = 2;
+
+ /* Slot number 2 may skip at most 2 bytes at the beginning. */
+ bp_tgt->placed_size = bp_tgt->shadow_len = BUNDLE_LEN - 2;
+
+ /* Store the whole bundle, except for the initial skipped bytes by the slot
+ number interpreted as bytes offset in PLACED_ADDRESS. */
+ memcpy (bp_tgt->shadow_contents, bundle + slotnum, bp_tgt->shadow_len);
+
+ /* Breakpoints already present in the code will get deteacted and not get
+ reinserted by bp_loc_is_permanent. Multiple breakpoints at the same
+ location cannot induce the internal error as they are optimized into
+ a single instance by update_global_location_list. */
+ instr_breakpoint = slotN_contents (bundle, slotnum);
+ if (instr_breakpoint == IA64_BREAKPOINT)
+ internal_error (__FILE__, __LINE__,
+ _("Address %s already contains a breakpoint."),
+ paddr_nz (bp_tgt->placed_address));
replace_slotN_contents (bundle, IA64_BREAKPOINT, slotnum);
+
if (val == 0)
- target_write_memory (addr, bundle, BUNDLE_LEN);
+ val = target_write_memory (addr + slotnum, bundle + slotnum,
+ bp_tgt->shadow_len);
+ do_cleanups (cleanup);
return val;
}
struct bp_target_info *bp_tgt)
{
CORE_ADDR addr = bp_tgt->placed_address;
- char bundle[BUNDLE_LEN];
+ gdb_byte bundle_mem[BUNDLE_LEN], bundle_saved[BUNDLE_LEN];
int slotnum = (addr & 0x0f) / SLOT_MULTIPLIER;
- long long instr;
+ long long instr_breakpoint, instr_saved;
int val;
int template;
struct cleanup *cleanup;
/* Disable the automatic memory restoration from breakpoints while
we read our instruction bundle. Otherwise, the general restoration
- mechanism kicks in and ends up corrupting our bundle, because it
- is not aware of the concept of instruction bundles. */
+ mechanism kicks in and we would possibly remove parts of the adjacent
+ placed breakpoints. It is due to our SHADOW_CONTENTS overlapping the real
+ breakpoint instruction bits region. */
cleanup = make_show_memory_breakpoints_cleanup (1);
- val = target_read_memory (addr, bundle, BUNDLE_LEN);
+ val = target_read_memory (addr, bundle_mem, BUNDLE_LEN);
- /* Check for L type instruction in 2nd slot, if present then
- bump up the slot number to the 3rd slot */
- template = extract_bit_field (bundle, 0, 5);
- if (slotnum == 1 && template_encoding_table[template][1] == L)
+ /* Check for L type instruction in slot 1, if present then bump up the slot
+ number to the slot 2. */
+ template = extract_bit_field (bundle_mem, 0, 5);
+ if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
+ slotnum = 2;
+
+ gdb_assert (bp_tgt->placed_size == BUNDLE_LEN - 2);
+ gdb_assert (bp_tgt->placed_size == bp_tgt->shadow_len);
+
+ instr_breakpoint = slotN_contents (bundle_mem, slotnum);
+ if (instr_breakpoint != IA64_BREAKPOINT)
{
- slotnum = 2;
+ warning (_("Cannot remove breakpoint at address %s, "
+ "no break instruction at such address."),
+ paddr_nz (bp_tgt->placed_address));
+ return -1;
}
- memcpy (&instr, bp_tgt->shadow_contents, sizeof instr);
- replace_slotN_contents (bundle, instr, slotnum);
+ /* Extract the original saved instruction from SLOTNUM normalizing its
+ bit-shift for INSTR_SAVED. */
+ memcpy (bundle_saved, bundle_mem, BUNDLE_LEN);
+ memcpy (bundle_saved + slotnum, bp_tgt->shadow_contents, bp_tgt->shadow_len);
+ instr_saved = slotN_contents (bundle_saved, slotnum);
+
+ /* In BUNDLE_MEM be careful to modify only the bits belonging to SLOTNUM and
+ never any other possibly also stored in SHADOW_CONTENTS. */
+ replace_slotN_contents (bundle_mem, instr_saved, slotnum);
if (val == 0)
- target_write_memory (addr, bundle, BUNDLE_LEN);
+ val = target_write_memory (addr, bundle_mem, BUNDLE_LEN);
do_cleanups (cleanup);
return val;
}
-/* We don't really want to use this, but remote.c needs to call it in order
- to figure out if Z-packets are supported or not. Oh, well. */
-const unsigned char *
+/* As gdbarch_breakpoint_from_pc ranges have byte granularity and ia64
+ instruction slots ranges are bit-granular (41 bits) we have to provide an
+ extended range as described for ia64_memory_insert_breakpoint. We also take
+ care of preserving the `break' instruction 21-bit (or 62-bit) parameter to
+ make a match for permanent breakpoints. */
+
+static const gdb_byte *
ia64_breakpoint_from_pc (struct gdbarch *gdbarch, CORE_ADDR *pcptr, int *lenptr)
{
- static unsigned char breakpoint[] =
- { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
- *lenptr = sizeof (breakpoint);
-#if 0
- *pcptr &= ~0x0f;
-#endif
- return breakpoint;
+ CORE_ADDR addr = *pcptr;
+ static gdb_byte bundle[BUNDLE_LEN];
+ int slotnum = (int) (*pcptr & 0x0f) / SLOT_MULTIPLIER;
+ long long instr_fetched;
+ int val;
+ int template;
+ struct cleanup *cleanup;
+
+ if (slotnum > 2)
+ error (_("Can't insert breakpoint for slot numbers greater than 2."));
+
+ addr &= ~0x0f;
+
+ /* Enable the automatic memory restoration from breakpoints while
+ we read our instruction bundle to match bp_loc_is_permanent. */
+ cleanup = make_show_memory_breakpoints_cleanup (0);
+ val = target_read_memory (addr, bundle, BUNDLE_LEN);
+ do_cleanups (cleanup);
+
+ /* The memory might be unreachable. This can happen, for instance,
+ when the user inserts a breakpoint at an invalid address. */
+ if (val != 0)
+ return NULL;
+
+ /* Check for L type instruction in slot 1, if present then bump up the slot
+ number to the slot 2. */
+ template = extract_bit_field (bundle, 0, 5);
+ if (slotnum == 1 && template_encoding_table[template][slotnum] == L)
+ slotnum = 2;
+
+ /* A break instruction has its all its opcode bits cleared except for
+ the parameter value. For L+X slot pair we are at the X slot (slot 2) so
+ we should not touch the L slot - the upper 41 bits of the parameter. */
+ instr_fetched = slotN_contents (bundle, slotnum);
+ instr_fetched &= 0x1003ffffc0;
+ replace_slotN_contents (bundle, instr_fetched, slotnum);
+
+ *lenptr = BUNDLE_LEN - 2;
+
+ /* SLOTNUM is possibly already locally modified - use caller's *PCPTR. */
+ return bundle + (*pcptr & 0x0f);
}
static CORE_ADDR
projects / binutils-gdb.git / commitdiff