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21c90ca166ee384d271e92a409c690a7faf945a2
binutils-gdb/gdb/ia64-linux-nat.c
Your Name 21c90ca166 gdb/aarch64: restore in-order watchpoint matching 
At Red Hat we have an out of tree AArch64 watchpoint test which broke
after this commit:

  commit cf16ab724a
  Date:   Tue Mar 12 17:08:18 2024 +0100

      [gdb/tdep] Fix gdb.base/watch-bitfields.exp on aarch64

The problem with AArch64 hardware watchpoints is that they (as I
understand it) are restricted to a minimum of 8 bytes.  This means
that, if the thing you are watching is less than 8-bytes, then there
is always scope for invalid watchpoint triggers caused by activity in
the part of the 8-bytes that are not being watched.

Or, as is the case in this RH test, multiple watchpoint are created
within an 8-byte region, and GDB can miss-identify which watchpoint
actually triggered.

Prior to the above commit the RH test was passing.  However, the test
was relying on, in the case of ambiguity, GDB selecting the first
created watchpoint.  That behaviour changed with the above commit.
Now GDB favours reporting non write breakpoints, and will only report
a write breakpoint if no non-write breakpoint exists in the same
region.

I originally posted a patch to try and tweak the existing logic to
restore enough of the original behaviour that the RH test would pass,
this can be found here (2 iterations):

  https://inbox.sourceware.org/gdb-patches/65e746b6394f04faa027e778f733eda95d20f368.1753115072.git.aburgess@redhat.com
  https://inbox.sourceware.org/gdb-patches/638cbe9b738c0c529f6370f90ba4a395711f63ae.1753971315.git.aburgess@redhat.com

Neither of these really resolved the problem, they fixed some cases,
but broke others.

Ultimately, the problem on AArch64 is that for a single watchpoint
trap, there could be multiple watchpoints that are potentially
responsible.  The existing API defined by the target_ops methods
stopped_by_watchpoint() and stopped_data_address() only allow for two
possible options:

  1. If stopped_by_watchpoint() is true then stopped_data_address()
     can return true and a single address which identifies all
     watchpoints at that single address, or

  2. If stopped_by_watchpoint() is true then stopped_data_address()
     can return false, in which case GDB will check all write
     watchpoints to see if any have changed, if they have, then GDB
     tells the user that that was the triggering watchpoint.

If we are in a situation where we have to choose between multiple
write and read watchpoints then the current API doesn't allow the
architecture specific code to tell GDB core about this case.

In this commit I propose that we change the target_ops API,
specifically, the method:

  bool target_ops::stopped_data_address (CORE_ADDR *);

will change to:

  std::vector<CORE_ADDR> target_ops::stopped_data_addresses ();

The architecture specific code can now return a set of watchpoint
addresses, allowing GDB to identify a set of watchpoints that might
have triggered.  GDB core can then select the most likely watchpoint,
and present that to the user.

As with the old API, target_ops::stopped_data_addresses should only be
called when target_ops::stopped_by_watchpoint is true, in which case
it's return values can be interpreted like this:

  a. An empty vector; this replaces the old case where false was
     returned.  GDB should check all the write watchpoints and select
     the one that changed as the responsible watchpoint.

  b. A single entry vector; all targets except AArch64 currently
     return at most a single entry vector.  The single address
     indicates the watchpoint(s) that triggered.

  c. A multi-entry vector; currently AArch64 only.  These addresses
     indicate the set of watchpoints that might have triggered.  GDB
     will check the write watchpoints to see which (if any) changed,
     and if no write watchpoints changed, GDB will present the first
     access watchpoint.

In the future, we might want to improve the handling of (c) so that
GDB tells the user that multiple access watchpoints might have
triggered, and then list all of them.  This might clear up some
confusion.  But I think that can be done in the future (I don't have
an immediate plan to work on this).  I think this change is already a
good improvement.

The changes for this are pretty extensive, but here's a basic summary:

  * Within gdb/ changing the API name from stopped_data_address to
    stopped_data_addresses throughout.  Comments are updated too where
    needed.

  * For targets other than AArch64, the existing code is retained with
    as few changes as possible, we only allow for a single address to
    be returned, the address is now wrapped in a vector.  Where we
    used to return false, we now return the empty vector.

  * For AArch64, the return a vector logic is pushed through to
    gdb/nat/aarch64-hw-point.{c,h}, and aarch64_stopped_data_address
    changes to aarch64_stopped_data_addresses, and is updated to
    return a vector of addresses.

  * In infrun.c there's some updates to some debug output.

  * In breakpoint.c the interesting changes are in
    watchpoints_triggered.  The existing code has three cases to
    handle:

    (i) target_stopped_by_watchpoint returns false.  This case is
        unchanged.

    (ii) target_stopped_data_address returns false.  This case is now
         calling target_stopped_data_addresses, and checks for the
	 empty vector, but otherwise is unchanged.

    (iii) target_stopped_data_address returns true, and a single
          address.  This code calls target_stopped_data_addresses, and
	  now handles the possibility of a vector containing multiple
	  entries.  We need to first loop over every watchpoint
	  setting its triggered status to 'no', then we check every
	  address in the vector setting matching watchpoint's
	  triggered status to 'yes'.  But the actual logic for if a
	  watchpoint matches an address or not is unchanged.

    The important thing to notice here is that in case (iii), before
    this patch, GDB could already set _multiple_ watchpoints to
    triggered.  For example, setting a read and write watchpoint on
    the same address would result in multiple watchpoints being marked
    as triggered.  This patch just extends this so that multiple
    watchpoints, at multiple addresses, can now be marked as
    triggered.

  * In remote.c there is an interesting change.  We need to allow
    gdbserver to pass the multiple addresses back to GDB.  To achieve
    this, I now allow multiple 'watch', 'rwatch', and 'awatch' tokens
    in a 'T' stop reply packet.  This change is largely backward
    compatible.  For old versions of GDB, GDB will just use the last
    such token as the watchpoint stop address.  For new GDBs, all of
    the addresses are collected and returned from the
    target_ops::stopped_data_addresses call.  If a new GDB connects to
    an old gdbserver then it'll only get a single watchpoint address
    in the 'T' packet, but that's no worse than we are now, and will
    not cause a GDB crash, GDB will just end up checking a restricted
    set of watchpoints (which is where we are right now).

  * In gdbserver/ the changes are pretty similar.  The API is renamed
    from ::stopped_data_address to ::stopped_data_addresses, and
    ::low_stopped_data_address to ::low_stopped_data_addresses.

  * For all targets except AArch64, the existing code is retained, we
    just wrap the single address into a vector.

  * For AArch64, we call aarch64_stopped_data_addresses, which returns
    the required vector.

For testing, I've built GDB on GNU/Linux for i386, x86-64, PPC64le,
ARM, and AArch64.  That still leaves a lot of targets possibly
impacted by this change as untested.  Which is a risk.  I certainly
wouldn't want to push this patch until after GDB 17 branches so we
have time to find and fix any regressions that are introduced.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33240
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=33252
2025-08-07 14:43:49 +01:00

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/* Functions specific to running gdb native on IA-64 running
GNU/Linux.
Copyright (C) 1999-2025 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 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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, see <http://www.gnu.org/licenses/>. */
#include "inferior.h"
#include "target.h"
#include "gdbarch.h"
#include "gdbcore.h"
#include "regcache.h"
#include "ia64-tdep.h"
#include "linux-nat.h"
#include <signal.h>
#include "nat/gdb_ptrace.h"
#include "gdbsupport/gdb_wait.h"
#ifdef HAVE_SYS_REG_H
#include <sys/reg.h>
#endif
#include <sys/syscall.h>
#include <sys/user.h>
#include <asm/ptrace_offsets.h>
#include <sys/procfs.h>
/* Prototypes for supply_gregset etc. */
#include "gregset.h"
#include "inf-ptrace.h"
class ia64_linux_nat_target final : public linux_nat_target
{
public:
/* Add our register access methods. */
void fetch_registers (struct regcache *, int) override;
void store_registers (struct regcache *, int) override;
enum target_xfer_status xfer_partial (enum target_object object,
const char *annex,
gdb_byte *readbuf,
const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len,
ULONGEST *xfered_len) override;
/* Override watchpoint routines. */
/* The IA-64 architecture can step over a watch point (without
triggering it again) if the "dd" (data debug fault disable) bit
in the processor status word is set.
This PSR bit is set in
ia64_linux_nat_target::stopped_by_watchpoint when the code there
has determined that a hardware watchpoint has indeed been hit.
The CPU will then be able to execute one instruction without
triggering a watchpoint. */
bool have_steppable_watchpoint () override { return true; }
int can_use_hw_breakpoint (enum bptype, int, int) override;
bool stopped_by_watchpoint () override;
std::vector<CORE_ADDR> stopped_data_addresses () override;
int insert_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
int remove_watchpoint (CORE_ADDR, int, enum target_hw_bp_type,
struct expression *) override;
/* Override linux_nat_target low methods. */
void low_new_thread (struct lwp_info *lp) override;
bool low_status_is_event (int status) override;
void enable_watchpoints_in_psr (ptid_t ptid);
};
static ia64_linux_nat_target the_ia64_linux_nat_target;
/* These must match the order of the register names.
Some sort of lookup table is needed because the offsets associated
with the registers are all over the board. */
static int u_offsets[] =
{
/* general registers */
-1, /* gr0 not available; i.e, it's always zero. */
PT_R1,
PT_R2,
PT_R3,
PT_R4,
PT_R5,
PT_R6,
PT_R7,
PT_R8,
PT_R9,
PT_R10,
PT_R11,
PT_R12,
PT_R13,
PT_R14,
PT_R15,
PT_R16,
PT_R17,
PT_R18,
PT_R19,
PT_R20,
PT_R21,
PT_R22,
PT_R23,
PT_R24,
PT_R25,
PT_R26,
PT_R27,
PT_R28,
PT_R29,
PT_R30,
PT_R31,
/* gr32 through gr127 not directly available via the ptrace interface. */
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
/* Floating point registers */
-1, -1, /* f0 and f1 not available (f0 is +0.0 and f1 is +1.0). */
PT_F2,
PT_F3,
PT_F4,
PT_F5,
PT_F6,
PT_F7,
PT_F8,
PT_F9,
PT_F10,
PT_F11,
PT_F12,
PT_F13,
PT_F14,
PT_F15,
PT_F16,
PT_F17,
PT_F18,
PT_F19,
PT_F20,
PT_F21,
PT_F22,
PT_F23,
PT_F24,
PT_F25,
PT_F26,
PT_F27,
PT_F28,
PT_F29,
PT_F30,
PT_F31,
PT_F32,
PT_F33,
PT_F34,
PT_F35,
PT_F36,
PT_F37,
PT_F38,
PT_F39,
PT_F40,
PT_F41,
PT_F42,
PT_F43,
PT_F44,
PT_F45,
PT_F46,
PT_F47,
PT_F48,
PT_F49,
PT_F50,
PT_F51,
PT_F52,
PT_F53,
PT_F54,
PT_F55,
PT_F56,
PT_F57,
PT_F58,
PT_F59,
PT_F60,
PT_F61,
PT_F62,
PT_F63,
PT_F64,
PT_F65,
PT_F66,
PT_F67,
PT_F68,
PT_F69,
PT_F70,
PT_F71,
PT_F72,
PT_F73,
PT_F74,
PT_F75,
PT_F76,
PT_F77,
PT_F78,
PT_F79,
PT_F80,
PT_F81,
PT_F82,
PT_F83,
PT_F84,
PT_F85,
PT_F86,
PT_F87,
PT_F88,
PT_F89,
PT_F90,
PT_F91,
PT_F92,
PT_F93,
PT_F94,
PT_F95,
PT_F96,
PT_F97,
PT_F98,
PT_F99,
PT_F100,
PT_F101,
PT_F102,
PT_F103,
PT_F104,
PT_F105,
PT_F106,
PT_F107,
PT_F108,
PT_F109,
PT_F110,
PT_F111,
PT_F112,
PT_F113,
PT_F114,
PT_F115,
PT_F116,
PT_F117,
PT_F118,
PT_F119,
PT_F120,
PT_F121,
PT_F122,
PT_F123,
PT_F124,
PT_F125,
PT_F126,
PT_F127,
/* Predicate registers - we don't fetch these individually. */
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
/* branch registers */
PT_B0,
PT_B1,
PT_B2,
PT_B3,
PT_B4,
PT_B5,
PT_B6,
PT_B7,
/* Virtual frame pointer and virtual return address pointer. */
-1, -1,
/* other registers */
PT_PR,
PT_CR_IIP, /* ip */
PT_CR_IPSR, /* psr */
PT_CFM, /* cfm */
/* kernel registers not visible via ptrace interface (?) */
-1, -1, -1, -1, -1, -1, -1, -1,
/* hole */
-1, -1, -1, -1, -1, -1, -1, -1,
PT_AR_RSC,
PT_AR_BSP,
PT_AR_BSPSTORE,
PT_AR_RNAT,
-1,
-1, /* Not available: FCR, IA32 floating control register. */
-1, -1,
-1, /* Not available: EFLAG */
-1, /* Not available: CSD */
-1, /* Not available: SSD */
-1, /* Not available: CFLG */
-1, /* Not available: FSR */
-1, /* Not available: FIR */
-1, /* Not available: FDR */
-1,
PT_AR_CCV,
-1, -1, -1,
PT_AR_UNAT,
-1, -1, -1,
PT_AR_FPSR,
-1, -1, -1,
-1, /* Not available: ITC */
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1,
PT_AR_PFS,
PT_AR_LC,
PT_AR_EC,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1,
/* nat bits - not fetched directly; instead we obtain these bits from
either rnat or unat or from memory. */
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1,
};
static CORE_ADDR
ia64_register_addr (struct gdbarch *gdbarch, int regno)
{
CORE_ADDR addr;
if (regno < 0 || regno >= gdbarch_num_regs (gdbarch))
error (_("Invalid register number %d."), regno);
if (u_offsets[regno] == -1)
addr = 0;
else
addr = (CORE_ADDR) u_offsets[regno];
return addr;
}
static int
ia64_cannot_fetch_register (struct gdbarch *gdbarch, int regno)
{
return regno < 0
|| regno >= gdbarch_num_regs (gdbarch)
|| u_offsets[regno] == -1;
}
static int
ia64_cannot_store_register (struct gdbarch *gdbarch, int regno)
{
/* Rationale behind not permitting stores to bspstore...
The IA-64 architecture provides bspstore and bsp which refer
memory locations in the RSE's backing store. bspstore is the
next location which will be written when the RSE needs to write
to memory. bsp is the address at which r32 in the current frame
would be found if it were written to the backing store.
The IA-64 architecture provides read-only access to bsp and
read/write access to bspstore (but only when the RSE is in
the enforced lazy mode). It should be noted that stores
to bspstore also affect the value of bsp. Changing bspstore
does not affect the number of dirty entries between bspstore
and bsp, so changing bspstore by N words will also cause bsp
to be changed by (roughly) N as well. (It could be N-1 or N+1
depending upon where the NaT collection bits fall.)
OTOH, the Linux kernel provides read/write access to bsp (and
currently read/write access to bspstore as well). But it
is definitely the case that if you change one, the other
will change at the same time. It is more useful to gdb to
be able to change bsp. So in order to prevent strange and
undesirable things from happening when a dummy stack frame
is popped (after calling an inferior function), we allow
bspstore to be read, but not written. (Note that popping
a (generic) dummy stack frame causes all registers that
were previously read from the inferior process to be written
back.) */
return regno < 0
|| regno >= gdbarch_num_regs (gdbarch)
|| u_offsets[regno] == -1
|| regno == IA64_BSPSTORE_REGNUM;
}
void
supply_gregset (struct regcache *regcache, const gregset_t *gregsetp)
{
int regi;
const greg_t *regp = (const greg_t *) gregsetp;
for (regi = IA64_GR0_REGNUM; regi <= IA64_GR31_REGNUM; regi++)
{
regcache->raw_supply (regi, regp + (regi - IA64_GR0_REGNUM));
}
/* FIXME: NAT collection bits are at index 32; gotta deal with these
somehow... */
regcache->raw_supply (IA64_PR_REGNUM, regp + 33);
for (regi = IA64_BR0_REGNUM; regi <= IA64_BR7_REGNUM; regi++)
{
regcache->raw_supply (regi, regp + 34 + (regi - IA64_BR0_REGNUM));
}
regcache->raw_supply (IA64_IP_REGNUM, regp + 42);
regcache->raw_supply (IA64_CFM_REGNUM, regp + 43);
regcache->raw_supply (IA64_PSR_REGNUM, regp + 44);
regcache->raw_supply (IA64_RSC_REGNUM, regp + 45);
regcache->raw_supply (IA64_BSP_REGNUM, regp + 46);
regcache->raw_supply (IA64_BSPSTORE_REGNUM, regp + 47);
regcache->raw_supply (IA64_RNAT_REGNUM, regp + 48);
regcache->raw_supply (IA64_CCV_REGNUM, regp + 49);
regcache->raw_supply (IA64_UNAT_REGNUM, regp + 50);
regcache->raw_supply (IA64_FPSR_REGNUM, regp + 51);
regcache->raw_supply (IA64_PFS_REGNUM, regp + 52);
regcache->raw_supply (IA64_LC_REGNUM, regp + 53);
regcache->raw_supply (IA64_EC_REGNUM, regp + 54);
}
void
fill_gregset (const struct regcache *regcache, gregset_t *gregsetp, int regno)
{
int regi;
greg_t *regp = (greg_t *) gregsetp;
#define COPY_REG(_idx_,_regi_) \
if ((regno == -1) || regno == _regi_) \
regcache->raw_collect (_regi_, regp + _idx_)
for (regi = IA64_GR0_REGNUM; regi <= IA64_GR31_REGNUM; regi++)
{
COPY_REG (regi - IA64_GR0_REGNUM, regi);
}
/* FIXME: NAT collection bits at index 32? */
COPY_REG (33, IA64_PR_REGNUM);
for (regi = IA64_BR0_REGNUM; regi <= IA64_BR7_REGNUM; regi++)
{
COPY_REG (34 + (regi - IA64_BR0_REGNUM), regi);
}
COPY_REG (42, IA64_IP_REGNUM);
COPY_REG (43, IA64_CFM_REGNUM);
COPY_REG (44, IA64_PSR_REGNUM);
COPY_REG (45, IA64_RSC_REGNUM);
COPY_REG (46, IA64_BSP_REGNUM);
COPY_REG (47, IA64_BSPSTORE_REGNUM);
COPY_REG (48, IA64_RNAT_REGNUM);
COPY_REG (49, IA64_CCV_REGNUM);
COPY_REG (50, IA64_UNAT_REGNUM);
COPY_REG (51, IA64_FPSR_REGNUM);
COPY_REG (52, IA64_PFS_REGNUM);
COPY_REG (53, IA64_LC_REGNUM);
COPY_REG (54, IA64_EC_REGNUM);
}
/* Given a pointer to a floating point register set in /proc format
(fpregset_t *), unpack the register contents and supply them as gdb's
idea of the current floating point register values. */
void
supply_fpregset (struct regcache *regcache, const fpregset_t *fpregsetp)
{
int regi;
const char *from;
const gdb_byte f_one[16] =
{ 0, 0, 0, 0, 0, 0, 0, 0x80, 0xff, 0xff, 0, 0, 0, 0, 0, 0 };
/* Kernel generated cores have fr1==0 instead of 1.0. Older GDBs
did the same. So ignore whatever might be recorded in fpregset_t
for fr0/fr1 and always supply their expected values. */
/* fr0 is always read as zero. */
regcache->raw_supply_zeroed (IA64_FR0_REGNUM);
/* fr1 is always read as one (1.0). */
regcache->raw_supply (IA64_FR1_REGNUM, f_one);
for (regi = IA64_FR2_REGNUM; regi <= IA64_FR127_REGNUM; regi++)
{
from = (const char *) &((*fpregsetp)[regi - IA64_FR0_REGNUM]);
regcache->raw_supply (regi, from);
}
}
/* Given a pointer to a floating point register set in /proc format
(fpregset_t *), update the register specified by REGNO from gdb's idea
of the current floating point register set. If REGNO is -1, update
them all. */
void
fill_fpregset (const struct regcache *regcache,
fpregset_t *fpregsetp, int regno)
{
int regi;
for (regi = IA64_FR0_REGNUM; regi <= IA64_FR127_REGNUM; regi++)
{
if ((regno == -1) || (regno == regi))
regcache->raw_collect (regi, &((*fpregsetp)[regi - IA64_FR0_REGNUM]));
}
}
#define IA64_PSR_DB (1UL << 24)
#define IA64_PSR_DD (1UL << 39)
void
ia64_linux_nat_target::enable_watchpoints_in_psr (ptid_t ptid)
{
struct regcache *regcache = get_thread_regcache (this, ptid);
ULONGEST psr;
regcache_cooked_read_unsigned (regcache, IA64_PSR_REGNUM, &psr);
if (!(psr & IA64_PSR_DB))
{
psr |= IA64_PSR_DB; /* Set the db bit - this enables hardware
watchpoints and breakpoints. */
regcache_cooked_write_unsigned (regcache, IA64_PSR_REGNUM, psr);
}
}
static long debug_registers[8];
static void
store_debug_register (ptid_t ptid, int idx, long val)
{
int tid;
tid = ptid.lwp ();
if (tid == 0)
tid = ptid.pid ();
(void) ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) (PT_DBR + 8 * idx), val);
}
static void
store_debug_register_pair (ptid_t ptid, int idx, long *dbr_addr,
long *dbr_mask)
{
if (dbr_addr)
store_debug_register (ptid, 2 * idx, *dbr_addr);
if (dbr_mask)
store_debug_register (ptid, 2 * idx + 1, *dbr_mask);
}
static int
is_power_of_2 (int val)
{
int i, onecount;
onecount = 0;
for (i = 0; i < 8 * sizeof (val); i++)
if (val & (1 << i))
onecount++;
return onecount <= 1;
}
int
ia64_linux_nat_target::insert_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
int idx;
long dbr_addr, dbr_mask;
int max_watchpoints = 4;
if (len <= 0 || !is_power_of_2 (len))
return -1;
for (idx = 0; idx < max_watchpoints; idx++)
{
dbr_mask = debug_registers[idx * 2 + 1];
if ((dbr_mask & (0x3UL << 62)) == 0)
{
/* Exit loop if both r and w bits clear. */
break;
}
}
if (idx == max_watchpoints)
return -1;
dbr_addr = (long) addr;
dbr_mask = (~(len - 1) & 0x00ffffffffffffffL); /* construct mask to match */
dbr_mask |= 0x0800000000000000L; /* Only match privilege level 3 */
switch (type)
{
case hw_write:
dbr_mask |= (1L << 62); /* Set w bit */
break;
case hw_read:
dbr_mask |= (1L << 63); /* Set r bit */
break;
case hw_access:
dbr_mask |= (3L << 62); /* Set both r and w bits */
break;
default:
return -1;
}
debug_registers[2 * idx] = dbr_addr;
debug_registers[2 * idx + 1] = dbr_mask;
for (const lwp_info *lp : all_lwps ())
{
store_debug_register_pair (lp->ptid, idx, &dbr_addr, &dbr_mask);
enable_watchpoints_in_psr (lp->ptid);
}
return 0;
}
int
ia64_linux_nat_target::remove_watchpoint (CORE_ADDR addr, int len,
enum target_hw_bp_type type,
struct expression *cond)
{
int idx;
long dbr_addr, dbr_mask;
int max_watchpoints = 4;
if (len <= 0 || !is_power_of_2 (len))
return -1;
for (idx = 0; idx < max_watchpoints; idx++)
{
dbr_addr = debug_registers[2 * idx];
dbr_mask = debug_registers[2 * idx + 1];
if ((dbr_mask & (0x3UL << 62)) && addr == (CORE_ADDR) dbr_addr)
{
debug_registers[2 * idx] = 0;
debug_registers[2 * idx + 1] = 0;
dbr_addr = 0;
dbr_mask = 0;
for (const lwp_info *lp : all_lwps ())
store_debug_register_pair (lp->ptid, idx, &dbr_addr, &dbr_mask);
return 0;
}
}
return -1;
}
void
ia64_linux_nat_target::low_new_thread (struct lwp_info *lp)
{
int i, any;
any = 0;
for (i = 0; i < 8; i++)
{
if (debug_registers[i] != 0)
any = 1;
store_debug_register (lp->ptid, i, debug_registers[i]);
}
if (any)
enable_watchpoints_in_psr (lp->ptid);
}
std::vector<CORE_ADDR>
ia64_linux_nat_target::stopped_data_addresses ()
{
CORE_ADDR psr;
siginfo_t siginfo;
regcache *regcache = get_thread_regcache (inferior_thread ());
if (!linux_nat_get_siginfo (inferior_ptid, &siginfo))
return {};
if (siginfo.si_signo != SIGTRAP
|| (siginfo.si_code & 0xffff) != 0x0004 /* TRAP_HWBKPT */)
return {};
regcache_cooked_read_unsigned (regcache, IA64_PSR_REGNUM, &psr);
psr |= IA64_PSR_DD; /* Set the dd bit - this will disable the watchpoint
for the next instruction. */
regcache_cooked_write_unsigned (regcache, IA64_PSR_REGNUM, psr);
return { (CORE_ADDR) siginfo.si_addr };
}
bool
ia64_linux_nat_target::stopped_by_watchpoint ()
{
return !stopped_data_addresses ().empty ();
}
int
ia64_linux_nat_target::can_use_hw_breakpoint (enum bptype type,
int cnt, int othertype)
{
return 1;
}
/* Fetch register REGNUM from the inferior. */
static void
ia64_linux_fetch_register (struct regcache *regcache, int regnum)
{
struct gdbarch *gdbarch = regcache->arch ();
CORE_ADDR addr;
size_t size;
PTRACE_TYPE_RET *buf;
pid_t pid;
int i;
/* r0 cannot be fetched but is always zero. */
if (regnum == IA64_GR0_REGNUM)
{
regcache->raw_supply_zeroed (regnum);
return;
}
/* fr0 cannot be fetched but is always zero. */
if (regnum == IA64_FR0_REGNUM)
{
regcache->raw_supply_zeroed (regnum);
return;
}
/* fr1 cannot be fetched but is always one (1.0). */
if (regnum == IA64_FR1_REGNUM)
{
const gdb_byte f_one[16] =
{ 0, 0, 0, 0, 0, 0, 0, 0x80, 0xff, 0xff, 0, 0, 0, 0, 0, 0 };
gdb_assert (sizeof (f_one) == register_size (gdbarch, regnum));
regcache->raw_supply (regnum, f_one);
return;
}
if (ia64_cannot_fetch_register (gdbarch, regnum))
{
regcache->raw_supply (regnum, NULL);
return;
}
pid = get_ptrace_pid (regcache->ptid ());
/* This isn't really an address, but ptrace thinks of it as one. */
addr = ia64_register_addr (gdbarch, regnum);
size = register_size (gdbarch, regnum);
gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
buf = (PTRACE_TYPE_RET *) alloca (size);
/* Read the register contents from the inferior a chunk at a time. */
for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
{
errno = 0;
buf[i] = ptrace (PT_READ_U, pid, (PTRACE_TYPE_ARG3)addr, 0);
if (errno != 0)
error (_("Couldn't read register %s (#%d): %s."),
gdbarch_register_name (gdbarch, regnum),
regnum, safe_strerror (errno));
addr += sizeof (PTRACE_TYPE_RET);
}
regcache->raw_supply (regnum, buf);
}
/* Fetch register REGNUM from the inferior. If REGNUM is -1, do this
for all registers. */
void
ia64_linux_nat_target::fetch_registers (struct regcache *regcache, int regnum)
{
if (regnum == -1)
for (regnum = 0;
regnum < gdbarch_num_regs (regcache->arch ());
regnum++)
ia64_linux_fetch_register (regcache, regnum);
else
ia64_linux_fetch_register (regcache, regnum);
}
/* Store register REGNUM into the inferior. */
static void
ia64_linux_store_register (const struct regcache *regcache, int regnum)
{
struct gdbarch *gdbarch = regcache->arch ();
CORE_ADDR addr;
size_t size;
PTRACE_TYPE_RET *buf;
pid_t pid;
int i;
if (ia64_cannot_store_register (gdbarch, regnum))
return;
pid = get_ptrace_pid (regcache->ptid ());
/* This isn't really an address, but ptrace thinks of it as one. */
addr = ia64_register_addr (gdbarch, regnum);
size = register_size (gdbarch, regnum);
gdb_assert ((size % sizeof (PTRACE_TYPE_RET)) == 0);
buf = (PTRACE_TYPE_RET *) alloca (size);
/* Write the register contents into the inferior a chunk at a time. */
regcache->raw_collect (regnum, buf);
for (i = 0; i < size / sizeof (PTRACE_TYPE_RET); i++)
{
errno = 0;
ptrace (PT_WRITE_U, pid, (PTRACE_TYPE_ARG3)addr, buf[i]);
if (errno != 0)
error (_("Couldn't write register %s (#%d): %s."),
gdbarch_register_name (gdbarch, regnum),
regnum, safe_strerror (errno));
addr += sizeof (PTRACE_TYPE_RET);
}
}
/* Store register REGNUM back into the inferior. If REGNUM is -1, do
this for all registers. */
void
ia64_linux_nat_target::store_registers (struct regcache *regcache, int regnum)
{
if (regnum == -1)
for (regnum = 0;
regnum < gdbarch_num_regs (regcache->arch ());
regnum++)
ia64_linux_store_register (regcache, regnum);
else
ia64_linux_store_register (regcache, regnum);
}
/* Implement the xfer_partial target_ops method. */
enum target_xfer_status
ia64_linux_nat_target::xfer_partial (enum target_object object,
const char *annex,
gdb_byte *readbuf, const gdb_byte *writebuf,
ULONGEST offset, ULONGEST len,
ULONGEST *xfered_len)
{
if (object == TARGET_OBJECT_UNWIND_TABLE && readbuf != NULL)
{
static long gate_table_size;
gdb_byte *tmp_buf;
long res;
/* Probe for the table size once. */
if (gate_table_size == 0)
gate_table_size = syscall (__NR_getunwind, NULL, 0);
if (gate_table_size < 0)
return TARGET_XFER_E_IO;
if (offset >= gate_table_size)
return TARGET_XFER_EOF;
tmp_buf = (gdb_byte *) alloca (gate_table_size);
res = syscall (__NR_getunwind, tmp_buf, gate_table_size);
if (res < 0)
return TARGET_XFER_E_IO;
gdb_assert (res == gate_table_size);
if (offset + len > gate_table_size)
len = gate_table_size - offset;
memcpy (readbuf, tmp_buf + offset, len);
*xfered_len = len;
return TARGET_XFER_OK;
}
return linux_nat_target::xfer_partial (object, annex, readbuf, writebuf,
offset, len, xfered_len);
}
/* For break.b instruction ia64 CPU forgets the immediate value and generates
SIGILL with ILL_ILLOPC instead of more common SIGTRAP with TRAP_BRKPT.
ia64 does not use gdbarch_decr_pc_after_break so we do not have to make any
difference for the signals here. */
bool
ia64_linux_nat_target::low_status_is_event (int status)
{
return WIFSTOPPED (status) && (WSTOPSIG (status) == SIGTRAP
|| WSTOPSIG (status) == SIGILL);
}
INIT_GDB_FILE (ia64_linux_nat)
{
/* Register the target. */
linux_target = &the_ia64_linux_nat_target;
add_inf_child_target (&the_ia64_linux_nat_target);
}
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