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AArch64: Read pauth registers

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Initialise the pauth registers when creating a target description, and store
the regnum of the first pauth register.

Use ptrace to read the registers in the pauth feature.

Do not allow the registers to be written.

gdb/ChangeLog:

	* aarch64-linux-nat.c (fetch_pauth_masks_from_thread): New
	function.
	(aarch64_linux_nat_target::fetch_registers): Read pauth registers.
	* aarch64-tdep.c (aarch64_cannot_store_register): New function.
	(aarch64_gdbarch_init): Add puth registers.
	* aarch64-tdep.h (struct gdbarch_tdep): Add pauth features.
	* arch/aarch64.h (AARCH64_PAUTH_DMASK_REGNUM): New define.
	(AARCH64_PAUTH_CMASK_REGNUM): Likewise.
This commit is contained in:
Alan Hayward 2019-03-22 10:31:02 +00:00
parent ee4fbcfa26
commit 76bed0fd94
5 changed files with 101 additions and 0 deletions
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12
gdb/ChangeLog
View File

@ -1,3 +1,15 @@
2019-03-22 Alan Hayward <alan.hayward@arm.com>
Jiong Wang <jiong.wang@arm.com>
* aarch64-linux-nat.c (fetch_pauth_masks_from_thread): New
function.
(aarch64_linux_nat_target::fetch_registers): Read pauth registers.
* aarch64-tdep.c (aarch64_cannot_store_register): New function.
(aarch64_gdbarch_init): Add puth registers.
* aarch64-tdep.h (struct gdbarch_tdep): Add pauth features.
* arch/aarch64.h (AARCH64_PAUTH_DMASK_REGNUM): New define.
(AARCH64_PAUTH_CMASK_REGNUM): Likewise.
2019-03-22 Alan Hayward <alan.hayward@arm.com>
Jiong Wang <jiong.wang@arm.com>

35
gdb/aarch64-linux-nat.c
View File

@ -423,6 +423,31 @@ store_sveregs_to_thread (struct regcache *regcache)
perror_with_name (_("Unable to store sve registers"));
}
/* Fill GDB's register array with the pointer authentication mask values from
the current thread. */
static void
fetch_pauth_masks_from_thread (struct regcache *regcache)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (regcache->arch ());
int ret;
struct iovec iovec;
uint64_t pauth_regset[2] = {0, 0};
int tid = regcache->ptid ().lwp ();
iovec.iov_base = &pauth_regset;
iovec.iov_len = sizeof (pauth_regset);
ret = ptrace (PTRACE_GETREGSET, tid, NT_ARM_PAC_MASK, &iovec);
if (ret != 0)
perror_with_name (_("unable to fetch pauth registers."));
regcache->raw_supply (AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base),
&pauth_regset[0]);
regcache->raw_supply (AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base),
&pauth_regset[1]);
}
/* Implement the "fetch_registers" target_ops method. */
void
@ -438,6 +463,9 @@ aarch64_linux_nat_target::fetch_registers (struct regcache *regcache,
fetch_sveregs_from_thread (regcache);
else
fetch_fpregs_from_thread (regcache);
if (tdep->has_pauth ())
fetch_pauth_masks_from_thread (regcache);
}
else if (regno < AARCH64_V0_REGNUM)
fetch_gregs_from_thread (regcache);
@ -445,6 +473,13 @@ aarch64_linux_nat_target::fetch_registers (struct regcache *regcache,
fetch_sveregs_from_thread (regcache);
else
fetch_fpregs_from_thread (regcache);
if (tdep->has_pauth ())
{
if (regno == AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base)
|| regno == AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base))
fetch_pauth_masks_from_thread (regcache);
}
}
/* Implement the "store_registers" target_ops method. */

43
gdb/aarch64-tdep.c
View File

@ -175,6 +175,14 @@ static const char *const aarch64_sve_register_names[] =
"ffr", "vg"
};
static const char *const aarch64_pauth_register_names[] =
{
/* Authentication mask for data pointer. */
"pauth_dmask",
/* Authentication mask for code pointer. */
"pauth_cmask"
};
/* AArch64 prologue cache structure. */
struct aarch64_prologue_cache
{
@ -2936,6 +2944,21 @@ aarch64_add_reggroups (struct gdbarch *gdbarch)
reggroup_add (gdbarch, restore_reggroup);
}
/* Implement the "cannot_store_register" gdbarch method. */
static int
aarch64_cannot_store_register (struct gdbarch *gdbarch, int regnum)
{
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
if (!tdep->has_pauth ())
return 0;
/* Pointer authentication registers are read-only. */
return (regnum == AARCH64_PAUTH_DMASK_REGNUM (tdep->pauth_reg_base)
|| regnum == AARCH64_PAUTH_CMASK_REGNUM (tdep->pauth_reg_base));
}
/* Initialize the current architecture based on INFO. If possible,
re-use an architecture from ARCHES, which is a list of
architectures already created during this debugging session.
@ -2956,8 +2979,10 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
const struct tdesc_feature *feature_core;
const struct tdesc_feature *feature_fpu;
const struct tdesc_feature *feature_sve;
const struct tdesc_feature *feature_pauth;
int num_regs = 0;
int num_pseudo_regs = 0;
int first_pauth_regnum = -1;
/* Ensure we always have a target description. */
if (!tdesc_has_registers (tdesc))
@ -2967,6 +2992,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
feature_core = tdesc_find_feature (tdesc, "org.gnu.gdb.aarch64.core");
feature_fpu = tdesc_find_feature (tdesc, "org.gnu.gdb.aarch64.fpu");
feature_sve = tdesc_find_feature (tdesc, "org.gnu.gdb.aarch64.sve");
feature_pauth = tdesc_find_feature (tdesc, "org.gnu.gdb.aarch64.pauth");
if (feature_core == NULL)
return NULL;
@ -3021,6 +3047,21 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
num_pseudo_regs += 32; /* add the Bn scalar register pseudos */
}
/* Add the pauth registers. */
if (feature_pauth != NULL)
{
first_pauth_regnum = num_regs;
/* Validate the descriptor provides the mandatory PAUTH registers and
allocate their numbers. */
for (i = 0; i < ARRAY_SIZE (aarch64_pauth_register_names); i++)
valid_p &= tdesc_numbered_register (feature_pauth, tdesc_data,
first_pauth_regnum + i,
aarch64_pauth_register_names[i]);
num_regs += i;
}
if (!valid_p)
{
tdesc_data_cleanup (tdesc_data);
@ -3054,6 +3095,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
tdep->jb_pc = -1; /* Longjump support not enabled by default. */
tdep->jb_elt_size = 8;
tdep->vq = aarch64_get_tdesc_vq (tdesc);
tdep->pauth_reg_base = first_pauth_regnum;
set_gdbarch_push_dummy_call (gdbarch, aarch64_push_dummy_call);
set_gdbarch_frame_align (gdbarch, aarch64_frame_align);
@ -3084,6 +3126,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
set_tdesc_pseudo_register_type (gdbarch, aarch64_pseudo_register_type);
set_tdesc_pseudo_register_reggroup_p (gdbarch,
aarch64_pseudo_register_reggroup_p);
set_gdbarch_cannot_store_register (gdbarch, aarch64_cannot_store_register);
/* ABI */
set_gdbarch_short_bit (gdbarch, 16);

8
gdb/aarch64-tdep.h
View File

@ -87,6 +87,14 @@ struct gdbarch_tdep
{
return vq != 0;
}
int pauth_reg_base;
/* Returns true if the target supports pauth. */
bool has_pauth () const
{
return pauth_reg_base != -1;
}
};
const target_desc *aarch64_read_description (uint64_t vq, bool pauth_p);

3
gdb/arch/aarch64.h
View File

@ -66,6 +66,9 @@ enum aarch64_regnum
#define AARCH64_B0_REGNUM (AARCH64_H0_REGNUM + 32)
#define AARCH64_SVE_V0_REGNUM (AARCH64_B0_REGNUM + 32)
#define AARCH64_PAUTH_DMASK_REGNUM(pauth_reg_base) (pauth_reg_base)
#define AARCH64_PAUTH_CMASK_REGNUM(pauth_reg_base) (pauth_reg_base + 1)
#define AARCH64_X_REGS_NUM 31
#define AARCH64_V_REGS_NUM 32
#define AARCH64_SVE_Z_REGS_NUM AARCH64_V_REGS_NUM