[v2,3/8] AArch64: Read pauth registers
Commit Message
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.
2019-03-06 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.
---
gdb/aarch64-linux-nat.c | 33 +++++++++++++++++++++++++++++++
gdb/aarch64-tdep.c | 43 +++++++++++++++++++++++++++++++++++++++++
gdb/aarch64-tdep.h | 8 ++++++++
gdb/arch/aarch64.h | 3 +++
4 files changed, 87 insertions(+)
Comments
On 2019-03-06 8:33 a.m., Alan Hayward wrote:
> @@ -445,6 +473,11 @@ 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);
> }
Just this nit:
The "outer" if should have curly braces.
Ref:
https://www.gnu.org/prep/standards/html_node/Syntactic-Conventions.html#Syntactic-Conventions
Simon
@@ -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 +473,11 @@ 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. */
@@ -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);
@@ -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);
@@ -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