[PATCH 0/2] xtensa: support THREADPTR register

[PATCH 0/2] xtensa: support THREADPTR register

[Max Filippov]

Hello,

this series makes THREADPTR register (used for TLS in xtensa linux)
available to native and remote gdb.

Max Filippov (2):
  gdb: xtensa-linux: support THREADPTR register
  gdbserver: xtensa: support THREADPTR register

 gdb/gdbserver/linux-xtensa-low.c | 9 +++++++++
 gdb/xtensa-linux-nat.c           | 8 ++++++++
 gdb/xtensa-tdep.c                | 3 +++
 gdb/xtensa-tdep.h                | 1 +
 4 files changed, 21 insertions(+)

-- 
2.1.4

[PATCH 2/2] gdbserver: xtensa: support THREADPTR register

[Max Filippov]

Provide aceess to the THREADPTR register to remote gdb.

2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
gdb/gdbserver/
	* linux-xtensa-low.c (regnum::R_THREADPTR): New enum member.
	(xtensa_fill_gregset): Call collect_register_by_name for
	threadptr register.
	(xtensa_store_gregset): Call supply_register_by_name for
	threadptr register.
---
 gdb/gdbserver/linux-xtensa-low.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/gdb/gdbserver/linux-xtensa-low.c b/gdb/gdbserver/linux-xtensa-low.c
index 73fbfe2..eca0289 100644
--- a/gdb/gdbserver/linux-xtensa-low.c
+++ b/gdb/gdbserver/linux-xtensa-low.c
@@ -36,6 +36,7 @@ enum regnum {
 	R_LBEG,	R_LEND,	R_LCOUNT,
 	R_SAR,
 	R_WS, R_WB,
+	R_THREADPTR,
 	R_A0 = 64
 };
 
@@ -86,6 +87,10 @@ xtensa_fill_gregset (struct regcache *regcache, void *buf)
       collect_register (regcache, i, ptr);
       ptr += register_size (tdesc, i);
     }
+
+#if XCHAL_HAVE_THREADPTR
+  collect_register_by_name (regcache, "threadptr", (char*)&rset[R_THREADPTR]);
+#endif
 }
 
 static void
@@ -133,6 +138,10 @@ xtensa_store_gregset (struct regcache *regcache, const void *buf)
   supply_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
   supply_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
   supply_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
+
+#if XCHAL_HAVE_THREADPTR
+  supply_register_by_name (regcache, "threadptr", (char*)&rset[R_THREADPTR]);
+#endif
 }
 
 /* Xtensa GNU/Linux PTRACE interface includes extended register set.  */
-- 
2.1.4

Re: [PATCH 2/2] gdbserver: xtensa: support THREADPTR register

[Luis Machado]

On 01/18/2017 05:56 PM, Max Filippov wrote:
> Provide aceess to the THREADPTR register to remote gdb.
>
> 2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
> gdb/gdbserver/


Similarly, drop the gdb/gdbserver/

> 	* linux-xtensa-low.c (regnum::R_THREADPTR): New enum member.
> 	(xtensa_fill_gregset): Call collect_register_by_name for
> 	threadptr register.
> 	(xtensa_store_gregset): Call supply_register_by_name for
> 	threadptr register.
> ---
>  gdb/gdbserver/linux-xtensa-low.c | 9 +++++++++
>  1 file changed, 9 insertions(+)
>
> diff --git a/gdb/gdbserver/linux-xtensa-low.c b/gdb/gdbserver/linux-xtensa-low.c
> index 73fbfe2..eca0289 100644
> --- a/gdb/gdbserver/linux-xtensa-low.c
> +++ b/gdb/gdbserver/linux-xtensa-low.c
> @@ -36,6 +36,7 @@ enum regnum {
>  	R_LBEG,	R_LEND,	R_LCOUNT,
>  	R_SAR,
>  	R_WS, R_WB,
> +	R_THREADPTR,
>  	R_A0 = 64
>  };

Does xtensa have xml register description support? It would be nice to 
have those described instead of hardcoding the entries like this.

>
> @@ -86,6 +87,10 @@ xtensa_fill_gregset (struct regcache *regcache, void *buf)
>        collect_register (regcache, i, ptr);
>        ptr += register_size (tdesc, i);
>      }
> +
> +#if XCHAL_HAVE_THREADPTR
> +  collect_register_by_name (regcache, "threadptr", (char*)&rset[R_THREADPTR]);

Missing spaces in the cast. "(char *) &rset[R_THREADPTR]"

How is XCHAL_HAVE_THREADPTR set? Is it a reliable way of confirming the 
presence of this register? Can a runtime check be used instead?

> +#endif
>  }
>
>  static void
> @@ -133,6 +138,10 @@ xtensa_store_gregset (struct regcache *regcache, const void *buf)
>    supply_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
>    supply_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
>    supply_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
> +
> +#if XCHAL_HAVE_THREADPTR
> +  supply_register_by_name (regcache, "threadptr", (char*)&rset[R_THREADPTR]);

Same as above regarding spaces and the cast construct and the 
XCHAL_HAVE_THREADPTR check.

Re: [PATCH 2/2] gdbserver: xtensa: support THREADPTR register

[Max Filippov]

On Mon, Feb 13, 2017 at 10:26 AM, Luis Machado
<lgustavo@codesourcery.com> wrote:
> On 01/18/2017 05:56 PM, Max Filippov wrote:
>>
>> Provide aceess to the THREADPTR register to remote gdb.
>>
>> 2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
>> gdb/gdbserver/
>
>
>
> Similarly, drop the gdb/gdbserver/
>
>>         * linux-xtensa-low.c (regnum::R_THREADPTR): New enum member.
>>         (xtensa_fill_gregset): Call collect_register_by_name for
>>         threadptr register.
>>         (xtensa_store_gregset): Call supply_register_by_name for
>>         threadptr register.
>> ---
>>  gdb/gdbserver/linux-xtensa-low.c | 9 +++++++++
>>  1 file changed, 9 insertions(+)
>>
>> diff --git a/gdb/gdbserver/linux-xtensa-low.c
>> b/gdb/gdbserver/linux-xtensa-low.c
>> index 73fbfe2..eca0289 100644
>> --- a/gdb/gdbserver/linux-xtensa-low.c
>> +++ b/gdb/gdbserver/linux-xtensa-low.c
>> @@ -36,6 +36,7 @@ enum regnum {
>>         R_LBEG, R_LEND, R_LCOUNT,
>>         R_SAR,
>>         R_WS, R_WB,
>> +       R_THREADPTR,
>>         R_A0 = 64
>>  };
>
>
> Does xtensa have xml register description support?

AFAIK no.

> It would be nice to have
> those described instead of hardcoding the entries like this.
>>
>> @@ -86,6 +87,10 @@ xtensa_fill_gregset (struct regcache *regcache, void
>> *buf)
>>        collect_register (regcache, i, ptr);
>>        ptr += register_size (tdesc, i);
>>      }
>> +
>> +#if XCHAL_HAVE_THREADPTR
>> +  collect_register_by_name (regcache, "threadptr",
>> (char*)&rset[R_THREADPTR]);
>
>
> Missing spaces in the cast. "(char *) &rset[R_THREADPTR]"

Will add.

> How is XCHAL_HAVE_THREADPTR set?

It is defined in the core configuration overlay, include/xtensa-config.h
This file is generated for each Xtensa core and is copied over to the
source tree before building gdb for that specific core.

> Is it a reliable way of confirming the presence of this register?

This is the primary source of configuration-specific information.

> Can a runtime check be used instead?

AFAIK this information is not provided anywhere else.

>> +#endif
>>  }
>>
>>  static void
>> @@ -133,6 +138,10 @@ xtensa_store_gregset (struct regcache *regcache,
>> const void *buf)
>>    supply_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
>>    supply_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
>>    supply_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
>> +
>> +#if XCHAL_HAVE_THREADPTR
>> +  supply_register_by_name (regcache, "threadptr",
>> (char*)&rset[R_THREADPTR]);
>
>
> Same as above regarding spaces and the cast construct and the
> XCHAL_HAVE_THREADPTR check.

Will fix.

-- 
Thanks.
-- Max

[PATCH 1/2] gdb: xtensa-linux: support THREADPTR register

[Max Filippov]

Make THREADPTR user register accessible.

2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
gdb/
	* xtensa-linux-nat.c (fill_gregset): Call regcache_raw_collect
	for THREADPTR register.
	(supply_gregset_reg): Call regcache_raw_supply for THREADPTR
	register.
	* xtensa-tdep.c (XTENSA_DBREGN_UREG): New definition.
	(xtensa_derive_tdep): Initialize tdep->threadptr_regnum.
	* xtensa-tdep.h (gdbarch_tdep::threadptr_regnum): New field.
---
 gdb/xtensa-linux-nat.c | 8 ++++++++
 gdb/xtensa-tdep.c      | 3 +++
 gdb/xtensa-tdep.h      | 1 +
 3 files changed, 12 insertions(+)

diff --git a/gdb/xtensa-linux-nat.c b/gdb/xtensa-linux-nat.c
index 2693939..0f77be7 100644
--- a/gdb/xtensa-linux-nat.c
+++ b/gdb/xtensa-linux-nat.c
@@ -84,6 +84,10 @@ fill_gregset (const struct regcache *regcache,
     regcache_raw_collect (regcache,
 			  gdbarch_tdep (gdbarch)->sar_regnum,
 			  &regs->sar);
+  if (regnum == gdbarch_tdep (gdbarch)->threadptr_regnum || regnum == -1)
+    regcache_raw_collect (regcache,
+			  gdbarch_tdep (gdbarch)->threadptr_regnum,
+			  &regs->threadptr);
   if (regnum >=gdbarch_tdep (gdbarch)->ar_base
       && regnum < gdbarch_tdep (gdbarch)->ar_base
 		    + gdbarch_tdep (gdbarch)->num_aregs)
@@ -150,6 +154,10 @@ supply_gregset_reg (struct regcache *regcache,
     regcache_raw_supply (regcache,
 			  gdbarch_tdep (gdbarch)->sar_regnum,
 			  &regs->sar);
+  if (regnum == gdbarch_tdep (gdbarch)->threadptr_regnum || regnum == -1)
+    regcache_raw_supply (regcache,
+			  gdbarch_tdep (gdbarch)->threadptr_regnum,
+			  &regs->threadptr);
   if (regnum >=gdbarch_tdep (gdbarch)->ar_base
       && regnum < gdbarch_tdep (gdbarch)->ar_base
 		    + gdbarch_tdep (gdbarch)->num_aregs)
diff --git a/gdb/xtensa-tdep.c b/gdb/xtensa-tdep.c
index 797e728..2c3e41e 100644
--- a/gdb/xtensa-tdep.c
+++ b/gdb/xtensa-tdep.c
@@ -3120,6 +3120,7 @@ xtensa_derive_tdep (struct gdbarch_tdep *tdep)
 
 /* Special registers 0..255 (core).  */
 #define XTENSA_DBREGN_SREG(n)  (0x0200+(n))
+#define XTENSA_DBREGN_UREG(n)  (0x0300+(n))
 
   for (rmap = tdep->regmap, n = 0; rmap->target_number != -1; n++, rmap++)
     {
@@ -3151,6 +3152,8 @@ xtensa_derive_tdep (struct gdbarch_tdep *tdep)
 	tdep->litbase_regnum = n;
       else if (rmap->target_number == XTENSA_DBREGN_SREG(230))
 	tdep->ps_regnum = n;
+      else if (rmap->target_number == XTENSA_DBREGN_UREG(231))
+	tdep->threadptr_regnum = n;
 #if 0
       else if (rmap->target_number == XTENSA_DBREGN_SREG(226))
 	tdep->interrupt_regnum = n;
diff --git a/gdb/xtensa-tdep.h b/gdb/xtensa-tdep.h
index 46aeecb..986aa68 100644
--- a/gdb/xtensa-tdep.h
+++ b/gdb/xtensa-tdep.h
@@ -204,6 +204,7 @@ struct gdbarch_tdep
   int lcount_regnum;
   int sar_regnum;		/* Register number of SAR.  */
   int litbase_regnum;		/* Register number of LITBASE.  */
+  int threadptr_regnum;		/* Register number of THREADPTR.  */
 
   int interrupt_regnum;		/* Register number for interrupt.  */
   int interrupt2_regnum;	/* Register number for interrupt2.  */
-- 
2.1.4

Re: [PATCH 1/2] gdb: xtensa-linux: support THREADPTR register

[Luis Machado]

On 01/18/2017 05:56 PM, Max Filippov wrote:
> Make THREADPTR user register accessible.
>
> 2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
> gdb/

Drop gdb/ from the ChangeLog.

> diff --git a/gdb/xtensa-tdep.c b/gdb/xtensa-tdep.c
> index 797e728..2c3e41e 100644
> --- a/gdb/xtensa-tdep.c
> +++ b/gdb/xtensa-tdep.c
> @@ -3120,6 +3120,7 @@ xtensa_derive_tdep (struct gdbarch_tdep *tdep)
>
>  /* Special registers 0..255 (core).  */
>  #define XTENSA_DBREGN_SREG(n)  (0x0200+(n))
> +#define XTENSA_DBREGN_UREG(n)  (0x0300+(n))

Maybe add a little comment about what UREG is and its use?

Otherwise i have no further comments on this particular patch.

Re: [PATCH 1/2] gdb: xtensa-linux: support THREADPTR register

[Max Filippov]

On Mon, Feb 13, 2017 at 10:17 AM, Luis Machado
<lgustavo@codesourcery.com> wrote:
> On 01/18/2017 05:56 PM, Max Filippov wrote:
>>
>> Make THREADPTR user register accessible.
>>
>> 2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
>> gdb/
>
>
> Drop gdb/ from the ChangeLog.

It's the commit message, not the actual ChangeLog.
I see that specifying location of the ChangeLog file where a section
of the commit message goes is common practice, is it considered bad?
Of course I will not put it to the ChangeLog.

>> diff --git a/gdb/xtensa-tdep.c b/gdb/xtensa-tdep.c
>> index 797e728..2c3e41e 100644
>> --- a/gdb/xtensa-tdep.c
>> +++ b/gdb/xtensa-tdep.c
>> @@ -3120,6 +3120,7 @@ xtensa_derive_tdep (struct gdbarch_tdep *tdep)
>>
>>  /* Special registers 0..255 (core).  */
>>  #define XTENSA_DBREGN_SREG(n)  (0x0200+(n))
>> +#define XTENSA_DBREGN_UREG(n)  (0x0300+(n))
>
>
> Maybe add a little comment about what UREG is and its use?

Will add.

> Otherwise i have no further comments on this particular patch.

-- 
Thanks.
-- Max

Re: [PATCH 1/2] gdb: xtensa-linux: support THREADPTR register

[Luis Machado]

On 02/14/2017 03:06 AM, Max Filippov wrote:
> On Mon, Feb 13, 2017 at 10:17 AM, Luis Machado
> <lgustavo@codesourcery.com> wrote:
>> On 01/18/2017 05:56 PM, Max Filippov wrote:
>>>
>>> Make THREADPTR user register accessible.
>>>
>>> 2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>
>>> gdb/
>>
>>
>> Drop gdb/ from the ChangeLog.

It is fine for the commit log, but we usually put it before the date:

gdb/
2017-01-18  Max Filippov  <jcmvbkbc@gmail.com>

Re: [PATCH 0/2] xtensa: support THREADPTR register

[Max Filippov]

ping?

On Wed, Jan 18, 2017 at 3:56 PM, Max Filippov <jcmvbkbc@gmail.com> wrote:
> Hello,
>
> this series makes THREADPTR register (used for TLS in xtensa linux)
> available to native and remote gdb.
>
> Max Filippov (2):
>   gdb: xtensa-linux: support THREADPTR register
>   gdbserver: xtensa: support THREADPTR register
>
>  gdb/gdbserver/linux-xtensa-low.c | 9 +++++++++
>  gdb/xtensa-linux-nat.c           | 8 ++++++++
>  gdb/xtensa-tdep.c                | 3 +++
>  gdb/xtensa-tdep.h                | 1 +
>  4 files changed, 21 insertions(+)
>
-- 
Thanks.
-- Max