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Re: [PATCH 3/3] gdbserver: xtensa: add call0 support
- From: Max Filippov <jcmvbkbc at gmail dot com>
- To: Luis Machado <lgustavo at codesourcery dot com>
- Cc: gdb-patches at sourceware dot org, Maxim Grigoriev <maxim2405 at gmail dot com>, Woody LaRue <larue at cadence dot com>, Marc Gauthier <marc at cadence dot com>
- Date: Tue, 14 Feb 2017 02:03:56 -0800
- Subject: Re: [PATCH 3/3] gdbserver: xtensa: add call0 support
- Authentication-results: sourceware.org; auth=none
- References: <1484783438-13780-1-git-send-email-jcmvbkbc@gmail.com> <1484783438-13780-4-git-send-email-jcmvbkbc@gmail.com> <f5ceabb5-071c-7305-83b3-3b268665e60c@codesourcery.com>
On Mon, Feb 13, 2017 at 10:43 AM, Luis Machado
<lgustavo@codesourcery.com> wrote:
> On 01/18/2017 05:50 PM, Max Filippov wrote:
>>
>> Correctly handle a0- registers on requests from remote gdb. This fixes
>>
>> 'Register 1 is not available'
>>
>> and subsequent assertion in the remote gdb connecting to the gdbserver:
>>
>> 'findvar.c:291: internal-error: value_of_register_lazy:
>> Assertion `frame_id_p(get_frame_id (frame))' failed.'
>>
>> The register structure is the same for windowed and call0 ABIs because
>> currently linux kernel internally requires windowed registers, so they
>> are always present.
>>
>> 2017-01-18 Max Filippov <jcmvbkbc@gmail.com>
>> gdb/gdbserver/
>
>
> Drop gdb/gdbserver/
>
>> * linux-xtensa-low.c (C0_NREGS): New definition.
>> (xtensa_fill_gregset): Call collect_register for all registers in
>> a0_regnum..a0_regnum + C0_NREGS range.
>> (xtensa_store_gregset): Call supply_register for all registers in
>> a0_regnum..a0_regnum + C0_NREGS range.
>> ---
>> gdb/gdbserver/linux-xtensa-low.c | 26 ++++++++++++++++++++++++++
>> 1 file changed, 26 insertions(+)
>>
>> diff --git a/gdb/gdbserver/linux-xtensa-low.c
>> b/gdb/gdbserver/linux-xtensa-low.c
>> index 98c0bf2..73fbfe2 100644
>> --- a/gdb/gdbserver/linux-xtensa-low.c
>> +++ b/gdb/gdbserver/linux-xtensa-low.c
>> @@ -39,12 +39,15 @@ enum regnum {
>> R_A0 = 64
>> };
>>
>> +#define C0_NREGS 16
>> +
>
>
> This is duplicating code from gdb/xtensa-linux-nat. Common nat code could be
> added to gdb/nat/ in an xtensa-specific file.
Ok.
>> static void
>> xtensa_fill_gregset (struct regcache *regcache, void *buf)
>> {
>> elf_greg_t* rset = (elf_greg_t*)buf;
>> const struct target_desc *tdesc = regcache->tdesc;
>> int ar0_regnum;
>> + int a0_regnum;
>> char *ptr;
>> int i;
>>
>> @@ -72,6 +75,17 @@ xtensa_fill_gregset (struct regcache *regcache, void
>> *buf)
>> collect_register_by_name (regcache, "ps", (char*)&rset[R_PS]);
>> collect_register_by_name (regcache, "windowbase", (char*)&rset[R_WB]);
>> collect_register_by_name (regcache, "windowstart", (char*)&rset[R_WS]);
>> +
>> + a0_regnum = find_regno (tdesc, "a0");
>> + ptr = (char *)&rset[R_A0 + 4 * rset[R_WB]];
>
>
> (char *) &rset... with space.
>
> More occurrences of this below.
Will fix.
>> +
>> + for (i = a0_regnum; i < a0_regnum + C0_NREGS; i++)
>> + {
>> + if (4 * rset[R_WB] + i - a0_regnum == XCHAL_NUM_AREGS)
>
>
> This looks slightly error-prone. Adding parenthesis around the expression
> would look better and avoid compiler warnings.
Will add. It builds without warnings for me though.
>> + ptr = (char *)&rset[R_A0];
>
>
> space issue mentioned above.
Will fix.
>> + collect_register (regcache, i, ptr);
>> + ptr += register_size (tdesc, i);
>> + }
>> }
>>
>> static void
>> @@ -80,6 +94,7 @@ xtensa_store_gregset (struct regcache *regcache, const
>> void *buf)
>> const elf_greg_t* rset = (const elf_greg_t*)buf;
>> const struct target_desc *tdesc = regcache->tdesc;
>> int ar0_regnum;
>> + int a0_regnum;
>> char *ptr;
>> int i;
>>
>> @@ -94,6 +109,17 @@ xtensa_store_gregset (struct regcache *regcache, const
>> void *buf)
>> ptr += register_size (tdesc, i);
>> }
>>
>> + a0_regnum = find_regno (tdesc, "a0");
>> + ptr = (char *)&rset[R_A0 + (4 * rset[R_WB]) % XCHAL_NUM_AREGS];
>> +
>
>
> space issue.
Will fix.
>> + for (i = a0_regnum; i < a0_regnum + C0_NREGS; i++)
>> + {
>> + if (4 * rset[R_WB] + i - a0_regnum == XCHAL_NUM_AREGS)
>
>
> parenthesis around the expression.
Will add.
--
Thanks.
-- Max