Re: [PATCH] Support AT_BSDFLAGS on FreeBSD.

[John Baldwin <jhb@FreeBSD.org>]

On 3/25/20 12:00 PM, Simon Marchi wrote:
> Hi John,
> 
> Could you please add a commit message that summarizes what this is (you can link
> to existing documentation) and what is the intent of this change?  Are there some
> user-visible changes, what are they?

I can add something.  To date there aren't any user-visible changes.  There is
one flag defined that indicates that the running FreeBSD kernel supports a new
'sigfastblock' system call that allows a thread to register a signal mask in user
memory that is treated as the signal mask so that sigprocmask() can just modify
that mask in userland without invoking actual system calls.  It's not documented
though aside from the upstream commit message.

> Thanks,
> 
> Simon
> 
> On 2020-03-25 1:25 p.m., John Baldwin wrote:
>> include/ChangeLog:
>>
>> 	* elf/common.h (AT_FREEBSD_BSDFLAGS): Define.
>>
>> gdb/ChangeLog:
>>
>> 	* fbsd-tdep.c (fbsd_print_auxv_entry): Handle AT_FREEBSD_BSDFLAGS.
>> ---
>>  gdb/ChangeLog        | 4 ++++
>>  gdb/fbsd-tdep.c      | 1 +
>>  include/ChangeLog    | 4 ++++
>>  include/elf/common.h | 1 +
>>  4 files changed, 10 insertions(+)
>>
>> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
>> index 5400a4e348..782e955358 100644
>> --- a/gdb/ChangeLog
>> +++ b/gdb/ChangeLog
>> @@ -1,3 +1,7 @@
>> +2020-03-25  John Baldwin  <jhb@FreeBSD.org>
>> +
>> +	* fbsd-tdep.c (fbsd_print_auxv_entry): Handle AT_FREEBSD_BSDFLAGS.
>> +
>>  2020-03-25  Hannes Domani  <ssbssa@yahoo.de>
>>  
>>  	* windows-nat.c (windows_add_all_dlls): Fix system dll paths.
>> diff --git a/gdb/fbsd-tdep.c b/gdb/fbsd-tdep.c
>> index ffffb18700..54f5149e5c 100644
>> --- a/gdb/fbsd-tdep.c
>> +++ b/gdb/fbsd-tdep.c
>> @@ -1597,6 +1597,7 @@ fbsd_print_auxv_entry (struct gdbarch *gdbarch, struct ui_file *file,
>>        TAG (EHDRFLAGS, _("ELF header e_flags"), AUXV_FORMAT_HEX);
>>        TAG (HWCAP, _("Machine-dependent CPU capability hints"), AUXV_FORMAT_HEX);
>>        TAG (HWCAP2, _("Extension of AT_HWCAP"), AUXV_FORMAT_HEX);
>> +      TAG (BSDFLAGS, _("ELF BSD flags"), AUXV_FORMAT_HEX);
>>      }
>>  
>>    fprint_auxv_entry (file, name, description, format, type, val);
>> diff --git a/include/ChangeLog b/include/ChangeLog
>> index 3d26a570ca..3f3e3caa0f 100644
>> --- a/include/ChangeLog
>> +++ b/include/ChangeLog
>> @@ -1,3 +1,7 @@
>> +2020-03-25  John Baldwin  <jhb@FreeBSD.org>
>> +
>> +	* elf/common.h (AT_FREEBSD_BSDFLAGS): Define.
>> +
>>  2020-03-24  Martin Liska  <mliska@suse.cz>
>>  
>>  	PR lto/94249
>> diff --git a/include/elf/common.h b/include/elf/common.h
>> index 1c84ccb430..6741c34a00 100644
>> --- a/include/elf/common.h
>> +++ b/include/elf/common.h
>> @@ -1251,6 +1251,7 @@
>>  #define AT_FREEBSD_EHDRFLAGS    24      /* e_flags field from ELF header. */
>>  #define AT_FREEBSD_HWCAP        25      /* CPU feature flags. */
>>  #define AT_FREEBSD_HWCAP2       26      /* CPU feature flags 2. */
>> +#define AT_FREEBSD_BSDFLAGS     27      /* ELF BSD Flags. */
>>  
>>  #define AT_SUN_UID      2000    /* Effective user ID.  */
>>  #define AT_SUN_RUID     2001    /* Real user ID.  */
>> -- 
>> 2.25.1
>>
> 


-- 
John Baldwin