[PATCH 0/3] Assume PT_GETXMMREGS is always present on *BSD/i386

[PATCH 0/3] Assume PT_GETXMMREGS is always present on *BSD/i386

[John Baldwin]

All of the BSD operating systems have included support for the XMM
register set for SSE since at least mid 2006.  This patch series
assumes it is present to reduce #ifdef's and remove a
no-longer-necessary configure check.

John Baldwin (3):
  i386-fbsd-nat: Assume PT_GETXMMREGS is present.
  i386-bsd-nat: Assume PT_GETXMMREGS is present.
  configure: Stop checking for PT_GETXMMREGS.

 gdb/configure       | 37 -------------------------------------
 gdb/configure.ac    | 20 --------------------
 gdb/i386-bsd-nat.c  | 10 ----------
 gdb/i386-fbsd-nat.c | 14 --------------
 4 files changed, 81 deletions(-)

-- 
2.34.1

[PATCH 1/3] i386-fbsd-nat: Assume PT_GETXMMREGS is present.

[John Baldwin]

PT_GETXMMREGS was first added in FreeBSD 6.0 released in November 2005.
The last FreeBSD release without support was 5.5 released in May 2006.
---
 gdb/i386-fbsd-nat.c | 14 --------------
 1 file changed, 14 deletions(-)

diff --git a/gdb/i386-fbsd-nat.c b/gdb/i386-fbsd-nat.c
index 6fb67434a2d..a6ced66250c 100644
--- a/gdb/i386-fbsd-nat.c
+++ b/gdb/i386-fbsd-nat.c
@@ -42,9 +42,7 @@ class i386_fbsd_nat_target final
   void fetch_registers (struct regcache *, int) override;
   void store_registers (struct regcache *, int) override;
 
-#if defined(PT_GETXMMREGS) || defined(PT_GETXSTATE_INFO)
   const struct target_desc *read_description () override;
-#endif
 
   void resume (ptid_t, int, enum gdb_signal) override;
 
@@ -59,9 +57,7 @@ static i386_fbsd_nat_target the_i386_fbsd_nat_target;
 static size_t xsave_len;
 #endif
 
-#ifdef HAVE_PT_GETXMMREGS
 static int have_ptrace_xmmregs;
-#endif
 
 /* Fetch register REGNUM from the inferior.  If REGNUM is -1, do this
    for all registers.  */
@@ -126,7 +122,6 @@ i386_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
       return;
     }
 #endif
-#ifdef HAVE_PT_GETXMMREGS
   if (have_ptrace_xmmregs != 0)
     {
       char xmmregs[I387_SIZEOF_FXSAVE];
@@ -137,7 +132,6 @@ i386_fbsd_nat_target::fetch_registers (struct regcache *regcache, int regnum)
       i387_supply_fxsave (regcache, regnum, xmmregs);
       return;
     }
-#endif
 
   struct fpreg fpregs;
 
@@ -214,7 +208,6 @@ i386_fbsd_nat_target::store_registers (struct regcache *regcache, int regnum)
       return;
     }
 #endif
-#ifdef HAVE_PT_GETXMMREGS
   if (have_ptrace_xmmregs != 0)
     {
       char xmmregs[I387_SIZEOF_FXSAVE];
@@ -228,7 +221,6 @@ i386_fbsd_nat_target::store_registers (struct regcache *regcache, int regnum)
 	perror_with_name (_("Couldn't write XMM registers"));
       return;
     }
-#endif
 
   struct fpreg fpregs;
 
@@ -324,7 +316,6 @@ i386fbsd_supply_pcb (struct regcache *regcache, struct pcb *pcb)
 }
 \f
 
-#if defined(PT_GETXMMREGS) || defined(PT_GETXSTATE_INFO)
 /* Implement the read_description method.  */
 
 const struct target_desc *
@@ -334,9 +325,7 @@ i386_fbsd_nat_target::read_description ()
   static int xsave_probed;
   static uint64_t xcr0;
 #endif
-#ifdef PT_GETXMMREGS
   static int xmm_probed;
-#endif
 
 #ifdef PT_GETXSTATE_INFO
   if (!xsave_probed)
@@ -356,7 +345,6 @@ i386_fbsd_nat_target::read_description ()
     return i386_target_description (xcr0, true);
 #endif
 
-#ifdef PT_GETXMMREGS
   if (!xmm_probed)
     {
       char xmmregs[I387_SIZEOF_FXSAVE];
@@ -369,11 +357,9 @@ i386_fbsd_nat_target::read_description ()
 
   if (have_ptrace_xmmregs)
     return i386_target_description (X86_XSTATE_SSE_MASK, true);
-#endif
 
   return i386_target_description (X86_XSTATE_X87_MASK, true);
 }
-#endif
 
 #if defined(HAVE_PT_GETDBREGS) && defined(USE_SIGTRAP_SIGINFO)
 /* Implement the supports_stopped_by_hw_breakpoints method.  */
-- 
2.34.1

[PATCH 2/3] i386-bsd-nat: Assume PT_GETXMMREGS is present.

[John Baldwin]

NetBSD has included PT_GETXMMREGS since 1.6 released in September
2002.  OpenBSD has included PT_GETXMMREGS since 3.8 released in
November 2005.
---
 gdb/i386-bsd-nat.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/gdb/i386-bsd-nat.c b/gdb/i386-bsd-nat.c
index bd9655c9ef9..97a9738c52b 100644
--- a/gdb/i386-bsd-nat.c
+++ b/gdb/i386-bsd-nat.c
@@ -92,11 +92,9 @@ static int i386bsd_r_reg_offset[] =
 #define GETREGS_SUPPLIES(regnum) \
   ((0 <= (regnum) && (regnum) <= 15))
 
-#ifdef HAVE_PT_GETXMMREGS
 /* Set to 1 if the kernel supports PT_GETXMMREGS.  Initialized to -1
    so that we try PT_GETXMMREGS the first time around.  */
 static int have_ptrace_xmmregs = -1;
-#endif
 \f
 
 /* Supply the general-purpose registers in GREGS, to REGCACHE.  */
@@ -162,7 +160,6 @@ i386bsd_fetch_inferior_registers (struct regcache *regcache, int regnum)
   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
     {
       struct fpreg fpregs;
-#ifdef HAVE_PT_GETXMMREGS
       char xmmregs[512];
 
       if (have_ptrace_xmmregs != 0
@@ -175,15 +172,12 @@ i386bsd_fetch_inferior_registers (struct regcache *regcache, int regnum)
       else
 	{
 	  have_ptrace_xmmregs = 0;
-#endif
 	  if (gdb_ptrace (PT_GETFPREGS, ptid,
 			  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
 
 	  i387_supply_fsave (regcache, -1, &fpregs);
-#ifdef HAVE_PT_GETXMMREGS
 	}
-#endif
     }
 }
 
@@ -214,7 +208,6 @@ i386bsd_store_inferior_registers (struct regcache *regcache, int regnum)
   if (regnum == -1 || regnum >= I386_ST0_REGNUM)
     {
       struct fpreg fpregs;
-#ifdef HAVE_PT_GETXMMREGS
       char xmmregs[512];
 
       if (have_ptrace_xmmregs != 0
@@ -232,7 +225,6 @@ i386bsd_store_inferior_registers (struct regcache *regcache, int regnum)
       else
 	{
 	  have_ptrace_xmmregs = 0;
-#endif
 	  if (gdb_ptrace (PT_GETFPREGS, ptid,
 			  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't get floating point status"));
@@ -242,9 +234,7 @@ i386bsd_store_inferior_registers (struct regcache *regcache, int regnum)
 	  if (gdb_ptrace (PT_SETFPREGS, ptid,
 			  (PTRACE_TYPE_ARG3) &fpregs, 0) == -1)
 	    perror_with_name (_("Couldn't write floating point status"));
-#ifdef HAVE_PT_GETXMMREGS
 	}
-#endif
     }
 }
 
-- 
2.34.1

[PATCH 3/3] configure: Stop checking for PT_GETXMMREGS.

[John Baldwin]

This request is present on all modern *BSD/i386 systems (those
released since mid-2006), and the *BSD/i386 targets now assume it is
present unconditionally.
---
 gdb/configure    | 37 -------------------------------------
 gdb/configure.ac | 20 --------------------
 2 files changed, 57 deletions(-)

diff --git a/gdb/configure b/gdb/configure
index 425bdb08a73..b34baff13be 100755
--- a/gdb/configure
+++ b/gdb/configure
@@ -16245,43 +16245,6 @@ $as_echo "#define HAVE_PT_GETDBREGS 1" >>confdefs.h
 
 fi
 
-# See if <sys/ptrace.h> provides the PT_GETXMMREGS request.
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for PT_GETXMMREGS" >&5
-$as_echo_n "checking for PT_GETXMMREGS... " >&6; }
-if ${gdb_cv_have_pt_getxmmregs+:} false; then :
-  $as_echo_n "(cached) " >&6
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-#include <sys/types.h>
-	 #include <sys/ptrace.h>
-int
-main ()
-{
-PT_GETXMMREGS;
-
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  gdb_cv_have_pt_getxmmregs=yes
-else
-  gdb_cv_have_pt_getxmmregs=no
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
-fi
-
-{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $gdb_cv_have_pt_getxmmregs" >&5
-$as_echo "$gdb_cv_have_pt_getxmmregs" >&6; }
-if test "$gdb_cv_have_pt_getxmmregs" = yes; then
-
-$as_echo "#define HAVE_PT_GETXMMREGS 1" >>confdefs.h
-
-fi
-
 # See if <sys/ptrace.h> supports LWP names on FreeBSD
 # Older FreeBSD versions don't have the pl_tdname member of
 # `struct ptrace_lwpinfo'.
diff --git a/gdb/configure.ac b/gdb/configure.ac
index c6fa19b20bc..bc8925ddd69 100644
--- a/gdb/configure.ac
+++ b/gdb/configure.ac
@@ -1486,26 +1486,6 @@ if test "$gdb_cv_have_pt_getdbregs" = yes; then
   [Define if sys/ptrace.h defines the PT_GETDBREGS request.])
 fi
 
-# See if <sys/ptrace.h> provides the PT_GETXMMREGS request.
-AC_MSG_CHECKING(for PT_GETXMMREGS)
-AC_CACHE_VAL(
-  [gdb_cv_have_pt_getxmmregs],
-  [AC_COMPILE_IFELSE(
-     [AC_LANG_PROGRAM(
-	[#include <sys/types.h>
-	 #include <sys/ptrace.h>],
-	[PT_GETXMMREGS;]
-      )],
-     [gdb_cv_have_pt_getxmmregs=yes],
-     [gdb_cv_have_pt_getxmmregs=no]
-   )]
-)
-AC_MSG_RESULT($gdb_cv_have_pt_getxmmregs)
-if test "$gdb_cv_have_pt_getxmmregs" = yes; then
-  AC_DEFINE(HAVE_PT_GETXMMREGS, 1,
-  [Define if sys/ptrace.h defines the PT_GETXMMREGS request.])
-fi
-
 # See if <sys/ptrace.h> supports LWP names on FreeBSD
 # Older FreeBSD versions don't have the pl_tdname member of
 # `struct ptrace_lwpinfo'.
-- 
2.34.1

Re: [PATCH 1/3] i386-fbsd-nat: Assume PT_GETXMMREGS is present.

[Simon Marchi]

On 2022-02-28 17:35, John Baldwin wrote:
> PT_GETXMMREGS was first added in FreeBSD 6.0 released in November 2005.
> The last FreeBSD release without support was 5.5 released in May 2006.
> ---
>  gdb/i386-fbsd-nat.c | 14 --------------
>  1 file changed, 14 deletions(-)
> 
> diff --git a/gdb/i386-fbsd-nat.c b/gdb/i386-fbsd-nat.c
> index 6fb67434a2d..a6ced66250c 100644
> --- a/gdb/i386-fbsd-nat.c
> +++ b/gdb/i386-fbsd-nat.c
> @@ -42,9 +42,7 @@ class i386_fbsd_nat_target final
>    void fetch_registers (struct regcache *, int) override;
>    void store_registers (struct regcache *, int) override;
>  
> -#if defined(PT_GETXMMREGS) || defined(PT_GETXSTATE_INFO)
>    const struct target_desc *read_description () override;
> -#endif
>  
>    void resume (ptid_t, int, enum gdb_signal) override;
>  
> @@ -59,9 +57,7 @@ static i386_fbsd_nat_target the_i386_fbsd_nat_target;
>  static size_t xsave_len;
>  #endif
>  
> -#ifdef HAVE_PT_GETXMMREGS
>  static int have_ptrace_xmmregs;

Is this variable (have_ptrace_xmmregs) still relevant?  In other words,
can the PT_GETXMMREGS request legitimately fail?

Simon

Re: [PATCH 1/3] i386-fbsd-nat: Assume PT_GETXMMREGS is present.

[John Baldwin]

On 3/1/22 6:22 AM, Simon Marchi wrote:
> 
> 
> On 2022-02-28 17:35, John Baldwin wrote:
>> PT_GETXMMREGS was first added in FreeBSD 6.0 released in November 2005.
>> The last FreeBSD release without support was 5.5 released in May 2006.
>> ---
>>   gdb/i386-fbsd-nat.c | 14 --------------
>>   1 file changed, 14 deletions(-)
>>
>> diff --git a/gdb/i386-fbsd-nat.c b/gdb/i386-fbsd-nat.c
>> index 6fb67434a2d..a6ced66250c 100644
>> --- a/gdb/i386-fbsd-nat.c
>> +++ b/gdb/i386-fbsd-nat.c
>> @@ -42,9 +42,7 @@ class i386_fbsd_nat_target final
>>     void fetch_registers (struct regcache *, int) override;
>>     void store_registers (struct regcache *, int) override;
>>   
>> -#if defined(PT_GETXMMREGS) || defined(PT_GETXSTATE_INFO)
>>     const struct target_desc *read_description () override;
>> -#endif
>>   
>>     void resume (ptid_t, int, enum gdb_signal) override;
>>   
>> @@ -59,9 +57,7 @@ static i386_fbsd_nat_target the_i386_fbsd_nat_target;
>>   static size_t xsave_len;
>>   #endif
>>   
>> -#ifdef HAVE_PT_GETXMMREGS
>>   static int have_ptrace_xmmregs;
> 
> Is this variable (have_ptrace_xmmregs) still relevant?  In other words,
> can the PT_GETXMMREGS request legitimately fail?

Yes, while the ptrace op always exists, it only works if the running CPU supports
SSE (and this is true in i386-bsd-nat.c as well).  Granted, the number of systems
running modern BSD operating systems on a CPU that doesn't include SSE support
(think Pentium or Pentium Pro class CPUs) may be vanishingly small to the point
of zero.

-- 
John Baldwin

Re: [PATCH 0/3] Assume PT_GETXMMREGS is always present on *BSD/i386

[Tom Tromey]

>>>>> "John" == John Baldwin <jhb@FreeBSD.org> writes:

John> All of the BSD operating systems have included support for the XMM
John> register set for SSE since at least mid 2006.  This patch series
John> assumes it is present to reduce #ifdef's and remove a
John> no-longer-necessary configure check.

FWIW, I skimmed these and they all seem fine to me.

Tom