Re: [PATCH][gdb/tdep] Use pid to choose x86_64 process 64/32-bitness

[Alan Hayward via Gdb-patches <gdb-patches@sourceware.org>]

On 19 May 2021, at 17:32, Tom de Vries <tdevries@suse.de<mailto:tdevries@suse.de>> wrote:




---
gdb/aarch64-linux-nat.c | 2 +-
gdb/arm-linux-nat.c     | 2 +-
gdb/ppc-linux-nat.c     | 4 +---
gdb/s390-linux-nat.c    | 2 +-
gdb/x86-linux-nat.c     | 5 +----
5 files changed, 5 insertions(+), 10 deletions(-)

diff --git a/gdb/aarch64-linux-nat.c b/gdb/aarch64-linux-nat.c
index ae8db2988c2..61224022f6a 100644
--- a/gdb/aarch64-linux-nat.c
+++ b/gdb/aarch64-linux-nat.c
@@ -723,7 +723,7 @@ aarch64_linux_nat_target::read_description ()
  gdb_byte regbuf[ARM_VFP3_REGS_SIZE];
  struct iovec iovec;

-  tid = inferior_ptid.lwp ();
+  tid = inferior_ptid.pid ();

A user level process is either AArch64 or AArch32, it can only change by execve().
All threads in a single process will be the same architecture.

As was mentioned above somewhere, SVE can have different vector lengths per thread.

Therefore, this needs to stay as lwp.

Maybe this needs a comment, something like:
// Use lwp as sve vector length can change per thread.


  iovec.iov_base = regbuf;
  iovec.iov_len = ARM_VFP3_REGS_SIZE;
diff --git a/gdb/arm-linux-nat.c b/gdb/arm-linux-nat.c
index 662dade0a12..b5b470b6876 100644
--- a/gdb/arm-linux-nat.c
+++ b/gdb/arm-linux-nat.c
@@ -537,7 +537,7 @@ arm_linux_nat_target::read_description ()
    {
      elf_gregset_t gpregs;
      struct iovec iov;
-      int tid = inferior_ptid.lwp ();
+      int tid = inferior_ptid.pid ();


Arm port is only ever going to be 32bits, so this change is probably not that useful.
Fine with the change for consistency reasons across the ports.

If making this change, could you also change the other inferior_ptid.lwp call in the
same function (line 559).



      iov.iov_base = &gpregs;
      iov.iov_len = sizeof (gpregs);
diff --git a/gdb/ppc-linux-nat.c b/gdb/ppc-linux-nat.c
index 171f5b386fa..06a30efeaef 100644
--- a/gdb/ppc-linux-nat.c
+++ b/gdb/ppc-linux-nat.c
@@ -1946,9 +1946,7 @@ ppc_linux_nat_target::auxv_parse (gdb_byte **readptr,
const struct target_desc *
ppc_linux_nat_target::read_description ()
{
-  int tid = inferior_ptid.lwp ();
-  if (tid == 0)
-    tid = inferior_ptid.pid ();
+  int tid = inferior_ptid.pid ();

  if (have_ptrace_getsetevrregs)
    {
diff --git a/gdb/s390-linux-nat.c b/gdb/s390-linux-nat.c
index 41b50ce4800..8f6eb61505b 100644
--- a/gdb/s390-linux-nat.c
+++ b/gdb/s390-linux-nat.c
@@ -988,7 +988,7 @@ s390_linux_nat_target::auxv_parse (gdb_byte **readptr,
const struct target_desc *
s390_linux_nat_target::read_description ()
{
-  int tid = s390_inferior_tid ();
+  int tid = inferior_ptid.pid ();

  have_regset_last_break
    = check_regset (tid, NT_S390_LAST_BREAK, 8);
diff --git a/gdb/x86-linux-nat.c b/gdb/x86-linux-nat.c
index 85c7f0ddc94..adea1ad0092 100644
--- a/gdb/x86-linux-nat.c
+++ b/gdb/x86-linux-nat.c
@@ -113,10 +113,7 @@ x86_linux_nat_target::read_description ()
  static uint64_t xcr0;
  uint64_t xcr0_features_bits;

-  /* GNU/Linux LWP ID's are process ID's.  */
-  tid = inferior_ptid.lwp ();
-  if (tid == 0)
-    tid = inferior_ptid.pid (); /* Not a threaded program.  */
+  tid = inferior_ptid.pid ();

#ifdef __x86_64__
  {


Thanks,
Alan.