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[2.29 COMMITTED] Fix output of LD_SHOW_AUXV=1.

From: Stefan Liebler <stli at linux dot ibm dot com>
To: GNU C Library <libc-alpha at sourceware dot org>, libc-stable at sourceware dot org
Cc: "Carlos O'Donell" <carlos at redhat dot com>
Date: Wed, 13 Mar 2019 10:54:29 +0100
Subject: [2.29 COMMITTED] Fix output of LD_SHOW_AUXV=1.
References: <dbc57505-7375-2344-d3db-c9fa65ced3ca@linux.ibm.com> <b5420a20-30f8-effc-799b-0661d2c0a3f9@redhat.com> <d1bd871f-c327-6ec1-0795-55129ac4901f@linux.ibm.com> <5b73a948-5209-14b0-61d1-aca82c99e192@redhat.com>

On 3/12/19 9:11 PM, Carlos O'Donell wrote:

On 3/12/19 11:06 AM, Stefan Liebler wrote:

commit 988376a08d6d36ea321203b9c039db4b266609ae
Author: Stefan Liebler <stli@linux.ibm.com>
Date:   Fri Mar 8 11:18:53 2019 +0100

     Fix output of LD_SHOW_AUXV=1.

Starting with commit 1616d034b61622836d3a36af53dcfca7624c844e

     the output was corrupted on some platforms as _dl_procinfo
     was called for every auxv entry and on some architectures like s390
     all entries were represented as "AT_HWCAP".

This patch is removing the condition and let _dl_procinfo decide if

     an entry is printed in a platform specific or generic way.
     This patch also adjusts all _dl_procinfo implementations which assumed
     that they are only called for AT_HWCAP or AT_HWCAP2. They are now just
     returning a non-zero-value for entries which are not handled platform
     specifc.

ChangeLog:* elf/dl-sysdep.c (_dl_show_auxv): Remove condition and always

             call _dl_procinfo.
             * sysdeps/unix/sysv/linux/s390/dl-procinfo.h (_dl_procinfo):
             Ignore types other than AT_HWCAP.
             * sysdeps/sparc/dl-procinfo.h (_dl_procinfo): Likewise.
             * sysdeps/unix/sysv/linux/i386/dl-procinfo.h (_dl_procinfo):
             Likewise.


Thanks for the cleanup, this makes it really clear how this is intended to work.

OK for master if you...
- Fix ARM and POWERPC backend _dl_procinfo to remove "/* This should not happen.  */"
   comment in dl-procinfo.c. It *does* happen now because we pass all options to
   the machine version first.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

Okay. I've adjusted those comments and committed the patch to master andbackported it to glibc release branch 2.29.


Thanks,
Stefan

diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
index 5f6c679a3f..5d19b100b2 100644
--- a/elf/dl-sysdep.c
+++ b/elf/dl-sysdep.c
@@ -328,14 +328,9 @@ _dl_show_auxv (void)
        assert (AT_NULL == 0);
        assert (AT_IGNORE == 1);

- if (av->a_type == AT_HWCAP || av->a_type == AT_HWCAP2

-	  || AT_L1I_CACHEGEOMETRY || AT_L1D_CACHEGEOMETRY
-	  || AT_L2_CACHEGEOMETRY || AT_L3_CACHEGEOMETRY)
-	{
-	  /* These are handled in a special way per platform.  */
-	  if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
-	    continue;
-	}
+      /* Some entries are handled in a special way per platform.  */
+      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
+	continue;


OK.

OK. ARM backend returns -1 with default handling.

OK. POWERPC backend return -1 with default handling.

if (idx < sizeof (auxvars) / sizeof (auxvars[0])

  	  && auxvars[idx].form != unknown)
diff --git a/sysdeps/sparc/dl-procinfo.h b/sysdeps/sparc/dl-procinfo.h
index 282b8c5117..cc2687e99b 100644
--- a/sysdeps/sparc/dl-procinfo.h
+++ b/sysdeps/sparc/dl-procinfo.h
@@ -32,7 +32,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
    int i;

/* Fallback to unknown output mechanism. */

-  if (type == AT_HWCAP2)
+  if (type != AT_HWCAP)

OK.

      return -1;

_dl_printf ("AT_HWCAP: ");

diff --git a/sysdeps/unix/sysv/linux/i386/dl-procinfo.h b/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
index 22b43431bc..3aef14c6c1 100644
--- a/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
+++ b/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
@@ -31,7 +31,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
    int i;

/* Fallback to unknown output mechanism. */

-  if (type == AT_HWCAP2)
+  if (type != AT_HWCAP)

OK.

      return -1;

_dl_printf ("AT_HWCAP: ");

diff --git a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
index 19329a335b..16739fd6cd 100644
--- a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
+++ b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
@@ -33,7 +33,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
    int i;

/* Fallback to unknown output mechanism. */

-  if (type == AT_HWCAP2)
+  if (type != AT_HWCAP)

OK.

      return -1;
_dl_printf ("AT_HWCAP: ");

commit daede01d78492f2f7b640966a2e60ff409be677a
Author: Stefan Liebler <stli@linux.ibm.com>
Date:   Fri Mar 8 11:18:53 2019 +0100

    Fix output of LD_SHOW_AUXV=1.
    
    Starting with commit 1616d034b61622836d3a36af53dcfca7624c844e
    the output was corrupted on some platforms as _dl_procinfo
    was called for every auxv entry and on some architectures like s390
    all entries were represented as "AT_HWCAP".
    
    This patch is removing the condition and let _dl_procinfo decide if
    an entry is printed in a platform specific or generic way.
    This patch also adjusts all _dl_procinfo implementations which assumed
    that they are only called for AT_HWCAP or AT_HWCAP2. They are now just
    returning a non-zero-value for entries which are not handled platform
    specifc.
    
    ChangeLog:
    
            * elf/dl-sysdep.c (_dl_show_auxv): Remove condition and always
            call _dl_procinfo.
            * sysdeps/unix/sysv/linux/s390/dl-procinfo.h (_dl_procinfo):
            Ignore types other than AT_HWCAP.
            * sysdeps/sparc/dl-procinfo.h (_dl_procinfo): Likewise.
            * sysdeps/unix/sysv/linux/i386/dl-procinfo.h (_dl_procinfo):
            Likewise.
            * sysdeps/powerpc/dl-procinfo.h (_dl_procinfo): Adjust comment
            in the case of falling back to generic output mechanism.
            * sysdeps/unix/sysv/linux/arm/dl-procinfo.h (_dl_procinfo):
            Likewise.

diff --git a/elf/dl-sysdep.c b/elf/dl-sysdep.c
index 5f6c679a3f..5d19b100b2 100644
--- a/elf/dl-sysdep.c
+++ b/elf/dl-sysdep.c
@@ -328,14 +328,9 @@ _dl_show_auxv (void)
       assert (AT_NULL == 0);
       assert (AT_IGNORE == 1);
 
-      if (av->a_type == AT_HWCAP || av->a_type == AT_HWCAP2
-	  || AT_L1I_CACHEGEOMETRY || AT_L1D_CACHEGEOMETRY
-	  || AT_L2_CACHEGEOMETRY || AT_L3_CACHEGEOMETRY)
-	{
-	  /* These are handled in a special way per platform.  */
-	  if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
-	    continue;
-	}
+      /* Some entries are handled in a special way per platform.  */
+      if (_dl_procinfo (av->a_type, av->a_un.a_val) == 0)
+	continue;
 
       if (idx < sizeof (auxvars) / sizeof (auxvars[0])
 	  && auxvars[idx].form != unknown)
diff --git a/sysdeps/powerpc/dl-procinfo.h b/sysdeps/powerpc/dl-procinfo.h
index f542f7318f..dfc3b33a72 100644
--- a/sysdeps/powerpc/dl-procinfo.h
+++ b/sysdeps/powerpc/dl-procinfo.h
@@ -225,7 +225,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
 	break;
       }
     default:
-      /* This should not happen.  */
+      /* Fallback to generic output mechanism.  */
       return -1;
     }
    _dl_printf ("\n");
diff --git a/sysdeps/sparc/dl-procinfo.h b/sysdeps/sparc/dl-procinfo.h
index 282b8c5117..64ee267fc7 100644
--- a/sysdeps/sparc/dl-procinfo.h
+++ b/sysdeps/sparc/dl-procinfo.h
@@ -31,8 +31,8 @@ _dl_procinfo (unsigned int type, unsigned long int word)
 {
   int i;
 
-  /* Fallback to unknown output mechanism.  */
-  if (type == AT_HWCAP2)
+  /* Fallback to generic output mechanism.  */
+  if (type != AT_HWCAP)
     return -1;
 
   _dl_printf ("AT_HWCAP:   ");
diff --git a/sysdeps/unix/sysv/linux/arm/dl-procinfo.h b/sysdeps/unix/sysv/linux/arm/dl-procinfo.h
index 66c00297b7..05c62c8687 100644
--- a/sysdeps/unix/sysv/linux/arm/dl-procinfo.h
+++ b/sysdeps/unix/sysv/linux/arm/dl-procinfo.h
@@ -67,7 +67,7 @@ _dl_procinfo (unsigned int type, unsigned long int word)
 	break;
       }
     default:
-      /* This should not happen.  */
+      /* Fallback to generic output mechanism.  */
       return -1;
     }
   _dl_printf ("\n");
diff --git a/sysdeps/unix/sysv/linux/i386/dl-procinfo.h b/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
index 22b43431bc..0585cdaa9c 100644
--- a/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
+++ b/sysdeps/unix/sysv/linux/i386/dl-procinfo.h
@@ -30,8 +30,8 @@ _dl_procinfo (unsigned int type, unsigned long int word)
      in the kernel sources.  */
   int i;
 
-  /* Fallback to unknown output mechanism.  */
-  if (type == AT_HWCAP2)
+  /* Fallback to generic output mechanism.  */
+  if (type != AT_HWCAP)
     return -1;
 
   _dl_printf ("AT_HWCAP:   ");
diff --git a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
index 19329a335b..d67fde368f 100644
--- a/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
+++ b/sysdeps/unix/sysv/linux/s390/dl-procinfo.h
@@ -32,8 +32,8 @@ _dl_procinfo (unsigned int type, unsigned long int word)
      in the kernel sources.  */
   int i;
 
-  /* Fallback to unknown output mechanism.  */
-  if (type == AT_HWCAP2)
+  /* Fallback to generic output mechanism.  */
+  if (type != AT_HWCAP)
     return -1;
 
   _dl_printf ("AT_HWCAP:   ");

References:
- [PATCH] Fix output of LD_SHOW_AUXV=1.
  - From: Stefan Liebler
- Re: [PATCH] Fix output of LD_SHOW_AUXV=1.
  - From: Carlos O'Donell
- Re: [PATCH] Fix output of LD_SHOW_AUXV=1.
  - From: Stefan Liebler
- Re: [PATCH] Fix output of LD_SHOW_AUXV=1.
  - From: Carlos O'Donell

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