x86: Support GNU_PROPERTY_X86_ISA_1_V[234] marker [BZ #26717]

GCC 11 supports -march=x86-64-v[234] to enable x86 micro-architecture ISA
levels:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97250

and -mneeded to emit GNU_PROPERTY_X86_ISA_1_NEEDED property with
GNU_PROPERTY_X86_ISA_1_V[234] marker:

https://gitlab.com/x86-psABIs/x86-64-ABI/-/merge_requests/13

Binutils support for GNU_PROPERTY_X86_ISA_1_V[234] marker were added by

commit b0ab06937385e0ae25cebf1991787d64f439bf12
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Oct 30 06:49:57 2020 -0700

    x86: Support GNU_PROPERTY_X86_ISA_1_BASELINE marker

and

commit 32930e4edbc06bc6f10c435dbcc63131715df678
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Fri Oct 9 05:05:57 2020 -0700

    x86: Support GNU_PROPERTY_X86_ISA_1_V[234] marker

GNU_PROPERTY_X86_ISA_1_NEEDED property in x86 ELF binaries indicate the
micro-architecture ISA level required to execute the binary.  The marker
must be added by programmers explicitly in one of 3 ways:

1. Pass -mneeded to GCC.
2. Add the marker in the linker inputs as this patch does.
3. Pass -z x86-64-v[234] to the linker.

Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
marker support to ld.so if binutils 2.32 or newer is used to build glibc:

1. Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
markers to elf.h.
2. Add GNU_PROPERTY_X86_ISA_1_BASELINE and GNU_PROPERTY_X86_ISA_1_V[234]
marker to abi-note.o based on the ISA level used to compile abi-note.o,
assuming that the same ISA level is used to compile the whole glibc.
3. Add isa_1 to cpu_features to record the supported x86 ISA level.
4. Rename _dl_process_cet_property_note to _dl_process_property_note and
add GNU_PROPERTY_X86_ISA_1_V[234] marker detection.
5. Update _rtld_main_check and _dl_open_check to check loaded objects
with the incompatible ISA level.
6. Add a testcase to verify that dlopen an x86-64-v4 shared object fails
on lesser platforms.
7. Use <get-isa-level.h> in dl-hwcaps-subdirs.c and tst-glibc-hwcaps.c.

Tested under i686, x32 and x86-64 modes on x86-64-v2, x86-64-v3 and
x86-64-v4 machines.

Marked elf/tst-isa-level-1 with x86-64-v4, ran it on x86-64-v3 machine
and got:

[hjl@gnu-cfl-2 build-x86_64-linux]$ ./elf/tst-isa-level-1
./elf/tst-isa-level-1: CPU ISA level is lower than required
[hjl@gnu-cfl-2 build-x86_64-linux]$

1 files changed, 83 insertions, 30 deletions

diff --git a/sysdeps/x86/dl-prop.h b/sysdeps/x86/dl-prop.h
index ce1667dc7a..56bd020b3c 100644
--- a/sysdeps/x86/dl-prop.h
+++ b/sysdeps/x86/dl-prop.h
@@ -19,14 +19,54 @@
 #ifndef _DL_PROP_H
 #define _DL_PROP_H
 
+#include <libintl.h>
+
 extern void _dl_cet_check (struct link_map *, const char *)
     attribute_hidden;
 extern void _dl_cet_open_check (struct link_map *)
     attribute_hidden;
 
+static void
+dl_isa_level_check (struct link_map *m, const char *program)
+{
+  const struct cpu_features *cpu_features = __get_cpu_features ();
+  unsigned int i;
+  struct link_map *l;
+
+  i = m->l_searchlist.r_nlist;
+  while (i-- > 0)
+    {
+      /* Check each shared object to see if ISA level is compatible.  */
+      l = m->l_initfini[i];
+
+      /* Skip ISA level check if functions have been executed.  */
+      if (l->l_init_called)
+	continue;
+
+#ifdef SHARED
+      /* Skip ISA level check for ld.so since ld.so won't run if its ISA
+	 level is higher than CPU.  */
+      if (l == &GL(dl_rtld_map) || l->l_real == &GL(dl_rtld_map))
+	continue;
+#endif
+
+      if ((l->l_x86_isa_1_needed & cpu_features->isa_1)
+	  != l->l_x86_isa_1_needed)
+	{
+	  if (program)
+	    _dl_fatal_printf ("%s: CPU ISA level is lower than required\n",
+			      *l->l_name != '\0' ? l->l_name : program);
+	  else
+	    _dl_signal_error (0, l->l_name, "dlopen",
+			      N_("CPU ISA level is lower than required"));
+	}
+    }
+}
+
 static inline void __attribute__ ((always_inline))
 _rtld_main_check (struct link_map *m, const char *program)
 {
+  dl_isa_level_check (m, program);
 #if CET_ENABLED
   _dl_cet_check (m, program);
 #endif
@@ -35,20 +75,18 @@ _rtld_main_check (struct link_map *m, const char *program)
 static inline void __attribute__ ((always_inline))
 _dl_open_check (struct link_map *m)
 {
+  dl_isa_level_check (m, NULL);
 #if CET_ENABLED
   _dl_cet_open_check (m);
 #endif
 }
 
 static inline void __attribute__ ((unused))
-_dl_process_cet_property_note (struct link_map *l,
-			      const ElfW(Nhdr) *note,
-			      const ElfW(Addr) size,
-			      const ElfW(Addr) align)
+_dl_process_property_note (struct link_map *l, const ElfW(Nhdr) *note,
+			   const ElfW(Addr) size, const ElfW(Addr) align)
 {
-#if CET_ENABLED
   /* Skip if we have seen a NT_GNU_PROPERTY_TYPE_0 note before.  */
-  if (l->l_cet != lc_unknown)
+  if (l->l_property != lc_property_unknown)
     return;
 
   /* The NT_GNU_PROPERTY_TYPE_0 note must be aliged to 4 bytes in
@@ -59,7 +97,8 @@ _dl_process_cet_property_note (struct link_map *l,
 
   const ElfW(Addr) start = (ElfW(Addr)) note;
 
-  unsigned int feature_1 = 0;
+  unsigned int feature_1_and = 0;
+  unsigned int isa_1_needed = 0;
   unsigned int last_type = 0;
 
   while ((ElfW(Addr)) (note + 1) - start < size)
@@ -71,11 +110,11 @@ _dl_process_cet_property_note (struct link_map *l,
 	{
 	  /* Stop if we see more than one GNU property note which may
 	     be generated by the older linker.  */
-	  if (l->l_cet != lc_unknown)
+	  if (l->l_property != lc_property_unknown)
 	    return;
 
-	  /* Check CET status now.  */
-	  l->l_cet = lc_none;
+	  /* Check CET status and ISA levels now.  */
+	  l->l_property = lc_property_none;
 
 	  /* Check for invalid property.  */
 	  if (note->n_descsz < 8
@@ -101,26 +140,37 @@ _dl_process_cet_property_note (struct link_map *l,
 
 	      last_type = type;
 
-	      if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
+	      if (type == GNU_PROPERTY_X86_FEATURE_1_AND
+		  || type == GNU_PROPERTY_X86_ISA_1_NEEDED)
 		{
-		  /* The size of GNU_PROPERTY_X86_FEATURE_1_AND is 4
-		     bytes.  When seeing GNU_PROPERTY_X86_FEATURE_1_AND,
-		     we stop the search regardless if its size is correct
-		     or not.  There is no point to continue if this note
-		     is ill-formed.  */
+		  /* The sizes of types which we are searching for are
+		     4 bytes.  There is no point to continue if this
+		     note is ill-formed.  */
 		  if (datasz != 4)
 		    return;
 
-		  feature_1 = *(unsigned int *) ptr;
-
-		  /* Keep searching for the next GNU property note
-		     generated by the older linker.  */
-		  break;
+		  /* NB: Stop the scan only after seeing all types which
+		     we are searching for.  */
+		  _Static_assert ((GNU_PROPERTY_X86_ISA_1_NEEDED >
+				   GNU_PROPERTY_X86_FEATURE_1_AND),
+				  "GNU_PROPERTY_X86_ISA_1_NEEDED > "
+				  "GNU_PROPERTY_X86_FEATURE_1_AND");
+		  if (type == GNU_PROPERTY_X86_FEATURE_1_AND)
+		    feature_1_and = *(unsigned int *) ptr;
+		  else
+		    {
+		      isa_1_needed = *(unsigned int *) ptr;
+
+		      /* Keep searching for the next GNU property note
+			 generated by the older linker.  */
+		      break;
+		    }
 		}
-	      else if (type > GNU_PROPERTY_X86_FEATURE_1_AND)
+	      else if (type > GNU_PROPERTY_X86_ISA_1_NEEDED)
 		{
-		  /* Stop since property type is in ascending order.  */
-		  return;
+		  /* Stop the scan since property type is in ascending
+		     order.  */
+		  break;
 		}
 
 	      /* Check the next property item.  */
@@ -137,18 +187,21 @@ _dl_process_cet_property_note (struct link_map *l,
     }
 
   /* We get here only if there is one or no GNU property note.  */
-  if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_IBT))
-    l->l_cet |= lc_ibt;
-  if ((feature_1 & GNU_PROPERTY_X86_FEATURE_1_SHSTK))
-    l->l_cet |= lc_shstk;
-#endif
+  if (isa_1_needed != 0 || feature_1_and != 0)
+    {
+      l->l_property = lc_property_valid;
+      l->l_x86_isa_1_needed = isa_1_needed;
+      l->l_x86_feature_1_and = feature_1_and;
+    }
+  else
+    l->l_property = lc_property_none;
 }
 
 static inline void __attribute__ ((unused))
 _dl_process_pt_note (struct link_map *l, int fd, const ElfW(Phdr) *ph)
 {
   const ElfW(Nhdr) *note = (const void *) (ph->p_vaddr + l->l_addr);
-  _dl_process_cet_property_note (l, note, ph->p_memsz, ph->p_align);
+  _dl_process_property_note (l, note, ph->p_memsz, ph->p_align);
 }
 
 static inline int __attribute__ ((always_inline))