x86: Add a GNU_PROPERTY_X86_ISA_1_USED note if needed

When -z separate-code, which is enabled by default for Linux/x86, is
used to create executable, ld won't place any data in the code-only
PT_LOAD segment.  If there are no data sections placed before the
code-only PT_LOAD segment, the program headers won't be mapped into
any PT_LOAD segment.  When the executable tries to access it (based
on the program header address passed in AT_PHDR), it will lead to
segfault.  This patch inserts a GNU_PROPERTY_X86_ISA_1_USED note if
there may be no data sections before the text section so that the
first PT_LOAD segment won't be code-only and will contain the program
header.

Testcases are adjusted to either pass "-z noseparate-code" to ld or
discard the .note.gnu.property section.  A Linux/x86 run-time test is
added.

bfd/

	PR ld/23428
	* elfxx-x86.c (_bfd_x86_elf_link_setup_gnu_properties): If the
	separate code program header is needed, make sure that the first
	read-only PT_LOAD segment has no code by adding a
	GNU_PROPERTY_X86_ISA_1_USED note.

ld/

	PR ld/23428
	* testsuite/ld-elf/linux-x86.S: New file.
	* testsuite/ld-elf/linux-x86.exp: Likewise.
	* testsuite/ld-elf/pr23428.c: Likewise.
	* testsuite/ld-elf/sec64k.exp: Pass "-z noseparate-code" to ld
	for Linux/x86 targets.
	* testsuite/ld-i386/abs-iamcu.d: Likewise.
	* testsuite/ld-i386/abs.d: Likewise.
	* testsuite/ld-i386/pr12718.d: Likewise.
	* testsuite/ld-i386/pr12921.d: Likewise.
	* testsuite/ld-x86-64/abs-k1om.d: Likewise.
	* testsuite/ld-x86-64/abs-l1om.d: Likewise.
	* testsuite/ld-x86-64/abs.d: Likewise.
	* testsuite/ld-x86-64/pr12718.d: Likewise.
	* testsuite/ld-x86-64/pr12921.d: Likewise.
	* testsuite/ld-linkonce/zeroeh.ld: Discard .note.gnu.property
	section.
	* testsuite/ld-scripts/print-memory-usage.t: Likewise.
	* testsuite/ld-scripts/size-2.t: Likewise.
	* testsuite/lib/ld-lib.exp (run_ld_link_exec_tests): Use ld
	to create executable if language is "asm".

1 files changed, 43 insertions, 0 deletions

diff --git a/ld/testsuite/ld-elf/pr23428.c b/ld/testsuite/ld-elf/pr23428.c
new file mode 100644
index 0000000..3631ed7
--- /dev/null
+++ b/ld/testsuite/ld-elf/pr23428.c
@@ -0,0 +1,43 @@
+#include <unistd.h>
+#include <link.h>
+#include <syscall.h>
+
+#define STRING_COMMA_LEN(STR) (STR), (sizeof (STR) - 1)
+
+int
+main (int argc, char **argv)
+{
+  char **ev = &argv[argc + 1];
+  char **evp = ev;
+  ElfW(auxv_t) *av;
+  const ElfW(Phdr) *phdr = NULL;
+  size_t phnum = 0;
+  size_t loadnum = 0;
+  int fd = STDOUT_FILENO;
+  size_t i;
+
+  while (*evp++ != NULL)
+    ;
+
+  av = (ElfW(auxv_t) *) evp;
+
+  for (; av->a_type != AT_NULL; ++av)
+    switch (av->a_type)
+      {
+      case AT_PHDR:
+	phdr = (const void *) av->a_un.a_val;
+	break;
+      case AT_PHNUM:
+	phnum = av->a_un.a_val;
+	break;
+      }
+
+  for (i = 0; i < phnum; i++, phdr++)
+    if (phdr->p_type == PT_LOAD)
+      loadnum++;
+
+  syscall (SYS_write, fd, STRING_COMMA_LEN ("PASS\n"));
+
+  syscall (SYS_exit, !loadnum);
+  return 0;
+}