Add support for MIPS O32 FPXX and .MIPS.abiflags

	* elf/elf.h (PT_MIPS_ABIFLAGS): Define.
	(Elf_MIPS_ABIFlags_v0): New structure.
	(EF_MIPS_FP64): Define.
	(MIPS_AFL_REG_NONE, MIPS_AFL_REG_32, MIPS_AFL_REG_64): Likewise.
	(MIPS_AFL_REG_128, MIPS_AFL_ASE_DSP, MIPS_AFL_ASE_DSP64): Likewise.
	(MIPS_AFL_ASE_DSPR2, MIPS_AFL_ASE_EVA, MIPS_AFL_ASE_MCU): Likewise.
	(MIPS_AFL_ASE_MDMX, MIPS_AFL_ASE_MIPS3D, MIPS_AFL_ASE_MT): Likewise.
	(MIPS_AFL_ASE_SMARTMIPS, MIPS_AFL_ASE_VIRT): Likewise.
	(MIPS_AFL_ASE_VIRT64, MIPS_AFL_ASE_MSA, MIPS_AFL_ASE_MSA64): Likewise.
	(MIPS_AFL_ASE_MIPS16, MIPS_AFL_ASE_MICROMIPS): Likewise.
	(MIPS_AFL_ASE_XPA, MIPS_AFL_EXT_XLR, MIPS_AFL_EXT_OCTEON2): Likewise.
	(MIPS_AFL_EXT_OCTEONP, MIPS_AFL_EXT_LOONGSON_3A): Likewise.
	(MIPS_AFL_EXT_OCTEON, MIPS_AFL_EXT_5900, MIPS_AFL_EXT_4010): Likewise.
	(MIPS_AFL_EXT_4100, MIPS_AFL_EXT_3900, MIPS_AFL_EXT_10000): Likewise.
	(MIPS_AFL_EXT_SB1, MIPS_AFL_EXT_4111, MIPS_AFL_EXT_4120): Likewise.
	(MIPS_AFL_EXT_5400, MIPS_AFL_EXT_5500): Likewise.
	(MIPS_AFL_EXT_LOONGSON_2E, MIPS_AFL_EXT_LOONGSON_2F): Likewise.
	(Val_GNU_MIPS_ABI_FP_ANY, Val_GNU_MIPS_ABI_FP_DOUBLE): New enum values.
	(Val_GNU_MIPS_ABI_FP_SINGLE, Val_GNU_MIPS_ABI_FP_SOFT): Likewise.
	(Val_GNU_MIPS_ABI_FP_OLD_64, Val_GNU_MIPS_ABI_FP_XX): Likewise.
	(Val_GNU_MIPS_ABI_FP_64, Val_GNU_MIPS_ABI_FP_64A): Likewise.
	(Val_GNU_MIPS_ABI_FP_MAX): Likewise.
	* sysdeps/mips/Makefile [subdir=elf]: Add tst-abi-interlink,
	tst-mode-switch-1, tst-mode-switch-2, tst-mode-switch-3 tests.
	* sysdeps/mips/bits/linkmap.h (struct link_map_machine): Add fpmode
	field.
	* sysdeps/mips/dl-machine.h (elf_machine_matches_host): Reject
	EF_MIPS_FP64.
	* sysdeps/mips/dl-machine-reject-phdr.h: New file.
	* sysdeps/mips/tst-abi-fp32mod.c: Likewise.
	* sysdeps/mips/tst-abi-fpxxmod.c: Likewise.
	* sysdeps/mips/tst-abi-fpxxomod.c: Likewise.
	* sysdeps/mips/tst-abi-fp64mod.c: Likewise.
	* sysdeps/mips/tst-abi-fp64amod.c: Likewise.
	* sysdeps/mips/tst-abi-interlink.c: Likewise.
	* sysdeps/mips/tst-mode-switch-1.c: Likewise.
	* sysdeps/mips/tst-mode-switch-2.c: Likewise.
	* sysdeps/mips/tst-mode-switch-3.c: Likewise.
	* sysdeps/unix/sysv/linux/mips/configure.ac (o32-fpabi): Define to
	record the current FP ABI extension.
	(mips-mode-switch): Define to show if kernel headers support mode
	switching.
	* sysdeps/unix/sysv/linux/mips/configure: Regenerate.
	* sysdeps/unix/sysv/linux/mips/ldsodefs.h: Increase maximum
	supported SYSV ABI version to 3.
	* sysdeps/unix/sysv/linux/mips/libc-abis: Add new MIPS_O32_FP64
	feature.

1 files changed, 326 insertions, 0 deletions

diff --git a/sysdeps/mips/dl-machine-reject-phdr.h b/sysdeps/mips/dl-machine-reject-phdr.h
new file mode 100644
index 0000000000..b277450c4d
--- /dev/null
+++ b/sysdeps/mips/dl-machine-reject-phdr.h
@@ -0,0 +1,326 @@
+/* Machine-dependent program header inspection for the ELF loader.
+   Copyright (C) 2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _DL_MACHINE_REJECT_PHDR_H
+#define _DL_MACHINE_REJECT_PHDR_H 1
+
+#include <unistd.h>
+#include <sys/prctl.h>
+
+#if defined PR_GET_FP_MODE && defined PR_SET_FP_MODE
+# define HAVE_PRCTL_FP_MODE 1
+#else
+# define HAVE_PRCTL_FP_MODE 0
+#endif
+
+/* Reject an object with a debug message.  */
+#define REJECT(str, args...)						      \
+  {									      \
+    if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))		      \
+      _dl_debug_printf (str, ##args);					      \
+    return true;							      \
+  }
+
+/* Search the program headers for the ABI Flags.  */
+
+static inline const ElfW(Phdr) *
+find_mips_abiflags (const ElfW(Phdr) *phdr, ElfW(Half) phnum)
+{
+  const ElfW(Phdr) *ph;
+
+  for (ph = phdr; ph < &phdr[phnum]; ++ph)
+    if (ph->p_type == PT_MIPS_ABIFLAGS)
+      return ph;
+  return NULL;
+}
+
+/* Cache the FP ABI value from the PT_MIPS_ABIFLAGS program header.  */
+
+static bool
+cached_fpabi_reject_phdr_p (struct link_map *l)
+{
+  if (l->l_mach.fpabi == 0)
+    {
+      const ElfW(Phdr) *ph = find_mips_abiflags (l->l_phdr, l->l_phnum);
+
+      if (ph)
+	{
+	  Elf_MIPS_ABIFlags_v0 * mips_abiflags;
+	  if (ph->p_filesz < sizeof (Elf_MIPS_ABIFlags_v0))
+	    REJECT ("   %s: malformed PT_MIPS_ABIFLAGS found\n", l->l_name);
+
+	  mips_abiflags = (Elf_MIPS_ABIFlags_v0 *) (l->l_addr + ph->p_vaddr);
+
+	  if (__glibc_unlikely (mips_abiflags->flags2 != 0))
+	    REJECT ("   %s: unknown MIPS.abiflags flags2: %u\n", l->l_name,
+		    mips_abiflags->flags2);
+
+	  l->l_mach.fpabi = mips_abiflags->fp_abi;
+	  l->l_mach.odd_spreg = (mips_abiflags->flags1
+				 & MIPS_AFL_FLAGS1_ODDSPREG) != 0;
+	}
+      else
+	{
+	  l->l_mach.fpabi = -1;
+	  l->l_mach.odd_spreg = true;
+	}
+    }
+  return false;
+}
+
+/* Return a description of the specified floating-point ABI.  */
+
+static const char *
+fpabi_string (int fpabi)
+{
+  switch (fpabi)
+    {
+    case Val_GNU_MIPS_ABI_FP_ANY:
+      return "Hard or soft float";
+    case Val_GNU_MIPS_ABI_FP_DOUBLE:
+      return "Hard float (double precision)";
+    case Val_GNU_MIPS_ABI_FP_SINGLE:
+      return "Hard float (single precision)";
+    case Val_GNU_MIPS_ABI_FP_SOFT:
+      return "Soft float";
+    case Val_GNU_MIPS_ABI_FP_OLD_64:
+      return "Unsupported FP64";
+    case Val_GNU_MIPS_ABI_FP_XX:
+      return "Hard float (32-bit CPU, Any FPU)";
+    case Val_GNU_MIPS_ABI_FP_64:
+      return "Hard float (32-bit CPU, 64-bit FPU)";
+    case Val_GNU_MIPS_ABI_FP_64A:
+      return "Hard float compat (32-bit CPU, 64-bit FPU)";
+    case -1:
+      return "Double precision, single precision or soft float";
+    default:
+      return "Unknown FP ABI";
+    }
+}
+
+/* A structure to describe the requirements of each FP ABI extension.
+   Each field says whether the ABI can be executed in that mode.  The FR0 field
+   is actually overloaded and means 'default' FR mode for the ABI.  I.e. For
+   O32 it is FR0 and for N32/N64 it is actually FR1.  Since this logic is
+   focussed on the intricacies of mode management for O32 we call the field
+   FR0.  */
+
+struct abi_req
+{
+  bool single;
+  bool soft;
+  bool fr0;
+  bool fr1;
+  bool fre;
+};
+
+/* FP ABI requirements for all Val_GNU_MIPS_ABI_FP_* values.  */
+
+static const struct abi_req reqs[Val_GNU_MIPS_ABI_FP_MAX + 1] =
+    {{true,  true,  true,  true,  true},  /* Any */
+     {false, false, true,  false, true},  /* Double-float */
+     {true,  false, false, false, false}, /* Single-float */
+     {false, true,  false, false, false}, /* Soft-float */
+     {false, false, false, false, false}, /* old-FP64 */
+     {false, false, true,  true,  true},  /* FPXX */
+     {false, false, false, true,  false}, /* FP64 */
+     {false, false, false, true,  true}}; /* FP64A */
+
+/* FP ABI requirements for objects without a PT_MIPS_ABIFLAGS segment.  */
+
+static const struct abi_req none_req = { true, true, true, false, true };
+
+/* Return true iff ELF program headers are incompatible with the running
+   host.  This verifies that floating-point ABIs are compatible and
+   re-configures the hardware mode if necessary.  This code handles both the
+   DT_NEEDED libraries and the dlopen'ed libraries.  It also accounts for the
+   impact of dlclose.  */
+
+static bool __attribute_used__
+elf_machine_reject_phdr_p (const ElfW(Phdr) *phdr, uint_fast16_t phnum,
+			   const char *buf, size_t len, struct link_map *map,
+			   int fd)
+{
+  const ElfW(Phdr) *ph = find_mips_abiflags (phdr, phnum);
+  struct link_map *l;
+  Lmid_t nsid;
+  int in_abi = -1;
+  struct abi_req in_req;
+  Elf_MIPS_ABIFlags_v0 *mips_abiflags = NULL;
+  bool perfect_match = false;
+#if _MIPS_SIM == _ABIO32
+  unsigned int cur_mode = -1;
+# if HAVE_PRCTL_FP_MODE
+  bool cannot_mode_switch = false;
+
+  /* Get the current hardware mode.  */
+  cur_mode = __prctl (PR_GET_FP_MODE);
+# endif
+#endif
+
+  /* Read the attributes section.  */
+  if (ph != NULL)
+    {
+      ElfW(Addr) size = ph->p_filesz;
+
+      if (ph->p_offset + size <= len)
+	mips_abiflags = (Elf_MIPS_ABIFlags_v0 *) (buf + ph->p_offset);
+      else
+	{
+	  mips_abiflags = alloca (size);
+	  __lseek (fd, ph->p_offset, SEEK_SET);
+	  if (__libc_read (fd, (void *) mips_abiflags, size) != size)
+	    REJECT ("   unable to read PT_MIPS_ABIFLAGS\n");
+	}
+
+      if (size < sizeof (Elf_MIPS_ABIFlags_v0))
+	REJECT ("   contains malformed PT_MIPS_ABIFLAGS\n");
+
+      if (__glibc_unlikely (mips_abiflags->flags2 != 0))
+	REJECT ("   unknown MIPS.abiflags flags2: %u\n", mips_abiflags->flags2);
+
+      in_abi = mips_abiflags->fp_abi;
+    }
+
+  /* ANY is compatible with anything.  */
+  perfect_match |= (in_abi == Val_GNU_MIPS_ABI_FP_ANY);
+
+  /* Unknown ABIs are rejected.  */
+  if (in_abi != -1 && in_abi > Val_GNU_MIPS_ABI_FP_MAX)
+    REJECT ("   uses unknown FP ABI: %u\n", in_abi);
+
+  /* Obtain the initial requirements.  */
+  in_req = (in_abi == -1) ? none_req : reqs[in_abi];
+
+  /* Check that the new requirement does not conflict with any currently
+     loaded object.  */
+  for (nsid = 0; nsid < DL_NNS; ++nsid)
+    for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
+      {
+	struct abi_req existing_req;
+
+	if (cached_fpabi_reject_phdr_p (l))
+	  return true;
+
+#if _MIPS_SIM == _ABIO32
+	/* A special case arises for O32 FP64 and FP64A where the kernel
+	   pre-dates PT_MIPS_ABIFLAGS.  These ABIs will be blindly loaded even
+	   if the hardware mode is unavailable or disabled.  In this
+	   circumstance the prctl call to obtain the current mode will fail.
+	   Detect this situation here and reject everything.  This will
+	   effectively prevent dynamically linked applications from failing in
+	   unusual ways but there is nothing we can do to help static
+	   applications.  */
+	if ((l->l_mach.fpabi == Val_GNU_MIPS_ABI_FP_64A
+	     || l->l_mach.fpabi == Val_GNU_MIPS_ABI_FP_64)
+	    && cur_mode == -1)
+	  REJECT ("   found %s running in the wrong mode\n",
+		  fpabi_string (l->l_mach.fpabi));
+#endif
+
+	/* Found a perfect match, success.  */
+	perfect_match |= (in_abi == l->l_mach.fpabi);
+
+	/* Unknown ABIs are rejected.  */
+	if (l->l_mach.fpabi != -1 && l->l_mach.fpabi > Val_GNU_MIPS_ABI_FP_MAX)
+	  REJECT ("   found unknown FP ABI: %u\n", l->l_mach.fpabi);
+
+	existing_req = (l->l_mach.fpabi == -1 ? none_req
+			: reqs[l->l_mach.fpabi]);
+
+	/* Merge requirements.  */
+	in_req.soft &= existing_req.soft;
+	in_req.single &= existing_req.single;
+	in_req.fr0 &= existing_req.fr0;
+	in_req.fr1 &= existing_req.fr1;
+	in_req.fre &= existing_req.fre;
+
+	/* If there is at least one mode which is still usable then the new
+	   object can be loaded.  */
+	if (in_req.single || in_req.soft || in_req.fr1 || in_req.fr0
+	    || in_req.fre)
+	  {
+#if _MIPS_SIM == _ABIO32 && HAVE_PRCTL_FP_MODE
+	    /* Account for loaded ABIs which prohibit mode switching.  */
+	    if (l->l_mach.fpabi == Val_GNU_MIPS_ABI_FP_XX)
+	      cannot_mode_switch |= l->l_mach.odd_spreg;
+#endif
+	  }
+	else
+	  REJECT ("   uses %s, already loaded %s\n",
+		  fpabi_string (in_abi),
+		  fpabi_string (l->l_mach.fpabi));
+      }
+
+#if _MIPS_SIM == _ABIO32
+  /* At this point we know that the newly loaded object is compatible with all
+     existing objects but the hardware mode may not be correct.  */
+  if ((in_req.fr1 || in_req.fre || in_req.fr0)
+      && !perfect_match)
+    {
+      if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
+	_dl_debug_printf ("   needs %s%s mode\n", in_req.fr0 ? "FR0 or " : "",
+			  (in_req.fre && !in_req.fr1) ? "FRE" : "FR1");
+
+      /* If the PR_GET_FP_MODE is not supported then only FR0 is available.
+	 If the overall requirements cannot be met by FR0 then reject the
+	 object.  */
+      if (cur_mode == -1)
+	return !in_req.fr0;
+
+# if HAVE_PRCTL_FP_MODE
+      {
+	unsigned int fr1_mode = PR_FP_MODE_FR;
+
+	/* It is not possible to change the mode of a thread which may be
+	   executing FPXX code with odd-singles.  If an FPXX object with
+	   odd-singles is loaded then just check the current mode is OK. This
+	   can be either the FR1 mode or FR0 if the requirements are met by
+	   FR0.  */
+	if (cannot_mode_switch)
+	  return (!(in_req.fre && cur_mode == (PR_FP_MODE_FR | PR_FP_MODE_FRE))
+		  && !(in_req.fr1 && cur_mode == PR_FP_MODE_FR)
+		  && !(in_req.fr0 && cur_mode == 0));
+
+	/* If the overall requirements can be satisfied by FRE but not FR1 then
+	   fr1_mode must become FRE.  */
+	if (in_req.fre && !in_req.fr1)
+	  fr1_mode |= PR_FP_MODE_FRE;
+
+	/* Set the new mode.  Use fr1_mode if the requirements cannot be met by
+	   FR0.  */
+	if (!in_req.fr0)
+	  return __prctl (PR_SET_FP_MODE, fr1_mode) != 0;
+	else if (__prctl (PR_SET_FP_MODE, /* fr0_mode */ 0) != 0)
+	  {
+	    /* Setting FR0 can validly fail on an R6 core so retry with the FR1
+	       mode as a fall back.  */
+	    if (errno != ENOTSUP)
+	      return true;
+
+	    return __prctl (PR_SET_FP_MODE, fr1_mode) != 0;
+	  }
+      }
+# endif /* HAVE_PRCTL_FP_MODE */
+    }
+#endif /* _MIPS_SIM == _ABIO32 */
+
+  return false;
+}
+
+#endif /* dl-machine-reject-phdr.h */