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-rw-r--r--sysdeps/mips/dl-trampoline.c513
1 files changed, 513 insertions, 0 deletions
diff --git a/sysdeps/mips/dl-trampoline.c b/sysdeps/mips/dl-trampoline.c
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+++ b/sysdeps/mips/dl-trampoline.c
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+/* PLT trampoline.  MIPS version.
+   Copyright (C) 1996-2014 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+   Contributed by Kazumoto Kojima <kkojima@info.kanagawa-u.ac.jp>.
+
+   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/>.  */
+
+/*  FIXME: Profiling of shared libraries is not implemented yet.  */
+
+#include <sysdep.h>
+#include <link.h>
+#include <elf.h>
+#include <ldsodefs.h>
+#include <dl-machine.h>
+#include <sysdep-cancel.h>
+
+/* Get link map for callers object containing STUB_PC.  */
+static inline struct link_map *
+elf_machine_runtime_link_map (ElfW(Addr) gpreg, ElfW(Addr) stub_pc)
+{
+  extern int _dl_mips_gnu_objects;
+
+  /* got[1] is reserved to keep its link map address for the shared
+     object generated by the gnu linker.  If all are such objects, we
+     can find the link map from current GPREG simply.  If not so, get
+     the link map for caller's object containing STUB_PC.  */
+
+  if (_dl_mips_gnu_objects)
+    {
+      ElfW(Addr) *got = elf_mips_got_from_gpreg (gpreg);
+      ElfW(Word) g1;
+
+      g1 = ((ElfW(Word) *) got)[1];
+
+      if ((g1 & ELF_MIPS_GNU_GOT1_MASK) != 0)
+	{
+	  struct link_map *l =
+	    (struct link_map *) (g1 & ~ELF_MIPS_GNU_GOT1_MASK);
+	  ElfW(Addr) base, limit;
+	  const ElfW(Phdr) *p = l->l_phdr;
+	  ElfW(Half) this, nent = l->l_phnum;
+
+	  /* For the common case of a stub being called from the containing
+	     object, STUB_PC will point to somewhere within the object that
+	     is described by the link map fetched via got[1].  Otherwise we
+	     have to scan all maps.  */
+	  for (this = 0; this < nent; this++)
+	    {
+	      if (p[this].p_type == PT_LOAD)
+		{
+		  base = p[this].p_vaddr + l->l_addr;
+		  limit = base + p[this].p_memsz;
+		  if (stub_pc >= base && stub_pc < limit)
+		    return l;
+		}
+	    }
+	}
+    }
+
+    struct link_map *l;
+    Lmid_t nsid;
+
+    for (nsid = 0; nsid < DL_NNS; ++nsid)
+      for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
+	{
+	  ElfW(Addr) base, limit;
+	  const ElfW(Phdr) *p = l->l_phdr;
+	  ElfW(Half) this, nent = l->l_phnum;
+
+	  for (this = 0; this < nent; ++this)
+	    {
+	      if (p[this].p_type == PT_LOAD)
+		{
+		  base = p[this].p_vaddr + l->l_addr;
+		  limit = base + p[this].p_memsz;
+		  if (stub_pc >= base && stub_pc < limit)
+		    return l;
+		}
+	    }
+	}
+
+  _dl_signal_error (0, NULL, NULL, "cannot find runtime link map");
+  return NULL;
+}
+
+/* Define mips specific runtime resolver. The function __dl_runtime_resolve
+   is called from assembler function _dl_runtime_resolve which converts
+   special argument registers t7 ($15) and t8 ($24):
+     t7  address to return to the caller of the function
+     t8  index for this function symbol in .dynsym
+   to usual c arguments.
+
+   Other architectures call fixup from dl-runtime.c in
+   _dl_runtime_resolve.  MIPS instead calls __dl_runtime_resolve.  We
+   have to use our own version because of the way the got section is
+   treated on MIPS (we've also got ELF_MACHINE_PLT defined).  */
+
+/* The flag _dl_mips_gnu_objects is set if all dynamic objects are
+   generated by the gnu linker. */
+int _dl_mips_gnu_objects = 1;
+
+/* This is called from assembly stubs below which the compiler can't see.  */
+static ElfW(Addr)
+__dl_runtime_resolve (ElfW(Word), ElfW(Word), ElfW(Addr), ElfW(Addr))
+		  __attribute_used__;
+
+static ElfW(Addr)
+__dl_runtime_resolve (ElfW(Word) sym_index,
+		      ElfW(Word) return_address,
+		      ElfW(Addr) old_gpreg,
+		      ElfW(Addr) stub_pc)
+{
+  struct link_map *l = elf_machine_runtime_link_map (old_gpreg, stub_pc);
+  const ElfW(Sym) *const symtab
+    = (const ElfW(Sym) *) D_PTR (l, l_info[DT_SYMTAB]);
+  const char *strtab = (const void *) D_PTR (l, l_info[DT_STRTAB]);
+  ElfW(Addr) *got
+    = (ElfW(Addr) *) D_PTR (l, l_info[DT_PLTGOT]);
+  const ElfW(Word) local_gotno
+    = (const ElfW(Word)) l->l_info[DT_MIPS (LOCAL_GOTNO)]->d_un.d_val;
+  const ElfW(Word) gotsym
+    = (const ElfW(Word)) l->l_info[DT_MIPS (GOTSYM)]->d_un.d_val;
+  const ElfW(Sym) *sym = &symtab[sym_index];
+  struct link_map *sym_map;
+  ElfW(Addr) value;
+
+  /* FIXME: The symbol versioning stuff is not tested yet.  */
+  if (__builtin_expect (ELFW(ST_VISIBILITY) (sym->st_other), 0) == 0)
+    {
+      switch (l->l_info[VERSYMIDX (DT_VERSYM)] != NULL)
+	{
+	default:
+	  {
+	    const ElfW(Half) *vernum =
+	      (const void *) D_PTR (l, l_info[VERSYMIDX (DT_VERSYM)]);
+	    ElfW(Half) ndx = vernum[sym_index] & 0x7fff;
+	    const struct r_found_version *version = &l->l_versions[ndx];
+
+	    if (version->hash != 0)
+	      {
+                /* We need to keep the scope around so do some locking.  This is
+		   not necessary for objects which cannot be unloaded or when
+		   we are not using any threads (yet).  */
+		if (!RTLD_SINGLE_THREAD_P)
+		  THREAD_GSCOPE_SET_FLAG ();
+
+		sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l,
+					       &sym, l->l_scope, version,
+					       ELF_RTYPE_CLASS_PLT, 0, 0);
+
+                /* We are done with the global scope.  */
+		if (!RTLD_SINGLE_THREAD_P)
+		  THREAD_GSCOPE_RESET_FLAG ();
+
+		break;
+	      }
+	    /* Fall through.  */
+	  }
+	case 0:
+	  {
+          /* We need to keep the scope around so do some locking.  This is
+	     not necessary for objects which cannot be unloaded or when
+	     we are not using any threads (yet).  */
+	  int flags = DL_LOOKUP_ADD_DEPENDENCY;
+	  if (!RTLD_SINGLE_THREAD_P)
+	    {
+	      THREAD_GSCOPE_SET_FLAG ();
+	      flags |= DL_LOOKUP_GSCOPE_LOCK;
+	    }
+
+	  sym_map = _dl_lookup_symbol_x (strtab + sym->st_name, l, &sym,
+					 l->l_scope, 0, ELF_RTYPE_CLASS_PLT,
+					 flags, 0);
+
+          /* We are done with the global scope.  */
+	  if (!RTLD_SINGLE_THREAD_P)
+	    THREAD_GSCOPE_RESET_FLAG ();
+	  }
+	}
+
+      /* Currently value contains the base load address of the object
+	 that defines sym.  Now add in the symbol offset.  */
+      value = (sym ? sym_map->l_addr + sym->st_value : 0);
+    }
+  else
+    /* We already found the symbol.  The module (and therefore its load
+       address) is also known.  */
+    value = l->l_addr + sym->st_value;
+
+  /* Apply the relocation with that value.  */
+  *(got + local_gotno + sym_index - gotsym) = value;
+
+  return value;
+}
+
+#if _MIPS_SIM == _ABIO32
+#define ELF_DL_FRAME_SIZE 40
+
+#define ELF_DL_SAVE_ARG_REGS "\
+	sw	$15, 36($29)\n						      \
+	sw	$4, 16($29)\n						      \
+	sw	$5, 20($29)\n						      \
+	sw	$6, 24($29)\n						      \
+	sw	$7, 28($29)\n						      \
+"
+
+#define ELF_DL_RESTORE_ARG_REGS "\
+	lw	$31, 36($29)\n						      \
+	lw	$4, 16($29)\n						      \
+	lw	$5, 20($29)\n						      \
+	lw	$6, 24($29)\n						      \
+	lw	$7, 28($29)\n						      \
+"
+
+/* The PLT resolver should also save and restore $2 and $3, which are used
+   as arguments to MIPS16 stub functions.  */
+#define ELF_DL_PLT_FRAME_SIZE 48
+
+#define ELF_DL_PLT_SAVE_ARG_REGS \
+	ELF_DL_SAVE_ARG_REGS "\
+	sw	$2, 40($29)\n						      \
+	sw	$3, 44($29)\n						      \
+"
+
+#define ELF_DL_PLT_RESTORE_ARG_REGS \
+	ELF_DL_RESTORE_ARG_REGS "\
+	lw	$2, 40($29)\n						      \
+	lw	$3, 44($29)\n						      \
+"
+
+#define IFABIO32(X) X
+#define IFNEWABI(X)
+
+#else /* _MIPS_SIM == _ABIN32 || _MIPS_SIM == _ABI64 */
+
+#define ELF_DL_FRAME_SIZE 80
+
+#define ELF_DL_SAVE_ARG_REGS "\
+	sd	$15, 72($29)\n						      \
+	sd	$4, 8($29)\n						      \
+	sd	$5, 16($29)\n						      \
+	sd	$6, 24($29)\n						      \
+	sd	$7, 32($29)\n						      \
+	sd	$8, 40($29)\n						      \
+	sd	$9, 48($29)\n						      \
+	sd	$10, 56($29)\n						      \
+	sd	$11, 64($29)\n						      \
+"
+
+#define ELF_DL_RESTORE_ARG_REGS "\
+	ld	$31, 72($29)\n						      \
+	ld	$4, 8($29)\n						      \
+	ld	$5, 16($29)\n						      \
+	ld	$6, 24($29)\n						      \
+	ld	$7, 32($29)\n						      \
+	ld	$8, 40($29)\n						      \
+	ld	$9, 48($29)\n						      \
+	ld	$10, 56($29)\n						      \
+	ld	$11, 64($29)\n						      \
+"
+
+/* The PLT resolver should also save and restore $2 and $3, which are used
+   as arguments to MIPS16 stub functions.  */
+#define ELF_DL_PLT_FRAME_SIZE 96
+
+#define ELF_DL_PLT_SAVE_ARG_REGS \
+	ELF_DL_SAVE_ARG_REGS "\
+	sd	$2, 80($29)\n						      \
+	sd	$3, 88($29)\n						      \
+"
+
+#define ELF_DL_PLT_RESTORE_ARG_REGS \
+	ELF_DL_RESTORE_ARG_REGS "\
+	ld	$2, 80($29)\n						      \
+	ld	$3, 88($29)\n						      \
+"
+
+#define IFABIO32(X)
+#define IFNEWABI(X) X
+
+#endif
+
+#ifndef __mips16
+asm ("\n\
+	.text\n\
+	.align	2\n\
+	.set	nomips16\n\
+	.globl	_dl_runtime_resolve\n\
+	.type	_dl_runtime_resolve,@function\n\
+	.ent	_dl_runtime_resolve\n\
+_dl_runtime_resolve:\n\
+	.frame	$29, " STRINGXP(ELF_DL_FRAME_SIZE) ", $31\n\
+	.set noreorder\n\
+	# Save GP.\n\
+1:	move	$3, $28\n\
+	# Save arguments and sp value in stack.\n\
+	" STRINGXP(PTR_SUBIU) "  $29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\
+	# Modify t9 ($25) so as to point .cpload instruction.\n\
+	" IFABIO32(STRINGXP(PTR_ADDIU) "	$25, (2f-1b)\n") "\
+	# Compute GP.\n\
+2:	" STRINGXP(SETUP_GP) "\n\
+	" STRINGXV(SETUP_GP64 (0, _dl_runtime_resolve)) "\n\
+	.set reorder\n\
+	# Save slot call pc.\n\
+	move	$2, $31\n\
+	" IFABIO32(STRINGXP(CPRESTORE(32))) "\n\
+	" ELF_DL_SAVE_ARG_REGS "\
+	move	$4, $24\n\
+	move	$5, $15\n\
+	move	$6, $3\n\
+	move	$7, $2\n\
+	jal	__dl_runtime_resolve\n\
+	" ELF_DL_RESTORE_ARG_REGS "\
+	" STRINGXP(RESTORE_GP64) "\n\
+	" STRINGXP(PTR_ADDIU) "	$29, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\
+	move	$25, $2\n\
+	jr	$25\n\
+	.end	_dl_runtime_resolve\n\
+	.previous\n\
+");
+
+/* Assembler veneer called from the PLT header code when using PLTs.
+
+   Code in each PLT entry and the PLT header fills in the arguments to
+   this function:
+
+   - $15 (o32 t7, n32/n64 t3) - caller's return address
+   - $24 (t8) - PLT entry index
+   - $25 (t9) - address of _dl_runtime_pltresolve
+   - o32 $28 (gp), n32/n64 $14 (t2) - address of .got.plt
+
+   Different registers are used for .got.plt because the ABI was
+   originally designed for o32, where gp was available (call
+   clobbered).  On n32/n64 gp is call saved.
+
+   _dl_fixup needs:
+
+   - $4 (a0) - link map address
+   - $5 (a1) - .rel.plt offset (== PLT entry index * 8)  */
+
+asm ("\n\
+	.text\n\
+	.align	2\n\
+	.set	nomips16\n\
+	.globl	_dl_runtime_pltresolve\n\
+	.type	_dl_runtime_pltresolve,@function\n\
+	.ent	_dl_runtime_pltresolve\n\
+_dl_runtime_pltresolve:\n\
+	.frame	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\
+	.set noreorder\n\
+	# Save arguments and sp value in stack.\n\
+1:	" STRINGXP(PTR_SUBIU) "	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
+	" IFABIO32(STRINGXP(PTR_L) "	$13, " STRINGXP(PTRSIZE) "($28)") "\n\
+	" IFNEWABI(STRINGXP(PTR_L) "	$13, " STRINGXP(PTRSIZE) "($14)") "\n\
+	# Modify t9 ($25) so as to point .cpload instruction.\n\
+	" IFABIO32(STRINGXP(PTR_ADDIU) "	$25, (2f-1b)\n") "\
+	# Compute GP.\n\
+2:	" STRINGXP(SETUP_GP) "\n\
+	" STRINGXV(SETUP_GP64 (0, _dl_runtime_pltresolve)) "\n\
+	.set reorder\n\
+	" IFABIO32(STRINGXP(CPRESTORE(32))) "\n\
+	" ELF_DL_PLT_SAVE_ARG_REGS "\
+	move	$4, $13\n\
+	sll	$5, $24, " STRINGXP(PTRLOG) " + 1\n\
+	jal	_dl_fixup\n\
+	move	$25, $2\n\
+	" ELF_DL_PLT_RESTORE_ARG_REGS "\
+	" STRINGXP(RESTORE_GP64) "\n\
+	" STRINGXP(PTR_ADDIU) "	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
+	jr	$25\n\
+	.end	_dl_runtime_pltresolve\n\
+	.previous\n\
+");
+
+#elif _MIPS_SIM == _ABIO32 /* __mips16 */
+/* MIPS16 version, O32 only.  */
+asm ("\n\
+	.text\n\
+	.align	2\n\
+	.set	mips16\n\
+	.globl	_dl_runtime_resolve\n\
+	.type	_dl_runtime_resolve,@function\n\
+	.ent	_dl_runtime_resolve\n\
+_dl_runtime_resolve:\n\
+	.frame	$29, " STRINGXP (ELF_DL_FRAME_SIZE) ", $31\n\
+	# Save arguments and sp value in stack.\n\t"
+# if _MIPS_ISA >= _MIPS_ISA_MIPS32
+	"save	" STRINGXP (ELF_DL_FRAME_SIZE) ", $4-$7, $ra\n\t"
+# else
+	"addiu	$sp, -" STRINGXP (ELF_DL_FRAME_SIZE) "\n\
+	sw	$7, 32($sp)\n\
+	sw	$6, 28($sp)\n\
+	sw	$5, 24($sp)\n\
+	sw	$4, 20($sp)\n\t"
+# endif
+	"# Preserve caller's $ra, for RESTORE instruction below.\n\
+	move	$5, $15\n\
+	sw	$5, 36($sp)\n\
+	# Compute GP into $2.\n\
+	li	$2, %hi(_gp_disp)\n\
+	addiu	$3, $pc, %lo(_gp_disp)\n\
+	sll	$2, 16\n\
+	addu	$2, $3\n\
+	lw	$3, %got(__dl_runtime_resolve)($2)\n\
+	move	$4, $24\n\
+	addiu	$3, %lo(__dl_runtime_resolve)\n\
+	move	$7, $ra\n\
+	move	$6, $28\n\
+	move	$25, $3\n\
+	jalr	$3\n\t"
+# if _MIPS_ISA >= _MIPS_ISA_MIPS32
+	"restore " STRINGXP(ELF_DL_FRAME_SIZE) ", $4-$7, $ra\n\t"
+# else
+	"# Restore $ra, move placed further down to hide latency.\n\
+	lw	$4, 36($sp)\n\
+	lw	$5, 24($sp)\n\
+	lw	$6, 28($sp)\n\
+	lw	$7, 32($sp)\n\
+	move	$ra, $4\n\
+	lw	$4, 20($sp)\n\
+	addiu	$sp, " STRINGXP(ELF_DL_FRAME_SIZE) "\n\t"
+# endif
+	"move	$25, $2\n\
+	jr	$2\n\
+	.end	_dl_runtime_resolve\n\
+	.previous\n\
+");
+
+asm ("\n\
+	.text\n\
+	.align	2\n\
+	.set	mips16\n\
+	.globl	_dl_runtime_pltresolve\n\
+	.type	_dl_runtime_pltresolve,@function\n\
+	.ent	_dl_runtime_pltresolve\n\
+_dl_runtime_pltresolve:\n\
+	.frame	$29, " STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $31\n\
+	# Save arguments and sp value in stack.\n\t"
+# if _MIPS_ISA >= _MIPS_ISA_MIPS32
+	"save	" STRINGXP(ELF_DL_PLT_FRAME_SIZE) ", $4-$7, $ra\n\t"
+# else
+	"addiu	$sp, -" STRINGXP(ELF_DL_PLT_FRAME_SIZE) "\n\
+	sw	$7, 40($sp)\n\
+	sw	$6, 36($sp)\n\
+	sw	$5, 32($sp)\n\
+	sw	$4, 28($sp)\n\t"
+# endif
+	"# Preserve MIPS16 stub function arguments.\n\
+	sw	$3, 20($sp)\n\
+	sw	$2, 16($sp)\n\
+	# Preserve caller's $ra, for RESTORE instruction below.\n\
+	move	$3, $15\n\
+	sw	$3, 44($sp)\n\
+	# Compute GP into $2.\n\
+	li	$2, %hi(_gp_disp)\n\
+	addiu	$3, $pc, %lo(_gp_disp)\n\
+	sll	$2, 16\n\
+	addu	$2, $3\n\
+	# Save GP value in slot.\n\
+	sw	$2, 24($sp)\n\
+	# Load _dl_fixup address.\n\
+	lw	$6, %call16(_dl_fixup)($2)\n\
+	# Load link map address.\n\
+	move	$3, $28\n\
+	lw	$4, " STRINGXP (PTRSIZE) "($3)\n\
+	move	$5, $24\n\
+	sll	$5, " STRINGXP (PTRLOG) " + 1\n\
+	# Call _dl_fixup.\n\
+	move	$25, $6\n\
+	jalr	$6\n\
+	move	$25, $2\n\
+	# Reload GP value into $28.\n\
+	lw	$3, 24($sp)\n\
+	move	$28, $3\n\
+	lw	$3, 16($sp)\n\
+	move	$15, $3\n\
+	lw	$3, 20($sp)\n\t"
+# if _MIPS_ISA >= _MIPS_ISA_MIPS32
+	"restore " STRINGXP (ELF_DL_PLT_FRAME_SIZE) ", $4-$7, $ra\n\t"
+# else
+	"# Restore $ra, move placed further down to hide latency.\n\
+	lw	$4, 44($sp)\n\
+	lw	$5, 32($sp)\n\
+	lw	$6, 36($sp)\n\
+	lw	$7, 40($sp)\n\
+	move	$ra, $4\n\
+	lw	$4, 28($sp)\n\
+	addiu	$sp, " STRINGXP (ELF_DL_PLT_FRAME_SIZE) "\n\t"
+# endif
+	".set	noreorder\n\
+	jr	$2\n\
+	 move	$2, $15\n\
+	.set	reorder\n\
+	.end	_dl_runtime_pltresolve\n\
+	.previous\n\
+");
+
+#else /* __mips16 && _MIPS_SIM != _ABIO32 */
+# error "MIPS16 support for N32/N64 not implemented"
+
+#endif /* __mips16 */
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