Support SecurePLTs for PowerPC. You need a toolchain that supports

config option --enable-secureplt. The assembler must also
supports R_PPC_REL16* relocations. gcc 4.1.1 and binutils 2.17
is known to do this.

Rules.mak

@@ -284,6 +284,8 @@ ifeq ($(TARGET_ARCH),powerpc)
 # faster code.
 	PICFLAG:=-fpic
 	PIEFLAG_NAME:=-fpie
+	PPC_HAS_REL16:=$(shell echo -e "\t.text\n\taddis 11,30,_GLOBAL_OFFSET_TABLE_-.@ha" | $(CC) -c -x assembler -o /dev/null -  2> /dev/null && echo -n y || echo -n n)
+	CPU_CFLAGS-$(PPC_HAS_REL16)+= -DHAVE_ASM_PPC_REL16
 endif
 
 ifeq ($(TARGET_ARCH),frv)

ldso/ldso/powerpc/dl-startup.h

@@ -16,8 +16,15 @@ asm(
     "	bl	_dl_start@local\n" /* Perform relocation */
     /*  Save the address of the apps entry point in CTR register */
     "	mtctr	3\n" /* application entry point */
+#ifdef HAVE_ASM_PPC_REL16
+    "	bcl	20,31,1f\n"
+    "1:	mflr	31\n"
+    "	addis	31,31,_GLOBAL_OFFSET_TABLE_-1b@ha\n"
+    "	addi	31,31,_GLOBAL_OFFSET_TABLE_-1b@l\n"
+#else
     "	bl	_GLOBAL_OFFSET_TABLE_-4@local\n" /*  Put our GOT pointer in r31, */
     "	mflr	31\n"
+#endif
     "	addi	1,1,16\n" /* Restore SP */
     "	lwz	7,_dl_skip_args@got(31)\n" /* load EA of _dl_skip_args */
     "	lwz	7,0(7)\n"	/* Load word from _dl_skip_args */

ldso/ldso/powerpc/dl-sysdep.h

@@ -89,23 +89,38 @@ void _dl_init_got(unsigned long *lpnt,struct elf_resolve *tpnt);
    DT_RELA table.  */
 #define ELF_MACHINE_PLTREL_OVERLAP 1
 
+/* Return the value of the GOT pointer.  */
+static inline Elf32_Addr * __attribute__ ((const))
+ppc_got (void)
+{
+	Elf32_Addr *got;
+#ifdef HAVE_ASM_PPC_REL16
+	asm ("	bcl 20,31,1f\n"
+	     "1:mflr %0\n"
+	     "	addis %0,%0,_GLOBAL_OFFSET_TABLE_-1b@ha\n"
+	     "	addi %0,%0,_GLOBAL_OFFSET_TABLE_-1b@l\n"
+	     : "=b" (got) : : "lr");
+#else
+	asm (" bl _GLOBAL_OFFSET_TABLE_-4@local"
+	     : "=l" (got));
+#endif
+	return got;
+}
+
 /* Return the link-time address of _DYNAMIC, stored as
    the first value in the GOT. */
-static inline Elf32_Addr
+static inline Elf32_Addr __attribute__ ((const))
 elf_machine_dynamic (void)
 {
-  Elf32_Addr *got;
-  asm (" bl _GLOBAL_OFFSET_TABLE_-4@local"
-       : "=l"(got));
-  return *got;
+	return *ppc_got();
 }
 
 /* Return the run-time load address of the shared object.  */
-static inline Elf32_Addr
+static inline Elf32_Addr __attribute__ ((const))
 elf_machine_load_address (void)
 {
-  unsigned int *got;
-  unsigned int *branchaddr;
+  Elf32_Addr *branchaddr;
+  Elf32_Addr runtime_dynamic;
 
   /* This is much harder than you'd expect.  Possibly I'm missing something.
      The 'obvious' way:
@@ -136,19 +151,17 @@ elf_machine_load_address (void)
      the address ourselves. That gives us the following code: */
 
   /* Get address of the 'b _DYNAMIC@local'...  */
-  asm ("bl 0f ;"
+  asm ("bcl 20,31,0f;"
        "b _DYNAMIC@local;"
        "0:"
        : "=l"(branchaddr));
 
-  /* ... and the address of the GOT.  */
-  asm (" bl _GLOBAL_OFFSET_TABLE_-4@local"
-       : "=l"(got));
-
   /* So now work out the difference between where the branch actually points,
      and the offset of that location in memory from the start of the file.  */
-  return ((Elf32_Addr)branchaddr - *got
-	  + ((int)(*branchaddr << 6 & 0xffffff00) >> 6));
+  runtime_dynamic = ((Elf32_Addr) branchaddr
+		     + ((Elf32_Sword) (*branchaddr << 6 & 0xffffff00) >> 6));
+
+  return runtime_dynamic - elf_machine_dynamic ();
 }
 
 static inline void
@@ -163,3 +176,12 @@ elf_machine_relative (Elf32_Addr load_off, const Elf32_Addr rel_addr,
 		*reloc_addr = load_off + rpnt->r_addend;
 	} while (--relative_count);
 }
+
+#define ARCH_NUM 1
+#define DT_PPC_GOT_IDX	(DT_NUM + OS_NUM)
+
+#define ARCH_DYNAMIC_INFO(dpnt,  dynamic, debug_addr) \
+do { \
+if (dpnt->d_tag == DT_PPC_GOT) \
+     dynamic[DT_PPC_GOT_IDX] = dpnt->d_un.d_ptr; \
+} while (0)

ldso/ldso/powerpc/elfinterp.c

@@ -41,6 +41,12 @@ void _dl_init_got(unsigned long *plt,struct elf_resolve *tpnt)
 	Elf32_Word rel_offset_words;
 	Elf32_Word dlrr = (Elf32_Word) _dl_linux_resolve;
 
+	if (tpnt->dynamic_info[DT_JMPREL] == 0)
+		return;
+	if (tpnt->dynamic_info[DT_PPC_GOT_IDX] != 0) {
+		tpnt->dynamic_info[DT_PPC_GOT_IDX] += tpnt->loadaddr;
+		return;
+	}
 	num_plt_entries = tpnt->dynamic_info[DT_PLTRELSZ] / sizeof(ELF_RELOC);
 	rel_offset_words = PLT_DATA_START_WORDS(num_plt_entries);
 	data_words = (Elf32_Word) (plt + rel_offset_words);
@@ -148,32 +154,35 @@ unsigned long _dl_linux_resolver(struct elf_resolve *tpnt, int reloc_entry)
 	if (_dl_debug_reloc && _dl_debug_detail)
 		_dl_dprintf(_dl_debug_file, "%x\n", finaladdr);
 #endif
-	delta = finaladdr - (Elf32_Word)reloc_addr;
-	if (delta<<6>>6 == delta) {
-		*reloc_addr = OPCODE_B(delta);
-	} else if (finaladdr <= 0x01fffffc) {
-		*reloc_addr = OPCODE_BA (finaladdr);
+	if (tpnt->dynamic_info[DT_PPC_GOT_IDX] != 0) {
+		*reloc_addr = finaladdr;
 	} else {
-		/* Warning: we don't handle double-sized PLT entries */
-		Elf32_Word *plt, *data_words, index, offset;
+		delta = finaladdr - (Elf32_Word)reloc_addr;
+		if (delta<<6>>6 == delta) {
+			*reloc_addr = OPCODE_B(delta);
+		} else if (finaladdr <= 0x01fffffc) {
+			*reloc_addr = OPCODE_BA (finaladdr);
+		} else {
+			/* Warning: we don't handle double-sized PLT entries */
+			Elf32_Word *plt, *data_words, index, offset;
+
+			plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
+			offset = reloc_addr - plt;
+			index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
+			data_words = (Elf32_Word *)tpnt->data_words;
+			reloc_addr += 1;
 
-		plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
-		offset = reloc_addr - plt;
-		index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
-		data_words = (Elf32_Word *)tpnt->data_words;
-		reloc_addr += 1;
+			data_words[index] = finaladdr;
+			PPC_SYNC;
+			*reloc_addr =  OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1)) * 4);
+		}
 
-		data_words[index] = finaladdr;
+		/* instructions were modified */
+		PPC_DCBST(reloc_addr);
 		PPC_SYNC;
-		*reloc_addr =  OPCODE_B ((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1)) * 4);
+		PPC_ICBI(reloc_addr);
+		PPC_ISYNC;
 	}
-
-	/* instructions were modified */
-	PPC_DCBST(reloc_addr);
-	PPC_SYNC;
-	PPC_ICBI(reloc_addr);
-	PPC_ISYNC;
-
 	return finaladdr;
 }
 
@@ -219,28 +228,33 @@ _dl_do_reloc (struct elf_resolve *tpnt,struct dyn_elf *scope,
 		goto out_nocode; /* No code code modified */
 	case R_PPC_JMP_SLOT:
 	{
-		Elf32_Sword delta = finaladdr - (Elf32_Word)reloc_addr;
-		if (delta<<6>>6 == delta) {
-			*reloc_addr = OPCODE_B(delta);
-		} else if (finaladdr <= 0x01fffffc) {
-			*reloc_addr = OPCODE_BA (finaladdr);
+		if (tpnt->dynamic_info[DT_PPC_GOT_IDX] != 0) {
+			*reloc_addr = finaladdr;
+			goto out_nocode; /* No code code modified */
 		} else {
-			/* Warning: we don't handle double-sized PLT entries */
-			Elf32_Word *plt, *data_words, index, offset;
-
-			plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
-			offset = reloc_addr - plt;
-			index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
-			data_words = (Elf32_Word *)tpnt->data_words;
-
-			data_words[index] = finaladdr;
-			reloc_addr[0] = OPCODE_LI(11,index*4);
-			reloc_addr[1] = OPCODE_B((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1)) * 4);
-
-			/* instructions were modified */
-			PPC_DCBST(reloc_addr+1);
-			PPC_SYNC;
-			PPC_ICBI(reloc_addr+1);
+			Elf32_Sword delta = finaladdr - (Elf32_Word)reloc_addr;
+			if (delta<<6>>6 == delta) {
+				*reloc_addr = OPCODE_B(delta);
+			} else if (finaladdr <= 0x01fffffc) {
+				*reloc_addr = OPCODE_BA (finaladdr);
+			} else {
+				/* Warning: we don't handle double-sized PLT entries */
+				Elf32_Word *plt, *data_words, index, offset;
+
+				plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
+				offset = reloc_addr - plt;
+				index = (offset - PLT_INITIAL_ENTRY_WORDS)/2;
+				data_words = (Elf32_Word *)tpnt->data_words;
+
+				data_words[index] = finaladdr;
+				reloc_addr[0] = OPCODE_LI(11,index*4);
+				reloc_addr[1] = OPCODE_B((PLT_LONGBRANCH_ENTRY_WORDS - (offset+1)) * 4);
+
+				/* instructions were modified */
+				PPC_DCBST(reloc_addr+1);
+				PPC_SYNC;
+				PPC_ICBI(reloc_addr+1);
+			}
 		}
 		break;
 	}
@@ -309,9 +323,22 @@ void _dl_parse_lazy_relocation_information(struct dyn_elf *rpnt,
 	Elf32_Word *plt, offset, i,  num_plt_entries, rel_offset_words;
 
 	num_plt_entries = rel_size / sizeof(ELF_RELOC);
+	plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
+	if (tpnt->dynamic_info[DT_PPC_GOT_IDX] != 0) {
+		/* Secure PLT */
+		Elf32_Addr *got = (Elf32_Addr *)tpnt->dynamic_info[DT_PPC_GOT_IDX];
+		Elf32_Word dlrr = (Elf32_Word) _dl_linux_resolve;
+
+		got[1] = (Elf32_Addr) dlrr;
+		got[2] = (Elf32_Addr) tpnt;
+
+		/* Relocate everything in .plt by the load address offset.  */
+		while (num_plt_entries-- != 0)
+			*plt++ += tpnt->loadaddr;
+		return;
+	}
 
 	rel_offset_words = PLT_DATA_START_WORDS(num_plt_entries);
-	plt = (Elf32_Word *)tpnt->dynamic_info[DT_PLTGOT];
 
 	/* Set up the lazy PLT entries.  */
 	offset = PLT_INITIAL_ENTRY_WORDS;

libc/sysdeps/linux/powerpc/brk.S

@@ -50,8 +50,15 @@ brk:
 	lwz     r6,8(r1)
 #ifdef __PIC__
 	mflr    r4
+# ifdef HAVE_ASM_PPC_REL16
+	bcl	20,31,1f
+1:	mflr	r5
+	addis	r5,r5,_GLOBAL_OFFSET_TABLE_-1b@ha
+	addi	r5,r5,_GLOBAL_OFFSET_TABLE_-1b@l
+# else	
 	bl      _GLOBAL_OFFSET_TABLE_@local-4
 	mflr    r5
+# endif
 	lwz     r5,__curbrk@got(r5)
 	mtlr    r4
 	stw     r3,0(r5)

libc/sysdeps/linux/powerpc/bsd-_setjmp.S

@@ -29,9 +29,7 @@
 
 _setjmp:
 	li r4,0			/* Set second argument to 0.  */
-#ifdef __PIC__
-	b __sigsetjmp@plt
-#else
-	b __sigsetjmp
-#endif
+
+	b __sigsetjmp@local
+
 .size     _setjmp,.-_setjmp

libc/sysdeps/linux/powerpc/bsd-setjmp.S

@@ -29,11 +29,9 @@
 
 __setjmp:
 	li r4,1			/* Set second argument to 1.  */
-#ifdef __PIC__
-	b __sigsetjmp@plt
-#else
-	b __sigsetjmp
-#endif
+
+	b __sigsetjmp@local
+
 .size     __setjmp,.-__setjmp
 
 .globl     setjmp;

libc/sysdeps/linux/powerpc/crt1.S

@@ -48,8 +48,15 @@ _start:
 	mr	r9,r1 	/* Save the stack pointer and pass it to __uClibc_main */
 	clrrwi	r1,r1,4	/* Align stack ptr to 16 bytes */
 #ifdef __PIC__
+# ifdef HAVE_ASM_PPC_REL16
+	bcl	20,31,1f
+1:	mflr	r31
+	addis	r31,r31,_GLOBAL_OFFSET_TABLE_-1b@ha
+	addi	r31,r31,_GLOBAL_OFFSET_TABLE_-1b@l
+# else
 	bl	_GLOBAL_OFFSET_TABLE_-4@local
 	mflr	r31
+# endif
 #endif
 	/* Set up an initial stack frame, and clear the LR.  */
 	li	r0,0

libc/sysdeps/linux/powerpc/setjmp.S

@@ -76,9 +76,7 @@ FP(	stfd fp29,((JB_FPRS+15*2)*4)(3))
 FP(	stfd fp30,((JB_FPRS+16*2)*4)(3))
 	stw  r31,((JB_GPRS+17)*4)(3)
 FP(	stfd fp31,((JB_FPRS+17*2)*4)(3))
-#ifdef __PIC__
-	b __sigjmp_save@plt
-#else
-	b __sigjmp_save
-#endif
+
+	b __sigjmp_save@local
+
 .size     __sigsetjmp,.-__sigsetjmp