PowerPC64 ELFv2 ABI 5/6: LD_AUDIT interface changes

The ELFv2 ABI changes the calling convention by passing and returning
structures in registers in more cases than the old ABI:
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01145.html
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01147.html

For the most part, this does not affect glibc, since glibc assembler
files do not use structure parameters / return values.  However, one
place is affected: the LD_AUDIT interface provides a structure to
the audit routine that contains all registers holding function
argument and return values for the intercepted PLT call.

Since the new ABI now sometimes uses registers to return values
that were never used for this purpose in the old ABI, this structure
has to be extended.  To force audit routines to be modified for the
new ABI if necessary, the patch defines v2 variants of the la_ppc64
types and routines.

In addition, the patch contains two unrelated changes to the
PLT trampoline routines: it fixes a bug where FPR return values
were stored in the wrong place, and it removes the unnecessary
save/restore of CR.

6 files changed, 186 insertions, 45 deletions

diff --git a/ChangeLog b/ChangeLog
index 0be780a..a0d32f2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,26 @@
+2013-11-12  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>
+	    Alan Modra  <amodra@gmail.com>
+
+	* sysdeps/powerpc/bits/link.h (La_ppc64v2_regs, La_ppc64v2_retval):
+	New versions for use with the ELFv2 ABI.
+	(la_ppc64v2_gnu_pltenter, la_ppc64v2_gnu_pltexit): Add prototypes.
+	* sysdeps/powerpc/lsdodefs.h (struct La_ppc64v2_regs): Add forward
+	declaration.
+	(struct La_ppc64v2_retval): Likewise.
+	(ARCH_PLTENTER_MEMBERS): Add ppc64v2_gnu_pltenter.
+	(ARCH_PLTEXIT_MEMBERS): Add ppc64v2_gnu_pltexit.
+	* sysdeps/powerpc/powerpc64/dl-machine.h (ARCH_LA_PLTENTER): Define
+	to ppc64v2_gnu_pltenter if _CALL_ELF == 2.
+	(ARCH_LA_PLTEXIT): Define to ppc64v2_gnu_pltexit if _CALL_ELF == 2.
+	* sysdeps/powerpc/powerpc64/dl-trampoline.S (_dl_runtime_resolve):
+	Do not save or restore CR.
+	(FRAME_SIZE, VR_RTN): Provide updated values for _CALL_ELF == 2.
+	(_dl_profile_resolve): Do no save or restore CR.  Support extended
+	return values for ELFv2 ABI.  Fix location of FPR return registers.
+	* sysdeps/powerpc/powerpc64/tst-audit.h (pltenter, pltexit): Provide
+	updated values for _CALL_ELF == 2.
+	(La_regs, La_retval, int_retval): Likewise.
+
 2013-12-04  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>
 
 	* sysdeps/powerpc/powerpc64/sysdep.h (FRAME_MIN_SIZE): Define.
diff --git a/sysdeps/powerpc/bits/link.h b/sysdeps/powerpc/bits/link.h
index f06092f..2f1da8b 100644
--- a/sysdeps/powerpc/bits/link.h
+++ b/sysdeps/powerpc/bits/link.h
@@ -63,7 +63,7 @@ extern unsigned int la_ppc32_gnu_pltexit (Elf32_Sym *__sym,
 
 __END_DECLS
 
-#else
+#elif _CALL_ELF != 2
 
 /* Registers for entry into PLT on PPC64.  */
 typedef struct La_ppc64_regs
@@ -107,4 +107,48 @@ extern unsigned int la_ppc64_gnu_pltexit (Elf64_Sym *__sym,
 
 __END_DECLS
 
+#else
+
+/* Registers for entry into PLT on PPC64 in the ELFv2 ABI.  */
+typedef struct La_ppc64v2_regs
+{
+  uint64_t lr_reg[8];
+  double lr_fp[13];
+  uint32_t __padding;
+  uint32_t lr_vrsave;
+  uint32_t lr_vreg[12][4] __attribute__ ((aligned (16)));
+  uint64_t lr_r1;
+  uint64_t lr_lr;
+} La_ppc64v2_regs;
+
+/* Return values for calls from PLT on PPC64 in the ELFv2 ABI.  */
+typedef struct La_ppc64v2_retval
+{
+  uint64_t lrv_r3;
+  uint64_t lrv_r4;
+  double lrv_fp[10];
+  uint32_t lrv_vreg[8][4] __attribute__ ((aligned (16)));
+} La_ppc64v2_retval;
+
+
+__BEGIN_DECLS
+
+extern Elf64_Addr la_ppc64v2_gnu_pltenter (Elf64_Sym *__sym,
+					   unsigned int __ndx,
+					   uintptr_t *__refcook,
+					   uintptr_t *__defcook,
+					   La_ppc64v2_regs *__regs,
+					   unsigned int *__flags,
+					   const char *__symname,
+					   long int *__framesizep);
+extern unsigned int la_ppc64v2_gnu_pltexit (Elf64_Sym *__sym,
+					    unsigned int __ndx,
+					    uintptr_t *__refcook,
+					    uintptr_t *__defcook,
+					    const La_ppc64v2_regs *__inregs,
+					    La_ppc64v2_retval *__outregs,
+					    const char *__symname);
+
+__END_DECLS
+
 #endif
diff --git a/sysdeps/powerpc/ldsodefs.h b/sysdeps/powerpc/ldsodefs.h
index ef849e9..435821c 100644
--- a/sysdeps/powerpc/ldsodefs.h
+++ b/sysdeps/powerpc/ldsodefs.h
@@ -25,6 +25,8 @@ struct La_ppc32_regs;
 struct La_ppc32_retval;
 struct La_ppc64_regs;
 struct La_ppc64_retval;
+struct La_ppc64v2_regs;
+struct La_ppc64v2_retval;
 
 #define ARCH_PLTENTER_MEMBERS						\
     Elf32_Addr (*ppc32_gnu_pltenter) (Elf32_Sym *, unsigned int, uintptr_t *, \
@@ -34,7 +36,12 @@ struct La_ppc64_retval;
     Elf64_Addr (*ppc64_gnu_pltenter) (Elf64_Sym *, unsigned int, uintptr_t *, \
 				      uintptr_t *, struct La_ppc64_regs *, \
 				      unsigned int *, const char *name,	\
-				      long int *framesizep)
+				      long int *framesizep);		\
+    Elf64_Addr (*ppc64v2_gnu_pltenter) (Elf64_Sym *, unsigned int,	\
+					uintptr_t *,  uintptr_t *,	\
+					struct La_ppc64v2_regs *,	\
+					unsigned int *, const char *name, \
+					long int *framesizep)
 
 #define ARCH_PLTEXIT_MEMBERS						\
     unsigned int (*ppc32_gnu_pltexit) (Elf32_Sym *, unsigned int,	\
@@ -47,7 +54,14 @@ struct La_ppc64_retval;
 				       uintptr_t *,			\
 				       uintptr_t *,			\
 				       const struct La_ppc64_regs *,	\
-				       struct La_ppc64_retval *, const char *)
+				       struct La_ppc64_retval *,	\
+				       const char *);			\
+    unsigned int (*ppc64v2_gnu_pltexit) (Elf64_Sym *, unsigned int,	\
+					 uintptr_t *,			\
+					 uintptr_t *,			\
+					 const struct La_ppc64v2_regs *,\
+					 struct La_ppc64v2_retval *,	\
+					 const char *)
 
 #include_next <ldsodefs.h>
 
diff --git a/sysdeps/powerpc/powerpc64/dl-machine.h b/sysdeps/powerpc/powerpc64/dl-machine.h
index eccfbb3..36f3916 100644
--- a/sysdeps/powerpc/powerpc64/dl-machine.h
+++ b/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -545,8 +545,13 @@ elf_machine_plt_value (struct link_map *map, const Elf64_Rela *reloc,
 
 
 /* Names of the architecture-specific auditing callback functions.  */
+#if _CALL_ELF != 2
 #define ARCH_LA_PLTENTER ppc64_gnu_pltenter
 #define ARCH_LA_PLTEXIT ppc64_gnu_pltexit
+#else
+#define ARCH_LA_PLTENTER ppc64v2_gnu_pltenter
+#define ARCH_LA_PLTEXIT ppc64v2_gnu_pltexit
+#endif
 
 #endif /* dl_machine_h */
 
diff --git a/sysdeps/powerpc/powerpc64/dl-trampoline.S b/sysdeps/powerpc/powerpc64/dl-trampoline.S
index 18c8a3a..69ce523 100644
--- a/sysdeps/powerpc/powerpc64/dl-trampoline.S
+++ b/sysdeps/powerpc/powerpc64/dl-trampoline.S
@@ -50,11 +50,8 @@ EALIGN(_dl_runtime_resolve, 4, 0)
 /* Store the LR in the LR Save area.  */
 	std	r0,FRAME_SIZE+FRAME_LR_SAVE(r1)
 	cfi_offset (lr, FRAME_LR_SAVE)
-	mfcr	r0
 	std	r9,INT_PARMS+48(r1)
 	std	r10,INT_PARMS+56(r1)
-/* I'm almost certain we don't have to save cr...  be safe.  */
-	std	r0,FRAME_SIZE+FRAME_CR_SAVE(r1)
 	bl	JUMPTARGET(_dl_fixup)
 #ifndef SHARED
 	nop
@@ -66,11 +63,9 @@ EALIGN(_dl_runtime_resolve, 4, 0)
 	ld	r8,INT_PARMS+40(r1)
 	ld	r7,INT_PARMS+32(r1)
 	mtlr	r0
-	ld	r0,FRAME_SIZE+FRAME_CR_SAVE(r1)
 	ld	r6,INT_PARMS+24(r1)
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
-	mtcrf	0xFF,r0
 /* Prepare for calling the function returned by fixup.  */
 	PPC64_LOAD_FUNCPTR r3
 	ld	r3,INT_PARMS+0(r1)
@@ -85,18 +80,30 @@ END(_dl_runtime_resolve)
 #undef FRAME_SIZE
 #undef INT_PARMS
 
-	/* Stack layout:
-	   (Note: some of these are not required for the ELFv2 ABI.)
-	  +592   previous backchain
-	  +584   spill_r31
-	  +576   spill_r30
-	  +560   v1
-	  +552   fp4
-	  +544   fp3
-	  +536   fp2
-	  +528   fp1
-	  +520   r4
-	  +512   r3
+	/* Stack layout:		ELFv2 ABI.
+					+752   previous backchain
+					+744   spill_r31
+					+736   spill_r30
+					+720   v8
+					+704   v7
+					+688   v6
+					+672   v5
+					+656   v4
+					+640   v3
+					+624   v2
+					+608   v1
+					+600   fp10
+	  ELFv1 ABI			+592   fp9
+	  +592   previous backchain	+584   fp8
+	  +584   spill_r31		+576   fp7
+	  +576   spill_r30		+568   fp6
+	  +560   v1			+560   fp5
+	  +552   fp4			+552   fp4
+	  +544   fp3			+544   fp3
+	  +536   fp2			+536   fp2
+	  +528   fp1			+528   fp1
+	  +520   r4			+520   r4
+	  +512   r3			+512   r3
 	   return values
           +504   free
 	  +496   stackframe
@@ -157,10 +164,15 @@ END(_dl_runtime_resolve)
 	  +8     CR save area
 	r1+0     stack back chain
 	*/
-#define FRAME_SIZE 592
+#if _CALL_ELF == 2
+# define FRAME_SIZE 752
+# define VR_RTN 608
+#else
+# define FRAME_SIZE 592
+# define VR_RTN 560
+#endif
 #define INT_RTN 512
 #define FPR_RTN 528
-#define VR_RTN 560
 #define STACK_FRAME 496
 #define CALLING_LR 488
 #define CALLING_SP 480
@@ -205,18 +217,14 @@ EALIGN(_dl_profile_resolve, 4, 0)
 	mflr	r5
 	std	r7,INT_PARMS+32(r1)
 	std	r8,INT_PARMS+40(r1)
-/* Store the LR in the LR Save area of the previous frame.  */
-/* XXX Do we have to do this?  */
+/* Store the LR in the LR Save area.  */
 	la	r8,FRAME_SIZE(r1)
 	std	r5,FRAME_SIZE+FRAME_LR_SAVE(r1)
 	cfi_offset (lr, FRAME_LR_SAVE)
 	std	r5,CALLING_LR(r1)
-	mfcr	r0
 	std	r9,INT_PARMS+48(r1)
 	std	r10,INT_PARMS+56(r1)
 	std	r8,CALLING_SP(r1)
-/* I'm almost certain we don't have to save cr...  be safe.  */
-	std	r0,FRAME_SIZE+FRAME_CR_SAVE(r1)
 	ld	r12,.LC__dl_hwcap@toc(r2)
 #ifdef SHARED
 	/* Load _rtld_local_ro._dl_hwcap.  */
@@ -319,11 +327,9 @@ L(restoreFXR):
 	ld	r8,INT_PARMS+40(r1)
 	ld	r7,INT_PARMS+32(r1)
 	mtlr	r0
-	ld	r0,FRAME_SIZE+FRAME_CR_SAVE(r1)
 	ld	r6,INT_PARMS+24(r1)
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
-	mtcrf	0xFF,r0
 /* Prepare for calling the function returned by fixup.  */
 	PPC64_LOAD_FUNCPTR r3
 	ld	r3,INT_PARMS+0(r1)
@@ -346,10 +352,11 @@ L(restoreFXR):
 	lfd	fp12,FPR_PARMS+88(r1)
 	lfd	fp13,FPR_PARMS+96(r1)
 /* Unwind the stack frame, and jump.  */
-	ld	r31,584(r1)
-	ld	r30,576(r1)
+	ld	r31,FRAME_SIZE-8(r1)
+	ld	r30,FRAME_SIZE-16(r1)
 	addi	r1,r1,FRAME_SIZE
 	bctr
+
 L(do_pltexit):
 	la	r10,(VR_PARMS+0)(r1)
 	la	r9,(VR_PARMS+16)(r1)
@@ -383,11 +390,9 @@ L(restoreFXR2):
 	ld	r8,INT_PARMS+40(r1)
 	ld	r7,INT_PARMS+32(r1)
 	mtlr	r0
-	ld	r0,FRAME_SIZE+FRAME_CR_SAVE(r1)
 	ld	r6,INT_PARMS+24(r1)
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
-	mtcrf	0xFF,r0
 /* Prepare for calling the function returned by fixup.  */
 	std	r2,FRAME_TOC_SAVE(r1)
 	PPC64_LOAD_FUNCPTR r3
@@ -413,16 +418,37 @@ L(restoreFXR2):
 /* But return here and store the return values.  */
 	std	r3,INT_RTN(r1)
 	std	r4,INT_RTN+8(r1)
-	stfd	fp1,FPR_PARMS+0(r1)
-	stfd	fp2,FPR_PARMS+8(r1)
+	stfd	fp1,FPR_RTN+0(r1)
+	stfd	fp2,FPR_RTN+8(r1)
 	cmpdi	cr0,r12,0
 	la	r10,VR_RTN(r1)
-	stfd	fp3,FPR_PARMS+16(r1)
-	stfd	fp4,FPR_PARMS+24(r1)
+	stfd	fp3,FPR_RTN+16(r1)
+	stfd	fp4,FPR_RTN+24(r1)
+#if _CALL_ELF == 2
+	la	r12,VR_RTN+16(r1)
+	stfd	fp5,FPR_RTN+32(r1)
+	stfd	fp6,FPR_RTN+40(r1)
+	li	r5,32
+	li	r6,64
+	stfd	fp7,FPR_RTN+48(r1)
+	stfd	fp8,FPR_RTN+56(r1)
+	stfd	fp9,FPR_RTN+64(r1)
+	stfd	fp10,FPR_RTN+72(r1)
+#endif
 	mr	r3,r31
 	mr	r4,r30
 	beq	L(callpltexit)
 	stvx	v2,0,r10
+#if _CALL_ELF == 2
+	stvx	v3,0,r12
+	stvx	v4,r5,r10
+	stvx	v5,r5,r12
+	addi	r5,r5,64
+	stvx	v6,r6,r10
+	stvx	v7,r6,r12
+	stvx	v8,r5,r10
+	stvx	v9,r5,r12
+#endif
 L(callpltexit):
 	addi	r5,r1,INT_PARMS
 	addi	r6,r1,INT_RTN
@@ -434,18 +460,39 @@ L(callpltexit):
 	lwz	r12,VR_VRSAVE(r1)
 	ld	r3,INT_RTN(r1)
 	ld	r4,INT_RTN+8(r1)
-	lfd	fp1,FPR_PARMS+0(r1)
-	lfd	fp2,FPR_PARMS+8(r1)
+	lfd	fp1,FPR_RTN+0(r1)
+	lfd	fp2,FPR_RTN+8(r1)
 	cmpdi	cr0,r12,0
-	la	r10,VR_RTN(r1)
-	lfd	fp3,FPR_PARMS+16(r1)
-	lfd	fp4,FPR_PARMS+24(r1)
+	la	r11,VR_RTN(r1)
+	lfd	fp3,FPR_RTN+16(r1)
+	lfd	fp4,FPR_RTN+24(r1)
+#if _CALL_ELF == 2
+	la	r12,VR_RTN+16(r1)
+	lfd	fp5,FPR_RTN+32(r1)
+	lfd	fp6,FPR_RTN+40(r1)
+	li	r30,32
+	li	r31,64
+	lfd	fp7,FPR_RTN+48(r1)
+	lfd	fp8,FPR_RTN+56(r1)
+	lfd	fp9,FPR_RTN+64(r1)
+	lfd	fp10,FPR_RTN+72(r1)
+#endif
 	beq	L(pltexitreturn)
-	lvx	v2,0,r10
+	lvx	v2,0,r11
+#if _CALL_ELF == 2
+	lvx	v3,0,r12
+	lvx	v4,r30,r11
+	lvx	v5,r30,r12
+	addi	r30,r30,64
+	lvx	v6,r31,r11
+	lvx	v7,r31,r12
+	lvx	v8,r30,r11
+	lvx	v9,r30,r12
+#endif
 L(pltexitreturn):
 	ld	r0,FRAME_SIZE+FRAME_LR_SAVE(r1)
-	ld	r31,584(r1)
-	ld	r30,576(r1)
+	ld	r31,FRAME_SIZE-8(r1)
+	ld	r30,FRAME_SIZE-16(r1)
 	mtlr	r0
 	ld	r1,0(r1)
 	blr
diff --git a/sysdeps/powerpc/powerpc64/tst-audit.h b/sysdeps/powerpc/powerpc64/tst-audit.h
index ad6545e..0fbe1fe 100644
--- a/sysdeps/powerpc/powerpc64/tst-audit.h
+++ b/sysdeps/powerpc/powerpc64/tst-audit.h
@@ -18,8 +18,16 @@
    License along with the GNU C Library.  If not, see
    <http://www.gnu.org/licenses/>.  */
 
+#if _CALL_ELF != 2
 #define pltenter la_ppc64_gnu_pltenter
 #define pltexit la_ppc64_gnu_pltexit
 #define La_regs La_ppc64_regs
 #define La_retval La_ppc64_retval
 #define int_retval lrv_r3
+#else
+#define pltenter la_ppc64v2_gnu_pltenter
+#define pltexit la_ppc64v2_gnu_pltexit
+#define La_regs La_ppc64v2_regs
+#define La_retval La_ppc64v2_retval
+#define int_retval lrv_r3
+#endif