PowerPC64 ELFv2 ABI 4/6: Stack frame layout changes

This updates glibc for the changes in the ELFv2 relating to the
stack frame layout.  These are described in more detail here:
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01149.html
http://gcc.gnu.org/ml/gcc-patches/2013-11/msg01146.html

Specifically, the "compiler and linker doublewords" were removed,
which has the effect that the save slot for the TOC register is
now at offset 24 rather than 40 to the stack pointer.

In addition, a function may now no longer necessarily assume that
its caller has set up a 64-byte register save area its use.

To address the first change, the patch goes through all assembler
files and replaces immediate offsets in instructions accessing the
ABI-defined stack slots by symbolic offsets.  Those already were
defined in ucontext_i.sym and used in some of the context routines,
but that doesn't really seem like the right place for those defines.

The patch instead defines those symbolic offsets in sysdeps.h,
in two variants for the old and new ABI, and uses them systematically
in all assembler files, not just the context routines.

The second change only affected a few assembler files that used
the save area to temporarily store some registers.  In those
cases where this happens within a leaf function, this patch
changes the code to store those registers to the "red zone"
below the stack pointer.  Otherwise, the functions already allocate
a stack frame, and the patch changes them to add extra space in
these frames as temporary space for the ELFv2 ABI.

5 files changed, 43 insertions, 59 deletions

diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/____longjmp_chk.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/____longjmp_chk.S
index 270e21e..ae576d6 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/____longjmp_chk.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/____longjmp_chk.S
@@ -33,24 +33,24 @@
 	cmpld	reg, r1;				\
 	bge+	.Lok;					\
 	mflr	r0;					\
-	std	r0,16(r1);				\
+	std	r0,FRAME_LR_SAVE(r1);			\
 	mr	r31,r3;					\
 	mr	r30,r4;					\
-	stdu	r1,-144(r1);				\
+	stdu	r1,-FRAME_MIN_SIZE-32(r1);		\
 	cfi_remember_state;				\
-	cfi_adjust_cfa_offset (144);			\
-	cfi_offset (lr, 16);				\
+	cfi_adjust_cfa_offset (FRAME_MIN_SIZE+32);	\
+	cfi_offset (lr, FRAME_LR_SAVE);			\
 	li	r3,0;					\
-	addi	r4,r1,112;				\
+	addi	r4,r1,FRAME_MIN_SIZE;			\
 	li	r0,__NR_sigaltstack;			\
 	sc;						\
 	/* Without working sigaltstack we cannot perform the test.  */ \
 	bso	.Lok2;					\
-	lwz	r0,112+8(r1);				\
+	lwz	r0,FRAME_MIN_SIZE+8(r1);		\
 	andi.	r4,r0,1;				\
 	beq	.Lfail;					\
-	ld	r0,112+16(r1);				\
-	ld	r4,112(r1);				\
+	ld	r0,FRAME_MIN_SIZE+16(r1);		\
+	ld	r4,FRAME_MIN_SIZE(r1);			\
 	add	r4,r4,r0;				\
 	sub	r3,r3,reg;				\
 	cmpld	r3,r0;					\
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/brk.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/brk.S
index 348aeb5..33cdf25 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/brk.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/brk.S
@@ -28,9 +28,9 @@
 ENTRY (__brk)
 	CALL_MCOUNT 1
 
-	std	r3,48(r1)
+	std	r3,-8(r1)
 	DO_CALL(SYS_ify(brk))
-	ld	r6,48(r1)
+	ld	r6,-8(r1)
 	ld	r5,.LC__curbrk@toc(r2)
 	std     r3,0(r5)
 	cmpld   r6,r3
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
index 4151d15..37d9d24 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
@@ -40,22 +40,22 @@ ENTRY (__clone)
 	cror	cr0*4+eq,cr1*4+eq,cr0*4+eq
 	beq-	cr0,L(badargs)
 
-	/* Save some regs in parm save area.  */
+	/* Save some regs in the "red zone".  */
 #ifdef RESET_PID
-	std	r29,48(r1)
+	std	r29,-24(r1)
 #endif
-	std	r30,56(r1)
-	std	r31,64(r1)
+	std	r30,-16(r1)
+	std	r31,-8(r1)
 #ifdef RESET_PID
-	cfi_offset(r29,48)
+	cfi_offset(r29,-24)
 #endif
-	cfi_offset(r30,56)
-	cfi_offset(r31,64)
+	cfi_offset(r30,-16)
+	cfi_offset(r31,-8)
 
 	/* Set up stack frame for child.  */
 	clrrdi	r4,r4,4
 	li	r0,0
-	stdu	r0,-112(r4) /* min stack frame is 112 bytes per ABI */
+	stdu	r0,-FRAME_MIN_SIZE_PARM(r4)
 
 	/* Save fn, args, stack across syscall.  */
 	mr	r30,r3			/* Function in r30.  */
@@ -97,12 +97,12 @@ L(nomoregetpid):
 L(oldpid):
 #endif
 
-	std	r2,40(r1)
+	std	r2,FRAME_TOC_SAVE(r1)
 	/* Call procedure.  */
 	PPC64_LOAD_FUNCPTR r30
 	mr	r3,r31
 	bctrl
-	ld	r2,40(r1)
+	ld	r2,FRAME_TOC_SAVE(r1)
 	/* Call _exit with result from procedure.  */
 #ifdef SHARED
 	b	JUMPTARGET(__GI__exit)
@@ -121,15 +121,15 @@ L(badargs):
 L(parent):
 	/* Parent.  Restore registers & return.  */
 #ifdef RESET_PID
-	cfi_offset(r29,48)
+	cfi_offset(r29,-24)
 #endif
-	cfi_offset(r30,56)
-	cfi_offset(r31,64)
+	cfi_offset(r30,-16)
+	cfi_offset(r31,-8)
 #ifdef RESET_PID
-	ld	r29,48(r1)
+	ld	r29,-24(r1)
 #endif
-	ld	r30,56(r1)
-	ld	r31,64(r1)
+	ld	r30,-16(r1)
+	ld	r31,-8(r1)
 #ifdef RESET_PID
 	cfi_restore(r29)
 #endif
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
index 018e55c..aba2d80 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/socket.S
@@ -46,8 +46,13 @@
 # endif
 #endif
 
-#define FRAMESIZE 128
-#define stackblock FRAMESIZE+48 /* offset to parm save area.  */
+#if _CALL_ELF == 2
+#define FRAMESIZE (FRAME_MIN_SIZE+16+64)
+#define stackblock (FRAME_MIN_SIZE+16)
+#else
+#define FRAMESIZE (FRAME_MIN_SIZE+16)
+#define stackblock (FRAMESIZE+FRAME_PARM_SAVE) /* offset to parm save area.  */
+#endif
 
 	.text
 ENTRY(__socket)
@@ -98,22 +103,22 @@ ENTRY(__socket)
 .Lsocket_cancel:
 	cfi_adjust_cfa_offset(FRAMESIZE)
 	mflr	r9
-	std	r9,FRAMESIZE+16(r1)
-	cfi_offset (lr, 16)
+	std	r9,FRAMESIZE+FRAME_LR_SAVE(r1)
+	cfi_offset (lr, FRAME_LR_SAVE)
 	CENABLE
-	std	r3,120(r1)
+	std	r3,FRAME_MIN_SIZE+8(r1)
 	li	r3,P(SOCKOP_,socket)
 	addi	r4,r1,stackblock
 	DO_CALL(SYS_ify(socketcall))
 	mfcr	r0
-	std	r3,112(r1)
-	std	r0,FRAMESIZE+8(r1)
-	cfi_offset (cr, 8)
-	ld  	r3,120(r1)
+	std	r3,FRAME_MIN_SIZE(r1)
+	std	r0,FRAMESIZE+FRAME_CR_SAVE(r1)
+	cfi_offset (cr, FRAME_CR_SAVE)
+	ld  	r3,FRAME_MIN_SIZE+8(r1)
 	CDISABLE
-	ld	r4,FRAMESIZE+16(r1)
-	ld	r0,FRAMESIZE+8(r1)
-	ld	r3,112(r1)
+	ld	r4,FRAMESIZE+FRAME_LR_SAVE(r1)
+	ld	r0,FRAMESIZE+FRAME_CR_SAVE(r1)
+	ld	r3,FRAME_MIN_SIZE(r1)
 	mtlr	r4
 	mtcr	r0
 	addi	r1,r1,FRAMESIZE
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym
index a35418d..8364e46 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/ucontext_i.sym
@@ -8,27 +8,6 @@ SIG_BLOCK
 SIG_SETMASK
 
 
--- Offsets of the fields in the powerpc64 ABI stack frame.
--- XXX Do these correspond to some struct?
-
-FRAME_BACKCHAIN		0
-FRAME_CR_SAVE		8
-FRAME_LR_SAVE		16
-FRAME_COMPILER_DW	24
-FRAME_LINKER_DW		32
-FRAME_TOC_SAVE		40
-FRAME_PARM_SAVE		48
-FRAME_PARM1_SAVE	48
-FRAME_PARM2_SAVE	56
-FRAME_PARM3_SAVE	64
-FRAME_PARM4_SAVE	72
-FRAME_PARM5_SAVE	80
-FRAME_PARM6_SAVE	88
-FRAME_PARM7_SAVE	96
-FRAME_PARM8_SAVE	104
-FRAME_PARM9_SAVE	112
-
-
 -- Offsets of the fields in the ucontext_t structure.
 #define ucontext(member)	offsetof (ucontext_t, member)
 #define mcontext(member)	ucontext (uc_mcontext.member)