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[PATCH] PowerPC64 ELFv2 ABI 1/6: Code refactoring

From: "Ulrich Weigand" <uweigand at de dot ibm dot com>
To: libc-alpha at sourceware dot org
Date: Tue, 12 Nov 2013 22:21:16 +0100 (CET)
Subject: [PATCH] PowerPC64 ELFv2 ABI 1/6: Code refactoring
Authentication-results: sourceware.org; auth=none
Hello,

this is the first patch to support the new ELFv2 ABI in glibc.

As preparation, this patch simply refactors some of the powerpc64 assembler
code to move all code related to creating function descriptors (.opd section)
or using function descriptors (function pointer call) into a central place
in sysdep.h.

Note that most locations creating .opd entries were already using macros
in sysdep.h, this patch simply extends this to the remaining places.

No relevant change in generated code expected.

Tested on powerpc64-linux and powerpc64le-linux.

OK for mainline?

Bye,
Ulrich


ChangeLog:

2013-11-12  Ulrich Weigand  <Ulrich.Weigand@de.ibm.com>

	* sysdeps/powerpc/powerpc64/sysdep.h [ASSEMBLER] (PPC64_LOAD_FUNCPTR):
	New assembler macro.
	[ASSEMBLER] (ENTRY_1): Do not switch to .text section here ...
	[ASSEMBLER] (ENTRY): ... but instead here ...
	[ASSEMBLER] (EALIGN): ... and here.
	[!ASSEMBLER] (PPC64_LOAD_FUNCPTR): New macro.
	[!ASSEMBLER] (ENTRY_1): New macro; set up .opd entry.
	[!ASSEMBLER] (ENTRY_2): Use it.
	* sysdeps/powerpc/powerpc64/dl-machine.h (RTLD_START): Update for
	ENTRY_2 changes.  Use PPC64_LOAD_FUNCPTR.
	* sysdeps/powerpc/powerpc64/dl-trampoline.S (_dl_runtime_resolve,
	_dl_profile_resolve): Use PPC64_LOAD_FUNCPTR.
	* sysdeps/powerpc/powerpc64/crti.S (_init, _fini): Use ENTRY_2.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S (clone):
	Use PPC64_LOAD_FUNCPTR.

Index: glibc/sysdeps/powerpc/powerpc64/sysdep.h
===================================================================
--- glibc.orig/sysdeps/powerpc/powerpc64/sysdep.h
+++ glibc/sysdeps/powerpc/powerpc64/sysdep.h
@@ -74,6 +74,14 @@
 #endif
 	.endm
 
+/* Macro to prepare for calling via a function pointer.  */
+	.macro PPC64_LOAD_FUNCPTR PTR
+	ld      r12,0(\PTR)
+	ld      r2,8(\PTR)
+	mtctr   r12
+	ld      r11,16(\PTR)
+	.endm
+
 #ifdef USE_PPC64_OVERLAPPING_OPD
 # define OPD_ENT(name)	.quad BODY_LABEL (name), .TOC.@tocbase
 #else
@@ -81,7 +89,6 @@
 #endif
 
 #define ENTRY_1(name)	\
-	.section	".text";		\
 	.type BODY_LABEL(name),@function;	\
 	.globl name;				\
 	.section ".opd","aw";			\
@@ -110,6 +117,7 @@ name##: OPD_ENT (name);				\
 #endif
 
 #define ENTRY(name)	\
+	.section	".text";		\
 	ENTRY_2(name)				\
 	.align ALIGNARG(2);			\
 BODY_LABEL(name):				\
@@ -127,6 +135,7 @@ BODY_LABEL(name):				\
 /* EALIGN is like ENTRY, but does alignment to 'words'*4 bytes
    past a 2^alignt boundary.  */
 #define EALIGN(name, alignt, words) \
+	.section	".text";		\
 	ENTRY_2(name)				\
 	.align ALIGNARG(alignt);		\
 	EALIGN_W_##words;			\
@@ -286,24 +295,42 @@ LT_LABELSUFFIX(name,_name_end): ; \
 
 #else /* !__ASSEMBLER__ */
 
+#define PPC64_LOAD_FUNCPTR(ptr) \
+	"ld 	12,0(" #ptr ");\n"					\
+	"ld	2,8(" #ptr ");\n"					\
+	"mtctr	12;\n"							\
+	"ld	11,16(" #ptr ");"
+
 #ifdef USE_PPC64_OVERLAPPING_OPD
 # define OPD_ENT(name)	".quad " BODY_PREFIX #name ", .TOC.@tocbase;"
 #else
 # define OPD_ENT(name)	".quad " BODY_PREFIX #name ", .TOC.@tocbase, 0;"
 #endif
 
+#define ENTRY_1(name)	\
+	".type   " BODY_PREFIX #name ",@function;\n"			\
+	".globl " #name ";\n"						\
+	".pushsection \".opd\",\"aw\";\n"				\
+	".align  3;\n"							\
+#name ":\n"								\
+	OPD_ENT (name) "\n"						\
+	".popsection;"
+
 #ifdef HAVE_ASM_GLOBAL_DOT_NAME
 # define DOT_PREFIX "."
 # define BODY_PREFIX "."
 # define ENTRY_2(name)	\
 	".globl " BODY_PREFIX #name ";\n"				\
+	ENTRY_1(name) "\n"						\
 	".size  " #name ", 24;"
 # define END_2(name)	\
 	".size " BODY_PREFIX #name ",.-" BODY_PREFIX #name ";"
 #else
 # define DOT_PREFIX ""
 # define BODY_PREFIX ".LY"
-# define ENTRY_2(name) ".type " #name ",@function;"
+# define ENTRY_2(name)	\
+	".type " #name ",@function;\n"					\
+	ENTRY_1(name)
 # define END_2(name)	\
 	".size " #name ",.-" BODY_PREFIX #name ";\n"			\
 	".size " BODY_PREFIX #name ",.-" BODY_PREFIX #name ";"
Index: glibc/sysdeps/powerpc/powerpc64/dl-machine.h
===================================================================
--- glibc.orig/sysdeps/powerpc/powerpc64/dl-machine.h
+++ glibc/sysdeps/powerpc/powerpc64/dl-machine.h
@@ -122,14 +122,7 @@ elf_machine_dynamic (void)
 #define RTLD_START \
   asm (".pushsection \".text\"\n"					\
 "	.align	2\n"							\
-"	.type	" BODY_PREFIX "_start,@function\n"			\
-"	.pushsection \".opd\",\"aw\"\n"					\
-"	.align	3\n"							\
-"	.globl	_start\n"						\
 "	" ENTRY_2(_start) "\n"						\
-"_start:\n"								\
-"	" OPD_ENT(_start) "\n"						\
-"	.popsection\n"							\
 BODY_PREFIX "_start:\n"							\
 /* We start with the following on the stack, from top:			\
    argc (4 bytes);							\
@@ -154,11 +147,6 @@ BODY_PREFIX "_start:\n"							\
 ".LT__start_name_end:\n"						\
 "	.align 2\n"							\
 "	" END_2(_start) "\n"						\
-"	.globl	_dl_start_user\n"					\
-"	.pushsection \".opd\",\"aw\"\n"					\
-"_dl_start_user:\n"							\
-"	" OPD_ENT(_dl_start_user) "\n"					\
-"	.popsection\n"							\
 "	.pushsection	\".toc\",\"aw\"\n"				\
 DL_STARTING_UP_DEF							\
 ".LC__rtld_local:\n"							\
@@ -170,7 +158,6 @@ DL_STARTING_UP_DEF							\
 ".LC__dl_fini:\n"							\
 "	.tc _dl_fini[TC],_dl_fini\n"					\
 "	.popsection\n"							\
-"	.type	" BODY_PREFIX "_dl_start_user,@function\n"		\
 "	" ENTRY_2(_dl_start_user) "\n"					\
 /* Now, we do our main work of calling initialisation procedures.	\
    The ELF ABI doesn't say anything about parameters for these,		\
@@ -228,10 +215,7 @@ BODY_PREFIX "_dl_start_user:\n"						\
 /* Now, call the start function descriptor at r30...  */		\
 "	.globl	._dl_main_dispatch\n"					\
 "._dl_main_dispatch:\n"							\
-"	ld	0,0(30)\n"						\
-"	ld	2,8(30)\n"						\
-"	mtctr	0\n"							\
-"	ld	11,16(30)\n"						\
+"	" PPC64_LOAD_FUNCPTR(30) "\n"					\
 "	bctr\n"								\
 ".LT__dl_start_user:\n"							\
 "	.long 0\n"							\
Index: glibc/sysdeps/powerpc/powerpc64/dl-trampoline.S
===================================================================
--- glibc.orig/sysdeps/powerpc/powerpc64/dl-trampoline.S
+++ glibc/sysdeps/powerpc/powerpc64/dl-trampoline.S
@@ -71,12 +71,8 @@ EALIGN(_dl_runtime_resolve, 4, 0)
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
 	mtcrf	0xFF,r0
-/* Load the target address, toc and static chain reg from the function
-   descriptor returned by fixup.  */
-	ld	r0,0(r3)
-	ld	r2,8(r3)
-	mtctr	r0
-	ld	r11,16(r3)
+/* Prepare for calling the function returned by fixup.  */
+	PPC64_LOAD_FUNCPTR r3
 	ld	r3,INT_PARMS+0(r1)
 /* Unwind the stack frame, and jump.  */
 	addi	r1,r1,FRAME_SIZE
@@ -322,13 +318,9 @@ L(restoreFXR):
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
 	mtcrf	0xFF,r0
-/* Load the target address, toc and static chain reg from the function
-   descriptor returned by fixup.  */
-	ld	r0,0(r3)
-	ld	r2,8(r3)
-	ld	r11,16(r3)
+/* Prepare for calling the function returned by fixup.  */
+	PPC64_LOAD_FUNCPTR r3
 	ld	r3,INT_PARMS+0(r1)
-	mtctr	r0
 /* Load the floating point registers.  */
 	lfd	fp1,FPR_PARMS+0(r1)
 	lfd	fp2,FPR_PARMS+8(r1)
@@ -386,14 +378,10 @@ L(restoreFXR2):
 	ld	r5,INT_PARMS+16(r1)
 	ld	r4,INT_PARMS+8(r1)
 	mtcrf	0xFF,r0
-/* Load the target address, toc and static chain reg from the function
-   descriptor returned by fixup.  */
-	ld	r0,0(r3)
+/* Prepare for calling the function returned by fixup.  */
 	std	r2,40(r1)
-	ld	r2,8(r3)
-	ld	r11,16(r3)
+	PPC64_LOAD_FUNCPTR r3
 	ld	r3,INT_PARMS+0(r1)
-	mtctr	r0
 /* Load the floating point registers.  */
 	lfd	fp1,FPR_PARMS+0(r1)
 	lfd	fp2,FPR_PARMS+8(r1)
Index: glibc/sysdeps/powerpc/powerpc64/crti.S
===================================================================
--- glibc.orig/sysdeps/powerpc/powerpc64/crti.S
+++ glibc/sysdeps/powerpc/powerpc64/crti.S
@@ -60,18 +60,8 @@
 .LC0:
 	.tc PREINIT_FUNCTION[TC], PREINIT_FUNCTION
 #endif
-	.type BODY_LABEL (_init), @function
-	.globl _init
-	.section ".opd", "aw"
-	.align 3
-_init:	OPD_ENT (_init)
-#ifdef HAVE_ASM_GLOBAL_DOT_NAME
-	.globl BODY_LABEL (_init)
-	.size _init, 24
-#else
-	.type _init, @function
-#endif
 	.section ".init", "ax", @progbits
+	ENTRY_2(_init)
 	.align ALIGNARG (2)
 BODY_LABEL (_init):
 	mflr 0
@@ -87,18 +77,8 @@ BODY_LABEL (_init):
 	nop
 1:
 
-	.type BODY_LABEL (_fini), @function
-	.globl _fini
-	.section ".opd", "aw"
-	.align 3
-_fini:	OPD_ENT (_fini)
-#ifdef HAVE_ASM_GLOBAL_DOT_NAME
-	.globl BODY_LABEL (_fini)
-	.size _fini, 24
-#else
-	.type _fini, @function
-#endif
 	.section ".fini", "ax", @progbits
+	ENTRY_2(_fini)
 	.align ALIGNARG (2)
 BODY_LABEL (_fini):
 	mflr 0
Index: glibc/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
===================================================================
--- glibc.orig/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
+++ glibc/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
@@ -99,9 +99,7 @@ L(oldpid):
 
 	std	r2,40(r1)
 	/* Call procedure.  */
-	ld	r0,0(r30)
-	ld	r2,8(r30)
-	mtctr	r0
+	PPC64_LOAD_FUNCPTR r30
 	mr	r3,r31
 	bctrl
 	ld	r2,40(r1)
-- 
  Dr. Ulrich Weigand
  GNU/Linux compilers and toolchain
  Ulrich.Weigand@de.ibm.com
Follow-Ups:
- Re: [PATCH] PowerPC64 ELFv2 ABI 1/6: Code refactoring
  - From: Adhemerval Zanella
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