[U-Boot-Users] [PATCH] PPC: Use r2 instead of r29 as global data pointer

Wolfgang Denk wd at denx.de
Thu Feb 14 23:14:42 CET 2008 

R29 was an unlucky choice as with recent toolchains (gcc-4.2.x) gcc
will refuse to use load/store multiple insns; instead, it issues a
list of simple load/store instructions upon function entry and exit,
resulting in bigger code size, which in turn makes the build for a
few boards fail.

Use r2 instead.

Signed-off-by: Wolfgang Denk <wd at denx.de>
---
 README                        |    4 ++--
 cpu/74xx_7xx/config.mk        |    2 +-
 cpu/mpc512x/config.mk         |    2 +-
 cpu/mpc5xx/config.mk          |    2 +-
 cpu/mpc5xxx/config.mk         |    2 +-
 cpu/mpc8220/config.mk         |    2 +-
 cpu/mpc824x/config.mk         |    2 +-
 cpu/mpc8260/config.mk         |    2 +-
 cpu/mpc83xx/config.mk         |    2 +-
 cpu/mpc85xx/config.mk         |    3 ++-
 cpu/mpc86xx/config.mk         |    2 +-
 cpu/mpc86xx/start.S           |    2 +-
 cpu/mpc8xx/config.mk          |    2 +-
 cpu/ppc4xx/config.mk          |    2 +-
 doc/README.standalone         |    2 +-
 examples/stubs.c              |    4 ++--
 examples/test_burst_lib.S     |    2 +-
 examples/x86-testapp.c        |    6 +++---
 include/asm-ppc/global_data.h |    2 +-
 19 files changed, 24 insertions(+), 23 deletions(-)

diff --git a/README b/README
index a5ffbb5..b4966a0 100644
--- a/README
+++ b/README
@@ -3499,7 +3499,7 @@ GCC's implementation.
 
 For PowerPC, the following registers have specific use:
 	R1:	stack pointer
-	R2:	TOC pointer
+	R2:	reserved for system use
 	R3-R4:	parameter passing and return values
 	R5-R10: parameter passing
 	R13:	small data area pointer
@@ -3508,7 +3508,7 @@ For PowerPC, the following registers have specific use:
 
 	(U-Boot also uses R14 as internal GOT pointer.)
 
-    ==> U-Boot will use R29 to hold a pointer to the global data
+    ==> U-Boot will use R2 to hold a pointer to the global data
 
     Note: on PPC, we could use a static initializer (since the
     address of the global data structure is known at compile time),
diff --git a/cpu/74xx_7xx/config.mk b/cpu/74xx_7xx/config.mk
index 417d99f..324f62b 100644
--- a/cpu/74xx_7xx/config.mk
+++ b/cpu/74xx_7xx/config.mk
@@ -23,4 +23,4 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
 
-PLATFORM_CPPFLAGS += -DCONFIG_74xx_7xx -ffixed-r2 -ffixed-r29 -mstring
+PLATFORM_CPPFLAGS += -DCONFIG_74xx_7xx -ffixed-r2 -mstring
diff --git a/cpu/mpc512x/config.mk b/cpu/mpc512x/config.mk
index 8a07c5a..5b7e1f2 100644
--- a/cpu/mpc512x/config.mk
+++ b/cpu/mpc512x/config.mk
@@ -22,4 +22,4 @@
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
 PLATFORM_CPPFLAGS += -DCONFIG_MPC512X -DCONFIG_E300 \
-			-ffixed-r2 -ffixed-r29 -msoft-float -mcpu=603e
+			-ffixed-r2 -msoft-float -mcpu=603e
diff --git a/cpu/mpc5xx/config.mk b/cpu/mpc5xx/config.mk
index 64cd600..6d66c32 100644
--- a/cpu/mpc5xx/config.mk
+++ b/cpu/mpc5xx/config.mk
@@ -30,7 +30,7 @@
 
 PLATFORM_RELFLAGS += 	-fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS +=	-DCONFIG_5xx -ffixed-r2 -ffixed-r29 -mpowerpc -msoft-float
+PLATFORM_CPPFLAGS +=	-DCONFIG_5xx -ffixed-r2 -mpowerpc -msoft-float
 
 # Use default linker script.  Board port can override in board/*/config.mk
 LDSCRIPT := $(SRCTREE)/cpu/mpc5xx/u-boot.lds
diff --git a/cpu/mpc5xxx/config.mk b/cpu/mpc5xxx/config.mk
index 0df51ba..b0ce2ee 100644
--- a/cpu/mpc5xxx/config.mk
+++ b/cpu/mpc5xxx/config.mk
@@ -23,7 +23,7 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS += -DCONFIG_MPC5xxx -ffixed-r2 -ffixed-r29 \
+PLATFORM_CPPFLAGS += -DCONFIG_MPC5xxx -ffixed-r2 \
 		     -mstring -mcpu=603e -mmultiple
 
 # Use default linker script.  Board port can override in board/*/config.mk
diff --git a/cpu/mpc8220/config.mk b/cpu/mpc8220/config.mk
index 8e3ba54..5819048 100644
--- a/cpu/mpc8220/config.mk
+++ b/cpu/mpc8220/config.mk
@@ -23,7 +23,7 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS += -DCONFIG_MPC8220 -ffixed-r2 -ffixed-r29 \
+PLATFORM_CPPFLAGS += -DCONFIG_MPC8220 -ffixed-r2 \
 		     -mstring -mcpu=603e -mmultiple
 
 # Use default linker script.  Board port can override in board/*/config.mk
diff --git a/cpu/mpc824x/config.mk b/cpu/mpc824x/config.mk
index 66207f4..1bb0487 100644
--- a/cpu/mpc824x/config.mk
+++ b/cpu/mpc824x/config.mk
@@ -23,7 +23,7 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
 
-PLATFORM_CPPFLAGS += -DCONFIG_MPC824X -ffixed-r2 -ffixed-r29 -mstring -mcpu=603e -msoft-float
+PLATFORM_CPPFLAGS += -DCONFIG_MPC824X -ffixed-r2 -mstring -mcpu=603e -msoft-float
 
 # Use default linker script.  Board port can override in board/*/config.mk
 LDSCRIPT := $(SRCTREE)/cpu/mpc824x/u-boot.lds
diff --git a/cpu/mpc8260/config.mk b/cpu/mpc8260/config.mk
index 683b6fb..2cb0270 100644
--- a/cpu/mpc8260/config.mk
+++ b/cpu/mpc8260/config.mk
@@ -23,7 +23,7 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS += -DCONFIG_8260 -DCONFIG_CPM2 -ffixed-r2 -ffixed-r29 \
+PLATFORM_CPPFLAGS += -DCONFIG_8260 -DCONFIG_CPM2 -ffixed-r2 \
 		     -mstring -mcpu=603e -mmultiple
 
 # Use default linker script.  Board port can override in board/*/config.mk
diff --git a/cpu/mpc83xx/config.mk b/cpu/mpc83xx/config.mk
index ecf8a60..2f0f1ce 100644
--- a/cpu/mpc83xx/config.mk
+++ b/cpu/mpc83xx/config.mk
@@ -23,7 +23,7 @@
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
 PLATFORM_CPPFLAGS += -DCONFIG_MPC83XX -DCONFIG_E300 \
-			-ffixed-r2 -ffixed-r29 -msoft-float
+			-ffixed-r2 -msoft-float
 
 # Use default linker script.  Board port can override in board/*/config.mk
 LDSCRIPT := $(SRCTREE)/cpu/mpc83xx/u-boot.lds
diff --git a/cpu/mpc85xx/config.mk b/cpu/mpc85xx/config.mk
index 6121074..f6df702 100644
--- a/cpu/mpc85xx/config.mk
+++ b/cpu/mpc85xx/config.mk
@@ -23,4 +23,5 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS += -DCONFIG_MPC85xx -DCONFIG_E500 -ffixed-r2 -ffixed-r29 -Wa,-me500 -msoft-float -mno-string
+PLATFORM_CPPFLAGS += -DCONFIG_MPC85xx -DCONFIG_E500 -ffixed-r2 \
+			-Wa,-me500 -msoft-float -mno-string
diff --git a/cpu/mpc86xx/config.mk b/cpu/mpc86xx/config.mk
index 3c54f4a..d767269 100644
--- a/cpu/mpc86xx/config.mk
+++ b/cpu/mpc86xx/config.mk
@@ -23,4 +23,4 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi
 
-PLATFORM_CPPFLAGS += -DCONFIG_MPC86xx -ffixed-r2 -ffixed-r29 -mstring
+PLATFORM_CPPFLAGS += -DCONFIG_MPC86xx -ffixed-r2 -mstring
diff --git a/cpu/mpc86xx/start.S b/cpu/mpc86xx/start.S
index fa9736b..09f4cee 100644
--- a/cpu/mpc86xx/start.S
+++ b/cpu/mpc86xx/start.S
@@ -723,7 +723,7 @@ relocate_code:
 
 	mr	r1,  r3		/* Set new stack pointer		*/
 	mr	r9,  r4		/* Save copy of Global Data pointer	*/
-	mr	r29, r9		/* Save for DECLARE_GLOBAL_DATA_PTR	*/
+	mr	r2,  r9		/* Save for DECLARE_GLOBAL_DATA_PTR	*/
 	mr	r10, r5		/* Save copy of Destination Address	*/
 
 	mr	r3,  r5				/* Destination Address	*/
diff --git a/cpu/mpc8xx/config.mk b/cpu/mpc8xx/config.mk
index bfa6625..6031e7f 100644
--- a/cpu/mpc8xx/config.mk
+++ b/cpu/mpc8xx/config.mk
@@ -23,4 +23,4 @@
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
 
-PLATFORM_CPPFLAGS += -DCONFIG_8xx -ffixed-r2 -ffixed-r29 -mstring -mcpu=860 -msoft-float
+PLATFORM_CPPFLAGS += -DCONFIG_8xx -ffixed-r2 -mstring -mcpu=860 -msoft-float
diff --git a/cpu/ppc4xx/config.mk b/cpu/ppc4xx/config.mk
index 4fd5108..311c97b 100644
--- a/cpu/ppc4xx/config.mk
+++ b/cpu/ppc4xx/config.mk
@@ -22,7 +22,7 @@
 #
 
 PLATFORM_RELFLAGS += -fPIC -ffixed-r14 -meabi -fno-strict-aliasing
-PLATFORM_CPPFLAGS += -DCONFIG_4xx -ffixed-r2 -ffixed-r29 -mstring -msoft-float
+PLATFORM_CPPFLAGS += -DCONFIG_4xx -ffixed-r2 -mstring -msoft-float
 
 cfg=$(shell grep configs $(OBJTREE)/include/config.h | sed 's/.*<\(configs.*\)>/\1/')
 is440=$(shell grep CONFIG_440 $(TOPDIR)/include/$(cfg))
diff --git a/doc/README.standalone b/doc/README.standalone
index 3998831..f9237a6 100644
--- a/doc/README.standalone
+++ b/doc/README.standalone
@@ -21,7 +21,7 @@ Design Notes on Exporting U-Boot Functions to Standalone Applications:
 2. The pointer to the jump table is passed to the application in a
    machine-dependent way. PowerPC, ARM and MIPS architectures use a
    dedicated register to hold the pointer to the 'global_data'
-   structure: r29 on PowerPC, r8 on ARM and k0 on MIPS. The x86
+   structure: r2 on PowerPC, r8 on ARM and k0 on MIPS. The x86
    architecture does not use such a register; instead, the pointer to
    the 'global_data' structure is passed as 'argv[-1]' pointer.
 
diff --git a/examples/stubs.c b/examples/stubs.c
index 571c4d5..9b3cadd 100644
--- a/examples/stubs.c
+++ b/examples/stubs.c
@@ -25,14 +25,14 @@ gd_t *global_data;
 	: : "i"(XF_ ## x * sizeof(void *)) : "eax", "ecx");
 #elif defined(CONFIG_PPC)
 /*
- * r29 holds the pointer to the global_data, r11 is a call-clobbered
+ * r2 holds the pointer to the global_data, r11 is a call-clobbered
  * register
  */
 #define EXPORT_FUNC(x) \
 	asm volatile (			\
 "	.globl " #x "\n"		\
 #x ":\n"				\
-"	lwz	%%r11, %0(%%r29)\n"	\
+"	lwz	%%r11, %0(%%r2)\n"	\
 "	lwz	%%r11, %1(%%r11)\n"	\
 "	mtctr	%%r11\n"		\
 "	bctr\n"				\
diff --git a/examples/test_burst_lib.S b/examples/test_burst_lib.S
index 5bb4981..aef4e32 100644
--- a/examples/test_burst_lib.S
+++ b/examples/test_burst_lib.S
@@ -70,7 +70,7 @@ mmu_init:
 	 * we can load the instruction and data TLB registers with the
 	 * same values.
 	 */
-	lwz	r9,20(r29)		/* gd->ram_size */
+	lwz	r9,20(r2)		/* gd->ram_size */
 	addis	r9,r9,-0x80
 
 	mr	r8, r9			/* Higher 8 Meg in SDRAM */
diff --git a/examples/x86-testapp.c b/examples/x86-testapp.c
index a1ab319..e8603d9 100644
--- a/examples/x86-testapp.c
+++ b/examples/x86-testapp.c
@@ -30,11 +30,11 @@ asm volatile (						\
 asm volatile (						\
 "	.globl mon_" #x "\n"				\
 "mon_" #x ":\n"						\
-"	lwz	%%r11, %0(%%r29)\n"			\
+"	lwz	%%r11, %0(%%r2)\n"			\
 "	lwz	%%r11, %1(%%r11)\n"			\
 "	mtctr	%%r11\n"				\
 "	bctr\n"					\
-	: : "i"(offsetof(xxx_t, pfunc)), "i"(XF_ ## x * sizeof(void *)) : "r11", "r29");
+	: : "i"(offsetof(xxx_t, pfunc)), "i"(XF_ ## x * sizeof(void *)) : "r11", "r2");
 #elif defined(__arm__)
 #define EXPORT_FUNC(x)					\
 asm volatile (						\
@@ -67,7 +67,7 @@ int main(void)
 #if defined(__i386__)
 	xxx_t *pq;
 #elif defined(__powerpc__)
-	register volatile xxx_t *pq asm("r29");
+	register volatile xxx_t *pq asm("r2");
 #elif defined(__arm__)
 	register volatile xxx_t *pq asm("r8");
 #elif defined(__mips__)
diff --git a/include/asm-ppc/global_data.h b/include/asm-ppc/global_data.h
index aa6384c..bacd02d 100644
--- a/include/asm-ppc/global_data.h
+++ b/include/asm-ppc/global_data.h
@@ -163,7 +163,7 @@ typedef	struct	global_data {
 #define	GD_FLG_SILENT	0x00004		/* Silent mode				*/
 
 #if 1
-#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r29")
+#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r2")
 #else /* We could use plain global data, but the resulting code is bigger */
 #define XTRN_DECLARE_GLOBAL_DATA_PTR	extern
 #define DECLARE_GLOBAL_DATA_PTR     XTRN_DECLARE_GLOBAL_DATA_PTR \
-- 
1.5.3.3

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