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* [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8
@ 2013-08-11 20:58 Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 1/3] ARM: make reserving the gd register a make variable Jeroen Hofstee
                   ` (5 more replies)
  0 siblings, 6 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-11 20:58 UTC (permalink / raw)
  To: u-boot

To be EABI compliant (r9 is a platform specific register) and as
a prepration for building u-boot with clang/llvm (with does / will
support r9 as reserved register), store the pointer to gd in r9.

Jeroen Hofstee (3):
  ARM: make reserving the gd register a make variable
  ARM,relocate: do not use r9
  ARM: use r9 for gd

 arch/arm/config.mk                   |  2 ++
 arch/arm/cpu/arm1136/config.mk       |  2 +-
 arch/arm/cpu/arm1176/config.mk       |  2 +-
 arch/arm/cpu/arm720t/config.mk       |  2 +-
 arch/arm/cpu/arm920t/config.mk       |  2 +-
 arch/arm/cpu/arm925t/config.mk       |  2 +-
 arch/arm/cpu/arm926ejs/config.mk     |  2 +-
 arch/arm/cpu/arm946es/config.mk      |  2 +-
 arch/arm/cpu/arm_intcm/config.mk     |  2 +-
 arch/arm/cpu/armv7/config.mk         |  2 +-
 arch/arm/cpu/armv7/rmobile/config.mk |  2 +-
 arch/arm/cpu/ixp/config.mk           |  2 +-
 arch/arm/cpu/pxa/config.mk           |  2 +-
 arch/arm/cpu/s3c44b0/config.mk       |  2 +-
 arch/arm/cpu/sa1100/config.mk        |  2 +-
 arch/arm/include/asm/global_data.h   |  2 +-
 arch/arm/lib/crt0.S                  | 16 ++++++++--------
 arch/arm/lib/relocate.S              |  6 +++---
 18 files changed, 28 insertions(+), 26 deletions(-)

-- 
1.8.1.2

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 1/3] ARM: make reserving the gd register a make variable
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
@ 2013-08-11 20:58 ` Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 2/3] ARM,relocate: do not use r9 Jeroen Hofstee
                   ` (4 subsequent siblings)
  5 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-11 20:58 UTC (permalink / raw)
  To: u-boot

Currently all ARM targets spell out that r8 needs to be a reserved
register, while using a common crt0.s. Move this to a common make
variable so it is not repeated (and can be easily changed)

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/config.mk                   | 2 ++
 arch/arm/cpu/arm1136/config.mk       | 2 +-
 arch/arm/cpu/arm1176/config.mk       | 2 +-
 arch/arm/cpu/arm720t/config.mk       | 2 +-
 arch/arm/cpu/arm920t/config.mk       | 2 +-
 arch/arm/cpu/arm925t/config.mk       | 2 +-
 arch/arm/cpu/arm926ejs/config.mk     | 2 +-
 arch/arm/cpu/arm946es/config.mk      | 2 +-
 arch/arm/cpu/arm_intcm/config.mk     | 2 +-
 arch/arm/cpu/armv7/config.mk         | 2 +-
 arch/arm/cpu/armv7/rmobile/config.mk | 2 +-
 arch/arm/cpu/ixp/config.mk           | 2 +-
 arch/arm/cpu/pxa/config.mk           | 2 +-
 arch/arm/cpu/s3c44b0/config.mk       | 2 +-
 arch/arm/cpu/sa1100/config.mk        | 2 +-
 15 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 540a119..5e382ab 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -98,3 +98,5 @@ endif
 ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
+
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
diff --git a/arch/arm/cpu/arm1136/config.mk b/arch/arm/cpu/arm1136/config.mk
index 1ef6061..daca1bd 100644
--- a/arch/arm/cpu/arm1136/config.mk
+++ b/arch/arm/cpu/arm1136/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
 PLATFORM_CPPFLAGS += -march=armv5
diff --git a/arch/arm/cpu/arm1176/config.mk b/arch/arm/cpu/arm1176/config.mk
index 917da03..163778a 100644
--- a/arch/arm/cpu/arm1176/config.mk
+++ b/arch/arm/cpu/arm1176/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
 PLATFORM_CPPFLAGS += -march=armv5t
diff --git a/arch/arm/cpu/arm720t/config.mk b/arch/arm/cpu/arm720t/config.mk
index 56b6280..f1fb6a8 100644
--- a/arch/arm/cpu/arm720t/config.mk
+++ b/arch/arm/cpu/arm720t/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS +=  -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS +=  -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi
 # =========================================================================
diff --git a/arch/arm/cpu/arm920t/config.mk b/arch/arm/cpu/arm920t/config.mk
index 58fd756..a6b2c6f 100644
--- a/arch/arm/cpu/arm920t/config.mk
+++ b/arch/arm/cpu/arm920t/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm925t/config.mk b/arch/arm/cpu/arm925t/config.mk
index 58fd756..a6b2c6f 100644
--- a/arch/arm/cpu/arm925t/config.mk
+++ b/arch/arm/cpu/arm925t/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm926ejs/config.mk b/arch/arm/cpu/arm926ejs/config.mk
index 917ff7e..a29634d 100644
--- a/arch/arm/cpu/arm926ejs/config.mk
+++ b/arch/arm/cpu/arm926ejs/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv5te
 # =========================================================================
diff --git a/arch/arm/cpu/arm946es/config.mk b/arch/arm/cpu/arm946es/config.mk
index 1e41c11..7465da1 100644
--- a/arch/arm/cpu/arm946es/config.mk
+++ b/arch/arm/cpu/arm946es/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm_intcm/config.mk b/arch/arm/cpu/arm_intcm/config.mk
index 1e41c11..7465da1 100644
--- a/arch/arm/cpu/arm_intcm/config.mk
+++ b/arch/arm/cpu/arm_intcm/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk
index ca4a9e7..22be8df 100644
--- a/arch/arm/cpu/armv7/config.mk
+++ b/arch/arm/cpu/armv7/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common -msoft-float $(OPTION_FIXED_GD)
 
 # If armv7-a is not supported by GCC fall-back to armv5, which is
 # supported by more tool-chains
diff --git a/arch/arm/cpu/armv7/rmobile/config.mk b/arch/arm/cpu/armv7/rmobile/config.mk
index 4f01610..fbf4b61 100644
--- a/arch/arm/cpu/armv7/rmobile/config.mk
+++ b/arch/arm/cpu/armv7/rmobile/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v7a.
 PLATFORM_CPPFLAGS += -march=armv5
diff --git a/arch/arm/cpu/ixp/config.mk b/arch/arm/cpu/ixp/config.mk
index 0f12f8b..ca2c182 100644
--- a/arch/arm/cpu/ixp/config.mk
+++ b/arch/arm/cpu/ixp/config.mk
@@ -8,7 +8,7 @@
 
 BIG_ENDIAN = y
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float -mbig-endian
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float -mbig-endian
 
 PLATFORM_CPPFLAGS += -mbig-endian -march=armv5te -mtune=strongarm1100
 
diff --git a/arch/arm/cpu/pxa/config.mk b/arch/arm/cpu/pxa/config.mk
index 535bca3..c6b8f0b 100644
--- a/arch/arm/cpu/pxa/config.mk
+++ b/arch/arm/cpu/pxa/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -mcpu=xscale
 # =========================================================================
diff --git a/arch/arm/cpu/s3c44b0/config.mk b/arch/arm/cpu/s3c44b0/config.mk
index b902ca3..424584a 100644
--- a/arch/arm/cpu/s3c44b0/config.mk
+++ b/arch/arm/cpu/s3c44b0/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi -msoft-float
 # =========================================================================
diff --git a/arch/arm/cpu/sa1100/config.mk b/arch/arm/cpu/sa1100/config.mk
index 576f685..d94e855 100644
--- a/arch/arm/cpu/sa1100/config.mk
+++ b/arch/arm/cpu/sa1100/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=strongarm1100
 # =========================================================================
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 2/3] ARM,relocate: do not use r9
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 1/3] ARM: make reserving the gd register a make variable Jeroen Hofstee
@ 2013-08-11 20:58 ` Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 3/3] ARM: use r9 for gd Jeroen Hofstee
                   ` (3 subsequent siblings)
  5 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-11 20:58 UTC (permalink / raw)
  To: u-boot

r9 is a platform-specific register in ARM EABI and not per
definition a general purpose register. Do not use it while
relocating so it can be used for gd.

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index ab90430..a62a556 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -22,7 +22,7 @@
 
 ENTRY(relocate_code)
 	ldr	r1, =__image_copy_start	/* r1 <- SRC &__image_copy_start */
-	subs	r9, r0, r1		/* r9 <- relocation offset */
+	subs	r4, r0, r1		/* r4 <- relocation offset */
 	beq	relocate_done		/* skip relocation */
 	ldr	r2, =__image_copy_end	/* r2 <- SRC &__image_copy_end */
 
@@ -44,9 +44,9 @@ fixloop:
 	bne	fixnext
 
 	/* relative fix: increase location by offset */
-	add	r0, r0, r9
+	add	r0, r0, r4
 	ldr	r1, [r0]
-	add	r1, r1, r9
+	add	r1, r1, r4
 	str	r1, [r0]
 fixnext:
 	cmp	r2, r3
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 3/3] ARM: use r9 for gd
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 1/3] ARM: make reserving the gd register a make variable Jeroen Hofstee
  2013-08-11 20:58 ` [U-Boot] [PATCH 2/3] ARM,relocate: do not use r9 Jeroen Hofstee
@ 2013-08-11 20:58 ` Jeroen Hofstee
  2013-08-12  5:53   ` Wolfgang Denk
  2013-08-11 22:08 ` [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Benoît Thébaudeau
                   ` (2 subsequent siblings)
  5 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-11 20:58 UTC (permalink / raw)
  To: u-boot

To be more EABI compliant and as a preparation for building
with clang, use the platform-specific r9 register for gd
instead of r8.

note: The FIQ is not updated since it is not used in u-boot,
and under discussion for the time being.

The following checkpatch warning is ignoredL
WARNING: Use of volatile is usually wrong: see
Documentation/volatile-considered-harmful.txt

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/config.mk                 |  2 +-
 arch/arm/include/asm/global_data.h |  2 +-
 arch/arm/lib/crt0.S                | 16 ++++++++--------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 5e382ab..5f6e032 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -99,4 +99,4 @@ ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
 
-OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r9)
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
index 79a9597..e126436 100644
--- a/arch/arm/include/asm/global_data.h
+++ b/arch/arm/include/asm/global_data.h
@@ -47,6 +47,6 @@ struct arch_global_data {
 
 #include <asm-generic/global_data.h>
 
-#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r8")
+#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r9")
 
 #endif /* __ASM_GBL_DATA_H */
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 960d12e..ac54b93 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -69,7 +69,7 @@ ENTRY(_main)
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
 	sub	sp, #GD_SIZE	/* allocate one GD above SP */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	mov	r8, sp		/* GD is above SP */
+	mov	r9, sp		/* GD is above SP */
 	mov	r0, #0
 	bl	board_init_f
 
@@ -81,15 +81,15 @@ ENTRY(_main)
  * 'here' but relocated.
  */
 
-	ldr	sp, [r8, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
+	ldr	sp, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	ldr	r8, [r8, #GD_BD]		/* r8 = gd->bd */
-	sub	r8, r8, #GD_SIZE		/* new GD is below bd */
+	ldr	r9, [r9, #GD_BD]		/* r9 = gd->bd */
+	sub	r9, r9, #GD_SIZE		/* new GD is below bd */
 
 	adr	lr, here
-	ldr	r0, [r8, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
+	ldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
 	add	lr, lr, r0
-	ldr	r0, [r8, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
+	ldr	r0, [r9, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
 	b	relocate_code
 here:
 
@@ -111,8 +111,8 @@ clbss_l:cmp	r0, r1			/* while not at end of BSS */
 	bl red_led_on
 
 	/* call board_init_r(gd_t *id, ulong dest_addr) */
-	mov	r0, r8			/* gd_t */
-	ldr	r1, [r8, #GD_RELOCADDR]	/* dest_addr */
+	mov     r0, r9                  /* gd_t */
+	ldr	r1, [r9, #GD_RELOCADDR]	/* dest_addr */
 	/* call board_init_r */
 	ldr	pc, =board_init_r	/* this is auto-relocated! */
 
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
                   ` (2 preceding siblings ...)
  2013-08-11 20:58 ` [U-Boot] [PATCH 3/3] ARM: use r9 for gd Jeroen Hofstee
@ 2013-08-11 22:08 ` Benoît Thébaudeau
  2013-08-12  5:49   ` Albert ARIBAUD
  2013-08-13 19:36   ` Jeroen Hofstee
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  5 siblings, 2 replies; 31+ messages in thread
From: Benoît Thébaudeau @ 2013-08-11 22:08 UTC (permalink / raw)
  To: u-boot

Dear Jeroen Hofstee,

On Sunday, August 11, 2013 10:58:36 PM, Jeroen Hofstee wrote:
> To be EABI compliant (r9 is a platform specific register) and as
> a prepration for building u-boot with clang/llvm (with does / will
> support r9 as reserved register), store the pointer to gd in r9.

If r9 is reserved, I understand that its current usage may conflict with clang's
but why would gd have to be stored in r9 for clang? Moreover, if r9 is reserved
for clang (reserved for what?), why can it be used for gd?

I'm also wondering if r9 as initialized by relocate.S is not sometimes used by
GCC to handle position-independent code within generated code, i.e. like the
static base feature described for r9 as a possible usage in the ARM EABI AAPCS
document (5.1.1). If this is the case, changing r9 to gd would break GCC code at
runtime.

Best regards,
Beno?t

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8
  2013-08-11 22:08 ` [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Benoît Thébaudeau
@ 2013-08-12  5:49   ` Albert ARIBAUD
  2013-08-13 19:36   ` Jeroen Hofstee
  1 sibling, 0 replies; 31+ messages in thread
From: Albert ARIBAUD @ 2013-08-12  5:49 UTC (permalink / raw)
  To: u-boot

Hi Beno?t,

On Mon, 12 Aug 2013 00:08:59 +0200 (CEST), Beno?t Th?baudeau
<benoit.thebaudeau@advansee.com> wrote:

> Dear Jeroen Hofstee,
> 
> On Sunday, August 11, 2013 10:58:36 PM, Jeroen Hofstee wrote:
> > To be EABI compliant (r9 is a platform specific register) and as
> > a prepration for building u-boot with clang/llvm (with does / will
> > support r9 as reserved register), store the pointer to gd in r9.
> 
> If r9 is reserved, I understand that its current usage may conflict with clang's
> but why would gd have to be stored in r9 for clang? Moreover, if r9 is reserved
> for clang (reserved for what?), why can it be used for gd?

Actually, you have to think about this the other way around:

1. In LLVM/clang, r9 can be reserved, i.e., LLVM/clang can be told to
not touch it at all, because it is the AAPCS platform register.

2. Because r9 is the AAPCS platform register, it is the natural choice
for GD.

> I'm also wondering if r9 as initialized by relocate.S is not sometimes used by
> GCC to handle position-independent code within generated code, i.e. like the
> static base feature described for r9 as a possible usage in the ARM EABI AAPCS
> document (5.1.1). If this is the case, changing r9 to gd would break GCC code at
> runtime.

This would be useful when your code gets moved around several times
during its lifetime, which is not a requirement in U-Boot. We get
perfectly working U-Boot relocation without a base register.

> Best regards,
> Beno?t

Amicalement,
-- 
Albert.

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 3/3] ARM: use r9 for gd
  2013-08-11 20:58 ` [U-Boot] [PATCH 3/3] ARM: use r9 for gd Jeroen Hofstee
@ 2013-08-12  5:53   ` Wolfgang Denk
  2013-08-12 14:44     ` Albert ARIBAUD
  0 siblings, 1 reply; 31+ messages in thread
From: Wolfgang Denk @ 2013-08-12  5:53 UTC (permalink / raw)
  To: u-boot

Dear Jeroen Hofstee,

In message <1376254719-15594-4-git-send-email-jeroen@myspectrum.nl> you wrote:
> To be more EABI compliant and as a preparation for building
> with clang, use the platform-specific r9 register for gd
> instead of r8.
> 
> note: The FIQ is not updated since it is not used in u-boot,
> and under discussion for the time being.
> 
> The following checkpatch warning is ignoredL
> WARNING: Use of volatile is usually wrong: see
> Documentation/volatile-considered-harmful.txt
> 
> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
> ---
>  arch/arm/config.mk                 |  2 +-
>  arch/arm/include/asm/global_data.h |  2 +-
>  arch/arm/lib/crt0.S                | 16 ++++++++--------
>  3 files changed, 10 insertions(+), 10 deletions(-)

IIRC, r9 is used as GOT pointer ?

In any case, please also update the README section of register usage
on ARM.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
To be awake is to be alive.        - Henry David Thoreau, in "Walden"

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 3/3] ARM: use r9 for gd
  2013-08-12  5:53   ` Wolfgang Denk
@ 2013-08-12 14:44     ` Albert ARIBAUD
  2013-08-12 15:23       ` Wolfgang Denk
  0 siblings, 1 reply; 31+ messages in thread
From: Albert ARIBAUD @ 2013-08-12 14:44 UTC (permalink / raw)
  To: u-boot

Hi Wolfgang,

On Mon, 12 Aug 2013 07:53:15 +0200, Wolfgang Denk <wd@denx.de> wrote:

> Dear Jeroen Hofstee,
> 
> In message <1376254719-15594-4-git-send-email-jeroen@myspectrum.nl> you wrote:
> > To be more EABI compliant and as a preparation for building
> > with clang, use the platform-specific r9 register for gd
> > instead of r8.
> > 
> > note: The FIQ is not updated since it is not used in u-boot,
> > and under discussion for the time being.
> > 
> > The following checkpatch warning is ignoredL
> > WARNING: Use of volatile is usually wrong: see
> > Documentation/volatile-considered-harmful.txt
> > 
> > Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
> > ---
> >  arch/arm/config.mk                 |  2 +-
> >  arch/arm/include/asm/global_data.h |  2 +-
> >  arch/arm/lib/crt0.S                | 16 ++++++++--------
> >  3 files changed, 10 insertions(+), 10 deletions(-)
> 
> IIRC, r9 is used as GOT pointer ?

No, it is not, well, not any more since GOT-based relocation was
replaced by ELF relocation, which requires no reserved register.

> In any case, please also update the README section of register usage
> on ARM.
> 
> Best regards,
> 
> Wolfgang Denk
> 


Amicalement,
-- 
Albert.

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 3/3] ARM: use r9 for gd
  2013-08-12 14:44     ` Albert ARIBAUD
@ 2013-08-12 15:23       ` Wolfgang Denk
  2013-08-13 19:41         ` Jeroen Hofstee
  0 siblings, 1 reply; 31+ messages in thread
From: Wolfgang Denk @ 2013-08-12 15:23 UTC (permalink / raw)
  To: u-boot

Dear Albert,

In message <20130812164406.5a6807e7@lilith> you wrote:
> 
> > IIRC, r9 is used as GOT pointer ?
> 
> No, it is not, well, not any more since GOT-based relocation was
> replaced by ELF relocation, which requires no reserved register.
> 
> > In any case, please also update the README section of register usage
> > on ARM.

I see, thanks for the explanation - so this is one more item thatneeds
to be fixed in the README.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,     MD: Wolfgang Denk & Detlev Zundel
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
Die Freiheit des Menschen liegt nicht darin, dass er tun kann, was er
will, sondern darin, dass er nicht tun muss, was er nicht will.
                                             -- Jean-Jacques Rousseau

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8
  2013-08-11 22:08 ` [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Benoît Thébaudeau
  2013-08-12  5:49   ` Albert ARIBAUD
@ 2013-08-13 19:36   ` Jeroen Hofstee
  1 sibling, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-13 19:36 UTC (permalink / raw)
  To: u-boot

Hello Beno?t,

On 08/12/2013 12:08 AM, Beno?t Th?baudeau wrote:
> On Sunday, August 11, 2013 10:58:36 PM, Jeroen Hofstee wrote:
>> To be EABI compliant (r9 is a platform specific register) and as
>> a prepration for building u-boot with clang/llvm (with does / will
>> support r9 as reserved register), store the pointer to gd in r9.
> If r9 is reserved, I understand that its current usage may conflict with clang's
> but why would gd have to be stored in r9 for clang? Moreover, if r9 is reserved
> for clang (reserved for what?), why can it be used for gd?
I know Albert already responded to this, but for completeness:
The reserved is from a compiler point of view, which is perhaps
a bit llvm nomenclature, Reserved means the compiler should
_not_ use it as a general purpose register; it is reserved for the
platform, U-boot in this case.
> I'm also wondering if r9 as initialized by relocate.S is not sometimes used by
> GCC to handle position-independent code within generated code, i.e. like the
> static base feature described for r9 as a possible usage in the ARM EABI AAPCS
> document (5.1.1). If this is the case, changing r9 to gd would break GCC code at
> runtime.
This is not needed / supported on U-boot arm. U-boot will actually
error at compile time if there are any symbols which are not pc relative.

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH 3/3] ARM: use r9 for gd
  2013-08-12 15:23       ` Wolfgang Denk
@ 2013-08-13 19:41         ` Jeroen Hofstee
  0 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-13 19:41 UTC (permalink / raw)
  To: u-boot

Hi,

On 08/12/2013 05:23 PM, Wolfgang Denk wrote:
> Dear Albert,
>
> In message <20130812164406.5a6807e7@lilith> you wrote:
>>> IIRC, r9 is used as GOT pointer ?
>> No, it is not, well, not any more since GOT-based relocation was
>> replaced by ELF relocation, which requires no reserved register.
>>
>>> In any case, please also update the README section of register usage
>>> on ARM.
> I see, thanks for the explanation - so this is one more item thatneeds
> to be fixed in the README.
Damn: "The role of register r9 is platform specific. A virtual platform may
assign any role to this register and _must document_ this usage" ;)

I will update the README for both.

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 0/4] ARM: use r9 for gd instead of r8
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
                   ` (3 preceding siblings ...)
  2013-08-11 22:08 ` [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Benoît Thébaudeau
@ 2013-08-14 18:25 ` Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable Jeroen Hofstee
                     ` (3 more replies)
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  5 siblings, 4 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-14 18:25 UTC (permalink / raw)
  To: u-boot

v2: update the README as requested by Wolfgang Denk

cc: wd at denx.de
Jeroen Hofstee (4):
  ARM: make reserving the gd register a make variable
  ARM,relocate: do not use r9
  ARM: use r9 for gd
  README: update ARM register usage

 README                               |  8 +++++---
 arch/arm/config.mk                   |  2 ++
 arch/arm/cpu/arm1136/config.mk       |  2 +-
 arch/arm/cpu/arm1176/config.mk       |  2 +-
 arch/arm/cpu/arm720t/config.mk       |  2 +-
 arch/arm/cpu/arm920t/config.mk       |  2 +-
 arch/arm/cpu/arm925t/config.mk       |  2 +-
 arch/arm/cpu/arm926ejs/config.mk     |  2 +-
 arch/arm/cpu/arm946es/config.mk      |  2 +-
 arch/arm/cpu/arm_intcm/config.mk     |  2 +-
 arch/arm/cpu/armv7/config.mk         |  2 +-
 arch/arm/cpu/armv7/rmobile/config.mk |  2 +-
 arch/arm/cpu/ixp/config.mk           |  2 +-
 arch/arm/cpu/pxa/config.mk           |  2 +-
 arch/arm/cpu/s3c44b0/config.mk       |  2 +-
 arch/arm/cpu/sa1100/config.mk        |  2 +-
 arch/arm/include/asm/global_data.h   |  2 +-
 arch/arm/lib/crt0.S                  | 16 ++++++++--------
 arch/arm/lib/relocate.S              |  6 +++---
 19 files changed, 33 insertions(+), 29 deletions(-)

-- 
1.8.1.2

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
@ 2013-08-14 18:25   ` Jeroen Hofstee
  2013-08-17 13:55     ` Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 2/4] ARM,relocate: do not use r9 Jeroen Hofstee
                     ` (2 subsequent siblings)
  3 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-14 18:25 UTC (permalink / raw)
  To: u-boot

Currently all ARM targets spell out that r8 needs to be a reserved
register, while using a common crt0.s. Move this to a common make
variable so it is not repeated (and can be easily changed)

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/config.mk                   | 2 ++
 arch/arm/cpu/arm1136/config.mk       | 2 +-
 arch/arm/cpu/arm1176/config.mk       | 2 +-
 arch/arm/cpu/arm720t/config.mk       | 2 +-
 arch/arm/cpu/arm920t/config.mk       | 2 +-
 arch/arm/cpu/arm925t/config.mk       | 2 +-
 arch/arm/cpu/arm926ejs/config.mk     | 2 +-
 arch/arm/cpu/arm946es/config.mk      | 2 +-
 arch/arm/cpu/arm_intcm/config.mk     | 2 +-
 arch/arm/cpu/armv7/config.mk         | 2 +-
 arch/arm/cpu/armv7/rmobile/config.mk | 2 +-
 arch/arm/cpu/ixp/config.mk           | 2 +-
 arch/arm/cpu/pxa/config.mk           | 2 +-
 arch/arm/cpu/s3c44b0/config.mk       | 2 +-
 arch/arm/cpu/sa1100/config.mk        | 2 +-
 15 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 540a119..5e382ab 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -98,3 +98,5 @@ endif
 ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
+
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
diff --git a/arch/arm/cpu/arm1136/config.mk b/arch/arm/cpu/arm1136/config.mk
index 1ef6061..daca1bd 100644
--- a/arch/arm/cpu/arm1136/config.mk
+++ b/arch/arm/cpu/arm1136/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
 PLATFORM_CPPFLAGS += -march=armv5
diff --git a/arch/arm/cpu/arm1176/config.mk b/arch/arm/cpu/arm1176/config.mk
index 917da03..163778a 100644
--- a/arch/arm/cpu/arm1176/config.mk
+++ b/arch/arm/cpu/arm1176/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v6.
 PLATFORM_CPPFLAGS += -march=armv5t
diff --git a/arch/arm/cpu/arm720t/config.mk b/arch/arm/cpu/arm720t/config.mk
index 56b6280..f1fb6a8 100644
--- a/arch/arm/cpu/arm720t/config.mk
+++ b/arch/arm/cpu/arm720t/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS +=  -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS +=  -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi
 # =========================================================================
diff --git a/arch/arm/cpu/arm920t/config.mk b/arch/arm/cpu/arm920t/config.mk
index 58fd756..a6b2c6f 100644
--- a/arch/arm/cpu/arm920t/config.mk
+++ b/arch/arm/cpu/arm920t/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm925t/config.mk b/arch/arm/cpu/arm925t/config.mk
index 58fd756..a6b2c6f 100644
--- a/arch/arm/cpu/arm925t/config.mk
+++ b/arch/arm/cpu/arm925t/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm926ejs/config.mk b/arch/arm/cpu/arm926ejs/config.mk
index 917ff7e..a29634d 100644
--- a/arch/arm/cpu/arm926ejs/config.mk
+++ b/arch/arm/cpu/arm926ejs/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv5te
 # =========================================================================
diff --git a/arch/arm/cpu/arm946es/config.mk b/arch/arm/cpu/arm946es/config.mk
index 1e41c11..7465da1 100644
--- a/arch/arm/cpu/arm946es/config.mk
+++ b/arch/arm/cpu/arm946es/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/arm_intcm/config.mk b/arch/arm/cpu/arm_intcm/config.mk
index 1e41c11..7465da1 100644
--- a/arch/arm/cpu/arm_intcm/config.mk
+++ b/arch/arm/cpu/arm_intcm/config.mk
@@ -5,7 +5,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS +=  -march=armv4
 # =========================================================================
diff --git a/arch/arm/cpu/armv7/config.mk b/arch/arm/cpu/armv7/config.mk
index ca4a9e7..22be8df 100644
--- a/arch/arm/cpu/armv7/config.mk
+++ b/arch/arm/cpu/armv7/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common -msoft-float $(OPTION_FIXED_GD)
 
 # If armv7-a is not supported by GCC fall-back to armv5, which is
 # supported by more tool-chains
diff --git a/arch/arm/cpu/armv7/rmobile/config.mk b/arch/arm/cpu/armv7/rmobile/config.mk
index 4f01610..fbf4b61 100644
--- a/arch/arm/cpu/armv7/rmobile/config.mk
+++ b/arch/arm/cpu/armv7/rmobile/config.mk
@@ -4,7 +4,7 @@
 #
 # SPDX-License-Identifier:	GPL-2.0+
 #
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 # Make ARMv5 to allow more compilers to work, even though its v7a.
 PLATFORM_CPPFLAGS += -march=armv5
diff --git a/arch/arm/cpu/ixp/config.mk b/arch/arm/cpu/ixp/config.mk
index 0f12f8b..ca2c182 100644
--- a/arch/arm/cpu/ixp/config.mk
+++ b/arch/arm/cpu/ixp/config.mk
@@ -8,7 +8,7 @@
 
 BIG_ENDIAN = y
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float -mbig-endian
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float -mbig-endian
 
 PLATFORM_CPPFLAGS += -mbig-endian -march=armv5te -mtune=strongarm1100
 
diff --git a/arch/arm/cpu/pxa/config.mk b/arch/arm/cpu/pxa/config.mk
index 535bca3..c6b8f0b 100644
--- a/arch/arm/cpu/pxa/config.mk
+++ b/arch/arm/cpu/pxa/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -mcpu=xscale
 # =========================================================================
diff --git a/arch/arm/cpu/s3c44b0/config.mk b/arch/arm/cpu/s3c44b0/config.mk
index b902ca3..424584a 100644
--- a/arch/arm/cpu/s3c44b0/config.mk
+++ b/arch/arm/cpu/s3c44b0/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=arm7tdmi -msoft-float
 # =========================================================================
diff --git a/arch/arm/cpu/sa1100/config.mk b/arch/arm/cpu/sa1100/config.mk
index 576f685..d94e855 100644
--- a/arch/arm/cpu/sa1100/config.mk
+++ b/arch/arm/cpu/sa1100/config.mk
@@ -6,7 +6,7 @@
 # SPDX-License-Identifier:	GPL-2.0+
 #
 
-PLATFORM_RELFLAGS += -fno-common -ffixed-r8 -msoft-float
+PLATFORM_RELFLAGS += -fno-common $(OPTION_FIXED_GD) -msoft-float
 
 PLATFORM_CPPFLAGS += -march=armv4 -mtune=strongarm1100
 # =========================================================================
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 2/4] ARM,relocate: do not use r9
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable Jeroen Hofstee
@ 2013-08-14 18:25   ` Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 4/4] README: update ARM register usage Jeroen Hofstee
  3 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-14 18:25 UTC (permalink / raw)
  To: u-boot

r9 is a platform-specific register in ARM EABI and not per
definition a general purpose register. Do not use it while
relocating so it can be used for gd.

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index ab90430..a62a556 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -22,7 +22,7 @@
 
 ENTRY(relocate_code)
 	ldr	r1, =__image_copy_start	/* r1 <- SRC &__image_copy_start */
-	subs	r9, r0, r1		/* r9 <- relocation offset */
+	subs	r4, r0, r1		/* r4 <- relocation offset */
 	beq	relocate_done		/* skip relocation */
 	ldr	r2, =__image_copy_end	/* r2 <- SRC &__image_copy_end */
 
@@ -44,9 +44,9 @@ fixloop:
 	bne	fixnext
 
 	/* relative fix: increase location by offset */
-	add	r0, r0, r9
+	add	r0, r0, r4
 	ldr	r1, [r0]
-	add	r1, r1, r9
+	add	r1, r1, r4
 	str	r1, [r0]
 fixnext:
 	cmp	r2, r3
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 2/4] ARM,relocate: do not use r9 Jeroen Hofstee
@ 2013-08-14 18:25   ` Jeroen Hofstee
  2013-08-17  9:40     ` Jeroen Hofstee
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 4/4] README: update ARM register usage Jeroen Hofstee
  3 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-14 18:25 UTC (permalink / raw)
  To: u-boot

To be more EABI compliant and as a preparation for building
with clang, use the platform-specific r9 register for gd
instead of r8.

note: The FIQ is not updated since it is not used in u-boot,
and under discussion for the time being.

The following checkpatch warning is ignored:
WARNING: Use of volatile is usually wrong: see
Documentation/volatile-considered-harmful.txt

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/config.mk                 |  2 +-
 arch/arm/include/asm/global_data.h |  2 +-
 arch/arm/lib/crt0.S                | 16 ++++++++--------
 3 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 5e382ab..5f6e032 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -99,4 +99,4 @@ ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
 
-OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r9)
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
index 79a9597..e126436 100644
--- a/arch/arm/include/asm/global_data.h
+++ b/arch/arm/include/asm/global_data.h
@@ -47,6 +47,6 @@ struct arch_global_data {
 
 #include <asm-generic/global_data.h>
 
-#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r8")
+#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r9")
 
 #endif /* __ASM_GBL_DATA_H */
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 960d12e..ac54b93 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -69,7 +69,7 @@ ENTRY(_main)
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
 	sub	sp, #GD_SIZE	/* allocate one GD above SP */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	mov	r8, sp		/* GD is above SP */
+	mov	r9, sp		/* GD is above SP */
 	mov	r0, #0
 	bl	board_init_f
 
@@ -81,15 +81,15 @@ ENTRY(_main)
  * 'here' but relocated.
  */
 
-	ldr	sp, [r8, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
+	ldr	sp, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	ldr	r8, [r8, #GD_BD]		/* r8 = gd->bd */
-	sub	r8, r8, #GD_SIZE		/* new GD is below bd */
+	ldr	r9, [r9, #GD_BD]		/* r9 = gd->bd */
+	sub	r9, r9, #GD_SIZE		/* new GD is below bd */
 
 	adr	lr, here
-	ldr	r0, [r8, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
+	ldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
 	add	lr, lr, r0
-	ldr	r0, [r8, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
+	ldr	r0, [r9, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
 	b	relocate_code
 here:
 
@@ -111,8 +111,8 @@ clbss_l:cmp	r0, r1			/* while not at end of BSS */
 	bl red_led_on
 
 	/* call board_init_r(gd_t *id, ulong dest_addr) */
-	mov	r0, r8			/* gd_t */
-	ldr	r1, [r8, #GD_RELOCADDR]	/* dest_addr */
+	mov     r0, r9                  /* gd_t */
+	ldr	r1, [r9, #GD_RELOCADDR]	/* dest_addr */
 	/* call board_init_r */
 	ldr	pc, =board_init_r	/* this is auto-relocated! */
 
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 4/4] README: update ARM register usage
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
                     ` (2 preceding siblings ...)
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd Jeroen Hofstee
@ 2013-08-14 18:25   ` Jeroen Hofstee
  3 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-14 18:25 UTC (permalink / raw)
  To: u-boot

Besides the change of this patchset it also updates the
README to reflect that GOT-generated relocations are no
longer supported on ARM.

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 README | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/README b/README
index 3918807..d8af074 100644
--- a/README
+++ b/README
@@ -5534,15 +5534,17 @@ On ARM, the following registers are used:
 
 	R0:	function argument word/integer result
 	R1-R3:	function argument word
-	R9:	GOT pointer
-	R10:	stack limit (used only if stack checking if enabled)
+	R9:	platform specific
+	R10:	stack limit (used only if stack checking is enabled)
 	R11:	argument (frame) pointer
 	R12:	temporary workspace
 	R13:	stack pointer
 	R14:	link register
 	R15:	program counter
 
-    ==> U-Boot will use R8 to hold a pointer to the global data
+    ==> U-Boot will use R9 to hold a pointer to the global data
+
+    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
 
 On Nios II, the ABI is documented here:
 	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd Jeroen Hofstee
@ 2013-08-17  9:40     ` Jeroen Hofstee
  2013-08-17 13:51       ` Jeroen Hofstee
  2013-08-19  3:08       ` Simon Glass
  0 siblings, 2 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-17  9:40 UTC (permalink / raw)
  To: u-boot

On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
> To be more EABI compliant and as a preparation for building
> with clang, use the platform-specific r9 register for gd
> instead of r8.
>
> note: The FIQ is not updated since it is not used in u-boot,
> and under discussion for the time being.
>
> The following checkpatch warning is ignored:
> WARNING: Use of volatile is usually wrong: see
> Documentation/volatile-considered-harmful.txt
>
> cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
> ---
>   arch/arm/config.mk                 |  2 +-
>   arch/arm/include/asm/global_data.h |  2 +-
>   arch/arm/lib/crt0.S                | 16 ++++++++--------
>   3 files changed, 10 insertions(+), 10 deletions(-)
>

This patch assumes only crt0.S sets the register used for
gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
manually, so all users of the common board.c are likely
bricked with the patch as is. Looking into it....

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-17  9:40     ` Jeroen Hofstee
@ 2013-08-17 13:51       ` Jeroen Hofstee
  2013-08-19  3:08       ` Simon Glass
  1 sibling, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-17 13:51 UTC (permalink / raw)
  To: u-boot

On 08/17/2013 11:40 AM, Jeroen Hofstee wrote:
> On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
>> To be more EABI compliant and as a preparation for building
>> with clang, use the platform-specific r9 register for gd
>> instead of r8.
>>
>> note: The FIQ is not updated since it is not used in u-boot,
>> and under discussion for the time being.
>>
>> The following checkpatch warning is ignored:
>> WARNING: Use of volatile is usually wrong: see
>> Documentation/volatile-considered-harmful.txt
>>
>> cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
>> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
>> ---
>>   arch/arm/config.mk                 |  2 +-
>>   arch/arm/include/asm/global_data.h |  2 +-
>>   arch/arm/lib/crt0.S                | 16 ++++++++--------
>>   3 files changed, 10 insertions(+), 10 deletions(-)
>>
>
> This patch assumes only crt0.S sets the register used for
> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
> manually, so all users of the common board.c are likely
> bricked with the patch as is. Looking into it....

Looking into this, it seems lowlevel_init.S could simply be removed
by placing the call to s_init at a better spot. As Tom pointed out,
this is already being discussed at [1]. As that is a topic of its own
I intend to simply change lowlevel_init.S to us r9 in this patchset.

Regards,
Jeroen

[1] 
http://u-boot.10912.n7.nabble.com/PATCH-1-3-arm-spl-Fix-SPL-booting-for-OMAP3-td156990.html

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable
  2013-08-14 18:25   ` [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable Jeroen Hofstee
@ 2013-08-17 13:55     ` Jeroen Hofstee
  2013-09-19  6:57       ` Albert ARIBAUD
  0 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-17 13:55 UTC (permalink / raw)
  To: u-boot

On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
> diff --git a/arch/arm/config.mk b/arch/arm/config.mk
> index 540a119..5e382ab 100644
> --- a/arch/arm/config.mk
> +++ b/arch/arm/config.mk
> @@ -98,3 +98,5 @@ endif
>   ifneq ($(CONFIG_SPL_BUILD),y)
>   ALL-y	+= checkarmreloc
>   endif
> +
> +OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)

I am leaking some debug code here, this can simply be an
assignment by value instead of a cc-option check.

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-17  9:40     ` Jeroen Hofstee
  2013-08-17 13:51       ` Jeroen Hofstee
@ 2013-08-19  3:08       ` Simon Glass
  2013-08-19 17:32         ` Jeroen Hofstee
  1 sibling, 1 reply; 31+ messages in thread
From: Simon Glass @ 2013-08-19  3:08 UTC (permalink / raw)
  To: u-boot

Hi Jeroen,

On Sat, Aug 17, 2013 at 3:40 AM, Jeroen Hofstee <jeroen@myspectrum.nl> wrote:
> On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
>>
>> To be more EABI compliant and as a preparation for building
>> with clang, use the platform-specific r9 register for gd
>> instead of r8.
>>
>> note: The FIQ is not updated since it is not used in u-boot,
>> and under discussion for the time being.
>>
>> The following checkpatch warning is ignored:
>> WARNING: Use of volatile is usually wrong: see
>> Documentation/volatile-considered-harmful.txt
>>
>> cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
>> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
>> ---
>>   arch/arm/config.mk                 |  2 +-
>>   arch/arm/include/asm/global_data.h |  2 +-
>>   arch/arm/lib/crt0.S                | 16 ++++++++--------
>>   3 files changed, 10 insertions(+), 10 deletions(-)
>>
>
> This patch assumes only crt0.S sets the register used for
> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
> manually, so all users of the common board.c are likely
> bricked with the patch as is. Looking into it....

I may misunderstood what you are saying here, but I believe that the
code in common/board_f.c which creates a global_data on the stack can
be removed for ARM now that Albert has tidied all this up with the
crt0.S changes, etc. So in common/board_f.c something like:

void board_init_f(ulong boot_flags)
{
/* These two archs set up the global_data before board_init_f() */
#if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
gd_t data;

gd = &data;
#endif

gd->flags = boot_flags;


Regards,
Simon

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-19  3:08       ` Simon Glass
@ 2013-08-19 17:32         ` Jeroen Hofstee
  2013-08-21 16:22           ` Jeroen Hofstee
  0 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-19 17:32 UTC (permalink / raw)
  To: u-boot

Hello Simon,

On 08/19/2013 05:08 AM, Simon Glass wrote:
> On Sat, Aug 17, 2013 at 3:40 AM, Jeroen Hofstee <jeroen@myspectrum.nl> wrote:
>>
>> This patch assumes only crt0.S sets the register used for
>> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
>> manually, so all users of the common board.c are likely
>> bricked with the patch as is. Looking into it....
> I may misunderstood what you are saying here,

Likely, this is not about how to set reserve gd, but why gd
is setup twice. The answer is because some more cleanup
is needed (which deserves its own patch).

> but I believe that the
> code in common/board_f.c which creates a global_data on the stack can
> be removed for ARM now that Albert has tidied all this up with the
> crt0.S changes, etc. So in common/board_f.c something like:
>
> void board_init_f(ulong boot_flags)
> {
> /* These two archs set up the global_data before board_init_f() */
> #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
> gd_t data;
>
> gd = &data;
> #endif
>
> gd->flags = boot_flags;
>

This won't work in general for ARM as  board_init_f
returns in the ARM specific board (and will be rather
ugly for the clang case).

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-19 17:32         ` Jeroen Hofstee
@ 2013-08-21 16:22           ` Jeroen Hofstee
  2013-08-21 23:44             ` Simon Glass
  0 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-08-21 16:22 UTC (permalink / raw)
  To: u-boot

Hello Simon,

On 08/19/2013 07:32 PM, Jeroen Hofstee wrote:
>
> On 08/19/2013 05:08 AM, Simon Glass wrote:
>> On Sat, Aug 17, 2013 at 3:40 AM, Jeroen Hofstee 
>> <jeroen@myspectrum.nl> wrote:
>>>
>>> This patch assumes only crt0.S sets the register used for
>>> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
>>> manually, so all users of the common board.c are likely
>>> bricked with the patch as is. Looking into it....
>> I may misunderstood what you are saying here,
>
> Likely, this is not about how to set reserve gd, but why gd
> is setup twice. The answer is because some more cleanup
> is needed (which deserves its own patch).
>

Right... Now I understand what you were talking about.  Gd is actually
setup _three_ times in a row:

1) cpu/armv7/lowlevel_init.S
2) ./arch/arm/lib/crt0.S
3) common/board_f.c

>> but I believe that the
>> code in common/board_f.c which creates a global_data on the stack can
>> be removed for ARM now that Albert has tidied all this up with the
>> crt0.S changes, etc. So in common/board_f.c something like:
>>
>> void board_init_f(ulong boot_flags)
>> {
>> /* These two archs set up the global_data before board_init_f() */
>> #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
>> gd_t data;
>>
>> gd = &data;
>> #endif
>>
>> gd->flags = boot_flags;
>>
>

Yup understood now, this makes sense (but as part of a cleanup patchset)

Thanks, Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd
  2013-08-21 16:22           ` Jeroen Hofstee
@ 2013-08-21 23:44             ` Simon Glass
  0 siblings, 0 replies; 31+ messages in thread
From: Simon Glass @ 2013-08-21 23:44 UTC (permalink / raw)
  To: u-boot

Hi Jeroen,

On Wed, Aug 21, 2013 at 10:22 AM, Jeroen Hofstee <jeroen@myspectrum.nl> wrote:
> Hello Simon,
>
>
> On 08/19/2013 07:32 PM, Jeroen Hofstee wrote:
>>
>>
>> On 08/19/2013 05:08 AM, Simon Glass wrote:
>>>
>>> On Sat, Aug 17, 2013 at 3:40 AM, Jeroen Hofstee <jeroen@myspectrum.nl>
>>> wrote:
>>>>
>>>>
>>>> This patch assumes only crt0.S sets the register used for
>>>> gd in asm. I just noticed cpu/armv7/lowlevel_init.S does set gd
>>>> manually, so all users of the common board.c are likely
>>>> bricked with the patch as is. Looking into it....
>>>
>>> I may misunderstood what you are saying here,
>>
>>
>> Likely, this is not about how to set reserve gd, but why gd
>> is setup twice. The answer is because some more cleanup
>> is needed (which deserves its own patch).
>>
>
> Right... Now I understand what you were talking about.  Gd is actually
> setup _three_ times in a row:

Yes.

>
> 1) cpu/armv7/lowlevel_init.S
> 2) ./arch/arm/lib/crt0.S
> 3) common/board_f.c
>
>
>>> but I believe that the
>>> code in common/board_f.c which creates a global_data on the stack can
>>> be removed for ARM now that Albert has tidied all this up with the
>>> crt0.S changes, etc. So in common/board_f.c something like:
>>>
>>> void board_init_f(ulong boot_flags)
>>> {
>>> /* These two archs set up the global_data before board_init_f() */
>>> #if !defined(CONFIG_X86) && !defined(CONFIG_ARM)
>>> gd_t data;
>>>
>>> gd = &data;
>>> #endif
>>>
>>> gd->flags = boot_flags;
>>>
>>
>
> Yup understood now, this makes sense (but as part of a cleanup patchset)

Agreed, no suggestion it should be done here - I just wanted to make
sure you are not working hard to preserve unnecessary code.

Regards,
Simon

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable
  2013-08-17 13:55     ` Jeroen Hofstee
@ 2013-09-19  6:57       ` Albert ARIBAUD
  2013-09-19 16:54         ` Jeroen Hofstee
  0 siblings, 1 reply; 31+ messages in thread
From: Albert ARIBAUD @ 2013-09-19  6:57 UTC (permalink / raw)
  To: u-boot

Hi Jeroen,

On Sat, 17 Aug 2013 15:55:16 +0200, Jeroen Hofstee
<jeroen@myspectrum.nl> wrote:

> On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
> > diff --git a/arch/arm/config.mk b/arch/arm/config.mk
> > index 540a119..5e382ab 100644
> > --- a/arch/arm/config.mk
> > +++ b/arch/arm/config.mk
> > @@ -98,3 +98,5 @@ endif
> >   ifneq ($(CONFIG_SPL_BUILD),y)
> >   ALL-y	+= checkarmreloc
> >   endif
> > +
> > +OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
> 
> I am leaking some debug code here, this can simply be an
> assignment by value instead of a cc-option check.

Does this mean you'll repost a version of this patch?

> Regards,
> Jeroen

Amicalement,
-- 
Albert.

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable
  2013-09-19  6:57       ` Albert ARIBAUD
@ 2013-09-19 16:54         ` Jeroen Hofstee
  0 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-19 16:54 UTC (permalink / raw)
  To: u-boot

Hello Albert,

On 09/19/2013 08:57 AM, Albert ARIBAUD wrote:
> On Sat, 17 Aug 2013 15:55:16 +0200, Jeroen Hofstee
> <jeroen@myspectrum.nl> wrote:
>
>> On 08/14/2013 08:25 PM, Jeroen Hofstee wrote:
>>> diff --git a/arch/arm/config.mk b/arch/arm/config.mk
>>> index 540a119..5e382ab 100644
>>> --- a/arch/arm/config.mk
>>> +++ b/arch/arm/config.mk
>>> @@ -98,3 +98,5 @@ endif
>>>    ifneq ($(CONFIG_SPL_BUILD),y)
>>>    ALL-y	+= checkarmreloc
>>>    endif
>>> +
>>> +OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
>> I am leaking some debug code here, this can simply be an
>> assignment by value instead of a cc-option check.
> Does this mean you'll repost a version of this patch?
>

yup, you get a v3. I intend to rebase on
http://patchwork.ozlabs.org/patch/273377/ as well.

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8
  2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
                   ` (4 preceding siblings ...)
  2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
@ 2013-09-21 12:04 ` Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 1/3] ARM,relocate: do not use r9 Jeroen Hofstee
                     ` (3 more replies)
  5 siblings, 4 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-21 12:04 UTC (permalink / raw)
  To: u-boot

Changes for v3:
Drop the unneeded cc-option for the fixed flag.

Drop "make reserving the gd register a make variable"
and use http://patchwork.ozlabs.org/patch/273377/
"ARM: refactor compiler options in config.mk" instead.

Changes for v2:
Update the README as requested by Wolfgang Denk

Jeroen Hofstee (3):
  ARM,relocate: do not use r9
  ARM: use r9 for gd
  README: update ARM register usage

 README                             |  8 +++++---
 arch/arm/config.mk                 |  2 +-
 arch/arm/cpu/armv7/lowlevel_init.S |  4 ++--
 arch/arm/include/asm/global_data.h |  2 +-
 arch/arm/lib/crt0.S                | 16 ++++++++--------
 arch/arm/lib/relocate.S            |  6 +++---
 6 files changed, 20 insertions(+), 18 deletions(-)

-- 
1.8.1.2

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 1/3] ARM,relocate: do not use r9
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
@ 2013-09-21 12:04   ` Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd Jeroen Hofstee
                     ` (2 subsequent siblings)
  3 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-21 12:04 UTC (permalink / raw)
  To: u-boot

r9 is a platform-specific register in ARM EABI and not per
definition a general purpose register. Do not use it while
relocating so it can be used for gd.

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm/lib/relocate.S b/arch/arm/lib/relocate.S
index ab90430..a62a556 100644
--- a/arch/arm/lib/relocate.S
+++ b/arch/arm/lib/relocate.S
@@ -22,7 +22,7 @@
 
 ENTRY(relocate_code)
 	ldr	r1, =__image_copy_start	/* r1 <- SRC &__image_copy_start */
-	subs	r9, r0, r1		/* r9 <- relocation offset */
+	subs	r4, r0, r1		/* r4 <- relocation offset */
 	beq	relocate_done		/* skip relocation */
 	ldr	r2, =__image_copy_end	/* r2 <- SRC &__image_copy_end */
 
@@ -44,9 +44,9 @@ fixloop:
 	bne	fixnext
 
 	/* relative fix: increase location by offset */
-	add	r0, r0, r9
+	add	r0, r0, r4
 	ldr	r1, [r0]
-	add	r1, r1, r9
+	add	r1, r1, r4
 	str	r1, [r0]
 fixnext:
 	cmp	r2, r3
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 1/3] ARM,relocate: do not use r9 Jeroen Hofstee
@ 2013-09-21 12:04   ` Jeroen Hofstee
  2013-09-21 15:30     ` Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 3/3] README: update ARM register usage Jeroen Hofstee
  2013-09-23 16:56   ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Albert ARIBAUD
  3 siblings, 1 reply; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-21 12:04 UTC (permalink / raw)
  To: u-boot

To be more EABI compliant and as a preparation for building
with clang, use the platform-specific r9 register for gd
instead of r8.

note: The FIQ is not updated since it is not used in u-boot,
and under discussion for the time being.

The following checkpatch warning is ignored:
WARNING: Use of volatile is usually wrong: see
Documentation/volatile-considered-harmful.txt

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>

---
This patch depends on http://patchwork.ozlabs.org/patch/273377/

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 arch/arm/config.mk                 |  2 +-
 arch/arm/cpu/armv7/lowlevel_init.S |  4 ++--
 arch/arm/include/asm/global_data.h |  2 +-
 arch/arm/lib/crt0.S                | 16 ++++++++--------
 4 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/arch/arm/config.mk b/arch/arm/config.mk
index 070dfab..6d1bca9 100644
--- a/arch/arm/config.mk
+++ b/arch/arm/config.mk
@@ -17,7 +17,7 @@ endif
 
 LDFLAGS_FINAL += --gc-sections
 PLATFORM_RELFLAGS += -ffunction-sections -fdata-sections \
-                     -fno-common -ffixed-r8 -msoft-float
+                     -fno-common -ffixed-r9 -msoft-float
 
 # Support generic board on ARM
 __HAVE_ARCH_GENERIC_BOARD := y
diff --git a/arch/arm/cpu/armv7/lowlevel_init.S b/arch/arm/cpu/armv7/lowlevel_init.S
index 82b2b86..69e3053 100644
--- a/arch/arm/cpu/armv7/lowlevel_init.S
+++ b/arch/arm/cpu/armv7/lowlevel_init.S
@@ -22,11 +22,11 @@ ENTRY(lowlevel_init)
 	ldr	sp, =CONFIG_SYS_INIT_SP_ADDR
 	bic	sp, sp, #7 /* 8-byte alignment for ABI compliance */
 #ifdef CONFIG_SPL_BUILD
-	ldr	r8, =gdata
+	ldr	r9, =gdata
 #else
 	sub	sp, #GD_SIZE
 	bic	sp, sp, #7
-	mov	r8, sp
+	mov	r9, sp
 #endif
 	/*
 	 * Save the old lr(passed in ip) and the current lr to stack
diff --git a/arch/arm/include/asm/global_data.h b/arch/arm/include/asm/global_data.h
index 79a9597..e126436 100644
--- a/arch/arm/include/asm/global_data.h
+++ b/arch/arm/include/asm/global_data.h
@@ -47,6 +47,6 @@ struct arch_global_data {
 
 #include <asm-generic/global_data.h>
 
-#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r8")
+#define DECLARE_GLOBAL_DATA_PTR     register volatile gd_t *gd asm ("r9")
 
 #endif /* __ASM_GBL_DATA_H */
diff --git a/arch/arm/lib/crt0.S b/arch/arm/lib/crt0.S
index 960d12e..ac54b93 100644
--- a/arch/arm/lib/crt0.S
+++ b/arch/arm/lib/crt0.S
@@ -69,7 +69,7 @@ ENTRY(_main)
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
 	sub	sp, #GD_SIZE	/* allocate one GD above SP */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	mov	r8, sp		/* GD is above SP */
+	mov	r9, sp		/* GD is above SP */
 	mov	r0, #0
 	bl	board_init_f
 
@@ -81,15 +81,15 @@ ENTRY(_main)
  * 'here' but relocated.
  */
 
-	ldr	sp, [r8, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
+	ldr	sp, [r9, #GD_START_ADDR_SP]	/* sp = gd->start_addr_sp */
 	bic	sp, sp, #7	/* 8-byte alignment for ABI compliance */
-	ldr	r8, [r8, #GD_BD]		/* r8 = gd->bd */
-	sub	r8, r8, #GD_SIZE		/* new GD is below bd */
+	ldr	r9, [r9, #GD_BD]		/* r9 = gd->bd */
+	sub	r9, r9, #GD_SIZE		/* new GD is below bd */
 
 	adr	lr, here
-	ldr	r0, [r8, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
+	ldr	r0, [r9, #GD_RELOC_OFF]		/* r0 = gd->reloc_off */
 	add	lr, lr, r0
-	ldr	r0, [r8, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
+	ldr	r0, [r9, #GD_RELOCADDR]		/* r0 = gd->relocaddr */
 	b	relocate_code
 here:
 
@@ -111,8 +111,8 @@ clbss_l:cmp	r0, r1			/* while not at end of BSS */
 	bl red_led_on
 
 	/* call board_init_r(gd_t *id, ulong dest_addr) */
-	mov	r0, r8			/* gd_t */
-	ldr	r1, [r8, #GD_RELOCADDR]	/* dest_addr */
+	mov     r0, r9                  /* gd_t */
+	ldr	r1, [r9, #GD_RELOCADDR]	/* dest_addr */
 	/* call board_init_r */
 	ldr	pc, =board_init_r	/* this is auto-relocated! */
 
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 3/3] README: update ARM register usage
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 1/3] ARM,relocate: do not use r9 Jeroen Hofstee
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd Jeroen Hofstee
@ 2013-09-21 12:04   ` Jeroen Hofstee
  2013-09-23 16:56   ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Albert ARIBAUD
  3 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-21 12:04 UTC (permalink / raw)
  To: u-boot

Besides the change of this patchset it also updates the
README to reflect that GOT-generated relocations are no
longer supported on ARM.

cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
---
 README | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/README b/README
index ccd47fa..ec3e60b 100644
--- a/README
+++ b/README
@@ -5588,15 +5588,17 @@ On ARM, the following registers are used:
 
 	R0:	function argument word/integer result
 	R1-R3:	function argument word
-	R9:	GOT pointer
-	R10:	stack limit (used only if stack checking if enabled)
+	R9:	platform specific
+	R10:	stack limit (used only if stack checking is enabled)
 	R11:	argument (frame) pointer
 	R12:	temporary workspace
 	R13:	stack pointer
 	R14:	link register
 	R15:	program counter
 
-    ==> U-Boot will use R8 to hold a pointer to the global data
+    ==> U-Boot will use R9 to hold a pointer to the global data
+
+    Note: on ARM, only R_ARM_RELATIVE relocations are supported.
 
 On Nios II, the ABI is documented here:
 	http://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf
-- 
1.8.1.2

^ permalink raw reply related	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd Jeroen Hofstee
@ 2013-09-21 15:30     ` Jeroen Hofstee
  0 siblings, 0 replies; 31+ messages in thread
From: Jeroen Hofstee @ 2013-09-21 15:30 UTC (permalink / raw)
  To: u-boot

Hello Albert,

On 09/21/2013 02:04 PM, Jeroen Hofstee wrote:
> cc: Albert ARIBAUD <albert.u.boot@aribaud.net>
>
> ---
> This patch depends on http://patchwork.ozlabs.org/patch/273377/
>
> Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>
> ---
>

Could you be so kind to remove the first --- and comment
if you apply this. As is, it will drop the signed off as well...
I can send a new version as well of course if you prefer that.

Regards,
Jeroen

^ permalink raw reply	[flat|nested] 31+ messages in thread
* [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8
  2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
                     ` (2 preceding siblings ...)
  2013-09-21 12:04   ` [U-Boot] [PATCH v3 3/3] README: update ARM register usage Jeroen Hofstee
@ 2013-09-23 16:56   ` Albert ARIBAUD
  3 siblings, 0 replies; 31+ messages in thread
From: Albert ARIBAUD @ 2013-09-23 16:56 UTC (permalink / raw)
  To: u-boot

Hi Jeroen,

On Sat, 21 Sep 2013 14:04:39 +0200, Jeroen Hofstee
<jeroen@myspectrum.nl> wrote:

> Changes for v3:
> Drop the unneeded cc-option for the fixed flag.
> 
> Drop "make reserving the gd register a make variable"
> and use http://patchwork.ozlabs.org/patch/273377/
> "ARM: refactor compiler options in config.mk" instead.
> 
> Changes for v2:
> Update the README as requested by Wolfgang Denk
> 
> Jeroen Hofstee (3):
>   ARM,relocate: do not use r9
>   ARM: use r9 for gd
>   README: update ARM register usage
> 
>  README                             |  8 +++++---
>  arch/arm/config.mk                 |  2 +-
>  arch/arm/cpu/armv7/lowlevel_init.S |  4 ++--
>  arch/arm/include/asm/global_data.h |  2 +-
>  arch/arm/lib/crt0.S                | 16 ++++++++--------
>  arch/arm/lib/relocate.S            |  6 +++---
>  6 files changed, 20 insertions(+), 18 deletions(-)
> 

Applied to u-boot-arm/master (with the fix to the 2/3 comment), thanks!

Amicalement,
-- 
Albert.

^ permalink raw reply	[flat|nested] 31+ messages in thread
end of thread, other threads:[~2013-09-23 16:56 UTC | newest]

Thread overview: 31+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2013-08-11 20:58 [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
2013-08-11 20:58 ` [U-Boot] [PATCH 1/3] ARM: make reserving the gd register a make variable Jeroen Hofstee
2013-08-11 20:58 ` [U-Boot] [PATCH 2/3] ARM,relocate: do not use r9 Jeroen Hofstee
2013-08-11 20:58 ` [U-Boot] [PATCH 3/3] ARM: use r9 for gd Jeroen Hofstee
2013-08-12  5:53   ` Wolfgang Denk
2013-08-12 14:44     ` Albert ARIBAUD
2013-08-12 15:23       ` Wolfgang Denk
2013-08-13 19:41         ` Jeroen Hofstee
2013-08-11 22:08 ` [U-Boot] [PATCH 0/3] ARM: use r9 for gd instead of r8 Benoît Thébaudeau
2013-08-12  5:49   ` Albert ARIBAUD
2013-08-13 19:36   ` Jeroen Hofstee
2013-08-14 18:25 ` [U-Boot] [PATCH v2 0/4] " Jeroen Hofstee
2013-08-14 18:25   ` [U-Boot] [PATCH v2 1/4] ARM: make reserving the gd register a make variable Jeroen Hofstee
2013-08-17 13:55     ` Jeroen Hofstee
2013-09-19  6:57       ` Albert ARIBAUD
2013-09-19 16:54         ` Jeroen Hofstee
2013-08-14 18:25   ` [U-Boot] [PATCH v2 2/4] ARM,relocate: do not use r9 Jeroen Hofstee
2013-08-14 18:25   ` [U-Boot] [PATCH v2 3/4] ARM: use r9 for gd Jeroen Hofstee
2013-08-17  9:40     ` Jeroen Hofstee
2013-08-17 13:51       ` Jeroen Hofstee
2013-08-19  3:08       ` Simon Glass
2013-08-19 17:32         ` Jeroen Hofstee
2013-08-21 16:22           ` Jeroen Hofstee
2013-08-21 23:44             ` Simon Glass
2013-08-14 18:25   ` [U-Boot] [PATCH v2 4/4] README: update ARM register usage Jeroen Hofstee
2013-09-21 12:04 ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Jeroen Hofstee
2013-09-21 12:04   ` [U-Boot] [PATCH v3 1/3] ARM,relocate: do not use r9 Jeroen Hofstee
2013-09-21 12:04   ` [U-Boot] [PATCH v3 2/3] ARM: use r9 for gd Jeroen Hofstee
2013-09-21 15:30     ` Jeroen Hofstee
2013-09-21 12:04   ` [U-Boot] [PATCH v3 3/3] README: update ARM register usage Jeroen Hofstee
2013-09-23 16:56   ` [U-Boot] [PATCH v3 0/3] ARM: use r9 for gd instead of r8 Albert ARIBAUD

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