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ARM: use r9 for gd instead of r8

PATCH New Jeroen Hofstee 6 participants 31 messages Aug 11, 2013 – Sep 23, 2013

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Jeroen Hofstee

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#0 lore raw

cover ARM: use r9 for gd instead of r8

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(-)
Signature · 1 line
1.8.1.2
author
#1 lore raw

PATCH 1/3 ARM: make reserving the gd register a make variable

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 <[email protected]>
---
 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(-)
arch/arm/config.mk +2 -0
index 540a119..5e382ab 100644
@@ -98,3 +98,5 @@ endif
 ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
+
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
arch/arm/cpu/arm1136/config.mk +1 -1
index 1ef6061..daca1bd 100644
@@ -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
arch/arm/cpu/arm1176/config.mk +1 -1
index 917da03..163778a 100644
@@ -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
arch/arm/cpu/arm720t/config.mk +1 -1
index 56b6280..f1fb6a8 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm920t/config.mk +1 -1
index 58fd756..a6b2c6f 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm925t/config.mk +1 -1
index 58fd756..a6b2c6f 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm926ejs/config.mk +1 -1
index 917ff7e..a29634d 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm946es/config.mk +1 -1
index 1e41c11..7465da1 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm_intcm/config.mk +1 -1
index 1e41c11..7465da1 100644
@@ -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
 # =========================================================================
arch/arm/cpu/armv7/config.mk +1 -1
index ca4a9e7..22be8df 100644
@@ -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
arch/arm/cpu/armv7/rmobile/config.mk +1 -1
index 4f01610..fbf4b61 100644
@@ -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
arch/arm/cpu/ixp/config.mk +1 -1
index 0f12f8b..ca2c182 100644
@@ -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
arch/arm/cpu/pxa/config.mk +1 -1
index 535bca3..c6b8f0b 100644
@@ -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
 # =========================================================================
arch/arm/cpu/s3c44b0/config.mk +1 -1
index b902ca3..424584a 100644
@@ -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
 # =========================================================================
arch/arm/cpu/sa1100/config.mk +1 -1
index 576f685..d94e855 100644
@@ -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
 # =========================================================================
Signature · 1 line
1.8.1.2
author
#2 lore raw

PATCH 2/3 ARM,relocate: do not use r9

In reply to Jeroen Hofstee

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 <[email protected]>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
arch/arm/lib/relocate.S +3 -3
index ab90430..a62a556 100644
@@ -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
Signature · 1 line
1.8.1.2
author
#3 lore raw

PATCH 3/3 ARM: use r9 for gd

In reply to Jeroen Hofstee

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 <[email protected]>
---
 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(-)
arch/arm/config.mk +1 -1
index 5e382ab..5f6e032 100644
@@ -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)
arch/arm/include/asm/global_data.h +1 -1
index 79a9597..e126436 100644
@@ -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 */
arch/arm/lib/crt0.S +8 -8
index 960d12e..ac54b93 100644
@@ -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! */
Signature · 1 line
1.8.1.2
#4 lore raw

PATCH 3/3 ARM: use r9 for gd

Dear Jeroen Hofstee,

Quoted 11 lines · In message <[email protected]> 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

Quoted 6 lines
Signed-off-by Jeroen Hofstee <[email protected]>
---
 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

Signature · 4 lines
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"
#5 lore raw

PATCH 3/3 ARM: use r9 for gd

Hi Wolfgang,

Quoted 14 lines · Wolfgang Denk

Dear Jeroen Hofstee,

Quoted 11 lines · In message <[email protected]> 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

Quoted 8 lines
Quoted 6 lines
Signed-off-by Jeroen Hofstee <[email protected]>
---
 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.

Quoted 7 lines

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

Best regards,

Wolfgang Denk

Amicalement,

Signature · 1 line
Albert.
#6 lore raw

PATCH 3/3 ARM: use r9 for gd

Dear Albert,

Quoted 8 lines · In message <20130812164406.5a6807e7@lilith> you wrote:
Quoted 2 lines

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.

Quoted 2 lines

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

Signature · 6 lines
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
author
#7 lore raw

PATCH 3/3 ARM: use r9 for gd

Hi,

Quoted 11 lines · Wolfgang Denk

Dear Albert,

Quoted 6 lines · In message <20130812164406.5a6807e7@lilith> you wrote:
Quoted 1 line

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.

Quoted 2 lines

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

#8 lore raw

cover ARM: use r9 for gd instead of r8

In reply to Jeroen Hofstee

Dear Jeroen Hofstee,

Quoted 3 lines · Jeroen Hofstee

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

#9 lore raw

cover ARM: use r9 for gd instead of r8

Hi Beno?t,

Quoted 10 lines · Beno?t Th?baudeau

Dear Jeroen Hofstee,

Quoted 3 lines · Jeroen Hofstee

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.

Quoted 5 lines

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.

Quoted 2 lines

Best regards,
Beno?t

Amicalement,

Signature · 1 line
Albert.
author
#10 lore raw

cover ARM: use r9 for gd instead of r8

In reply to Benoît Thébaudeau

Hello Beno?t,

Quoted 7 lines · Beno?t Th?baudeau
Quoted 3 lines · Jeroen Hofstee

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.

Quoted 5 lines

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

author
#11 lore raw

v2 cover ARM: use r9 for gd instead of r8

In reply to Jeroen Hofstee

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(-)
Signature · 1 line
1.8.1.2
author
#12 lore raw

PATCH v2 1/4 ARM: make reserving the gd register a make variable

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 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(-)
arch/arm/config.mk +2 -0
index 540a119..5e382ab 100644
@@ -98,3 +98,5 @@ endif
 ifneq ($(CONFIG_SPL_BUILD),y)
 ALL-y	+= checkarmreloc
 endif
+
+OPTION_FIXED_GD=$(call cc-option, -ffixed-r8)
arch/arm/cpu/arm1136/config.mk +1 -1
index 1ef6061..daca1bd 100644
@@ -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
arch/arm/cpu/arm1176/config.mk +1 -1
index 917da03..163778a 100644
@@ -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
arch/arm/cpu/arm720t/config.mk +1 -1
index 56b6280..f1fb6a8 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm920t/config.mk +1 -1
index 58fd756..a6b2c6f 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm925t/config.mk +1 -1
index 58fd756..a6b2c6f 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm926ejs/config.mk +1 -1
index 917ff7e..a29634d 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm946es/config.mk +1 -1
index 1e41c11..7465da1 100644
@@ -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
 # =========================================================================
arch/arm/cpu/arm_intcm/config.mk +1 -1
index 1e41c11..7465da1 100644
@@ -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
 # =========================================================================
arch/arm/cpu/armv7/config.mk +1 -1
index ca4a9e7..22be8df 100644
@@ -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
arch/arm/cpu/armv7/rmobile/config.mk +1 -1
index 4f01610..fbf4b61 100644
@@ -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
arch/arm/cpu/ixp/config.mk +1 -1
index 0f12f8b..ca2c182 100644
@@ -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
arch/arm/cpu/pxa/config.mk +1 -1
index 535bca3..c6b8f0b 100644
@@ -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
 # =========================================================================
arch/arm/cpu/s3c44b0/config.mk +1 -1
index b902ca3..424584a 100644
@@ -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
 # =========================================================================
arch/arm/cpu/sa1100/config.mk +1 -1
index 576f685..d94e855 100644
@@ -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
 # =========================================================================
Signature · 1 line
1.8.1.2
author
#13 lore raw

PATCH v2 1/4 ARM: make reserving the gd register a make variable

arch/arm/config.mk endif · line 102

Quoted 10 lines · Jeroen Hofstee
arch/arm/config.mk +2 -0
index 540a119..5e382ab 100644
@@ -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

#14 lore raw

PATCH v2 1/4 ARM: make reserving the gd register a make variable

Hi Jeroen,

Quoted 14 lines · Jeroen Hofstee

arch/arm/config.mk endif · line 102

Quoted 10 lines · Jeroen Hofstee
arch/arm/config.mk +2 -0
index 540a119..5e382ab 100644
@@ -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?

Quoted 2 lines

Regards,
Jeroen

Amicalement,

Signature · 1 line
Albert.
author
#15 lore raw

PATCH v2 1/4 ARM: make reserving the gd register a make variable

Hello Albert,

Quoted 16 lines · Albert ARIBAUD
Quoted 13 lines · Jeroen Hofstee

arch/arm/config.mk endif · line 102

Quoted 10 lines · Jeroen Hofstee
arch/arm/config.mk +2 -0
index 540a119..5e382ab 100644
@@ -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.

Quoted 2 lines

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

author
#16 lore raw

PATCH v2 2/4 ARM,relocate: do not use r9

In reply to Jeroen Hofstee

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
arch/arm/lib/relocate.S +3 -3
index ab90430..a62a556 100644
@@ -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
Signature · 1 line
1.8.1.2
author
#17 lore raw

PATCH v2 3/4 ARM: use r9 for gd

In reply to Jeroen Hofstee

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 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(-)
arch/arm/config.mk +1 -1
index 5e382ab..5f6e032 100644
@@ -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)
arch/arm/include/asm/global_data.h +1 -1
index 79a9597..e126436 100644
@@ -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 */
arch/arm/lib/crt0.S +8 -8
index 960d12e..ac54b93 100644
@@ -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! */
Signature · 1 line
1.8.1.2
author
#18 lore raw

PATCH v2 3/4 ARM: use r9 for gd

Quoted 11 lines · Jeroen Hofstee

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

Quoted 8 lines
cc Albert ARIBAUD <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
  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

author
#19 lore raw

PATCH v2 3/4 ARM: use r9 for gd

Quoted 21 lines · Jeroen Hofstee
Quoted 11 lines · Jeroen Hofstee

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

Quoted 8 lines
cc Albert ARIBAUD <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
  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(-)
Quoted 4 lines

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

#20 lore raw

PATCH v2 3/4 ARM: use r9 for gd

In reply to Jeroen Hofstee

Hi Jeroen,

Quoted 22 lines · Jeroen Hofstee
Quoted 12 lines · Jeroen Hofstee

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

Quoted 8 lines
cc Albert ARIBAUD <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
  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(-)
Quoted 4 lines

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

author
#21 lore raw

PATCH v2 3/4 ARM: use r9 for gd

Hello Simon,

Quoted 7 lines · Simon Glass
Quoted 5 lines · Jeroen Hofstee

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).

Quoted 11 lines

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;

Quoted 5 lines

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

author
#22 lore raw

PATCH v2 3/4 ARM: use r9 for gd

Hello Simon,

Quoted 9 lines · Jeroen Hofstee
Quoted 7 lines · Simon Glass
Quoted 5 lines · Jeroen Hofstee

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....

Quoted 6 lines
Quoted 1 line

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

Quoted 11 lines
Quoted 11 lines

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;

Quoted 6 lines
Quoted 5 lines

gd = &data;
#endif

gd->flags = boot_flags;

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

Thanks, Regards,
Jeroen

#23 lore raw

PATCH v2 3/4 ARM: use r9 for gd

Hi Jeroen,

Quoted 20 lines · Jeroen Hofstee

Hello Simon,

Quoted 16 lines · Jeroen Hofstee
Quoted 11 lines · Simon Glass
Quoted 6 lines · Jeroen Hofstee

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,

Quoted 7 lines
Quoted 4 lines

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.

Quoted 17 lines

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

Quoted 11 lines
Quoted 11 lines

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;

Quoted 8 lines
Quoted 6 lines
Quoted 5 lines

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

author
#24 lore raw

PATCH v2 4/4 README: update ARM register usage

In reply to Jeroen Hofstee

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 README | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
README +5 -3
index 3918807..d8af074 100644
@@ -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
Signature · 1 line
1.8.1.2
author
#25 lore raw

v3 cover ARM: use r9 for gd instead of r8

In reply to Jeroen Hofstee

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(-)
Signature · 1 line
1.8.1.2
author
#26 lore raw

PATCH v3 1/3 ARM,relocate: do not use r9

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 arch/arm/lib/relocate.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)
arch/arm/lib/relocate.S +3 -3
index ab90430..a62a556 100644
@@ -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
Signature · 1 line
1.8.1.2
author
#27 lore raw

PATCH v3 2/3 ARM: use r9 for gd

In reply to Jeroen Hofstee

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 <[email protected]>

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

Signed-off-by Jeroen Hofstee <[email protected]>
---
 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(-)
arch/arm/config.mk +1 -1
index 070dfab..6d1bca9 100644
@@ -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
arch/arm/cpu/armv7/lowlevel_init.S +2 -2
index 82b2b86..69e3053 100644
@@ -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
arch/arm/include/asm/global_data.h +1 -1
index 79a9597..e126436 100644
@@ -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 */
arch/arm/lib/crt0.S +8 -8
index 960d12e..ac54b93 100644
@@ -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! */
Signature · 1 line
1.8.1.2
author
#29 lore raw

PATCH v3 3/3 README: update ARM register usage

In reply to Jeroen Hofstee

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 <[email protected]>
Signed-off-by Jeroen Hofstee <[email protected]>
---
 README | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)
README +5 -3
index ccd47fa..ec3e60b 100644
@@ -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
Signature · 1 line
1.8.1.2
#30 lore raw

v3 cover ARM: use r9 for gd instead of r8

In reply to Jeroen Hofstee

Hi Jeroen,

Quoted 15 lines · Jeroen Hofstee

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

Quoted 8 lines
 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,

Signature · 1 line
Albert.