[U-Boot-Users] [PATCH] Allow building mips versions with ELDK 3.1.1

[U-Boot-Users] [PATCH] Allow building mips versions with ELDK 3.1.1

[Vlad Lungu]

.gpword works only with local symbols on certain binutils versions

Signed-off-by: Vlad Lungu <vlad.lungu@windrvier.com>
---
 cpu/mips/start.S |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/cpu/mips/start.S b/cpu/mips/start.S
index 6e1a78c..947128d 100644
--- a/cpu/mips/start.S
+++ b/cpu/mips/start.S
@@ -345,7 +345,8 @@ relocate_code:
 	jr	t0
 	nop
 
-	.gpword	_GLOBAL_OFFSET_TABLE_	/* _GLOBAL_OFFSET_TABLE_ - _gp	*/
+	.word 	_gp
+	.word	_GLOBAL_OFFSET_TABLE_
 	.word	uboot_end_data
 	.word	uboot_end
 	.word	num_got_entries
@@ -358,8 +359,10 @@ in_ram:
 	 * generated by GNU ld. Skip these reserved entries from relocation.
 	 */
 	lw	t3, -4(t0)	/* t3 <-- num_got_entries	*/
-	lw	t4, -16(t0)	/* t4 <-- (_GLOBAL_OFFSET_TABLE_ - _gp)	*/
-	add	t4, t4, gp	/* t4 now holds _GLOBAL_OFFSET_TABLE_	*/
+	lw	t4, -16(t0)	/* t4 <-- _GLOBAL_OFFSET_TABLE_	*/
+	lw	t5, -20(t0)	/* t5 <-- _gp	*/
+	sub	t4, t5		/* compute offset*/
+	add	t4, t4, gp	/* t4 now holds relocated _GLOBAL_OFFSET_TABLE_	*/
 	addi	t4, t4, 8	/* Skipping first two entries.	*/
 	li	t2, 2
 1:
-- 
1.5.4

[U-Boot-Users] [PATCH] Allow building mips versions with ELDK 3.1.1

[Wolfgang Denk]

In message <481EE9A0.60403@windriver.com> you wrote:
> .gpword works only with local symbols on certain binutils versions
> 
> Signed-off-by: Vlad Lungu <vlad.lungu@windrvier.com>
> ---
>  cpu/mips/start.S |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)

Applied, thanks a lot.

This fixes the start.S erros/warnings.

So the only obvious problem remaining for MIPS are the cache.S
warnings:

cache.S:243: Warning: Pretending global symbol used as branch target is local.
cache.S:250: Warning: Pretending global symbol used as branch target is local.


Best regards,

Wolfgang Denk

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[U-Boot-Users] [PATCH] Allow building mips versions with ELDK 3.1.1

[Shinya Kuribayashi]

Wolfgang Denk wrote:
> In message <481EE9A0.60403@windriver.com> you wrote:
>> .gpword works only with local symbols on certain binutils versions
>>
>> Signed-off-by: Vlad Lungu <vlad.lungu@windrvier.com>
>> ---
>>  cpu/mips/start.S |    9 ++++++---
>>  1 files changed, 6 insertions(+), 3 deletions(-)
> 
> Applied, thanks a lot.
> 
> This fixes the start.S erros/warnings.

This patch works with my two different CPUs. Thanks!

> So the only obvious problem remaining for MIPS are the cache.S
> warnings:
> 
> cache.S:243: Warning: Pretending global symbol used as branch target is local.
> cache.S:250: Warning: Pretending global symbol used as branch target is local.

Assembler might be sensitive to global symbol references under PIC code
because they should be processed through GOT in principle.

Therefore, we should have set up function entry point explicitly like:

diff --git a/cpu/mips/cache.S b/cpu/mips/cache.S
index 8024a2e..7966079 100644
--- a/cpu/mips/cache.S
+++ b/cpu/mips/cache.S
@@ -239,14 +239,16 @@ NESTED(mips_cache_reset, 0, ra)
         */
        move    a1, t2
        move    a2, t4
-       bal     mips_init_icache
+       PTR_LA  t7, mips_init_icache
+       jalr    t7
 
        /*
         * then initialize D-cache.
         */
        move    a1, t3
        move    a2, t5
-       bal     mips_init_dcache
+       PTR_LA  t7, mips_init_dcache
+       jalr    t7
 
        jr      RA
        END(mips_cache_reset)

I'll post the patch later.

thanks,

  Shinya