[U-Boot] [PATCH] powerpc/mpc85xx: Use GOT when loading IVORs post-relocation

[Shaohui Xie]

Tested on T4240QDS_NAND and T4240QDS_SDCARD, the hang issue fixed.
Thanks!

Best Regards, 
Shaohui Xie

> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Friday, April 24, 2015 9:02 AM
> To: u-boot at lists.denx.de; Sun York-R58495
> Cc: Wood Scott-B07421; Alexander Graf; Xie Shaohui-B21989
> Subject: [PATCH] powerpc/mpc85xx: Use GOT when loading IVORs post-
> relocation
> 
> Commit 96d2bb952bb ("powerpc/mpc85xx: Don't relocate exception vectors")
> simplified IVOR initialization a bit too much, failing to use the post-
> relocation offset.  This doesn't cause a problem with normal NOR boot, in
> which both the pre-relocation and post-relocation addresses are 64 KiB
> aligned.  However, if TEXT_BASE is only 4 KiB aligned, such as for
> NAND/SD/etc. boot on some targets, as well as the QEMU target, the post-
> relocation address will not be the same in the lower 16 bits, as
> reserve_uboot() ensures that the relocation address is always 64 KiB
> aligned even if the pre-relocation address was not.
> 
> Use the GOT to get the proper post-relocation offsets.
> 
> Fixes: 96d2bb952bb ("powerpc/mpc85xx: Don't relocate exception vectors")
> Signed-off-by: Scott Wood <scottwood at freescale.com>
> Cc: Alexander Graf <agraf at suse.de>
> Cc: Shaohui Xie <Shaohui.Xie at freescale.com>
> ---
>  arch/powerpc/cpu/mpc85xx/start.S | 35 ++++++++++++++++++++--------------
> -
>  1 file changed, 20 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/powerpc/cpu/mpc85xx/start.S
> b/arch/powerpc/cpu/mpc85xx/start.S
> index 28f04ee..e61d8e0 100644
> --- a/arch/powerpc/cpu/mpc85xx/start.S
> +++ b/arch/powerpc/cpu/mpc85xx/start.S
> @@ -1664,41 +1664,46 @@ clear_bss:
>  	 */
>  	.globl	trap_init
>  trap_init:
> +	mflr	r11
> +	bl	_GLOBAL_OFFSET_TABLE_-4
> +	mflr	r12
> +
>  	/* Update IVORs as per relocation */
>  	mtspr	IVPR,r3
> 
> -	li	r4,CriticalInput at l
> +	lwz	r4,CriticalInput at got(r12)
>  	mtspr	IVOR0,r4	/* 0: Critical input */
> -	li	r4,MachineCheck at l
> +	lwz	r4,MachineCheck at got(r12)
>  	mtspr	IVOR1,r4	/* 1: Machine check */
> -	li	r4,DataStorage at l
> +	lwz	r4,DataStorage at got(r12)
>  	mtspr	IVOR2,r4	/* 2: Data storage */
> -	li	r4,InstStorage at l
> +	lwz	r4,InstStorage at got(r12)
>  	mtspr	IVOR3,r4	/* 3: Instruction storage */
> -	li	r4,ExtInterrupt at l
> +	lwz	r4,ExtInterrupt at got(r12)
>  	mtspr	IVOR4,r4	/* 4: External interrupt */
> -	li	r4,Alignment at l
> +	lwz	r4,Alignment at got(r12)
>  	mtspr	IVOR5,r4	/* 5: Alignment */
> -	li	r4,ProgramCheck at l
> +	lwz	r4,ProgramCheck at got(r12)
>  	mtspr	IVOR6,r4	/* 6: Program check */
> -	li	r4,FPUnavailable at l
> +	lwz	r4,FPUnavailable at got(r12)
>  	mtspr	IVOR7,r4	/* 7: floating point unavailable */
> -	li	r4,SystemCall at l
> +	lwz	r4,SystemCall at got(r12)
>  	mtspr	IVOR8,r4	/* 8: System call */
>  	/* 9: Auxiliary processor unavailable(unsupported) */
> -	li	r4,Decrementer at l
> +	lwz	r4,Decrementer at got(r12)
>  	mtspr	IVOR10,r4	/* 10: Decrementer */
> -	li	r4,IntervalTimer at l
> +	lwz	r4,IntervalTimer at got(r12)
>  	mtspr	IVOR11,r4	/* 11: Interval timer */
> -	li	r4,WatchdogTimer at l
> +	lwz	r4,WatchdogTimer at got(r12)
>  	mtspr	IVOR12,r4	/* 12: Watchdog timer */
> -	li	r4,DataTLBError at l
> +	lwz	r4,DataTLBError at got(r12)
>  	mtspr	IVOR13,r4	/* 13: Data TLB error */
> -	li	r4,InstructionTLBError at l
> +	lwz	r4,InstructionTLBError at got(r12)
>  	mtspr	IVOR14,r4	/* 14: Instruction TLB error */
> -	li	r4,DebugBreakpoint at l
> +	lwz	r4,DebugBreakpoint at got(r12)
>  	mtspr	IVOR15,r4	/* 15: Debug */
> 
> +	mtlr	r11
>  	blr
> 
>  .globl unlock_ram_in_cache
> --
> 2.1.0