[U-Boot] [PATCH v7 1/5] core support of arm64

[FengHua]

> -----原始邮件-----
> 发件人: "Scott Wood" <scottwood at freescale.com>
> 发送时间: 2013年9月12日 星期四
> 收件人: fenghua at phytium.com.cn
> 抄送: u-boot at lists.denx.de, trini at ti.com
> 主题: Re: [U-Boot] [PATCH v7 1/5] core support of arm64
> 
> On Tue, 2013-09-10 at 16:12 +0800, fenghua at phytium.com.cn wrote:
> > +/*
> > + * Enter Exception.
> > + * This will save the processor state that is X0~X29/LR/SP/ELR/PSTATE
> > + * to the stack frame.
> > + */
> > +#define	EXCEPTION_ENTRY				\
> 
> asm macros are nicer.
> 
> > +	sub	sp, sp, S_FRAME_SIZE - S_LR	;\
> > +	push	x28, x29			;\
> > +	push	x26, x27			;\
> > +	push	x24, x25			;\
> > +	push	x22, x23			;\
> > +	push	x20, x21			;\
> > +	push	x18, x19			;\
> > +	push	x16, x17			;\
> > +	push	x14, x15			;\
> > +	push	x12, x13			;\
> > +	push	x10, x11			;\
> > +	push	x8, x9				;\
> > +	push	x6, x7				;\
> > +	push	x4, x5				;\
> > +	push	x2, x3				;\
> > +	push	x0, x1				;\
> > +	add	x21, sp, S_FRAME_SIZE		;\
> 
> You just happened to pick x21 for this on your rewrite?
> 
The preservation of exception state just should be that.
If this got problem, I'd like to remove it. Actually, it's unnecessary currently.

Best regards,

> > +						;\
> > +	/* Could be running at EL1 or EL2 */	;\
> > +	mrs	x0, CurrentEL			;\
> > +	cmp	x0, 0x4				;\
> > +	b.eq	1f				;\
> > +	cmp	x0, 0x8				;\
> > +	b.eq	2f				;\
> > +	b	3f				;\
> > +1:	mrs	x22, elr_el1			;\
> > +	mrs	x23, spsr_el1			;\
> 
> Likewise x22 and x23.  Taking Linux code and altering details is not the
> same thing as writing from scratch and does not free the code from
> GPLv2-only or the need to attribute.
> 
> Given how many times we've gone back and forth on this sort of thing,
> I'm rather nervous about the legal status of this patchset in general.
> What other copying is there that I haven't noticed?
> 
> -Scott
> 
> 
>