Subject: Re: [v2][PATCH 1/7] powerpc/book3e: support CONFIG_RELOCATABLE

From: "tiejun.chen" <[email-masked]>
Date: Tue, 9 Jul 2013 15:55:25 +0800

On 07/03/2013 07:52 PM, Sethi Varun-B16395 wrote:
>
>
>> -----Original Message-----
>> From: Linuxppc-dev [mailto:linuxppc-dev-
>> bounces+varun.sethi=[email-masked]] On Behalf Of Tiejun
>> Chen
>> Sent: Thursday, June 20, 2013 1:23 PM
>> To: [email-masked]
>> Cc: [email-masked]; [email-masked]
>> Subject: [v2][PATCH 1/7] powerpc/book3e: support CONFIG_RELOCATABLE
>>
>> book3e is different with book3s since 3s includes the exception vectors
>> code in head_64.S as it relies on absolute addressing which is only
>> possible within this compilation unit. So we have to get that label
>> address with got.
>>
>> And when boot a relocated kernel, we should reset ipvr properly again
>> after .relocate.
>>
>> Signed-off-by: Tiejun Chen <[email-masked]>
>> ---
>>   arch/powerpc/include/asm/exception-64e.h |    8 ++++++++
>>   arch/powerpc/kernel/exceptions-64e.S     |   15 ++++++++++++++-
>>   arch/powerpc/kernel/head_64.S            |   22 ++++++++++++++++++++++
>>   arch/powerpc/lib/feature-fixups.c        |    7 +++++++
>>   4 files changed, 51 insertions(+), 1 deletion(-)
>>
>> diff --git a/arch/powerpc/include/asm/exception-64e.h
>> b/arch/powerpc/include/asm/exception-64e.h
>> index 51fa43e..89e940d 100644
>> --- a/arch/powerpc/include/asm/exception-64e.h
>> +++ b/arch/powerpc/include/asm/exception-64e.h
>> @@ -214,10 +214,18 @@ exc_##label##_book3e:
>>   #define TLB_MISS_STATS_SAVE_INFO_BOLTED  #endif
>>
>> +#ifndef CONFIG_RELOCATABLE
>>   #define SET_IVOR(vector_number, vector_offset)	\
>>   	li	r3,vector_offset@l; 		\
>>   	ori	r3,r3,interrupt_base_book3e@l;	\
>>   	mtspr	SPRN_IVOR##vector_number,r3;
>> +#else
>> +#define SET_IVOR(vector_number, vector_offset)	\
>> +	LOAD_REG_ADDR(r3,interrupt_base_book3e);\
>> +	rlwinm	r3,r3,0,15,0;			\
>> +	ori	r3,r3,vector_offset@l;		\
>> +	mtspr	SPRN_IVOR##vector_number,r3;
>> +#endif
>>
> [Sethi Varun-B16395] Please add a documentation note here.

Okay.

>
>>   #endif /* _ASM_POWERPC_EXCEPTION_64E_H */
>>
>> diff --git a/arch/powerpc/kernel/exceptions-64e.S
>> b/arch/powerpc/kernel/exceptions-64e.S
>> index 645170a..4b23119 100644
>> --- a/arch/powerpc/kernel/exceptions-64e.S
>> +++ b/arch/powerpc/kernel/exceptions-64e.S
>> @@ -1097,7 +1097,15 @@ skpinv:	addi	r6,r6,1
>> 	/* Increment */
>>    * r4 = MAS0 w/TLBSEL & ESEL for the temp mapping
>>    */
>>   	/* Now we branch the new virtual address mapped by this entry */
>> +#ifdef CONFIG_RELOCATABLE
>> +	/* We have to find out address from lr. */
>> +	bl	1f		/* Find our address */
>> +1:	mflr	r6
>> +	addi	r6,r6,(2f - 1b)
>> +	tovirt(r6,r6)
>> +#else
>>   	LOAD_REG_IMMEDIATE(r6,2f)
>> +#endif
>>   	lis	r7,MSR_KERNEL@h
>>   	ori	r7,r7,MSR_KERNEL@l
>>   	mtspr	SPRN_SRR0,r6
>> @@ -1348,9 +1356,14 @@ _GLOBAL(book3e_secondary_thread_init)
>>   	mflr	r28
>>   	b	3b
>>
>> -_STATIC(init_core_book3e)
>> +_GLOBAL(init_core_book3e)
>>   	/* Establish the interrupt vector base */
>> +#ifdef CONFIG_RELOCATABLE
>> +	tovirt(r2,r2)
>> +	LOAD_REG_ADDR(r3, interrupt_base_book3e) #else
>>   	LOAD_REG_IMMEDIATE(r3, interrupt_base_book3e)
>> +#endif
>>   	mtspr	SPRN_IVPR,r3
>>   	sync
>>   	blr
> [Sethi Varun-B16395] Please add a documentation note here as well.

Okay.

>
>> diff --git a/arch/powerpc/kernel/head_64.S
>> b/arch/powerpc/kernel/head_64.S index b61363d..0942f3a 100644
>> --- a/arch/powerpc/kernel/head_64.S
>> +++ b/arch/powerpc/kernel/head_64.S
>> @@ -414,12 +414,22 @@ _STATIC(__after_prom_start)
>>   	/* process relocations for the final address of the kernel */
>>   	lis	r25,PAGE_OFFSET@highest	/* compute virtual base of kernel */
>>   	sldi	r25,r25,32
>> +#if defined(CONFIG_PPC_BOOK3E)
>> +	tovirt(r26,r26)			/* on booke, we already run at
>> PAGE_OFFSET */
>> +#endif
>>   	lwz	r7,__run_at_load-_stext(r26)
>> +#if defined(CONFIG_PPC_BOOK3E)
>> +	tophys(r26,r26)			/* Restore for the remains. */
>> +#endif
>>   	cmplwi	cr0,r7,1	/* flagged to stay where we are ? */
>>   	bne	1f
>>   	add	r25,r25,r26
>>   1:	mr	r3,r25
>>   	bl	.relocate
>> +#if defined(CONFIG_PPC_BOOK3E)
>> +	/* We should set ivpr again after .relocate. */
>> +	bl	.init_core_book3e
>> +#endif
>>   #endif
>>
> [Sethi Varun-B16395] A more detailed note over here would be useful.

Okay.

>
>>   /*
>> @@ -447,12 +457,24 @@ _STATIC(__after_prom_start)
>>    * variable __run_at_load, if it is set the kernel is treated as
>> relocatable
>>    * kernel, otherwise it will be moved to PHYSICAL_START
>>    */
>> +#if defined(CONFIG_PPC_BOOK3E)
>> +	tovirt(r26,r26)			/* on booke, we already run at
>> PAGE_OFFSET */
>> +#endif
>>   	lwz	r7,__run_at_load-_stext(r26)
>> +#if defined(CONFIG_PPC_BOOK3E)
>> +	tophys(r26,r26)			/* Restore for the remains. */
>> +#endif
>>   	cmplwi	cr0,r7,1
>>   	bne	3f
>>
>> +#ifdef CONFIG_PPC_BOOK3E
>> +	LOAD_REG_ADDR(r5, interrupt_end_book3e)
>> +	LOAD_REG_ADDR(r11, _stext)
>> +	sub	r5,r5,r11
>> +#else
>>   	/* just copy interrupts */
>>   	LOAD_REG_IMMEDIATE(r5, __end_interrupts - _stext)
>> +#endif
>>   	b	5f
>>   3:
>>   #endif
>> diff --git a/arch/powerpc/lib/feature-fixups.c
>> b/arch/powerpc/lib/feature-fixups.c
>> index 7a8a748..13f20ed 100644
>> --- a/arch/powerpc/lib/feature-fixups.c
>> +++ b/arch/powerpc/lib/feature-fixups.c
>> @@ -135,13 +135,20 @@ void do_final_fixups(void)  #if
>> defined(CONFIG_PPC64) && defined(CONFIG_RELOCATABLE)
>>   	int *src, *dest;
>>   	unsigned long length;
>> +#ifdef CONFIG_PPC_BOOK3E
>> +	extern char interrupt_end_book3e[];
>> +#endif
> [Sethi Varun-B16395] You can simply move this to sections.h and remove the ifdefs.

I would replace interrupt_end_book3e with __end_interrupts then we can have a 
unique label for book3e and book3s as Bharat mentioned previously.

Thanks

Tiejun