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* [PATCH v2] riscv: Set text_offset correctly for M-Mode
@ 2020-10-22 20:30 Sean Anderson
  2020-10-22 23:55 ` Damien Le Moal
  0 siblings, 1 reply; 3+ messages in thread
From: Sean Anderson @ 2020-10-22 20:30 UTC (permalink / raw)
  To: linux-riscv
  Cc: Damien Le Moal, Albert Ou, Anup Patel, Sean Anderson,
	Atish Patra, Palmer Dabbelt, Paul Walmsley

M-Mode Linux is loaded at the start of RAM, not 2MB later. Perhaps this
should be calculated based on PAGE_OFFSET somehow? Even better would be to
deprecate text_offset and instead introduce something absolute.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
---

Changes in v2:
- RISCV_S_MODE does not exist; use RISCV_M_MODE instead

 arch/riscv/kernel/head.S | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
index 0a4e81b8dc79..5a0ae2eaf5e2 100644
--- a/arch/riscv/kernel/head.S
+++ b/arch/riscv/kernel/head.S
@@ -27,12 +27,17 @@ ENTRY(_start)
 	/* reserved */
 	.word 0
 	.balign 8
+#ifdef CONFIG_RISCV_M_MODE
+	/* Image load offset (0MB) from start of RAM for M-mode */
+	.dword 0
+#else
 #if __riscv_xlen == 64
 	/* Image load offset(2MB) from start of RAM */
 	.dword 0x200000
 #else
 	/* Image load offset(4MB) from start of RAM */
 	.dword 0x400000
 #endif
+#endif
 	/* Effective size of kernel image */
 	.dword _end - _start
-- 
2.28.0


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^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] riscv: Set text_offset correctly for M-Mode
  2020-10-22 20:30 [PATCH v2] riscv: Set text_offset correctly for M-Mode Sean Anderson
@ 2020-10-22 23:55 ` Damien Le Moal
  2020-11-06  1:43   ` Palmer Dabbelt
  0 siblings, 1 reply; 3+ messages in thread
From: Damien Le Moal @ 2020-10-22 23:55 UTC (permalink / raw)
  To: Sean Anderson, linux-riscv
  Cc: Anup Patel, Albert Ou, Palmer Dabbelt, Atish Patra, Paul Walmsley

On 2020/10/23 5:30, Sean Anderson wrote:
> M-Mode Linux is loaded at the start of RAM, not 2MB later. Perhaps this
> should be calculated based on PAGE_OFFSET somehow? Even better would be to
> deprecate text_offset and instead introduce something absolute.
> 
> Signed-off-by: Sean Anderson <seanga2@gmail.com>
> ---
> 
> Changes in v2:
> - RISCV_S_MODE does not exist; use RISCV_M_MODE instead
> 
>  arch/riscv/kernel/head.S | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
> index 0a4e81b8dc79..5a0ae2eaf5e2 100644
> --- a/arch/riscv/kernel/head.S
> +++ b/arch/riscv/kernel/head.S
> @@ -27,12 +27,17 @@ ENTRY(_start)
>  	/* reserved */
>  	.word 0
>  	.balign 8
> +#ifdef CONFIG_RISCV_M_MODE
> +	/* Image load offset (0MB) from start of RAM for M-mode */
> +	.dword 0
> +#else
>  #if __riscv_xlen == 64
>  	/* Image load offset(2MB) from start of RAM */
>  	.dword 0x200000
>  #else
>  	/* Image load offset(4MB) from start of RAM */
>  	.dword 0x400000
>  #endif
> +#endif
>  	/* Effective size of kernel image */
>  	.dword _end - _start
> 

Looks good to me. Added this to my upcoming pile of patches for Kendryte and
tested. No problems.

Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
Tested-by: Damien Le Moal <damien.lemoal@wdc.com>

-- 
Damien Le Moal
Western Digital Research

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^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH v2] riscv: Set text_offset correctly for M-Mode
  2020-10-22 23:55 ` Damien Le Moal
@ 2020-11-06  1:43   ` Palmer Dabbelt
  0 siblings, 0 replies; 3+ messages in thread
From: Palmer Dabbelt @ 2020-11-06  1:43 UTC (permalink / raw)
  To: Damien Le Moal
  Cc: aou, anup, seanga2, Atish Patra, Paul Walmsley, linux-riscv

On Thu, 22 Oct 2020 16:55:33 PDT (-0700), Damien Le Moal wrote:
>> On 2020/10/23 5:30, Sean Anderson wrote:
>> M-Mode Linux is loaded at the start of RAM, not 2MB later. Perhaps this
>> should be calculated based on PAGE_OFFSET somehow? Even better would be to
>> deprecate text_offset and instead introduce something absolute.
>> 
>> Signed-off-by: Sean Anderson <seanga2@gmail.com>
>> ---
>> 
>> Changes in v2:
>> - RISCV_S_MODE does not exist; use RISCV_M_MODE instead
>> 
>>  arch/riscv/kernel/head.S | 5 +++++
>>  1 file changed, 5 insertions(+)
>> 
>> diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S
>> index 0a4e81b8dc79..5a0ae2eaf5e2 100644
>> --- a/arch/riscv/kernel/head.S
>> +++ b/arch/riscv/kernel/head.S
>> @@ -27,12 +27,17 @@ ENTRY(_start)
>>  	/* reserved */
>>  	.word 0
>>  	.balign 8
>> +#ifdef CONFIG_RISCV_M_MODE
>> +	/* Image load offset (0MB) from start of RAM for M-mode */
>> +	.dword 0
>> +#else
>>  #if __riscv_xlen == 64
>>  	/* Image load offset(2MB) from start of RAM */
>>  	.dword 0x200000
>>  #else
>>  	/* Image load offset(4MB) from start of RAM */
>>  	.dword 0x400000
>>  #endif
>> +#endif
>>  	/* Effective size of kernel image */
>>  	.dword _end - _start
>> 
>
> Looks good to me. Added this to my upcoming pile of patches for Kendryte and
> tested. No problems.
> 
> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com>
> Tested-by: Damien Le Moal <damien.lemoal@wdc.com>

Thanks.  This is on fixes.

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^ permalink raw reply	[flat|nested] 3+ messages in thread

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2020-10-22 20:30 [PATCH v2] riscv: Set text_offset correctly for M-Mode Sean Anderson
2020-10-22 23:55 ` Damien Le Moal
2020-11-06  1:43   ` Palmer Dabbelt

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