Re: [U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-17 Thread Chen-Yu Tsai 
On Fri, Oct 14, 2016 at 8:14 AM, Chenhui Zhao  wrote:
> On Thu, Oct 13, 2016 at 5:52 PM, Chen-Yu Tsai  wrote:
>> On Sat, Oct 8, 2016 at 7:08 PM, Chenhui Zhao  wrote:
>>> Save and restore core registers from r4 to r12 so that PSCI code won't
>>> break their value.
>>>
>>> Signed-off-by: Chenhui Zhao 
>>> Signed-off-by: Alison Wang 
>>> Signed-off-by: Abhimanyu Saini 
>>> ---
>>>  arch/arm/cpu/armv7/psci.S | 4 ++--
>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
>>> index 6a36208..746297c 100644
>>> --- a/arch/arm/cpu/armv7/psci.S
>>> +++ b/arch/arm/cpu/armv7/psci.S
>>> @@ -152,7 +152,7 @@ _psci_table:
>>> .word   0
>>>
>>>  _smc_psci:
>>> -   push{r4-r7,lr}
>>> +   push{r4-r12,lr}
>>
>> This change is not needed. This function only uses r4-r7.
>> Any subroutines called should save variable registers (r4-r12)
>> themselves, per the ARM calling conventions.
>>
>> ChenYu
>>
>
> I do not think it is a normal calling, instead it is an exception
> handler. In the exception context,
> it is necessary to save/restore all registers.

It should be the same for an exception handler. You only save the
registers that you clobber, at each function level.

ChenYu

>
> Sorry, my mail server has something wrong.
>
> Chenhui
>
>>>
>>> @ Switch to secure
>>> mrc p15, 0, r7, c1, c1, 0
>>> @@ -175,7 +175,7 @@ _smc_psci:
>>> @ Switch back to non-secure
>>>  2: mcr p15, 0, r7, c1, c1, 0
>>>
>>> -   pop {r4-r7, lr}
>>> +   pop {r4-r12, lr}
>>> movspc, lr  @ Return to the kernel
>>>
>>>  @ Requires dense and single-cluster CPU ID space
>>> --
>>> 1.9.1
>>>
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Re: [U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-13 Thread Chenhui Zhao 
On Thu, Oct 13, 2016 at 5:52 PM, Chen-Yu Tsai  wrote:
> On Sat, Oct 8, 2016 at 7:08 PM, Chenhui Zhao  wrote:
>> Save and restore core registers from r4 to r12 so that PSCI code won't
>> break their value.
>>
>> Signed-off-by: Chenhui Zhao 
>> Signed-off-by: Alison Wang 
>> Signed-off-by: Abhimanyu Saini 
>> ---
>>  arch/arm/cpu/armv7/psci.S | 4 ++--
>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
>> index 6a36208..746297c 100644
>> --- a/arch/arm/cpu/armv7/psci.S
>> +++ b/arch/arm/cpu/armv7/psci.S
>> @@ -152,7 +152,7 @@ _psci_table:
>> .word   0
>>
>>  _smc_psci:
>> -   push{r4-r7,lr}
>> +   push{r4-r12,lr}
>
> This change is not needed. This function only uses r4-r7.
> Any subroutines called should save variable registers (r4-r12)
> themselves, per the ARM calling conventions.
>
> ChenYu
>

I do not think it is a normal calling, instead it is an exception
handler. In the exception context,
it is necessary to save/restore all registers.

Sorry, my mail server has something wrong.

Chenhui

>>
>> @ Switch to secure
>> mrc p15, 0, r7, c1, c1, 0
>> @@ -175,7 +175,7 @@ _smc_psci:
>> @ Switch back to non-secure
>>  2: mcr p15, 0, r7, c1, c1, 0
>>
>> -   pop {r4-r7, lr}
>> +   pop {r4-r12, lr}
>> movspc, lr  @ Return to the kernel
>>
>>  @ Requires dense and single-cluster CPU ID space
>> --
>> 1.9.1
>>
>> ___
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Re: [U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-13 Thread C.H. Zhao 



From: Chen-Yu Tsai <w...@csie.org>
Sent: Thursday, October 13, 2016 5:52 PM
To: C.H. Zhao
Cc: U-Boot Mailing List; Albert ARIBAUD; z.chen...@gmail.com
Subject: Re: [U-Boot] [PATCH] arm: psci: save and restore registers from r4 to 
r12

On Sat, Oct 8, 2016 at 7:08 PM, Chenhui Zhao <chenhui.z...@nxp.com> wrote:
> Save and restore core registers from r4 to r12 so that PSCI code won't
> break their value.
>
> Signed-off-by: Chenhui Zhao <chenhui.z...@nxp.com>
> Signed-off-by: Alison Wang <alison.w...@nxp.com>
> Signed-off-by: Abhimanyu Saini <abhimanyu.sa...@nxp.com>
> ---
>  arch/arm/cpu/armv7/psci.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
> index 6a36208..746297c 100644
> --- a/arch/arm/cpu/armv7/psci.S
> +++ b/arch/arm/cpu/armv7/psci.S
> @@ -152,7 +152,7 @@ _psci_table:
> .word   0
>
>  _smc_psci:
> -   push{r4-r7,lr}
> +   push{r4-r12,lr}

This change is not needed. This function only uses r4-r7.
Any subroutines called should save variable registers (r4-r12)
themselves, per the ARM calling conventions.

ChenYu


[Chenhui] I do not think it is a normal calling, instead it is an exception 
handler. In the exception context,
it is necessary to save/restore all registers.

>
> @ Switch to secure
> mrc p15, 0, r7, c1, c1, 0
> @@ -175,7 +175,7 @@ _smc_psci:
> @ Switch back to non-secure
>  2: mcr p15, 0, r7, c1, c1, 0
>
> -   pop {r4-r7, lr}
> +   pop {r4-r12, lr}
> movspc, lr  @ Return to the kernel
>
>  @ Requires dense and single-cluster CPU ID space
> --
> 1.9.1
>
> ___
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Re: [U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-13 Thread Chen-Yu Tsai 
On Sat, Oct 8, 2016 at 7:08 PM, Chenhui Zhao  wrote:
> Save and restore core registers from r4 to r12 so that PSCI code won't
> break their value.
>
> Signed-off-by: Chenhui Zhao 
> Signed-off-by: Alison Wang 
> Signed-off-by: Abhimanyu Saini 
> ---
>  arch/arm/cpu/armv7/psci.S | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
> index 6a36208..746297c 100644
> --- a/arch/arm/cpu/armv7/psci.S
> +++ b/arch/arm/cpu/armv7/psci.S
> @@ -152,7 +152,7 @@ _psci_table:
> .word   0
>
>  _smc_psci:
> -   push{r4-r7,lr}
> +   push{r4-r12,lr}

This change is not needed. This function only uses r4-r7.
Any subroutines called should save variable registers (r4-r12)
themselves, per the ARM calling conventions.

ChenYu

>
> @ Switch to secure
> mrc p15, 0, r7, c1, c1, 0
> @@ -175,7 +175,7 @@ _smc_psci:
> @ Switch back to non-secure
>  2: mcr p15, 0, r7, c1, c1, 0
>
> -   pop {r4-r7, lr}
> +   pop {r4-r12, lr}
> movspc, lr  @ Return to the kernel
>
>  @ Requires dense and single-cluster CPU ID space
> --
> 1.9.1
>
> ___
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[U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-08 Thread Chenhui Zhao 
Save and restore core registers from r4 to r12 so that PSCI code won't
break their value.

Signed-off-by: Chenhui Zhao 
Signed-off-by: Alison Wang 
Signed-off-by: Abhimanyu Saini 
---
 arch/arm/cpu/armv7/psci.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index 6a36208..746297c 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -152,7 +152,7 @@ _psci_table:
.word   0
 
 _smc_psci:
-   push{r4-r7,lr}
+   push{r4-r12,lr}
 
@ Switch to secure
mrc p15, 0, r7, c1, c1, 0
@@ -175,7 +175,7 @@ _smc_psci:
@ Switch back to non-secure
 2: mcr p15, 0, r7, c1, c1, 0
 
-   pop {r4-r7, lr}
+   pop {r4-r12, lr}
movspc, lr  @ Return to the kernel
 
 @ Requires dense and single-cluster CPU ID space
-- 
1.9.1

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[U-Boot] [PATCH] arm: psci: save and restore registers from r4 to r12

2016-10-08 Thread Chenhui Zhao 
Save and restore core registers from r4 to r12 so that PSCI code won't
break their value.

Signed-off-by: Chenhui Zhao 
Signed-off-by: Alison Wang 
Signed-off-by: Abhimanyu Saini 
---
 arch/arm/cpu/armv7/psci.S | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/cpu/armv7/psci.S b/arch/arm/cpu/armv7/psci.S
index 6a36208..746297c 100644
--- a/arch/arm/cpu/armv7/psci.S
+++ b/arch/arm/cpu/armv7/psci.S
@@ -152,7 +152,7 @@ _psci_table:
.word   0
 
 _smc_psci:
-   push{r4-r7,lr}
+   push{r4-r12,lr}
 
@ Switch to secure
mrc p15, 0, r7, c1, c1, 0
@@ -175,7 +175,7 @@ _smc_psci:
@ Switch back to non-secure
 2: mcr p15, 0, r7, c1, c1, 0
 
-   pop {r4-r7, lr}
+   pop {r4-r12, lr}
movspc, lr  @ Return to the kernel
 
 @ Requires dense and single-cluster CPU ID space
-- 
1.9.1

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