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[PATCH 05/14] ppc/vof: Fix unaligned FDT property access

Akihiko Odaki posted 14 patches 5 months ago
Maintainers: Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, John Snow <jsnow@redhat.com>, BALATON Zoltan <balaton@eik.bme.hu>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Alexey Kardashevskiy <aik@ozlabs.ru>, David Gibson <david@gibson.dropbear.id.au>, Nicholas Piggin <npiggin@gmail.com>, Daniel Henrique Barboza <danielhb413@gmail.com>, Harsh Prateek Bora <harshpb@linux.ibm.com>, "Michael S. Tsirkin" <mst@redhat.com>, "Alex Bennée" <alex.bennee@linaro.org>, Peter Xu <peterx@redhat.com>, Fabiano Rosas <farosas@suse.de>, Paolo Bonzini <pbonzini@redhat.com>, David Hildenbrand <david@redhat.com>, Thomas Huth <thuth@redhat.com>, Laurent Vivier <lvivier@redhat.com>
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[PATCH 05/14] ppc/vof: Fix unaligned FDT property access
Posted by Akihiko Odaki 5 months ago 
FDT properties are aligned by 4 bytes, not 8 bytes.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 hw/ppc/vof.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
index e3b430a81f4f..b5b6514d79fc 100644
--- a/hw/ppc/vof.c
+++ b/hw/ppc/vof.c
@@ -646,7 +646,7 @@ static void vof_dt_memory_available(void *fdt, GArray *claimed, uint64_t base)
     mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen);
     g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc));
     if (sc == 2) {
-        mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + sizeof(uint32_t) * ac));
+        mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac);
     } else {
         mem0_end = be32_to_cpu(*(uint32_t *)(mem0_reg + sizeof(uint32_t) * ac));
     }

-- 
2.45.2
Re: [PATCH 05/14] ppc/vof: Fix unaligned FDT property access
Posted by Philippe Mathieu-Daudé 5 months ago 
On 26/6/24 13:06, Akihiko Odaki wrote:
> FDT properties are aligned by 4 bytes, not 8 bytes.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>   hw/ppc/vof.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
> index e3b430a81f4f..b5b6514d79fc 100644
> --- a/hw/ppc/vof.c
> +++ b/hw/ppc/vof.c
> @@ -646,7 +646,7 @@ static void vof_dt_memory_available(void *fdt, GArray *claimed, uint64_t base)
>       mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen);
>       g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc));
>       if (sc == 2) {
> -        mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + sizeof(uint32_t) * ac));
> +        mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac);
>       } else {
>           mem0_end = be32_to_cpu(*(uint32_t *)(mem0_reg + sizeof(uint32_t) * ac));

OK but please keep API uses consistent, so convert other uses please.

>       }
>
Re: [PATCH 05/14] ppc/vof: Fix unaligned FDT property access
Posted by Akihiko Odaki 5 months ago 
On 2024/06/26 21:03, Philippe Mathieu-Daudé wrote:
> On 26/6/24 13:06, Akihiko Odaki wrote:
>> FDT properties are aligned by 4 bytes, not 8 bytes.
>>
>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>> ---
>>   hw/ppc/vof.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
>> index e3b430a81f4f..b5b6514d79fc 100644
>> --- a/hw/ppc/vof.c
>> +++ b/hw/ppc/vof.c
>> @@ -646,7 +646,7 @@ static void vof_dt_memory_available(void *fdt, 
>> GArray *claimed, uint64_t base)
>>       mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen);
>>       g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc));
>>       if (sc == 2) {
>> -        mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + 
>> sizeof(uint32_t) * ac));
>> +        mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac);
>>       } else {
>>           mem0_end = be32_to_cpu(*(uint32_t *)(mem0_reg + 
>> sizeof(uint32_t) * ac));
> 
> OK but please keep API uses consistent, so convert other uses please.

This is the only unaligned access.
Re: [PATCH 05/14] ppc/vof: Fix unaligned FDT property access
Posted by Philippe Mathieu-Daudé 5 months ago 
On 27/6/24 15:12, Akihiko Odaki wrote:
> On 2024/06/26 21:03, Philippe Mathieu-Daudé wrote:
>> On 26/6/24 13:06, Akihiko Odaki wrote:
>>> FDT properties are aligned by 4 bytes, not 8 bytes.
>>>
>>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>>> ---
>>>   hw/ppc/vof.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
>>> index e3b430a81f4f..b5b6514d79fc 100644
>>> --- a/hw/ppc/vof.c
>>> +++ b/hw/ppc/vof.c
>>> @@ -646,7 +646,7 @@ static void vof_dt_memory_available(void *fdt, 
>>> GArray *claimed, uint64_t base)
>>>       mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen);
>>>       g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc));
>>>       if (sc == 2) {
>>> -        mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + 
>>> sizeof(uint32_t) * ac));
>>> +        mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac);
>>>       } else {
>>>           mem0_end = be32_to_cpu(*(uint32_t *)(mem0_reg + 
>>> sizeof(uint32_t) * ac));
>>
>> OK but please keep API uses consistent, so convert other uses please.
> 
> This is the only unaligned access.

What I mean with consistent API use is either use the be64_to_cpu and
be32_to_cpu API, or ldq_be_p and ldl_be_p. A mix of both makes review
more confusing.
Re: [PATCH 05/14] ppc/vof: Fix unaligned FDT property access
Posted by Akihiko Odaki 5 months ago 
On 2024/06/27 23:02, Philippe Mathieu-Daudé wrote:
> On 27/6/24 15:12, Akihiko Odaki wrote:
>> On 2024/06/26 21:03, Philippe Mathieu-Daudé wrote:
>>> On 26/6/24 13:06, Akihiko Odaki wrote:
>>>> FDT properties are aligned by 4 bytes, not 8 bytes.
>>>>
>>>> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
>>>> ---
>>>>   hw/ppc/vof.c | 2 +-
>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/hw/ppc/vof.c b/hw/ppc/vof.c
>>>> index e3b430a81f4f..b5b6514d79fc 100644
>>>> --- a/hw/ppc/vof.c
>>>> +++ b/hw/ppc/vof.c
>>>> @@ -646,7 +646,7 @@ static void vof_dt_memory_available(void *fdt, 
>>>> GArray *claimed, uint64_t base)
>>>>       mem0_reg = fdt_getprop(fdt, offset, "reg", &proplen);
>>>>       g_assert(mem0_reg && proplen == sizeof(uint32_t) * (ac + sc));
>>>>       if (sc == 2) {
>>>> -        mem0_end = be64_to_cpu(*(uint64_t *)(mem0_reg + 
>>>> sizeof(uint32_t) * ac));
>>>> +        mem0_end = ldq_be_p(mem0_reg + sizeof(uint32_t) * ac);
>>>>       } else {
>>>>           mem0_end = be32_to_cpu(*(uint32_t *)(mem0_reg + 
>>>> sizeof(uint32_t) * ac));
>>>
>>> OK but please keep API uses consistent, so convert other uses please.
>>
>> This is the only unaligned access.
> 
> What I mean with consistent API use is either use the be64_to_cpu and
> be32_to_cpu API, or ldq_be_p and ldl_be_p. A mix of both makes review
> more confusing.

The desired semantics are different in these two cases so I believe it 
is natural to use different APIs; ldq_be_p() for an unaligned 64-bit 
access and be32_to_cpu(*(uint32_t *)) for an aligned 32-bit access.

Patchew 2.1-devel-b67e4c2

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