[RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Alexey Kardashevskiy]

The immediate problem is that after
0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
the kernel silently reboots. The reason is that early_ioremap() returns
broken addresses as it uses slot_virt[] array which initialized with
offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
when early_ioremap_setup() is called. __kernel_io_end is initialized
little bit later in early_init_mmu().

This fixes the initialization by swapping early_ioremap_setup and
early_init_mmu.

This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
seems to make sense, unless there is some weird logic with redefining
FIXADDR_SIZE as the compiling goes.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
 arch/powerpc/kernel/setup_64.c               | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
index a666d561b44d..54a06129794b 100644
--- a/arch/powerpc/include/asm/book3s/64/pgtable.h
+++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
@@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
 #define  PHB_IO_END	(KERN_IO_START + FULL_IO_SIZE)
 #define IOREMAP_BASE	(PHB_IO_END)
 #define IOREMAP_START	(ioremap_bot)
-#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
 #define FIXADDR_SIZE	SZ_32M
+#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
 
 /* Advertise special mapping type for AGP */
 #define HAVE_PAGE_AGP
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index b779d25761cf..ce09fe5debf4 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
 	apply_feature_fixups();
 	setup_feature_keys();
 
-	early_ioremap_setup();
 
 	/* Initialize the hash table or TLB handling */
 	early_init_mmu();
 
+	early_ioremap_setup();
+
 	/*
 	 * After firmware and early platform setup code has set things up,
 	 * we note the SPR values for configurable control/performance
-- 
2.30.2

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Alexey Kardashevskiy]

Hm, my thunderbird says it is not cc:'ed but git sendmail says it did cc:


Server: localhost
MAIL FROM:<aik@ozlabs.ru>
RCPT TO:<linuxppc-dev@lists.ozlabs.org>
RCPT TO:<aik@ozlabs.ru>
RCPT TO:<mpe@ellerman.id.au>
RCPT TO:<christophe.leroy@csgroup.eu>
From: Alexey Kardashevskiy <aik@ozlabs.ru>
To: linuxppc-dev@lists.ozlabs.org
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
         Michael Ellerman <mpe@ellerman.id.au>,
         Christophe Leroy <christophe.leroy@csgroup.eu>
Subject: [RFC PATCH kernel] powerpc: Fix early setup to make 
early_ioremap work


Not sure what to believe.


On 20/05/2021 13:29, Alexey Kardashevskiy wrote:
> The immediate problem is that after
> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
> the kernel silently reboots. The reason is that early_ioremap() returns
> broken addresses as it uses slot_virt[] array which initialized with
> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
> when early_ioremap_setup() is called. __kernel_io_end is initialized
> little bit later in early_init_mmu().
> 
> This fixes the initialization by swapping early_ioremap_setup and
> early_init_mmu.
> 
> This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
> seems to make sense, unless there is some weird logic with redefining
> FIXADDR_SIZE as the compiling goes.
> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> ---
>   arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>   arch/powerpc/kernel/setup_64.c               | 3 ++-
>   2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index a666d561b44d..54a06129794b 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
>   #define  PHB_IO_END	(KERN_IO_START + FULL_IO_SIZE)
>   #define IOREMAP_BASE	(PHB_IO_END)
>   #define IOREMAP_START	(ioremap_bot)
> -#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
>   #define FIXADDR_SIZE	SZ_32M
> +#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
>   
>   /* Advertise special mapping type for AGP */
>   #define HAVE_PAGE_AGP
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index b779d25761cf..ce09fe5debf4 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
>   	apply_feature_fixups();
>   	setup_feature_keys();
>   
> -	early_ioremap_setup();
>   
>   	/* Initialize the hash table or TLB handling */
>   	early_init_mmu();
>   
> +	early_ioremap_setup();
> +
>   	/*
>   	 * After firmware and early platform setup code has set things up,
>   	 * we note the SPR values for configurable control/performance
> 

-- 
Alexey

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Christophe Leroy]

Le 20/05/2021 à 05:33, Alexey Kardashevskiy a écrit :
> Hm, my thunderbird says it is not cc:'ed but git sendmail says it did cc:
> 
> 
> Server: localhost
> MAIL FROM:<aik@ozlabs.ru>
> RCPT TO:<linuxppc-dev@lists.ozlabs.org>
> RCPT TO:<aik@ozlabs.ru>
> RCPT TO:<mpe@ellerman.id.au>
> RCPT TO:<christophe.leroy@csgroup.eu>
> From: Alexey Kardashevskiy <aik@ozlabs.ru>
> To: linuxppc-dev@lists.ozlabs.org
> Cc: Alexey Kardashevskiy <aik@ozlabs.ru>,
>          Michael Ellerman <mpe@ellerman.id.au>,
>          Christophe Leroy <christophe.leroy@csgroup.eu>
> Subject: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work
> 
> 
> Not sure what to believe.

I got the patch.

If you are looking at the mail you received from the ppc list, I think the list removes the members 
of the list from the Cc: in order to avoid the mail being received multiple times.

Christophe

> 
> 
> On 20/05/2021 13:29, Alexey Kardashevskiy wrote:
>> The immediate problem is that after
>> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
>> the kernel silently reboots. The reason is that early_ioremap() returns
>> broken addresses as it uses slot_virt[] array which initialized with
>> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
>> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
>> when early_ioremap_setup() is called. __kernel_io_end is initialized
>> little bit later in early_init_mmu().
>>
>> This fixes the initialization by swapping early_ioremap_setup and
>> early_init_mmu.
>>
>> This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
>> seems to make sense, unless there is some weird logic with redefining
>> FIXADDR_SIZE as the compiling goes.
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>> ---
>>   arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>>   arch/powerpc/kernel/setup_64.c               | 3 ++-
>>   2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
>> b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index a666d561b44d..54a06129794b 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
>>   #define  PHB_IO_END    (KERN_IO_START + FULL_IO_SIZE)
>>   #define IOREMAP_BASE    (PHB_IO_END)
>>   #define IOREMAP_START    (ioremap_bot)
>> -#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>   #define FIXADDR_SIZE    SZ_32M
>> +#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>   /* Advertise special mapping type for AGP */
>>   #define HAVE_PAGE_AGP
>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>> index b779d25761cf..ce09fe5debf4 100644
>> --- a/arch/powerpc/kernel/setup_64.c
>> +++ b/arch/powerpc/kernel/setup_64.c
>> @@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
>>       apply_feature_fixups();
>>       setup_feature_keys();
>> -    early_ioremap_setup();
>>       /* Initialize the hash table or TLB handling */
>>       early_init_mmu();
>> +    early_ioremap_setup();
>> +
>>       /*
>>        * After firmware and early platform setup code has set things up,
>>        * we note the SPR values for configurable control/performance
>>
> 

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Christophe Leroy]

Le 20/05/2021 à 05:29, Alexey Kardashevskiy a écrit :
> The immediate problem is that after
> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
> the kernel silently reboots. The reason is that early_ioremap() returns
> broken addresses as it uses slot_virt[] array which initialized with
> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
> when early_ioremap_setup() is called. __kernel_io_end is initialized
> little bit later in early_init_mmu().
> 
> This fixes the initialization by swapping early_ioremap_setup and
> early_init_mmu.

Hum ... Chris tested it on a T2080RDB, that must be a book3e.

So we missed it. I guess your fix is right.

> 
> This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
> seems to make sense, unless there is some weird logic with redefining
> FIXADDR_SIZE as the compiling goes.

Well, I don't think the order of defines matters, the change should be kept out of the fix.
But if you want it anyway, then I'd suggest to move it before IOREMAP_BASE in order to keep the 3 
IOREMAP_xxx together.

> 
> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>

Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>

> ---
>   arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>   arch/powerpc/kernel/setup_64.c               | 3 ++-
>   2 files changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index a666d561b44d..54a06129794b 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
>   #define  PHB_IO_END	(KERN_IO_START + FULL_IO_SIZE)
>   #define IOREMAP_BASE	(PHB_IO_END)
>   #define IOREMAP_START	(ioremap_bot)
> -#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
>   #define FIXADDR_SIZE	SZ_32M
> +#define IOREMAP_END	(KERN_IO_END - FIXADDR_SIZE)
>   
>   /* Advertise special mapping type for AGP */
>   #define HAVE_PAGE_AGP
> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
> index b779d25761cf..ce09fe5debf4 100644
> --- a/arch/powerpc/kernel/setup_64.c
> +++ b/arch/powerpc/kernel/setup_64.c
> @@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
>   	apply_feature_fixups();
>   	setup_feature_keys();
>   
> -	early_ioremap_setup();
>   
>   	/* Initialize the hash table or TLB handling */
>   	early_init_mmu();
>   
> +	early_ioremap_setup();
> +
>   	/*
>   	 * After firmware and early platform setup code has set things up,
>   	 * we note the SPR values for configurable control/performance
> 

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Alexey Kardashevskiy]

On 20/05/2021 15:46, Christophe Leroy wrote:
> 
> 
> Le 20/05/2021 à 05:29, Alexey Kardashevskiy a écrit :
>> The immediate problem is that after
>> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
>> the kernel silently reboots. The reason is that early_ioremap() returns
>> broken addresses as it uses slot_virt[] array which initialized with
>> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
>> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
>> when early_ioremap_setup() is called. __kernel_io_end is initialized
>> little bit later in early_init_mmu().
>>
>> This fixes the initialization by swapping early_ioremap_setup and
>> early_init_mmu.
> 
> Hum ... Chris tested it on a T2080RDB, that must be a book3e.
> 
> So we missed it. I guess your fix is right.


Oh cool.

>>
>> This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
>> seems to make sense, unless there is some weird logic with redefining
>> FIXADDR_SIZE as the compiling goes.
> 
> Well, I don't think the order of defines matters, the change should be 
> kept out of the fix.

When I see this:

#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
#define FIXADDR_SIZE    SZ_32M


... I have to think harder what FIXADDR_SIZE was in the first macro and 
in what order the preprocessor expands them.


> But if you want it anyway, then I'd suggest to move it before 
> IOREMAP_BASE in order to keep the 3 IOREMAP_xxx together.

Up to Michael, I guess.


> 
>>
>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
> 
> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> 
>> ---
>>   arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>>   arch/powerpc/kernel/setup_64.c               | 3 ++-
>>   2 files changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
>> b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index a666d561b44d..54a06129794b 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
>>   #define  PHB_IO_END    (KERN_IO_START + FULL_IO_SIZE)
>>   #define IOREMAP_BASE    (PHB_IO_END)
>>   #define IOREMAP_START    (ioremap_bot)
>> -#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>   #define FIXADDR_SIZE    SZ_32M
>> +#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>   /* Advertise special mapping type for AGP */
>>   #define HAVE_PAGE_AGP
>> diff --git a/arch/powerpc/kernel/setup_64.c 
>> b/arch/powerpc/kernel/setup_64.c
>> index b779d25761cf..ce09fe5debf4 100644
>> --- a/arch/powerpc/kernel/setup_64.c
>> +++ b/arch/powerpc/kernel/setup_64.c
>> @@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
>>       apply_feature_fixups();
>>       setup_feature_keys();
>> -    early_ioremap_setup();
>>       /* Initialize the hash table or TLB handling */
>>       early_init_mmu();
>> +    early_ioremap_setup();
>> +
>>       /*
>>        * After firmware and early platform setup code has set things up,
>>        * we note the SPR values for configurable control/performance
>>

-- 
Alexey

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Christophe Leroy]

Le 20/05/2021 à 07:52, Alexey Kardashevskiy a écrit :
> 
> 
> On 20/05/2021 15:46, Christophe Leroy wrote:
>>
>>
>> Le 20/05/2021 à 05:29, Alexey Kardashevskiy a écrit :
>>> The immediate problem is that after
>>> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
>>> the kernel silently reboots. The reason is that early_ioremap() returns
>>> broken addresses as it uses slot_virt[] array which initialized with
>>> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
>>> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
>>> when early_ioremap_setup() is called. __kernel_io_end is initialized
>>> little bit later in early_init_mmu().
>>>
>>> This fixes the initialization by swapping early_ioremap_setup and
>>> early_init_mmu.
>>
>> Hum ... Chris tested it on a T2080RDB, that must be a book3e.
>>
>> So we missed it. I guess your fix is right.
> 
> 
> Oh cool.

I forgot, your patch should include Fixes: tags.

Fixes: 265c3491c4bc ("powerpc: Add support for GENERIC_EARLY_IOREMAP")

If you still change the FIXADDR_SIZE, then it must also have:

Fixes: 9ccba66d4d2a ("powerpc/64: Fix the definition of the fixmap area")

> 
>>>
>>> This also fixes IOREMAP_END to use FIXADDR_SIZE defined just next to it,
>>> seems to make sense, unless there is some weird logic with redefining
>>> FIXADDR_SIZE as the compiling goes.
>>
>> Well, I don't think the order of defines matters, the change should be kept out of the fix.
> 
> When I see this:
> 
> #define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
> #define FIXADDR_SIZE    SZ_32M
> 
> 
> ... I have to think harder what FIXADDR_SIZE was in the first macro and in what order the 
> preprocessor expands them.
> 
> 
>> But if you want it anyway, then I'd suggest to move it before IOREMAP_BASE in order to keep the 3 
>> IOREMAP_xxx together.
> 
> Up to Michael, I guess.
> 
> 
>>
>>>
>>> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
>>
>> Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
>>
>>> ---
>>>   arch/powerpc/include/asm/book3s/64/pgtable.h | 2 +-
>>>   arch/powerpc/kernel/setup_64.c               | 3 ++-
>>>   2 files changed, 3 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h 
>>> b/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> index a666d561b44d..54a06129794b 100644
>>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>>> @@ -325,8 +325,8 @@ extern unsigned long pci_io_base;
>>>   #define  PHB_IO_END    (KERN_IO_START + FULL_IO_SIZE)
>>>   #define IOREMAP_BASE    (PHB_IO_END)
>>>   #define IOREMAP_START    (ioremap_bot)
>>> -#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>>   #define FIXADDR_SIZE    SZ_32M
>>> +#define IOREMAP_END    (KERN_IO_END - FIXADDR_SIZE)
>>>   /* Advertise special mapping type for AGP */
>>>   #define HAVE_PAGE_AGP
>>> diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
>>> index b779d25761cf..ce09fe5debf4 100644
>>> --- a/arch/powerpc/kernel/setup_64.c
>>> +++ b/arch/powerpc/kernel/setup_64.c
>>> @@ -369,11 +369,12 @@ void __init early_setup(unsigned long dt_ptr)
>>>       apply_feature_fixups();
>>>       setup_feature_keys();
>>> -    early_ioremap_setup();
>>>       /* Initialize the hash table or TLB handling */
>>>       early_init_mmu();
>>> +    early_ioremap_setup();
>>> +
>>>       /*
>>>        * After firmware and early platform setup code has set things up,
>>>        * we note the SPR values for configurable control/performance
>>>
> 

Re: [RFC PATCH kernel] powerpc: Fix early setup to make early_ioremap work

[Michael Ellerman]

On Thu, 20 May 2021 13:29:19 +1000, Alexey Kardashevskiy wrote:
> The immediate problem is that after
> 0bd3f9e953bd ("powerpc/legacy_serial: Use early_ioremap()")
> the kernel silently reboots. The reason is that early_ioremap() returns
> broken addresses as it uses slot_virt[] array which initialized with
> offsets from FIXADDR_TOP == IOREMAP_END+FIXADDR_SIZE ==
> KERN_IO_END- FIXADDR_SIZ + FIXADDR_SIZE == __kernel_io_end which is 0
> when early_ioremap_setup() is called. __kernel_io_end is initialized
> little bit later in early_init_mmu().
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc: Fix early setup to make early_ioremap work
      https://git.kernel.org/powerpc/c/e2f5efd0f0e229bd110eab513e7c0331d61a4649

cheers