[v2,1/5] arm64: mm: Move zone_dma_bits initialization into zone_sizes_init()
diff mbox series

Message ID 20201010151235.20585-2-nsaenzjulienne@suse.de
State New, archived
Headers show
Series
  • arm64: Default to 32-bit wide ZONE_DMA
Related show

Commit Message

Nicolas Saenz Julienne Oct. 10, 2020, 3:12 p.m. UTC
There no use for initializing it earlier in arm64_memblock_init().

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---
 arch/arm64/mm/init.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

Comments

Catalin Marinas Oct. 12, 2020, 11:37 a.m. UTC | #1
On Sat, Oct 10, 2020 at 05:12:31PM +0200, Nicolas Saenz Julienne wrote:
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index f6902a2b4ea6..0eca5865dcb1 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -196,14 +196,16 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
>  	unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
>  
>  #ifdef CONFIG_ZONE_DMA
> +	zone_dma_bits = ARM64_ZONE_DMA_BITS;
> +
>  	if (IS_ENABLED(CONFIG_ACPI)) {
>  		extern unsigned int acpi_iort_get_zone_dma_size(void);
>  
>  		zone_dma_bits = min(zone_dma_bits,
>  				    acpi_iort_get_zone_dma_size());
> -		arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
>  	}
>  
> +	arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
>  	max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
>  #endif
>  #ifdef CONFIG_ZONE_DMA32
> @@ -394,11 +396,6 @@ void __init arm64_memblock_init(void)
>  
>  	early_init_fdt_scan_reserved_mem();
>  
> -	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
> -		zone_dma_bits = ARM64_ZONE_DMA_BITS;
> -		arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
> -	}

arm64_dma_phys_limit is used by memblock_alloc_low() (via
ARCH_LOW_ADDRESS_LIMIT). I think it's too late to leave its
initialisation to zone_sizes_init().
Ard Biesheuvel Oct. 12, 2020, 2:23 p.m. UTC | #2
On Mon, 12 Oct 2020 at 13:37, Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Sat, Oct 10, 2020 at 05:12:31PM +0200, Nicolas Saenz Julienne wrote:
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index f6902a2b4ea6..0eca5865dcb1 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -196,14 +196,16 @@ static void __init zone_sizes_init(unsigned long min, unsigned long max)
> >       unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
> >
> >  #ifdef CONFIG_ZONE_DMA
> > +     zone_dma_bits = ARM64_ZONE_DMA_BITS;
> > +
> >       if (IS_ENABLED(CONFIG_ACPI)) {
> >               extern unsigned int acpi_iort_get_zone_dma_size(void);
> >
> >               zone_dma_bits = min(zone_dma_bits,
> >                                   acpi_iort_get_zone_dma_size());
> > -             arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
> >       }
> >
> > +     arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
> >       max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
> >  #endif
> >  #ifdef CONFIG_ZONE_DMA32
> > @@ -394,11 +396,6 @@ void __init arm64_memblock_init(void)
> >
> >       early_init_fdt_scan_reserved_mem();
> >
> > -     if (IS_ENABLED(CONFIG_ZONE_DMA)) {
> > -             zone_dma_bits = ARM64_ZONE_DMA_BITS;
> > -             arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
> > -     }
>
> arm64_dma_phys_limit is used by memblock_alloc_low() (via
> ARCH_LOW_ADDRESS_LIMIT). I think it's too late to leave its
> initialisation to zone_sizes_init().
>

The only generic caller of memblock_alloc_low() is swiotlb_init(),
which is called much later. So at that point, we definitely need
ARCH_LOW_ADDRESS_LIMIT to be set correctly, but that means doing it in
zone_sizes_init() is early enough.

So the only problematic reference seems to be crashkernel_reserve() afaict.

Patch
diff mbox series

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index f6902a2b4ea6..0eca5865dcb1 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -196,14 +196,16 @@  static void __init zone_sizes_init(unsigned long min, unsigned long max)
 	unsigned long max_zone_pfns[MAX_NR_ZONES]  = {0};
 
 #ifdef CONFIG_ZONE_DMA
+	zone_dma_bits = ARM64_ZONE_DMA_BITS;
+
 	if (IS_ENABLED(CONFIG_ACPI)) {
 		extern unsigned int acpi_iort_get_zone_dma_size(void);
 
 		zone_dma_bits = min(zone_dma_bits,
 				    acpi_iort_get_zone_dma_size());
-		arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
 	}
 
+	arm64_dma_phys_limit = max_zone_phys(zone_dma_bits);
 	max_zone_pfns[ZONE_DMA] = PFN_DOWN(arm64_dma_phys_limit);
 #endif
 #ifdef CONFIG_ZONE_DMA32
@@ -394,11 +396,6 @@  void __init arm64_memblock_init(void)
 
 	early_init_fdt_scan_reserved_mem();
 
-	if (IS_ENABLED(CONFIG_ZONE_DMA)) {
-		zone_dma_bits = ARM64_ZONE_DMA_BITS;
-		arm64_dma_phys_limit = max_zone_phys(ARM64_ZONE_DMA_BITS);
-	}
-
 	if (IS_ENABLED(CONFIG_ZONE_DMA32))
 		arm64_dma32_phys_limit = max_zone_phys(32);
 	else