[v3,1/4] RISC-V: Fix compilation without RISCV_ISA_ZICBOM

  From: Andrew Jones <ajones@ventanamicro.com>

riscv_cbom_block_size and riscv_init_cbom_blocksize() should always
be available and riscv_init_cbom_blocksize() should always be
invoked, even when compiling without RISCV_ISA_ZICBOM enabled. This
is because disabling RISCV_ISA_ZICBOM means "don't use zicbom
instructions in the kernel" not "pretend there isn't zicbom, even
when there is". When zicbom is available, whether the kernel enables
its use with RISCV_ISA_ZICBOM or not, KVM will offer it to guests.
Ensure we can build KVM and that the block size is initialized even
when compiling without RISCV_ISA_ZICBOM.

Fixes: 8f7e001e0325 ("RISC-V: Clean up the Zicbom block size probing")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/mm/cacheflush.c      | 41 +++++++++++++++++++++++++++++++++
 arch/riscv/mm/dma-noncoherent.c | 41 ---------------------------------
 2 files changed, 41 insertions(+), 41 deletions(-)
  

Hi Palmer,

On Wed, Oct 19, 2022 at 5:46 PM Anup Patel <apatel@ventanamicro.com> wrote:
>
> From: Andrew Jones <ajones@ventanamicro.com>
>
> riscv_cbom_block_size and riscv_init_cbom_blocksize() should always
> be available and riscv_init_cbom_blocksize() should always be
> invoked, even when compiling without RISCV_ISA_ZICBOM enabled. This
> is because disabling RISCV_ISA_ZICBOM means "don't use zicbom
> instructions in the kernel" not "pretend there isn't zicbom, even
> when there is". When zicbom is available, whether the kernel enables
> its use with RISCV_ISA_ZICBOM or not, KVM will offer it to guests.
> Ensure we can build KVM and that the block size is initialized even
> when compiling without RISCV_ISA_ZICBOM.
>
> Fixes: 8f7e001e0325 ("RISC-V: Clean up the Zicbom block size probing")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>

Currently, the KVM RISC-V compilation is broken for toolchains not
having Zicbom support.

I plan to take this patch through the KVM RISC-V tree and I will be
sending a PR by the end of this week. Let me know if you want this
patch to go through the RISC-V tree.

Regards,
Anup

> ---
>  arch/riscv/mm/cacheflush.c      | 41 +++++++++++++++++++++++++++++++++
>  arch/riscv/mm/dma-noncoherent.c | 41 ---------------------------------
>  2 files changed, 41 insertions(+), 41 deletions(-)
>
> diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
> index 6cb7d96ad9c7..f318b2553612 100644
> --- a/arch/riscv/mm/cacheflush.c
> +++ b/arch/riscv/mm/cacheflush.c
> @@ -3,6 +3,8 @@
>   * Copyright (C) 2017 SiFive
>   */
>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <asm/cacheflush.h>
>
>  #ifdef CONFIG_SMP
> @@ -86,3 +88,42 @@ void flush_icache_pte(pte_t pte)
>                 flush_icache_all();
>  }
>  #endif /* CONFIG_MMU */
> +
> +unsigned int riscv_cbom_block_size;
> +EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> +
> +#ifdef CONFIG_RISCV_ISA_ZICBOM
> +void riscv_init_cbom_blocksize(void)
> +{
> +       struct device_node *node;
> +       unsigned long cbom_hartid;
> +       u32 val, probed_block_size;
> +       int ret;
> +
> +       probed_block_size = 0;
> +       for_each_of_cpu_node(node) {
> +               unsigned long hartid;
> +
> +               ret = riscv_of_processor_hartid(node, &hartid);
> +               if (ret)
> +                       continue;
> +
> +               /* set block-size for cbom extension if available */
> +               ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> +               if (ret)
> +                       continue;
> +
> +               if (!probed_block_size) {
> +                       probed_block_size = val;
> +                       cbom_hartid = hartid;
> +               } else {
> +                       if (probed_block_size != val)
> +                               pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> +                                       cbom_hartid, hartid);
> +               }
> +       }
> +
> +       if (probed_block_size)
> +               riscv_cbom_block_size = probed_block_size;
> +}
> +#endif
> diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
> index b0add983530a..d919efab6eba 100644
> --- a/arch/riscv/mm/dma-noncoherent.c
> +++ b/arch/riscv/mm/dma-noncoherent.c
> @@ -8,13 +8,8 @@
>  #include <linux/dma-direct.h>
>  #include <linux/dma-map-ops.h>
>  #include <linux/mm.h>
> -#include <linux/of.h>
> -#include <linux/of_device.h>
>  #include <asm/cacheflush.h>
>
> -unsigned int riscv_cbom_block_size;
> -EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> -
>  static bool noncoherent_supported;
>
>  void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
> @@ -77,42 +72,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>         dev->dma_coherent = coherent;
>  }
>
> -#ifdef CONFIG_RISCV_ISA_ZICBOM
> -void riscv_init_cbom_blocksize(void)
> -{
> -       struct device_node *node;
> -       unsigned long cbom_hartid;
> -       u32 val, probed_block_size;
> -       int ret;
> -
> -       probed_block_size = 0;
> -       for_each_of_cpu_node(node) {
> -               unsigned long hartid;
> -
> -               ret = riscv_of_processor_hartid(node, &hartid);
> -               if (ret)
> -                       continue;
> -
> -               /* set block-size for cbom extension if available */
> -               ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> -               if (ret)
> -                       continue;
> -
> -               if (!probed_block_size) {
> -                       probed_block_size = val;
> -                       cbom_hartid = hartid;
> -               } else {
> -                       if (probed_block_size != val)
> -                               pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> -                                       cbom_hartid, hartid);
> -               }
> -       }
> -
> -       if (probed_block_size)
> -               riscv_cbom_block_size = probed_block_size;
> -}
> -#endif
> -
>  void riscv_noncoherent_supported(void)
>  {
>         WARN(!riscv_cbom_block_size,
> --
> 2.34.1
>
  

Hi Anup,

Am Mittwoch, 19. Oktober 2022, 14:16:19 CEST schrieb Anup Patel:
> From: Andrew Jones <ajones@ventanamicro.com>
> 
> riscv_cbom_block_size and riscv_init_cbom_blocksize() should always
> be available and riscv_init_cbom_blocksize() should always be
> invoked, even when compiling without RISCV_ISA_ZICBOM enabled. This
> is because disabling RISCV_ISA_ZICBOM means "don't use zicbom
> instructions in the kernel" not "pretend there isn't zicbom, even
> when there is". When zicbom is available, whether the kernel enables
> its use with RISCV_ISA_ZICBOM or not, KVM will offer it to guests.
> Ensure we can build KVM and that the block size is initialized even
> when compiling without RISCV_ISA_ZICBOM.

either I'm way very low on coffee or something is strange here :-) .

I can fully grasp the need to init the cbom blocksize for guests, even when
the main kernel isn't using it, but below in the patch itself it is still:

+#ifdef CONFIG_RISCV_ISA_ZICBOM
+void riscv_init_cbom_blocksize(void)
+{
[...]

so the init_cbom_blocksize function is still inside a RISCV_ISA_ZICBOM
ifdef?


Heiko


> 
> Fixes: 8f7e001e0325 ("RISC-V: Clean up the Zicbom block size probing")
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  arch/riscv/mm/cacheflush.c      | 41 +++++++++++++++++++++++++++++++++
>  arch/riscv/mm/dma-noncoherent.c | 41 ---------------------------------
>  2 files changed, 41 insertions(+), 41 deletions(-)
> 
> diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
> index 6cb7d96ad9c7..f318b2553612 100644
> --- a/arch/riscv/mm/cacheflush.c
> +++ b/arch/riscv/mm/cacheflush.c
> @@ -3,6 +3,8 @@
>   * Copyright (C) 2017 SiFive
>   */
>  
> +#include <linux/of.h>
> +#include <linux/of_device.h>
>  #include <asm/cacheflush.h>
>  
>  #ifdef CONFIG_SMP
> @@ -86,3 +88,42 @@ void flush_icache_pte(pte_t pte)
>  		flush_icache_all();
>  }
>  #endif /* CONFIG_MMU */
> +
> +unsigned int riscv_cbom_block_size;
> +EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> +
> +#ifdef CONFIG_RISCV_ISA_ZICBOM
> +void riscv_init_cbom_blocksize(void)
> +{
> +	struct device_node *node;
> +	unsigned long cbom_hartid;
> +	u32 val, probed_block_size;
> +	int ret;
> +
> +	probed_block_size = 0;
> +	for_each_of_cpu_node(node) {
> +		unsigned long hartid;
> +
> +		ret = riscv_of_processor_hartid(node, &hartid);
> +		if (ret)
> +			continue;
> +
> +		/* set block-size for cbom extension if available */
> +		ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> +		if (ret)
> +			continue;
> +
> +		if (!probed_block_size) {
> +			probed_block_size = val;
> +			cbom_hartid = hartid;
> +		} else {
> +			if (probed_block_size != val)
> +				pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> +					cbom_hartid, hartid);
> +		}
> +	}
> +
> +	if (probed_block_size)
> +		riscv_cbom_block_size = probed_block_size;
> +}
> +#endif
> diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
> index b0add983530a..d919efab6eba 100644
> --- a/arch/riscv/mm/dma-noncoherent.c
> +++ b/arch/riscv/mm/dma-noncoherent.c
> @@ -8,13 +8,8 @@
>  #include <linux/dma-direct.h>
>  #include <linux/dma-map-ops.h>
>  #include <linux/mm.h>
> -#include <linux/of.h>
> -#include <linux/of_device.h>
>  #include <asm/cacheflush.h>
>  
> -unsigned int riscv_cbom_block_size;
> -EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> -
>  static bool noncoherent_supported;
>  
>  void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
> @@ -77,42 +72,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>  	dev->dma_coherent = coherent;
>  }
>  
> -#ifdef CONFIG_RISCV_ISA_ZICBOM
> -void riscv_init_cbom_blocksize(void)
> -{
> -	struct device_node *node;
> -	unsigned long cbom_hartid;
> -	u32 val, probed_block_size;
> -	int ret;
> -
> -	probed_block_size = 0;
> -	for_each_of_cpu_node(node) {
> -		unsigned long hartid;
> -
> -		ret = riscv_of_processor_hartid(node, &hartid);
> -		if (ret)
> -			continue;
> -
> -		/* set block-size for cbom extension if available */
> -		ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> -		if (ret)
> -			continue;
> -
> -		if (!probed_block_size) {
> -			probed_block_size = val;
> -			cbom_hartid = hartid;
> -		} else {
> -			if (probed_block_size != val)
> -				pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> -					cbom_hartid, hartid);
> -		}
> -	}
> -
> -	if (probed_block_size)
> -		riscv_cbom_block_size = probed_block_size;
> -}
> -#endif
> -
>  void riscv_noncoherent_supported(void)
>  {
>  	WARN(!riscv_cbom_block_size,
>
  

On 19/10/2022 13:30, Heiko Stuebner wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi Anup,
> 
> Am Mittwoch, 19. Oktober 2022, 14:16:19 CEST schrieb Anup Patel:
>> From: Andrew Jones <ajones@ventanamicro.com>
>>
>> riscv_cbom_block_size and riscv_init_cbom_blocksize() should always
>> be available and riscv_init_cbom_blocksize() should always be
>> invoked, even when compiling without RISCV_ISA_ZICBOM enabled. This
>> is because disabling RISCV_ISA_ZICBOM means "don't use zicbom
>> instructions in the kernel" not "pretend there isn't zicbom, even
>> when there is". When zicbom is available, whether the kernel enables
>> its use with RISCV_ISA_ZICBOM or not, KVM will offer it to guests.
>> Ensure we can build KVM and that the block size is initialized even
>> when compiling without RISCV_ISA_ZICBOM.
> 
> either I'm way very low on coffee or something is strange here :-) .
> 
> I can fully grasp the need to init the cbom blocksize for guests, even when
> the main kernel isn't using it, but below in the patch itself it is still:
> 
> +#ifdef CONFIG_RISCV_ISA_ZICBOM
> +void riscv_init_cbom_blocksize(void)
> +{
> [...]
> 
> so the init_cbom_blocksize function is still inside a RISCV_ISA_ZICBOM
> ifdef?

FWIW:
Drew's patch, or at least the version of it that I have been using/did
a review of, does not have init_cbom_blocksize() inside such a #ifdef.

> 
> 
> Heiko
> 
> 
>>
>> Fixes: 8f7e001e0325 ("RISC-V: Clean up the Zicbom block size probing")
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
>> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
>> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
>> ---
>>   arch/riscv/mm/cacheflush.c      | 41 +++++++++++++++++++++++++++++++++
>>   arch/riscv/mm/dma-noncoherent.c | 41 ---------------------------------
>>   2 files changed, 41 insertions(+), 41 deletions(-)
>>
>> diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
>> index 6cb7d96ad9c7..f318b2553612 100644
>> --- a/arch/riscv/mm/cacheflush.c
>> +++ b/arch/riscv/mm/cacheflush.c
>> @@ -3,6 +3,8 @@
>>    * Copyright (C) 2017 SiFive
>>    */
>>
>> +#include <linux/of.h>
>> +#include <linux/of_device.h>
>>   #include <asm/cacheflush.h>
>>
>>   #ifdef CONFIG_SMP
>> @@ -86,3 +88,42 @@ void flush_icache_pte(pte_t pte)
>>                flush_icache_all();
>>   }
>>   #endif /* CONFIG_MMU */
>> +
>> +unsigned int riscv_cbom_block_size;
>> +EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
>> +
>> +#ifdef CONFIG_RISCV_ISA_ZICBOM
>> +void riscv_init_cbom_blocksize(void)
>> +{
>> +     struct device_node *node;
>> +     unsigned long cbom_hartid;
>> +     u32 val, probed_block_size;
>> +     int ret;
>> +
>> +     probed_block_size = 0;
>> +     for_each_of_cpu_node(node) {
>> +             unsigned long hartid;
>> +
>> +             ret = riscv_of_processor_hartid(node, &hartid);
>> +             if (ret)
>> +                     continue;
>> +
>> +             /* set block-size for cbom extension if available */
>> +             ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
>> +             if (ret)
>> +                     continue;
>> +
>> +             if (!probed_block_size) {
>> +                     probed_block_size = val;
>> +                     cbom_hartid = hartid;
>> +             } else {
>> +                     if (probed_block_size != val)
>> +                             pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
>> +                                     cbom_hartid, hartid);
>> +             }
>> +     }
>> +
>> +     if (probed_block_size)
>> +             riscv_cbom_block_size = probed_block_size;
>> +}
>> +#endif
>> diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
>> index b0add983530a..d919efab6eba 100644
>> --- a/arch/riscv/mm/dma-noncoherent.c
>> +++ b/arch/riscv/mm/dma-noncoherent.c
>> @@ -8,13 +8,8 @@
>>   #include <linux/dma-direct.h>
>>   #include <linux/dma-map-ops.h>
>>   #include <linux/mm.h>
>> -#include <linux/of.h>
>> -#include <linux/of_device.h>
>>   #include <asm/cacheflush.h>
>>
>> -unsigned int riscv_cbom_block_size;
>> -EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
>> -
>>   static bool noncoherent_supported;
>>
>>   void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
>> @@ -77,42 +72,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
>>        dev->dma_coherent = coherent;
>>   }
>>
>> -#ifdef CONFIG_RISCV_ISA_ZICBOM
>> -void riscv_init_cbom_blocksize(void)
>> -{
>> -     struct device_node *node;
>> -     unsigned long cbom_hartid;
>> -     u32 val, probed_block_size;
>> -     int ret;
>> -
>> -     probed_block_size = 0;
>> -     for_each_of_cpu_node(node) {
>> -             unsigned long hartid;
>> -
>> -             ret = riscv_of_processor_hartid(node, &hartid);
>> -             if (ret)
>> -                     continue;
>> -
>> -             /* set block-size for cbom extension if available */
>> -             ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
>> -             if (ret)
>> -                     continue;
>> -
>> -             if (!probed_block_size) {
>> -                     probed_block_size = val;
>> -                     cbom_hartid = hartid;
>> -             } else {
>> -                     if (probed_block_size != val)
>> -                             pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
>> -                                     cbom_hartid, hartid);
>> -             }
>> -     }
>> -
>> -     if (probed_block_size)
>> -             riscv_cbom_block_size = probed_block_size;
>> -}
>> -#endif
>> -
>>   void riscv_noncoherent_supported(void)
>>   {
>>        WARN(!riscv_cbom_block_size,
>>
> 
> 
> 
> 
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
  

On Wed, Oct 19, 2022 at 6:01 PM Heiko Stuebner <heiko@sntech.de> wrote:
>
> Hi Anup,
>
> Am Mittwoch, 19. Oktober 2022, 14:16:19 CEST schrieb Anup Patel:
> > From: Andrew Jones <ajones@ventanamicro.com>
> >
> > riscv_cbom_block_size and riscv_init_cbom_blocksize() should always
> > be available and riscv_init_cbom_blocksize() should always be
> > invoked, even when compiling without RISCV_ISA_ZICBOM enabled. This
> > is because disabling RISCV_ISA_ZICBOM means "don't use zicbom
> > instructions in the kernel" not "pretend there isn't zicbom, even
> > when there is". When zicbom is available, whether the kernel enables
> > its use with RISCV_ISA_ZICBOM or not, KVM will offer it to guests.
> > Ensure we can build KVM and that the block size is initialized even
> > when compiling without RISCV_ISA_ZICBOM.
>
> either I'm way very low on coffee or something is strange here :-) .
>
> I can fully grasp the need to init the cbom blocksize for guests, even when
> the main kernel isn't using it, but below in the patch itself it is still:

The Guest might have pass-through access to a device which is not
cache-coherent whereas Host might have all devices cache-coherent.

>
> +#ifdef CONFIG_RISCV_ISA_ZICBOM
> +void riscv_init_cbom_blocksize(void)
> +{
> [...]
>
> so the init_cbom_blocksize function is still inside a RISCV_ISA_ZICBOM
> ifdef?

Argh, I mixed changes from my previous patch and Drew's patch.

I will quickly send v4. Thanks for catching.

Regards,
Anup

>
>
> Heiko
>
>
> >
> > Fixes: 8f7e001e0325 ("RISC-V: Clean up the Zicbom block size probing")
> > Reported-by: kernel test robot <lkp@intel.com>
> > Signed-off-by: Andrew Jones <ajones@ventanamicro.com>
> > Signed-off-by: Anup Patel <apatel@ventanamicro.com>
> > Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> > ---
> >  arch/riscv/mm/cacheflush.c      | 41 +++++++++++++++++++++++++++++++++
> >  arch/riscv/mm/dma-noncoherent.c | 41 ---------------------------------
> >  2 files changed, 41 insertions(+), 41 deletions(-)
> >
> > diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
> > index 6cb7d96ad9c7..f318b2553612 100644
> > --- a/arch/riscv/mm/cacheflush.c
> > +++ b/arch/riscv/mm/cacheflush.c
> > @@ -3,6 +3,8 @@
> >   * Copyright (C) 2017 SiFive
> >   */
> >
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> >  #include <asm/cacheflush.h>
> >
> >  #ifdef CONFIG_SMP
> > @@ -86,3 +88,42 @@ void flush_icache_pte(pte_t pte)
> >               flush_icache_all();
> >  }
> >  #endif /* CONFIG_MMU */
> > +
> > +unsigned int riscv_cbom_block_size;
> > +EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> > +
> > +#ifdef CONFIG_RISCV_ISA_ZICBOM
> > +void riscv_init_cbom_blocksize(void)
> > +{
> > +     struct device_node *node;
> > +     unsigned long cbom_hartid;
> > +     u32 val, probed_block_size;
> > +     int ret;
> > +
> > +     probed_block_size = 0;
> > +     for_each_of_cpu_node(node) {
> > +             unsigned long hartid;
> > +
> > +             ret = riscv_of_processor_hartid(node, &hartid);
> > +             if (ret)
> > +                     continue;
> > +
> > +             /* set block-size for cbom extension if available */
> > +             ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> > +             if (ret)
> > +                     continue;
> > +
> > +             if (!probed_block_size) {
> > +                     probed_block_size = val;
> > +                     cbom_hartid = hartid;
> > +             } else {
> > +                     if (probed_block_size != val)
> > +                             pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> > +                                     cbom_hartid, hartid);
> > +             }
> > +     }
> > +
> > +     if (probed_block_size)
> > +             riscv_cbom_block_size = probed_block_size;
> > +}
> > +#endif
> > diff --git a/arch/riscv/mm/dma-noncoherent.c b/arch/riscv/mm/dma-noncoherent.c
> > index b0add983530a..d919efab6eba 100644
> > --- a/arch/riscv/mm/dma-noncoherent.c
> > +++ b/arch/riscv/mm/dma-noncoherent.c
> > @@ -8,13 +8,8 @@
> >  #include <linux/dma-direct.h>
> >  #include <linux/dma-map-ops.h>
> >  #include <linux/mm.h>
> > -#include <linux/of.h>
> > -#include <linux/of_device.h>
> >  #include <asm/cacheflush.h>
> >
> > -unsigned int riscv_cbom_block_size;
> > -EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
> > -
> >  static bool noncoherent_supported;
> >
> >  void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
> > @@ -77,42 +72,6 @@ void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
> >       dev->dma_coherent = coherent;
> >  }
> >
> > -#ifdef CONFIG_RISCV_ISA_ZICBOM
> > -void riscv_init_cbom_blocksize(void)
> > -{
> > -     struct device_node *node;
> > -     unsigned long cbom_hartid;
> > -     u32 val, probed_block_size;
> > -     int ret;
> > -
> > -     probed_block_size = 0;
> > -     for_each_of_cpu_node(node) {
> > -             unsigned long hartid;
> > -
> > -             ret = riscv_of_processor_hartid(node, &hartid);
> > -             if (ret)
> > -                     continue;
> > -
> > -             /* set block-size for cbom extension if available */
> > -             ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
> > -             if (ret)
> > -                     continue;
> > -
> > -             if (!probed_block_size) {
> > -                     probed_block_size = val;
> > -                     cbom_hartid = hartid;
> > -             } else {
> > -                     if (probed_block_size != val)
> > -                             pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
> > -                                     cbom_hartid, hartid);
> > -             }
> > -     }
> > -
> > -     if (probed_block_size)
> > -             riscv_cbom_block_size = probed_block_size;
> > -}
> > -#endif
> > -
> >  void riscv_noncoherent_supported(void)
> >  {
> >       WARN(!riscv_cbom_block_size,
> >
>
>
>
>