[PATCH] iomem: remove __weak ioremap_cache helper

[PATCH] iomem: remove __weak ioremap_cache helper

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

No portable code calls into this function any more, and on
architectures that don't use or define their own, it causes
a warning:

kernel/iomem.c:10:22: warning: no previous prototype for 'ioremap_cache' [-Wmissing-prototypes]
   10 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)

Fold it into the only caller that uses it on architectures
without the #define.

Note that the fallback to ioremap is probably still wrong on
those architectures, but this is what it's always done there.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 kernel/iomem.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/kernel/iomem.c b/kernel/iomem.c
index 9682471e64717..dc2120776e1c3 100644
--- a/kernel/iomem.c
+++ b/kernel/iomem.c
@@ -5,18 +5,14 @@
 #include <linux/mm.h>
 #include <linux/ioremap.h>
 
-#ifndef ioremap_cache
-/* temporary while we convert existing ioremap_cache users to memremap */
-__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
-{
-	return ioremap(offset, size);
-}
-#endif
-
 #ifndef arch_memremap_wb
 static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
 {
+#ifdef ioremap_cache
 	return (__force void *)ioremap_cache(offset, size);
+#else
+	return (__force void *)ioremap(offset, size);
+#endif
 }
 #endif
 
-- 
2.39.2

Re: [PATCH] iomem: remove __weak ioremap_cache helper

[Baoquan He]

Hi Arnd,

On 07/26/23 at 04:54pm, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> No portable code calls into this function any more, and on
> architectures that don't use or define their own, it causes
> a warning:
> 
> kernel/iomem.c:10:22: warning: no previous prototype for 'ioremap_cache' [-Wmissing-prototypes]
>    10 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
> 
> Fold it into the only caller that uses it on architectures
> without the #define.
> 
> Note that the fallback to ioremap is probably still wrong on
> those architectures, but this is what it's always done there.

Do we need to add a definition of ioremap_cache in asm-generic/io.h like
ioremap_wc|wt?

#ifndef ioremap_cache
#define ioremap_cahce ioremap
#endif

Unless it's for sure that drivers calling ioremap_cache are only built in
on those architecures defining it. Or we just want to see the breakage
on those ARCH-es so that they will add their own definition.

Not sure if I missed anything when understanding this.

drivers/acpi/apei/bert.c:       boot_error_region = ioremap_cache(bert_tab->address, region_len);
drivers/acpi/apei/einj.c:       trigger_tab = ioremap_cache(trigger_paddr, sizeof(*trigger_tab));
drivers/acpi/apei/einj.c:       trigger_tab = ioremap_cache(trigger_paddr, table_size);
drivers/acpi/apei/erst.c:       erst_erange.vaddr = ioremap_cache(erst_erange.base,
drivers/firmware/efi/memmap.c: * Setup a mapping of the EFI memory map using ioremap_cache(). This
drivers/firmware/meson/meson_sm.c:      return ioremap_cache(sm_phy_base, size);
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:                adev->mman.aper_base_kaddr = ioremap_cache(adev->gmc.aper_base,
drivers/gpu/drm/hyperv/hyperv_drm_drv.c:        hv->vram = ioremap_cache(hv->mem->start, hv->fb_size);
drivers/gpu/drm/ttm/ttm_bo_util.c:                      map->virtual = ioremap_cache(res, size);
drivers/gpu/drm/ttm/ttm_bo_util.c:                      vaddr_iomem = ioremap_cache(mem->bus.offset,
drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() maps decrypted */
drivers/hv/hv.c:                        = (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() maps decrypted */
drivers/hv/hv.c:                        = (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
drivers/mtd/devices/bcm47xxsflash.c:            b47s->window = ioremap_cache(res->start, resource_size(res));
drivers/mtd/maps/pxa2xx-flash.c:        info->map.cached = ioremap_cache(info->map.phys, info->map.size);
drivers/soc/fsl/qbman/qman_ccsr.c:      void __iomem *tmpp = ioremap_cache(addr, sz);
drivers/video/fbdev/hyperv_fb.c:        fb_virt = ioremap_cache(par->mem->start, screen_fb_size);
include/acpi/acpi_io.h:       return ioremap_cache(phys, size);

> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  kernel/iomem.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/iomem.c b/kernel/iomem.c
> index 9682471e64717..dc2120776e1c3 100644
> --- a/kernel/iomem.c
> +++ b/kernel/iomem.c
> @@ -5,18 +5,14 @@
>  #include <linux/mm.h>
>  #include <linux/ioremap.h>
>  
> -#ifndef ioremap_cache
> -/* temporary while we convert existing ioremap_cache users to memremap */
> -__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
> -{
> -	return ioremap(offset, size);
> -}
> -#endif
> -
>  #ifndef arch_memremap_wb
>  static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
>  {
> +#ifdef ioremap_cache
>  	return (__force void *)ioremap_cache(offset, size);
> +#else
> +	return (__force void *)ioremap(offset, size);
> +#endif
>  }
>  #endif
>  
> -- 
> 2.39.2
> 

Re: [PATCH] iomem: remove __weak ioremap_cache helper

[Arnd Bergmann]

On Thu, Jul 27, 2023, at 02:21, Baoquan He wrote:
> On 07/26/23 at 04:54pm, Arnd Bergmann wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> No portable code calls into this function any more, and on
>> architectures that don't use or define their own, it causes
>> a warning:
>> 
>> kernel/iomem.c:10:22: warning: no previous prototype for 'ioremap_cache' [-Wmissing-prototypes]
>>    10 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
>> 
>> Fold it into the only caller that uses it on architectures
>> without the #define.
>> 
>> Note that the fallback to ioremap is probably still wrong on
>> those architectures, but this is what it's always done there.
>
> Do we need to add a definition of ioremap_cache in asm-generic/io.h like
> ioremap_wc|wt?
>
> #ifndef ioremap_cache
> #define ioremap_cahce ioremap
> #endif

No, we really want to eliminate ioremap_cache() from the API,
not make it more visible.

> Unless it's for sure that drivers calling ioremap_cache are only built in
> on those architecures defining it. Or we just want to see the breakage
> on those ARCH-es so that they will add their own definition.

Right now, it's only possible to call ioremap_cache() on the couple
of architectures that explicitly declare this in their asm/io.h header
(arm, arm64, ia64, loongarch, mips, powerpc, sh, x86, and xtensa).

I think we could also go ahead and remove it from sh and xtensa.

> Not sure if I missed anything when understanding this.
>
> drivers/acpi/apei/bert.c:       boot_error_region = 
> ioremap_cache(bert_tab->address, region_len);
> drivers/acpi/apei/einj.c:       trigger_tab = 
> ioremap_cache(trigger_paddr, sizeof(*trigger_tab));
> drivers/acpi/apei/einj.c:       trigger_tab = 
> ioremap_cache(trigger_paddr, table_size);
> drivers/acpi/apei/erst.c:       erst_erange.vaddr = 
> ioremap_cache(erst_erange.base,
> include/acpi/acpi_io.h:       return ioremap_cache(phys, size);

acpi is used on x86, arm64 ia64, and loongarch

> drivers/firmware/meson/meson_sm.c:      return 
> ioremap_cache(sm_phy_base, size);

arm/arm64 specific

> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:                
> adev->mman.aper_base_kaddr = ioremap_cache(adev->gmc.aper_base,
> drivers/gpu/drm/hyperv/hyperv_drm_drv.c:        hv->vram = 
> ioremap_cache(hv->mem->start, hv->fb_size);
> drivers/gpu/drm/ttm/ttm_bo_util.c:                      map->virtual = 
> ioremap_cache(res, size);
> drivers/gpu/drm/ttm/ttm_bo_util.c:                      vaddr_iomem = 
> ioremap_cache(mem->bus.offset,

All guardeded with an x86 check

> drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() 
> maps decrypted */
> drivers/hv/hv.c:                        = (void *)ioremap_cache(base, 
> HV_HYP_PAGE_SIZE);
> drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() 
> maps decrypted */
> drivers/hv/hv.c:                        = (void *)ioremap_cache(base, 
> HV_HYP_PAGE_SIZE);
> drivers/video/fbdev/hyperv_fb.c:        fb_virt = 
> ioremap_cache(par->mem->start, screen_fb_size);

x86 and arm64 specific

> drivers/mtd/devices/bcm47xxsflash.c:            b47s->window = 
> ioremap_cache(res->start, resource_size(res));
> drivers/mtd/maps/pxa2xx-flash.c:        info->map.cached = 
> ioremap_cache(info->map.phys, info->map.size);
> drivers/soc/fsl/qbman/qman_ccsr.c:      void __iomem *tmpp = 
> ioremap_cache(addr, sz);

arm/arm64 specific.

There is also one more caller in mips that gets used by dmi:

arch/mips/include/asm/dmi.h:#define dmi_early_remap(x, l)		ioremap_cache(x, l)
arch/mips/include/asm/dmi.h:#define dmi_remap(x, l)			ioremap_cache(x, l)

      Arnd

Re: [PATCH] iomem: remove __weak ioremap_cache helper

[Baoquan He]

On 07/27/23 at 10:18am, Arnd Bergmann wrote:
> On Thu, Jul 27, 2023, at 02:21, Baoquan He wrote:
> > On 07/26/23 at 04:54pm, Arnd Bergmann wrote:
> >> From: Arnd Bergmann <arnd@arndb.de>
> >> 
> >> No portable code calls into this function any more, and on
> >> architectures that don't use or define their own, it causes
> >> a warning:
> >> 
> >> kernel/iomem.c:10:22: warning: no previous prototype for 'ioremap_cache' [-Wmissing-prototypes]
> >>    10 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
> >> 
> >> Fold it into the only caller that uses it on architectures
> >> without the #define.
> >> 
> >> Note that the fallback to ioremap is probably still wrong on
> >> those architectures, but this is what it's always done there.
> >
> > Do we need to add a definition of ioremap_cache in asm-generic/io.h like
> > ioremap_wc|wt?
> >
> > #ifndef ioremap_cache
> > #define ioremap_cahce ioremap
> > #endif
> 
> No, we really want to eliminate ioremap_cache() from the API,
> not make it more visible.

Got it now, thanks a lot for explanation.

> 
> > Unless it's for sure that drivers calling ioremap_cache are only built in
> > on those architecures defining it. Or we just want to see the breakage
> > on those ARCH-es so that they will add their own definition.
> 
> Right now, it's only possible to call ioremap_cache() on the couple
> of architectures that explicitly declare this in their asm/io.h header
> (arm, arm64, ia64, loongarch, mips, powerpc, sh, x86, and xtensa).
> 
> I think we could also go ahead and remove it from sh and xtensa.

Agree, if no actual need of ioremap_cache() on sh and xtensa.

> 
> > Not sure if I missed anything when understanding this.
> >
> > drivers/acpi/apei/bert.c:       boot_error_region = 
> > ioremap_cache(bert_tab->address, region_len);
> > drivers/acpi/apei/einj.c:       trigger_tab = 
> > ioremap_cache(trigger_paddr, sizeof(*trigger_tab));
> > drivers/acpi/apei/einj.c:       trigger_tab = 
> > ioremap_cache(trigger_paddr, table_size);
> > drivers/acpi/apei/erst.c:       erst_erange.vaddr = 
> > ioremap_cache(erst_erange.base,
> > include/acpi/acpi_io.h:       return ioremap_cache(phys, size);
> 
> acpi is used on x86, arm64 ia64, and loongarch
> 
> > drivers/firmware/meson/meson_sm.c:      return 
> > ioremap_cache(sm_phy_base, size);
> 
> arm/arm64 specific
> 
> > drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:                
> > adev->mman.aper_base_kaddr = ioremap_cache(adev->gmc.aper_base,
> > drivers/gpu/drm/hyperv/hyperv_drm_drv.c:        hv->vram = 
> > ioremap_cache(hv->mem->start, hv->fb_size);
> > drivers/gpu/drm/ttm/ttm_bo_util.c:                      map->virtual = 
> > ioremap_cache(res, size);
> > drivers/gpu/drm/ttm/ttm_bo_util.c:                      vaddr_iomem = 
> > ioremap_cache(mem->bus.offset,
> 
> All guardeded with an x86 check
> 
> > drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() 
> > maps decrypted */
> > drivers/hv/hv.c:                        = (void *)ioremap_cache(base, 
> > HV_HYP_PAGE_SIZE);
> > drivers/hv/hv.c:                /* Mask out vTOM bit. ioremap_cache() 
> > maps decrypted */
> > drivers/hv/hv.c:                        = (void *)ioremap_cache(base, 
> > HV_HYP_PAGE_SIZE);
> > drivers/video/fbdev/hyperv_fb.c:        fb_virt = 
> > ioremap_cache(par->mem->start, screen_fb_size);
> 
> x86 and arm64 specific
> 
> > drivers/mtd/devices/bcm47xxsflash.c:            b47s->window = 
> > ioremap_cache(res->start, resource_size(res));
> > drivers/mtd/maps/pxa2xx-flash.c:        info->map.cached = 
> > ioremap_cache(info->map.phys, info->map.size);
> > drivers/soc/fsl/qbman/qman_ccsr.c:      void __iomem *tmpp = 
> > ioremap_cache(addr, sz);
> 
> arm/arm64 specific.
> 
> There is also one more caller in mips that gets used by dmi:
> 
> arch/mips/include/asm/dmi.h:#define dmi_early_remap(x, l)		ioremap_cache(x, l)
> arch/mips/include/asm/dmi.h:#define dmi_remap(x, l)			ioremap_cache(x, l)
> 
>       Arnd
> 

Re: [PATCH] iomem: remove __weak ioremap_cache helper

[Baoquan He]

On 07/26/23 at 04:54pm, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> No portable code calls into this function any more, and on
> architectures that don't use or define their own, it causes
> a warning:
> 
> kernel/iomem.c:10:22: warning: no previous prototype for 'ioremap_cache' [-Wmissing-prototypes]
>    10 | __weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
> 
> Fold it into the only caller that uses it on architectures
> without the #define.
> 
> Note that the fallback to ioremap is probably still wrong on
> those architectures, but this is what it's always done there.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  kernel/iomem.c | 12 ++++--------
>  1 file changed, 4 insertions(+), 8 deletions(-)
> 
> diff --git a/kernel/iomem.c b/kernel/iomem.c
> index 9682471e64717..dc2120776e1c3 100644
> --- a/kernel/iomem.c
> +++ b/kernel/iomem.c
> @@ -5,18 +5,14 @@
>  #include <linux/mm.h>
>  #include <linux/ioremap.h>
>  
> -#ifndef ioremap_cache
> -/* temporary while we convert existing ioremap_cache users to memremap */
> -__weak void __iomem *ioremap_cache(resource_size_t offset, unsigned long size)
> -{
> -	return ioremap(offset, size);
> -}
> -#endif
> -
>  #ifndef arch_memremap_wb
>  static void *arch_memremap_wb(resource_size_t offset, unsigned long size)
>  {
> +#ifdef ioremap_cache
>  	return (__force void *)ioremap_cache(offset, size);
> +#else
> +	return (__force void *)ioremap(offset, size);
> +#endif
>  }
>  #endif

This looks good to me, thanks.

Reviewed-by: Baoquan He <bhe@redhat.com>

Re: [PATCH] iomem: remove __weak ioremap_cache helper

[Christoph Hellwig]

Ah, nice:

Reviewed-by: Christoph Hellwig <hch@lst.de>