Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Date:   Tue, 16 May 2023 09:52:39 +0300
From:   Mike Rapoport <rppt@kernel.org>
To:     Baoquan He <bhe@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-mm@kvack.org, arnd@arndb.de, christophe.leroy@csgroup.eu,
        hch@infradead.org, agordeev@linux.ibm.com,
        wangkefeng.wang@huawei.com, schnelle@linux.ibm.com,
        David.Laight@aculab.com, shorne@gmail.com, willy@infradead.org,
        deller@gmx.de,
        "James E.J. Bottomley" <James.Bottomley@hansenpartnership.com>,
        linux-parisc@vger.kernel.org
Subject: Re: [PATCH v5 RESEND 13/17] parisc: mm: Convert to GENERIC_IOREMAP
Message-ID: <ZGMoN/FiwWnvjAjS@kernel.org>
References: <20230515090848.833045-1-bhe@redhat.com>
 <20230515090848.833045-14-bhe@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230515090848.833045-14-bhe@redhat.com>
Precedence: bulk

On Mon, May 15, 2023 at 05:08:44PM +0800, Baoquan He wrote:
> By taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(),
> generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap()
> and iounmap() are all visible and available to arch. Arch needs to
> provide wrapper functions to override the generic versions if there's
> arch specific handling in its ioremap_prot(), ioremap() or iounmap().
> This change will simplify implementation by removing duplicated codes
> with generic_ioremap_prot() and generic_iounmap(), and has the equivalent
> functioality as before.
> 
> Here, add wrapper function ioremap_prot() for parisc's special operation
> when iounmap().
> 
> Meanwhile, add macro ARCH_HAS_IOREMAP_WC since the added ioremap_wc()
> will conflict with the one in include/asm-generic/iomap.h, then an
> compiling error is seen:

Looks like this paragraph is outdated, as an earlier patch in the series
removes use of ARCH_HAS_IOREMAP_WC?
 
> ./include/asm-generic/iomap.h:97: warning: "ioremap_wc" redefined
>    97 | #define ioremap_wc ioremap
> 
> And benefit from the commit 437b6b35362b ("parisc: Use the generic
> IO helpers"), those macros don't need be added any more.
> 
> Signed-off-by: Baoquan He <bhe@redhat.com>
> Acked-by: Helge Deller <deller@gmx.de>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: linux-parisc@vger.kernel.org
> ---
>  arch/parisc/Kconfig          |  1 +
>  arch/parisc/include/asm/io.h | 15 ++++++---
>  arch/parisc/mm/ioremap.c     | 62 +++---------------------------------
>  3 files changed, 15 insertions(+), 63 deletions(-)
> 
> diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
> index 466a25525364..be6ab4530390 100644
> --- a/arch/parisc/Kconfig
> +++ b/arch/parisc/Kconfig
> @@ -36,6 +36,7 @@ config PARISC
>  	select GENERIC_ATOMIC64 if !64BIT
>  	select GENERIC_IRQ_PROBE
>  	select GENERIC_PCI_IOMAP
> +	select GENERIC_IOREMAP
>  	select ARCH_HAVE_NMI_SAFE_CMPXCHG
>  	select GENERIC_SMP_IDLE_THREAD
>  	select GENERIC_ARCH_TOPOLOGY if SMP
> diff --git a/arch/parisc/include/asm/io.h b/arch/parisc/include/asm/io.h
> index c05e781be2f5..366537042465 100644
> --- a/arch/parisc/include/asm/io.h
> +++ b/arch/parisc/include/asm/io.h
> @@ -125,12 +125,17 @@ static inline void gsc_writeq(unsigned long long val, unsigned long addr)
>  /*
>   * The standard PCI ioremap interfaces
>   */
> -void __iomem *ioremap(unsigned long offset, unsigned long size);
> -#define ioremap_wc			ioremap
> -#define ioremap_uc			ioremap
> -#define pci_iounmap			pci_iounmap
> +#define ioremap_prot ioremap_prot
> +
> +#define _PAGE_IOREMAP (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | \
> +		       _PAGE_ACCESSED | _PAGE_NO_CACHE)
>  
> -extern void iounmap(const volatile void __iomem *addr);
> +#define ioremap_wc(addr, size)  \
> +	ioremap_prot((addr), (size), _PAGE_IOREMAP)
> +#define ioremap_uc(addr, size)  \
> +	ioremap_prot((addr), (size), _PAGE_IOREMAP)
> +
> +#define pci_iounmap			pci_iounmap
>  
>  void memset_io(volatile void __iomem *addr, unsigned char val, int count);
>  void memcpy_fromio(void *dst, const volatile void __iomem *src, int count);
> diff --git a/arch/parisc/mm/ioremap.c b/arch/parisc/mm/ioremap.c
> index 345ff0b66499..fd996472dfe7 100644
> --- a/arch/parisc/mm/ioremap.c
> +++ b/arch/parisc/mm/ioremap.c
> @@ -13,25 +13,9 @@
>  #include <linux/io.h>
>  #include <linux/mm.h>
>  
> -/*
> - * Generic mapping function (not visible outside):
> - */
> -
> -/*
> - * Remap an arbitrary physical address space into the kernel virtual
> - * address space.
> - *
> - * NOTE! We need to allow non-page-aligned mappings too: we will obviously
> - * have to convert them into an offset in a page-aligned mapping, but the
> - * caller shouldn't need to know that small detail.
> - */
> -void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
> +void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
> +			   unsigned long prot)
>  {
> -	void __iomem *addr;
> -	struct vm_struct *area;
> -	unsigned long offset, last_addr;
> -	pgprot_t pgprot;
> -
>  #ifdef CONFIG_EISA
>  	unsigned long end = phys_addr + size - 1;
>  	/* Support EISA addresses */
> @@ -40,11 +24,6 @@ void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
>  		phys_addr |= F_EXTEND(0xfc000000);
>  #endif
>  
> -	/* Don't allow wraparound or zero size */
> -	last_addr = phys_addr + size - 1;
> -	if (!size || last_addr < phys_addr)
> -		return NULL;
> -
>  	/*
>  	 * Don't allow anybody to remap normal RAM that we're using..
>  	 */
> @@ -62,39 +41,6 @@ void __iomem *ioremap(unsigned long phys_addr, unsigned long size)
>  		}
>  	}
>  
> -	pgprot = __pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY |
> -			  _PAGE_ACCESSED | _PAGE_NO_CACHE);
> -
> -	/*
> -	 * Mappings have to be page-aligned
> -	 */
> -	offset = phys_addr & ~PAGE_MASK;
> -	phys_addr &= PAGE_MASK;
> -	size = PAGE_ALIGN(last_addr + 1) - phys_addr;
> -
> -	/*
> -	 * Ok, go for it..
> -	 */
> -	area = get_vm_area(size, VM_IOREMAP);
> -	if (!area)
> -		return NULL;
> -
> -	addr = (void __iomem *) area->addr;
> -	if (ioremap_page_range((unsigned long)addr, (unsigned long)addr + size,
> -			       phys_addr, pgprot)) {
> -		vunmap(addr);
> -		return NULL;
> -	}
> -
> -	return (void __iomem *) (offset + (char __iomem *)addr);
> -}
> -EXPORT_SYMBOL(ioremap);
> -
> -void iounmap(const volatile void __iomem *io_addr)
> -{
> -	unsigned long addr = (unsigned long)io_addr & PAGE_MASK;
> -
> -	if (is_vmalloc_addr((void *)addr))
> -		vunmap((void *)addr);
> +	return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
>  }
> -EXPORT_SYMBOL(iounmap);
> +EXPORT_SYMBOL(ioremap_prot);
> -- 
> 2.34.1
> 
> 

-- 
Sincerely yours,
Mike.