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Message-Id: <87lgcusc6z.fsf@linux.vnet.ibm.com>
Date: Tue, 08 May 2018 15:26:20 +0530
From: "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>
To: Christophe Leroy <christophe.leroy@....fr>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: Re: [PATCH 09/17] powerpc: make __ioremap_caller() common to PPC32 and PPC64
Christophe Leroy <christophe.leroy@....fr> writes:
> Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
> ---
> arch/powerpc/include/asm/book3s/64/pgtable.h | 1 +
> arch/powerpc/mm/ioremap.c | 126 +++++++--------------------
> 2 files changed, 34 insertions(+), 93 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
> index c5c6ead06bfb..2bebdd8302cb 100644
> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
> @@ -18,6 +18,7 @@
> #define _PAGE_RO 0
> #define _PAGE_USER 0
> #define _PAGE_HWWRITE 0
> +#define _PAGE_COHERENT 0
This is something I was trying to avoid when I split the headers. We do
support _PAGE_USER it is !_PAGE_PRIVILEGED. It gets really confusing
when we have these conflicting names because we are trying to make code
common across platforms.
>
> #define _PAGE_EXEC 0x00001 /* execute permission */
> #define _PAGE_WRITE 0x00002 /* write access allowed */
> diff --git a/arch/powerpc/mm/ioremap.c b/arch/powerpc/mm/ioremap.c
> index 65d611d44d38..59be5dfcb3e9 100644
> --- a/arch/powerpc/mm/ioremap.c
> +++ b/arch/powerpc/mm/ioremap.c
> @@ -33,95 +33,6 @@ unsigned long ioremap_bot;
> unsigned long ioremap_bot = IOREMAP_BASE;
> #endif
>
> -#ifdef CONFIG_PPC32
> -
> -void __iomem *
> -__ioremap_caller(phys_addr_t addr, unsigned long size, unsigned long flags,
> - void *caller)
> -{
> - unsigned long v, i;
> - phys_addr_t p;
> - int err;
> -
> - /* Make sure we have the base flags */
> - if ((flags & _PAGE_PRESENT) == 0)
> - flags |= pgprot_val(PAGE_KERNEL);
> -
> - /* Non-cacheable page cannot be coherent */
> - if (flags & _PAGE_NO_CACHE)
> - flags &= ~_PAGE_COHERENT;
> -
> - /*
> - * Choose an address to map it to.
> - * Once the vmalloc system is running, we use it.
> - * Before then, we use space going up from IOREMAP_BASE
> - * (ioremap_bot records where we're up to).
> - */
> - p = addr & PAGE_MASK;
> - size = PAGE_ALIGN(addr + size) - p;
> -
> - /*
> - * If the address lies within the first 16 MB, assume it's in ISA
> - * memory space
> - */
> - if (p < 16*1024*1024)
> - p += _ISA_MEM_BASE;
> -
> -#ifndef CONFIG_CRASH_DUMP
> - /*
> - * Don't allow anybody to remap normal RAM that we're using.
> - * mem_init() sets high_memory so only do the check after that.
> - */
> - if (slab_is_available() && (p < virt_to_phys(high_memory)) &&
> - page_is_ram(__phys_to_pfn(p))) {
> - printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
> - (unsigned long long)p, __builtin_return_address(0));
> - return NULL;
> - }
> -#endif
> -
> - if (size == 0)
> - return NULL;
> -
> - /*
> - * Is it already mapped? Perhaps overlapped by a previous
> - * mapping.
> - */
> - v = p_block_mapped(p);
> - if (v)
> - goto out;
> -
> - if (slab_is_available()) {
> - struct vm_struct *area;
> - area = get_vm_area_caller(size, VM_IOREMAP, caller);
> - if (area == 0)
> - return NULL;
> - area->phys_addr = p;
> - v = (unsigned long) area->addr;
> - } else {
> - v = ioremap_bot;
> - ioremap_bot += size;
> - }
> -
> - /*
> - * Should check if it is a candidate for a BAT mapping
> - */
> -
> - err = 0;
> - for (i = 0; i < size && err == 0; i += PAGE_SIZE)
> - err = map_kernel_page(v+i, p+i, flags);
> - if (err) {
> - if (slab_is_available())
> - vunmap((void *)v);
> - return NULL;
> - }
> -
> -out:
> - return (void __iomem *) (v + ((unsigned long)addr & ~PAGE_MASK));
> -}
> -
> -#else
> -
> /**
> * __ioremap_at - Low level function to establish the page tables
> * for an IO mapping
> @@ -135,6 +46,10 @@ void __iomem * __ioremap_at(phys_addr_t pa, void *ea, unsigned long size,
> if ((flags & _PAGE_PRESENT) == 0)
> flags |= pgprot_val(PAGE_KERNEL);
>
> + /* Non-cacheable page cannot be coherent */
> + if (flags & _PAGE_NO_CACHE)
> + flags &= ~_PAGE_COHERENT;
> +
> /* We don't support the 4K PFN hack with ioremap */
> if (flags & H_PAGE_4K_PFN)
> return NULL;
> @@ -187,6 +102,33 @@ void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
> if ((size == 0) || (paligned == 0))
> return NULL;
>
> + /*
> + * If the address lies within the first 16 MB, assume it's in ISA
> + * memory space
> + */
> + if (IS_ENABLED(CONFIG_PPC32) && paligned < 16*1024*1024)
> + paligned += _ISA_MEM_BASE;
> +
> + /*
> + * Don't allow anybody to remap normal RAM that we're using.
> + * mem_init() sets high_memory so only do the check after that.
> + */
> + if (!IS_ENABLED(CONFIG_CRASH_DUMP) &&
> + slab_is_available() && (paligned < virt_to_phys(high_memory)) &&
> + page_is_ram(__phys_to_pfn(paligned))) {
> + printk("__ioremap(): phys addr 0x%llx is RAM lr %ps\n",
> + (u64)paligned, __builtin_return_address(0));
> + return NULL;
> + }
> +
> + /*
> + * Is it already mapped? Perhaps overlapped by a previous
> + * mapping.
> + */
> + ret = (void __iomem *)p_block_mapped(paligned);
> + if (ret)
> + goto out;
> +
> if (slab_is_available()) {
> struct vm_struct *area;
>
> @@ -205,14 +147,12 @@ void __iomem * __ioremap_caller(phys_addr_t addr, unsigned long size,
> if (ret)
> ioremap_bot += size;
> }
> -
> +out:
> if (ret)
> - ret += addr & ~PAGE_MASK;
> + ret += (unsigned long)addr & ~PAGE_MASK;
> return ret;
> }
>
> -#endif
> -
> /*
> * Unmap an IO region and remove it from imalloc'd list.
> * Access to IO memory should be serialized by driver.
> --
> 2.13.3
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