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Date: Fri, 18 Sep 2009 14:17:09 +0200
From: Ingo Molnar <mingo@...e.hu>
To: David Miller <davem@...emloft.net>,
Andrew Morton <akpm@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, a.p.zijlstra@...llo.nl,
jens.axboe@...cle.com, Paul Mackerras <paulus@...ba.org>,
Fr??d??ric Weisbecker <fweisbec@...il.com>,
Steven Rostedt <rostedt@...dmis.org>
Subject: Re: [PATCH 1/2]: mm: Make vmalloc_user() align base kernel virtual
address to SHMLBA.
( Andrew, this patch has mm/* effects - any objections? Would still like
to get this into v2.6.32. )
* David Miller <davem@...emloft.net> wrote:
> When a vmalloc'd area is mmap'd into userspace, some kind of
> co-ordination is necessary for this to work on platforms with cpu
> D-caches which can have aliases.
>
> Otherwise kernel side writes won't be seen properly in userspace and
> vice versa.
>
> If the kernel side mapping and the user side one have the same
> alignment, modulo SHMLBA, this can work as long as VM_SHARED is
> shared of VMA and for all current users this is true. VM_SHARED
> will force SHMLBA alignment of the user side mmap on platforms
> with D-cache aliasing matters.
>
> The bulk of this patch is just making it so that a specific alignment
> can be passed down into __get_vm_area_node(). All existing callers
> pass in '1' which preserves existing behavior. vmalloc_user() gives
> SHMLBA for the alignment.
>
> As a side effect this should get the video media drivers and other
> vmalloc_user() users into more working shape on such systems.
>
> Signed-off-by: David S. Miller <davem@...emloft.net>
> ---
> mm/vmalloc.c | 48 ++++++++++++++++++++++++++----------------------
> 1 files changed, 26 insertions(+), 22 deletions(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index f8189a4..be15e03 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -29,6 +29,7 @@
> #include <asm/atomic.h>
> #include <asm/uaccess.h>
> #include <asm/tlbflush.h>
> +#include <asm/shmparam.h>
>
>
> /*** Page table manipulation functions ***/
> @@ -1123,13 +1124,12 @@ DEFINE_RWLOCK(vmlist_lock);
> struct vm_struct *vmlist;
>
> static struct vm_struct *__get_vm_area_node(unsigned long size,
> - unsigned long flags, unsigned long start, unsigned long end,
> - int node, gfp_t gfp_mask, void *caller)
> + unsigned long align, unsigned long flags, unsigned long start,
> + unsigned long end, int node, gfp_t gfp_mask, void *caller)
> {
> static struct vmap_area *va;
> struct vm_struct *area;
> struct vm_struct *tmp, **p;
> - unsigned long align = 1;
>
> BUG_ON(in_interrupt());
> if (flags & VM_IOREMAP) {
> @@ -1187,7 +1187,7 @@ static struct vm_struct *__get_vm_area_node(unsigned long size,
> struct vm_struct *__get_vm_area(unsigned long size, unsigned long flags,
> unsigned long start, unsigned long end)
> {
> - return __get_vm_area_node(size, flags, start, end, -1, GFP_KERNEL,
> + return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
> __builtin_return_address(0));
> }
> EXPORT_SYMBOL_GPL(__get_vm_area);
> @@ -1196,7 +1196,7 @@ struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
> unsigned long start, unsigned long end,
> void *caller)
> {
> - return __get_vm_area_node(size, flags, start, end, -1, GFP_KERNEL,
> + return __get_vm_area_node(size, 1, flags, start, end, -1, GFP_KERNEL,
> caller);
> }
>
> @@ -1211,22 +1211,22 @@ struct vm_struct *__get_vm_area_caller(unsigned long size, unsigned long flags,
> */
> struct vm_struct *get_vm_area(unsigned long size, unsigned long flags)
> {
> - return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END,
> + return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
> -1, GFP_KERNEL, __builtin_return_address(0));
> }
>
> struct vm_struct *get_vm_area_caller(unsigned long size, unsigned long flags,
> void *caller)
> {
> - return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END,
> + return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
> -1, GFP_KERNEL, caller);
> }
>
> struct vm_struct *get_vm_area_node(unsigned long size, unsigned long flags,
> int node, gfp_t gfp_mask)
> {
> - return __get_vm_area_node(size, flags, VMALLOC_START, VMALLOC_END, node,
> - gfp_mask, __builtin_return_address(0));
> + return __get_vm_area_node(size, 1, flags, VMALLOC_START, VMALLOC_END,
> + node, gfp_mask, __builtin_return_address(0));
> }
>
> static struct vm_struct *find_vm_area(const void *addr)
> @@ -1385,7 +1385,8 @@ void *vmap(struct page **pages, unsigned int count,
> }
> EXPORT_SYMBOL(vmap);
>
> -static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
> +static void *__vmalloc_node(unsigned long size, unsigned long align,
> + gfp_t gfp_mask, pgprot_t prot,
> int node, void *caller);
> static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
> pgprot_t prot, int node, void *caller)
> @@ -1399,7 +1400,7 @@ static void *__vmalloc_area_node(struct vm_struct *area, gfp_t gfp_mask,
> area->nr_pages = nr_pages;
> /* Please note that the recursion is strictly bounded. */
> if (array_size > PAGE_SIZE) {
> - pages = __vmalloc_node(array_size, gfp_mask | __GFP_ZERO,
> + pages = __vmalloc_node(array_size, 1, gfp_mask | __GFP_ZERO,
> PAGE_KERNEL, node, caller);
> area->flags |= VM_VPAGES;
> } else {
> @@ -1458,6 +1459,7 @@ void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
> /**
> * __vmalloc_node - allocate virtually contiguous memory
> * @size: allocation size
> + * @align: desired alignment
> * @gfp_mask: flags for the page level allocator
> * @prot: protection mask for the allocated pages
> * @node: node to use for allocation or -1
> @@ -1467,8 +1469,9 @@ void *__vmalloc_area(struct vm_struct *area, gfp_t gfp_mask, pgprot_t prot)
> * allocator with @gfp_mask flags. Map them into contiguous
> * kernel virtual space, using a pagetable protection of @prot.
> */
> -static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
> - int node, void *caller)
> +static void *__vmalloc_node(unsigned long size, unsigned long align,
> + gfp_t gfp_mask, pgprot_t prot,
> + int node, void *caller)
> {
> struct vm_struct *area;
> void *addr;
> @@ -1478,8 +1481,8 @@ static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
> if (!size || (size >> PAGE_SHIFT) > num_physpages)
> return NULL;
>
> - area = __get_vm_area_node(size, VM_ALLOC, VMALLOC_START, VMALLOC_END,
> - node, gfp_mask, caller);
> + area = __get_vm_area_node(size, align, VM_ALLOC, VMALLOC_START,
> + VMALLOC_END, node, gfp_mask, caller);
>
> if (!area)
> return NULL;
> @@ -1498,7 +1501,7 @@ static void *__vmalloc_node(unsigned long size, gfp_t gfp_mask, pgprot_t prot,
>
> void *__vmalloc(unsigned long size, gfp_t gfp_mask, pgprot_t prot)
> {
> - return __vmalloc_node(size, gfp_mask, prot, -1,
> + return __vmalloc_node(size, 1, gfp_mask, prot, -1,
> __builtin_return_address(0));
> }
> EXPORT_SYMBOL(__vmalloc);
> @@ -1514,7 +1517,7 @@ EXPORT_SYMBOL(__vmalloc);
> */
> void *vmalloc(unsigned long size)
> {
> - return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
> + return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
> -1, __builtin_return_address(0));
> }
> EXPORT_SYMBOL(vmalloc);
> @@ -1531,7 +1534,8 @@ void *vmalloc_user(unsigned long size)
> struct vm_struct *area;
> void *ret;
>
> - ret = __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
> + ret = __vmalloc_node(size, SHMLBA,
> + GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO,
> PAGE_KERNEL, -1, __builtin_return_address(0));
> if (ret) {
> area = find_vm_area(ret);
> @@ -1554,7 +1558,7 @@ EXPORT_SYMBOL(vmalloc_user);
> */
> void *vmalloc_node(unsigned long size, int node)
> {
> - return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
> + return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL,
> node, __builtin_return_address(0));
> }
> EXPORT_SYMBOL(vmalloc_node);
> @@ -1577,7 +1581,7 @@ EXPORT_SYMBOL(vmalloc_node);
>
> void *vmalloc_exec(unsigned long size)
> {
> - return __vmalloc_node(size, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
> + return __vmalloc_node(size, 1, GFP_KERNEL | __GFP_HIGHMEM, PAGE_KERNEL_EXEC,
> -1, __builtin_return_address(0));
> }
>
> @@ -1598,7 +1602,7 @@ void *vmalloc_exec(unsigned long size)
> */
> void *vmalloc_32(unsigned long size)
> {
> - return __vmalloc_node(size, GFP_VMALLOC32, PAGE_KERNEL,
> + return __vmalloc_node(size, 1, GFP_VMALLOC32, PAGE_KERNEL,
> -1, __builtin_return_address(0));
> }
> EXPORT_SYMBOL(vmalloc_32);
> @@ -1615,7 +1619,7 @@ void *vmalloc_32_user(unsigned long size)
> struct vm_struct *area;
> void *ret;
>
> - ret = __vmalloc_node(size, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
> + ret = __vmalloc_node(size, 1, GFP_VMALLOC32 | __GFP_ZERO, PAGE_KERNEL,
> -1, __builtin_return_address(0));
> if (ret) {
> area = find_vm_area(ret);
> --
> 1.6.4.2
--
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