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alistair23-linux/drivers/staging/android/ashmem.h

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ashmem: Anonymous shared memory subsystem The anonymous shared memory (ashmem) subsystem provides a Unix-y,file-based shared memory interface to user-space. It works like anonymous memory (e.g. mmapping fd=0) except if you share the file descriptor via the usual means, you will share the mapping. The shared memory can be accessed via both mmap or file I/O. The backing store is a simple shmem file. Additionally, ashmem introduces the concept of page pinning. Pinned pages (the default) behave like any anonymous memory. Unpinned pages are available to the kernel for eviction during VM pressure. When repinning the pages, the return value instructs user-space as to any eviction. In this manner, user-space processes may implement caching and similar resource management that efficiently integrates with kernel memory management. Signed-off-by: Robert Love <rlove@google.com> ashmem: Don't install fault handler for private mmaps. Ashmem is used to create named private heaps. If this heap is backed by a tmpfs file it will allocate two pages for every page touched. In 2.6.27, the extra page would later be freed, but 2.6.29 does not scan anonymous pages when running without swap so the memory is not freed while the file is referenced. This change changes the behavior of private ashmem mmaps to match /dev/zero instead tmpfs. Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: Add common prefix to name reported in /proc/pid/maps Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: don't require a page aligned size This makes ashmem more similar to shmem and mmap, by not requiring the specified size to be page aligned, instead rounding it internally as needed. Signed-off-by: Marco Nelissen <marcone@android.com> [jstultz: Improved commit subject and included patch description from rlove. Also moved ashmem files to staging dir, and reworked code to avoid touching mm/shmem.c while we're in staging.] CC: Brian Swetland <swetland@google.com> CC: Colin Cross <ccross@android.com> CC: Arve Hjønnevåg <arve@android.com> CC: Dima Zavin <dima@android.com> CC: Robert Love <rlove@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-20 17:49:48 -07:00
/*
* include/linux/ashmem.h
*
* Copyright 2008 Google Inc.
* Author: Robert Love
*
* This file is dual licensed. It may be redistributed and/or modified
* under the terms of the Apache 2.0 License OR version 2 of the GNU
* General Public License.
*/
#ifndef _LINUX_ASHMEM_H
#define _LINUX_ASHMEM_H
#include <linux/limits.h>
#include <linux/ioctl.h>
staging: android: ashmem: Add support for 32bit ashmem calls in a 64bit kernel Android's shared memory subsystem, Ashmem, does not support calls from a 32bit userspace in a 64 bit kernel. This patch adds support for syscalls coming from a 32bit userspace in a 64bit kernel. The patch has been successfully tested on ARMv8 AEM(64bit platform model) and Versatile Express A9(32bit platform). v2: Fix missing compat.h include. Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com> Acked-by: Arve Hjønnevåg <arve@android.com> Acked-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-05 08:27:38 -07:00
#include <linux/compat.h>
ashmem: Anonymous shared memory subsystem The anonymous shared memory (ashmem) subsystem provides a Unix-y,file-based shared memory interface to user-space. It works like anonymous memory (e.g. mmapping fd=0) except if you share the file descriptor via the usual means, you will share the mapping. The shared memory can be accessed via both mmap or file I/O. The backing store is a simple shmem file. Additionally, ashmem introduces the concept of page pinning. Pinned pages (the default) behave like any anonymous memory. Unpinned pages are available to the kernel for eviction during VM pressure. When repinning the pages, the return value instructs user-space as to any eviction. In this manner, user-space processes may implement caching and similar resource management that efficiently integrates with kernel memory management. Signed-off-by: Robert Love <rlove@google.com> ashmem: Don't install fault handler for private mmaps. Ashmem is used to create named private heaps. If this heap is backed by a tmpfs file it will allocate two pages for every page touched. In 2.6.27, the extra page would later be freed, but 2.6.29 does not scan anonymous pages when running without swap so the memory is not freed while the file is referenced. This change changes the behavior of private ashmem mmaps to match /dev/zero instead tmpfs. Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: Add common prefix to name reported in /proc/pid/maps Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: don't require a page aligned size This makes ashmem more similar to shmem and mmap, by not requiring the specified size to be page aligned, instead rounding it internally as needed. Signed-off-by: Marco Nelissen <marcone@android.com> [jstultz: Improved commit subject and included patch description from rlove. Also moved ashmem files to staging dir, and reworked code to avoid touching mm/shmem.c while we're in staging.] CC: Brian Swetland <swetland@google.com> CC: Colin Cross <ccross@android.com> CC: Arve Hjønnevåg <arve@android.com> CC: Dima Zavin <dima@android.com> CC: Robert Love <rlove@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-20 17:49:48 -07:00
staging: android: Split uapi out of ashmem.h Move the userspace interface of ashmem.h to drivers/staging/android/uapi/ashmem.h Cc: Greg KH <gregkh@linuxfoundation.org> Cc: Colin Cross <ccross@android.com> Cc: Android Kernel Team <kernel-team@android.com> Signed-off-by: Colin Cross <ccross@android.com> [jstultz: Minor commit message tweak] Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-02-17 14:58:31 -07:00
#include "uapi/ashmem.h"
ashmem: Anonymous shared memory subsystem The anonymous shared memory (ashmem) subsystem provides a Unix-y,file-based shared memory interface to user-space. It works like anonymous memory (e.g. mmapping fd=0) except if you share the file descriptor via the usual means, you will share the mapping. The shared memory can be accessed via both mmap or file I/O. The backing store is a simple shmem file. Additionally, ashmem introduces the concept of page pinning. Pinned pages (the default) behave like any anonymous memory. Unpinned pages are available to the kernel for eviction during VM pressure. When repinning the pages, the return value instructs user-space as to any eviction. In this manner, user-space processes may implement caching and similar resource management that efficiently integrates with kernel memory management. Signed-off-by: Robert Love <rlove@google.com> ashmem: Don't install fault handler for private mmaps. Ashmem is used to create named private heaps. If this heap is backed by a tmpfs file it will allocate two pages for every page touched. In 2.6.27, the extra page would later be freed, but 2.6.29 does not scan anonymous pages when running without swap so the memory is not freed while the file is referenced. This change changes the behavior of private ashmem mmaps to match /dev/zero instead tmpfs. Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: Add common prefix to name reported in /proc/pid/maps Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: don't require a page aligned size This makes ashmem more similar to shmem and mmap, by not requiring the specified size to be page aligned, instead rounding it internally as needed. Signed-off-by: Marco Nelissen <marcone@android.com> [jstultz: Improved commit subject and included patch description from rlove. Also moved ashmem files to staging dir, and reworked code to avoid touching mm/shmem.c while we're in staging.] CC: Brian Swetland <swetland@google.com> CC: Colin Cross <ccross@android.com> CC: Arve Hjønnevåg <arve@android.com> CC: Dima Zavin <dima@android.com> CC: Robert Love <rlove@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-20 17:49:48 -07:00
staging: android: ashmem: Add support for 32bit ashmem calls in a 64bit kernel Android's shared memory subsystem, Ashmem, does not support calls from a 32bit userspace in a 64 bit kernel. This patch adds support for syscalls coming from a 32bit userspace in a 64bit kernel. The patch has been successfully tested on ARMv8 AEM(64bit platform model) and Versatile Express A9(32bit platform). v2: Fix missing compat.h include. Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com> Acked-by: Arve Hjønnevåg <arve@android.com> Acked-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-05 08:27:38 -07:00
/* support of 32bit userspace on 64bit platforms */
#ifdef CONFIG_COMPAT
#define COMPAT_ASHMEM_SET_SIZE _IOW(__ASHMEMIOC, 3, compat_size_t)
#define COMPAT_ASHMEM_SET_PROT_MASK _IOW(__ASHMEMIOC, 5, unsigned int)
#endif
ashmem: Anonymous shared memory subsystem The anonymous shared memory (ashmem) subsystem provides a Unix-y,file-based shared memory interface to user-space. It works like anonymous memory (e.g. mmapping fd=0) except if you share the file descriptor via the usual means, you will share the mapping. The shared memory can be accessed via both mmap or file I/O. The backing store is a simple shmem file. Additionally, ashmem introduces the concept of page pinning. Pinned pages (the default) behave like any anonymous memory. Unpinned pages are available to the kernel for eviction during VM pressure. When repinning the pages, the return value instructs user-space as to any eviction. In this manner, user-space processes may implement caching and similar resource management that efficiently integrates with kernel memory management. Signed-off-by: Robert Love <rlove@google.com> ashmem: Don't install fault handler for private mmaps. Ashmem is used to create named private heaps. If this heap is backed by a tmpfs file it will allocate two pages for every page touched. In 2.6.27, the extra page would later be freed, but 2.6.29 does not scan anonymous pages when running without swap so the memory is not freed while the file is referenced. This change changes the behavior of private ashmem mmaps to match /dev/zero instead tmpfs. Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: Add common prefix to name reported in /proc/pid/maps Signed-off-by: Arve Hjønnevåg <arve@android.com> ashmem: don't require a page aligned size This makes ashmem more similar to shmem and mmap, by not requiring the specified size to be page aligned, instead rounding it internally as needed. Signed-off-by: Marco Nelissen <marcone@android.com> [jstultz: Improved commit subject and included patch description from rlove. Also moved ashmem files to staging dir, and reworked code to avoid touching mm/shmem.c while we're in staging.] CC: Brian Swetland <swetland@google.com> CC: Colin Cross <ccross@android.com> CC: Arve Hjønnevåg <arve@android.com> CC: Dima Zavin <dima@android.com> CC: Robert Love <rlove@google.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-12-20 17:49:48 -07:00
#endif /* _LINUX_ASHMEM_H */
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