From 8ced0c6231ead26eca8cb416dcb7cc1c2cdd41d8 Mon Sep 17 00:00:00 2001 From: Todd Kjos Date: Fri, 8 Feb 2019 10:35:15 -0800 Subject: binder: add functions to copy to/from binder buffers Avoid vm_area when copying to or from binder buffers. Instead, new copy functions are added that copy from kernel space to binder buffer space. These use kmap_atomic() and kunmap_atomic() to create temporary mappings and then memcpy() is used to copy within that page. Also, kmap_atomic() / kunmap_atomic() use the appropriate cache flushing to support VIVT cache architectures. Allow binder to build if CPU_CACHE_VIVT is defined. Several uses of the new functions are added here. More to follow in subsequent patches. Signed-off-by: Todd Kjos Signed-off-by: Greg Kroah-Hartman --- drivers/android/binder_alloc.c | 59 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 59 insertions(+) (limited to 'drivers/android/binder_alloc.c') diff --git a/drivers/android/binder_alloc.c b/drivers/android/binder_alloc.c index 94c0d85c4e75..2eebff4be83e 100644 --- a/drivers/android/binder_alloc.c +++ b/drivers/android/binder_alloc.c @@ -1166,3 +1166,62 @@ binder_alloc_copy_user_to_buffer(struct binder_alloc *alloc, } return 0; } + +static void binder_alloc_do_buffer_copy(struct binder_alloc *alloc, + bool to_buffer, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + void *ptr, + size_t bytes) +{ + /* All copies must be 32-bit aligned and 32-bit size */ + BUG_ON(!check_buffer(alloc, buffer, buffer_offset, bytes)); + + while (bytes) { + unsigned long size; + struct page *page; + pgoff_t pgoff; + void *tmpptr; + void *base_ptr; + + page = binder_alloc_get_page(alloc, buffer, + buffer_offset, &pgoff); + size = min_t(size_t, bytes, PAGE_SIZE - pgoff); + base_ptr = kmap_atomic(page); + tmpptr = base_ptr + pgoff; + if (to_buffer) + memcpy(tmpptr, ptr, size); + else + memcpy(ptr, tmpptr, size); + /* + * kunmap_atomic() takes care of flushing the cache + * if this device has VIVT cache arch + */ + kunmap_atomic(base_ptr); + bytes -= size; + pgoff = 0; + ptr = ptr + size; + buffer_offset += size; + } +} + +void binder_alloc_copy_to_buffer(struct binder_alloc *alloc, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + void *src, + size_t bytes) +{ + binder_alloc_do_buffer_copy(alloc, true, buffer, buffer_offset, + src, bytes); +} + +void binder_alloc_copy_from_buffer(struct binder_alloc *alloc, + void *dest, + struct binder_buffer *buffer, + binder_size_t buffer_offset, + size_t bytes) +{ + binder_alloc_do_buffer_copy(alloc, false, buffer, buffer_offset, + dest, bytes); +} + -- cgit v1.2.3