kernel/arch/xtensa/include/asm/uaccess.h, branch linux-rolling-stable

uaccess: remove CONFIG_SET_FS

2022-02-25T08:36:06Z

There are no remaining callers of set_fs(), so CONFIG_SET_FS can be removed globally, along with the thread_info field and any references to it. This turns access_ok() into a cheaper check against TASK_SIZE_MAX. As CONFIG_SET_FS is now gone, drop all remaining references to set_fs()/get_fs(), mm_segment_t, user_addr_max() and uaccess_kernel(). Acked-by: Sam Ravnborg # for sparc32 changes Acked-by: "Eric W. Biederman" Tested-by: Sergey Matyukevich # for arc changes Acked-by: Stafford Horne # [openrisc, asm-generic] Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann

uaccess: generalize access_ok()

2022-02-25T08:36:05Z

There are many different ways that access_ok() is defined across architectures, but in the end, they all just compare against the user_addr_max() value or they accept anything. Provide one definition that works for most architectures, checking against TASK_SIZE_MAX for user processes or skipping the check inside of uaccess_kernel() sections. For architectures without CONFIG_SET_FS(), this should be the fastest check, as it comes down to a single comparison of a pointer against a compile-time constant, while the architecture specific versions tend to do something more complex for historic reasons or get something wrong. Type checking for __user annotations is handled inconsistently across architectures, but this is easily simplified as well by using an inline function that takes a 'const void __user *' argument. A handful of callers need an extra __user annotation for this. Some architectures had trick to use 33-bit or 65-bit arithmetic on the addresses to calculate the overflow, however this simpler version uses fewer registers, which means it can produce better object code in the end despite needing a second (statically predicted) branch. Reviewed-by: Christoph Hellwig Acked-by: Mark Rutland [arm64, asm-generic] Acked-by: Geert Uytterhoeven Acked-by: Stafford Horne Acked-by: Dinh Nguyen Signed-off-by: Arnd Bergmann

asm-generic: reverse GENERIC_{STRNCPY_FROM,STRNLEN}_USER symbols

2021-07-30T08:30:21Z

Most architectures do not need a custom implementation, and in most cases the generic implementation is preferred, so change the polariy on these Kconfig symbols to require architectures to select them when they provide their own version. The new name is CONFIG_ARCH_HAS_{STRNCPY_FROM,STRNLEN}_USER. The remaining architectures at the moment are: ia64, mips, parisc, um and xtensa. We should probably convert these as well, but I was not sure how far to take this series. Thomas Bogendoerfer had some concerns about converting mips but may still do some more detailed measurements to see which version is better. Cc: "James E.J. Bottomley" Cc: Anton Ivanov Cc: Christian Borntraeger Cc: Heiko Carstens Cc: Helge Deller Cc: Jeff Dike Cc: Max Filippov Cc: Richard Weinberger Cc: Thomas Bogendoerfer Cc: Vasily Gorbik Cc: linux-ia64@vger.kernel.org Cc: linux-mips@vger.kernel.org Cc: linux-parisc@vger.kernel.org Cc: linux-s390@vger.kernel.org Cc: linux-um@lists.infradead.org Cc: linux-xtensa@linux-xtensa.org Acked-by: Geert Uytterhoeven Acked-by: Helge Deller # parisc Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann

xtensa: uaccess: Add missing __user to strncpy_from_user() prototype

2020-11-17T13:09:28Z

When adding __user annotations in commit 2adf5352a34a, the strncpy_from_user() function declaration for the CONFIG_GENERIC_STRNCPY_FROM_USER case was missed. Fix it. Reported-by: kernel test robot Signed-off-by: Laurent Pinchart Message-Id: <20200831210937.17938-1-laurent.pinchart@ideasonboard.com> Signed-off-by: Max Filippov

uaccess: remove segment_eq

2020-08-12T17:57:58Z

segment_eq is only used to implement uaccess_kernel. Just open code uaccess_kernel in the arch uaccess headers and remove one layer of indirection. Signed-off-by: Christoph Hellwig Signed-off-by: Andrew Morton Acked-by: Linus Torvalds Acked-by: Greentime Hu Acked-by: Geert Uytterhoeven Cc: Nick Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Link: http://lkml.kernel.org/r/20200710135706.537715-5-hch@lst.de Signed-off-by: Linus Torvalds

xtensa: add missing __user annotations to asm/uaccess.h

2020-05-22T23:09:00Z

clear_user, strncpy_user, strnlen_user and their helpers operate on user pointers, but don't have their arguments marked as __user. Add __user annotation to userspace pointers of those functions. Fix open-coded access check in the strnlen_user while at it. Signed-off-by: Max Filippov

xtensa: fix error paths in __get_user_{check,size}

2020-05-22T23:09:00Z

Error paths in __get_user_check and __get_user_size directly assing 0 to the result. It causes the following sparse warnings: sparse: warning: Using plain integer as NULL pointer Convert 0 to the type pointed to by the user pointer before assigning it. Signed-off-by: Max Filippov

xtensa: fix type conversion in __get_user_size

2020-05-22T21:33:52Z

8-byte access in __get_user_size converts pointer to temporary variable to the type of original user pointer and then dereferences it, resulting in the following sparse warning: sparse: warning: dereference of noderef expression Instead dereference the original user pointer under the __typeof__ and add indirection outside. Signed-off-by: Max Filippov

xtensa: add missing user annotations to {get,put}_user_check

2020-05-22T21:32:13Z

__get_user_check and __put_user_check use temporary pointer but don't mark it as __user, resulting in sparse warnings: sparse: warning: incorrect type in initializer (different address spaces) sparse: expected long *__pu_addr sparse: got long [noderef] *ret sparse: warning: incorrect type in argument 1 (different address spaces) sparse: expected void [noderef] *to sparse: got long *__pu_addr Add __user annotation to temporary pointer in __get_user_check and __put_user_check. Reported-by: kbuild test robot Reported-by: Arnd Bergmann Signed-off-by: Max Filippov

xtensa: use "m" constraint instead of "a" in uaccess.h assembly

2019-11-26T19:33:38Z

Use "m" constraint instead of "r" for the address, as "m" allows compiler to access adjacent locations using base + offset, while "r" requires updating the base register every time. Use %[mem] * 0 + v to replace offset part of %[mem] expansion with v. It is impossible to change address alignment through the offset part on xtensa, so just ignore offset in alignment checks. Signed-off-by: Max Filippov