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2022-02-25uaccess: generalize access_ok()Arnd Bergmann1-2/+3
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 <hch@lst.de> Acked-by: Mark Rutland <mark.rutland@arm.com> [arm64, asm-generic] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Stafford Horne <shorne@gmail.com> Acked-by: Dinh Nguyen <dinguyen@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2022-02-25uaccess: add generic __{get,put}_kernel_nofaultArnd Bergmann1-2/+0
Nine architectures are still missing __{get,put}_kernel_nofault: alpha, ia64, microblaze, nds32, nios2, openrisc, sh, sparc32, xtensa. Add a generic version that lets everything use the normal copy_{from,to}_kernel_nofault() code based on these, removing the last use of get_fs()/set_fs() from architecture-independent code. Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-12-22um: remove set_fsChristoph Hellwig1-2/+19
Remove address space overrides using set_fs() for User Mode Linux. Note that just like the existing kernel access case of the uaccess routines the new nofault kernel handlers do not actually have any exception handling. This is probably broken, but not change to the status quo. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Richard Weinberger <richard@nod.at>
2021-07-28asm-generic: remove extra strn{cpy_from,len}_user declarationsArnd Bergmann1-4/+1
As these are now in asm-generic, it's no longer necessary to declare them in the architecture. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2021-07-23asm-generic/uaccess.h: remove __strncpy_from_user/__strnlen_userArnd Bergmann1-4/+4
This is a preparation for changing over architectures to the generic implementation one at a time. As there are no callers of either __strncpy_from_user() or __strnlen_user(), fold these into the strncpy_from_user() and strnlen_user() functions to make each implementation independent of the others. Many of these implementations have known bugs, but the intention here is to not change behavior at all and stay compatible with those bugs for the moment. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2019-09-15um: Add SPDX headers for files in arch/um/includeAlex Dewar1-1/+1
Convert files to use SPDX header. All files are licensed under the GPLv2. Signed-off-by: Alex Dewar <alex.dewar@gmx.co.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2017-03-29um: switch to RAW_COPY_USERAl Viro1-4/+4
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-28asm-generic/uaccess.h: don't mess with __copy_{to,from}_userAl Viro1-2/+0
only h8300 actually used those; might as well define them there. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-28new helper: uaccess_kernel()Al Viro1-1/+1
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-03-06uaccess: drop duplicate includes from asm/uaccess.hAl Viro1-1/+0
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2015-05-31um: Rework uaccess codeRichard Weinberger1-151/+25
Rework UML's uaccess code to reuse as much as possible from asm-generic/uaccess.c. Signed-off-by: Richard Weinberger <richard@nod.at>
2011-11-02um: kill um_uaccess.hAl Viro1-5/+84
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Richard Weinberger <richard@nod.at>
2008-10-23x86, um: initial part of asm-um moveAl Viro1-0/+99
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: H. Peter Anvin <hpa@zytor.com>