From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dinh Nguyen Date: Thu, 24 Feb 2022 22:31:04 -0600 Subject: [OpenRISC] [PATCH v2 13/18] uaccess: generalize access_ok() In-Reply-To: <20220216131332.1489939-14-arnd@kernel.org> References: <20220216131332.1489939-1-arnd@kernel.org> <20220216131332.1489939-14-arnd@kernel.org> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: openrisc@lists.librecores.org On 2/16/22 07:13, Arnd Bergmann wrote: > From: Arnd Bergmann > > 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] > Signed-off-by: Arnd Bergmann > --- > arch/Kconfig | 7 ++++ > arch/alpha/include/asm/uaccess.h | 34 +++------------ > arch/arc/include/asm/uaccess.h | 29 ------------- > arch/arm/include/asm/uaccess.h | 20 +-------- > arch/arm64/include/asm/uaccess.h | 11 ++--- > arch/csky/include/asm/uaccess.h | 8 ---- > arch/hexagon/include/asm/uaccess.h | 25 ------------ > arch/ia64/include/asm/uaccess.h | 5 +-- > arch/m68k/Kconfig.cpu | 1 + > arch/m68k/include/asm/uaccess.h | 19 +-------- > arch/microblaze/include/asm/uaccess.h | 8 +--- > arch/mips/include/asm/uaccess.h | 29 +------------ > arch/nds32/include/asm/uaccess.h | 7 +--- > arch/nios2/include/asm/uaccess.h | 11 +---- Acked-by: Dinh Nguyen