From 12700c17fc286149324f92d6d380bc48e43f253d Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 15 Feb 2022 17:55:04 +0100 Subject: uaccess: generalize access_ok() 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 --- arch/nds32/include/asm/uaccess.h | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) (limited to 'arch/nds32/include/asm/uaccess.h') diff --git a/arch/nds32/include/asm/uaccess.h b/arch/nds32/include/asm/uaccess.h index 37a40981deb3..832d642a4068 100644 --- a/arch/nds32/include/asm/uaccess.h +++ b/arch/nds32/include/asm/uaccess.h @@ -38,18 +38,15 @@ extern int fixup_exception(struct pt_regs *regs); #define get_fs() (current_thread_info()->addr_limit) #define user_addr_max get_fs +#define uaccess_kernel() (get_fs() == KERNEL_DS) static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; } -#define uaccess_kernel() (get_fs() == KERNEL_DS) +#include -#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs() -size)) - -#define access_ok(addr, size) \ - __range_ok((unsigned long)addr, (unsigned long)size) /* * Single-value transfer routines. They automatically use the right * size if we just have the right pointer type. Note that the functions -- cgit v1.2.3-59-g8ed1b