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/nios2/include/asm/uaccess.h | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'arch/nios2') diff --git a/arch/nios2/include/asm/uaccess.h b/arch/nios2/include/asm/uaccess.h index a5cbe07cf0da..6664ddc0e8e5 100644 --- a/arch/nios2/include/asm/uaccess.h +++ b/arch/nios2/include/asm/uaccess.h @@ -30,19 +30,10 @@ #define get_fs() (current_thread_info()->addr_limit) #define set_fs(seg) (current_thread_info()->addr_limit = (seg)) -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) - -#define __access_ok(addr, len) \ - (((signed long)(((long)get_fs().seg) & \ - ((long)(addr) | (((long)(addr)) + (len)) | (len)))) == 0) - -#define access_ok(addr, len) \ - likely(__access_ok((unsigned long)(addr), (unsigned long)(len))) +#include # define __EX_TABLE_SECTION ".section __ex_table,\"a\"\n" -#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE) - /* * Zero Userspace */ -- cgit v1.2.3