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/parisc/Kconfig | 1 + arch/parisc/include/asm/uaccess.h | 12 +++--------- 2 files changed, 4 insertions(+), 9 deletions(-) (limited to 'arch/parisc') diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig index 43c1c880def6..15039fdd5413 100644 --- a/arch/parisc/Kconfig +++ b/arch/parisc/Kconfig @@ -1,6 +1,7 @@ # SPDX-License-Identifier: GPL-2.0 config PARISC def_bool y + select ALTERNATE_USER_ADDRESS_SPACE select ARCH_32BIT_OFF_T if !64BIT select ARCH_MIGHT_HAVE_PC_PARPORT select HAVE_FUNCTION_TRACER diff --git a/arch/parisc/include/asm/uaccess.h b/arch/parisc/include/asm/uaccess.h index 0925bbd6db67..187f4bdff13e 100644 --- a/arch/parisc/include/asm/uaccess.h +++ b/arch/parisc/include/asm/uaccess.h @@ -11,15 +11,9 @@ #include #include -/* - * Note that since kernel addresses are in a separate address space on - * parisc, we don't need to do anything for access_ok(). - * We just let the page fault handler do the right thing. This also means - * that put_user is the same as __put_user, etc. - */ - -#define access_ok(uaddr, size) \ - ( (uaddr) == (uaddr) ) +#define TASK_SIZE_MAX DEFAULT_TASK_SIZE +#include +#include #define put_user __put_user #define get_user __get_user -- cgit v1.2.3