From 5e6e9852d6f76e01b2e6803c74258afa5b432bc5 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 3 Sep 2020 16:22:35 +0200 Subject: uaccess: add infrastructure for kernel builds with set_fs() Add a CONFIG_SET_FS option that is selected by architecturess that implement set_fs, which is all of them initially. If the option is not set stubs for routines related to overriding the address space are provided so that architectures can start to opt out of providing set_fs. Signed-off-by: Christoph Hellwig Reviewed-by: Kees Cook Signed-off-by: Al Viro --- include/linux/uaccess.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include') diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 94b285411659..70073c802b48 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -8,6 +8,7 @@ #include +#ifdef CONFIG_SET_FS /* * Force the uaccess routines to be wired up for actual userspace access, * overriding any possible set_fs(KERNEL_DS) still lingering around. Undone @@ -25,6 +26,23 @@ static inline void force_uaccess_end(mm_segment_t oldfs) { set_fs(oldfs); } +#else /* CONFIG_SET_FS */ +typedef struct { + /* empty dummy */ +} mm_segment_t; + +#define uaccess_kernel() (false) +#define user_addr_max() (TASK_SIZE_MAX) + +static inline mm_segment_t force_uaccess_begin(void) +{ + return (mm_segment_t) { }; +} + +static inline void force_uaccess_end(mm_segment_t oldfs) +{ +} +#endif /* CONFIG_SET_FS */ /* * Architectures should provide two primitives (raw_copy_{to,from}_user()) -- cgit v1.2.3