From 47058bb54b57962b3958a936ddbc59355e4c5504 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 3 Sep 2020 16:22:40 +0200 Subject: x86: remove address space overrides using set_fs() Stop providing the possibility to override the address space using set_fs() now that there is no need for that any more. To properly handle the TASK_SIZE_MAX checking for 4 vs 5-level page tables on x86 a new alternative is introduced, which just like the one in entry_64.S has to use the hardcoded virtual address bits to escape the fact that TASK_SIZE_MAX isn't actually a constant when 5-level page tables are enabled. Signed-off-by: Christoph Hellwig Reviewed-by: Kees Cook Signed-off-by: Al Viro --- arch/x86/include/asm/uaccess.h | 26 +------------------------- 1 file changed, 1 insertion(+), 25 deletions(-) (limited to 'arch/x86/include/asm/uaccess.h') diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index ecefaffd15d4..a4ceda0510ea 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -12,30 +12,6 @@ #include #include -/* - * The fs value determines whether argument validity checking should be - * performed or not. If get_fs() == USER_DS, checking is performed, with - * get_fs() == KERNEL_DS, checking is bypassed. - * - * For historical reasons, these macros are grossly misnamed. - */ - -#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) - -#define KERNEL_DS MAKE_MM_SEG(-1UL) -#define USER_DS MAKE_MM_SEG(TASK_SIZE_MAX) - -#define get_fs() (current->thread.addr_limit) -static inline void set_fs(mm_segment_t fs) -{ - current->thread.addr_limit = fs; - /* On user-mode return, check fs is correct */ - set_thread_flag(TIF_FSCHECK); -} - -#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg) -#define user_addr_max() (current->thread.addr_limit.seg) - /* * Test whether a block of memory is a valid user space address. * Returns 0 if the range is valid, nonzero otherwise. @@ -93,7 +69,7 @@ static inline bool pagefault_disabled(void); #define access_ok(addr, size) \ ({ \ WARN_ON_IN_IRQ(); \ - likely(!__range_not_ok(addr, size, user_addr_max())); \ + likely(!__range_not_ok(addr, size, TASK_SIZE_MAX)); \ }) /* -- cgit v1.2.3-59-g8ed1b