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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-03 02:39:59 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-05-03 20:37:22 +0300 |
commit | b9bd9f605c4a6f04a83e6640a7d1d6dda80f17ca (patch) | |
tree | 30790cb30af3d655b84b933a5175a4490d5b035b /arch/x86/include/asm/uaccess.h | |
parent | 6ccdc91d6af922f3ded5de494ff27daedeb6d6c9 (diff) | |
download | linux-b9bd9f605c4a6f04a83e6640a7d1d6dda80f17ca.tar.xz |
x86: uaccess: move 32-bit and 64-bit parts into proper <asm/uaccess_N.h> header
The x86 <asm/uaccess.h> file has grown features that are specific to
x86-64 like LAM support and the related access_ok() changes. They
really should be in the <asm/uaccess_64.h> file and not pollute the
generic x86 header.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
-rw-r--r-- | arch/x86/include/asm/uaccess.h | 87 |
1 files changed, 3 insertions, 84 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index cad17e11aa83..8bae40a66282 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -16,83 +16,10 @@ #include <asm/extable.h> #include <asm/tlbflush.h> -#ifdef CONFIG_ADDRESS_MASKING -/* - * Mask out tag bits from the address. - * - * Magic with the 'sign' allows to untag userspace pointer without any branches - * while leaving kernel addresses intact. - */ -static inline unsigned long __untagged_addr(unsigned long addr) -{ - long sign; - - /* - * Refer tlbstate_untag_mask directly to avoid RIP-relative relocation - * in alternative instructions. The relocation gets wrong when gets - * copied to the target place. - */ - asm (ALTERNATIVE("", - "sar $63, %[sign]\n\t" /* user_ptr ? 0 : -1UL */ - "or %%gs:tlbstate_untag_mask, %[sign]\n\t" - "and %[sign], %[addr]\n\t", X86_FEATURE_LAM) - : [addr] "+r" (addr), [sign] "=r" (sign) - : "m" (tlbstate_untag_mask), "[sign]" (addr)); - - return addr; -} - -#define untagged_addr(addr) ({ \ - unsigned long __addr = (__force unsigned long)(addr); \ - (__force __typeof__(addr))__untagged_addr(__addr); \ -}) - -static inline unsigned long __untagged_addr_remote(struct mm_struct *mm, - unsigned long addr) -{ - long sign = addr >> 63; - - mmap_assert_locked(mm); - addr &= (mm)->context.untag_mask | sign; - - return addr; -} - -#define untagged_addr_remote(mm, addr) ({ \ - unsigned long __addr = (__force unsigned long)(addr); \ - (__force __typeof__(addr))__untagged_addr_remote(mm, __addr); \ -}) - +#ifdef CONFIG_X86_32 +# include <asm/uaccess_32.h> #else -#define untagged_addr(addr) (addr) -#endif - -#ifdef CONFIG_X86_64 -/* - * On x86-64, we may have tag bits in the user pointer. Rather than - * mask them off, just change the rules for __access_ok(). - * - * Make the rule be that 'ptr+size' must not overflow, and must not - * have the high bit set. Compilers generally understand about - * unsigned overflow and the CF bit and generate reasonable code for - * this. Although it looks like the combination confuses at least - * clang (and instead of just doing an "add" followed by a test of - * SF and CF, you'll see that unnecessary comparison). - * - * For the common case of small sizes that can be checked at compile - * time, don't even bother with the addition, and just check that the - * base pointer is ok. - */ -static inline bool __access_ok(const void __user *ptr, unsigned long size) -{ - if (__builtin_constant_p(size <= PAGE_SIZE) && size <= PAGE_SIZE) { - return (long)ptr >= 0; - } else { - unsigned long sum = size + (unsigned long)ptr; - return (long) sum >= 0 && sum >= (unsigned long)ptr; - } -} -#define __access_ok __access_ok +# include <asm/uaccess_64.h> #endif #include <asm-generic/access_ok.h> @@ -583,14 +510,6 @@ extern struct movsl_mask { #define ARCH_HAS_NOCACHE_UACCESS 1 -#ifdef CONFIG_X86_32 -unsigned long __must_check clear_user(void __user *mem, unsigned long len); -unsigned long __must_check __clear_user(void __user *mem, unsigned long len); -# include <asm/uaccess_32.h> -#else -# include <asm/uaccess_64.h> -#endif - /* * The "unsafe" user accesses aren't really "unsafe", but the naming * is a big fat warning: you have to not only do the access_ok() |