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5de7bcaadf
Similarly to the previous commit, this renames the somewhat confusingly named function. But in this case, it was at least less confusing: the __copy_from_user_inatomic_nocache is indeed copying from user memory, and it is indeed ok to be used in an atomic context, so it will not warn about it. But the previous commit also removed the NTB mis-use of the __copy_from_user_inatomic_nocache() function, and as a result every call-site is now _actually_ doing a real user copy. That means that we can now do the proper user pointer verification too. End result: add proper address checking, remove the double underscores, and change the "nocache" to "nontemporal" to more accurately describe what this x86-only function actually does. It might be worth noting that only the target is non-temporal: the actual user accesses are normal memory accesses. Also worth noting is that non-x86 targets (and on older 32-bit x86 CPU's before XMM2 in the Pentium III) we end up just falling back on a regular user copy, so nothing can actually depend on the non-temporal semantics, but that has always been true. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
342 lines
10 KiB
C
342 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* User address space access functions.
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* The non inlined parts of asm-i386/uaccess.h are here.
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*
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* Copyright 1997 Andi Kleen <ak@muc.de>
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* Copyright 1997 Linus Torvalds
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*/
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#include <linux/export.h>
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#include <linux/uaccess.h>
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#include <asm/asm.h>
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#ifdef CONFIG_X86_INTEL_USERCOPY
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/*
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* Alignment at which movsl is preferred for bulk memory copies.
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*/
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struct movsl_mask movsl_mask __read_mostly;
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#endif
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static inline int __movsl_is_ok(unsigned long a1, unsigned long a2, unsigned long n)
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{
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#ifdef CONFIG_X86_INTEL_USERCOPY
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if (n >= 64 && ((a1 ^ a2) & movsl_mask.mask))
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return 0;
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#endif
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return 1;
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}
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#define movsl_is_ok(a1, a2, n) \
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__movsl_is_ok((unsigned long)(a1), (unsigned long)(a2), (n))
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/*
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* Zero Userspace
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*/
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#define __do_clear_user(addr,size) \
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do { \
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int __d0; \
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might_fault(); \
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__asm__ __volatile__( \
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ASM_STAC "\n" \
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"0: rep stosl\n" \
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" movl %2,%0\n" \
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"1: rep stosb\n" \
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"2: " ASM_CLAC "\n" \
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_ASM_EXTABLE_TYPE_REG(0b, 2b, EX_TYPE_UCOPY_LEN4, %2) \
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_ASM_EXTABLE_UA(1b, 2b) \
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: "=&c"(size), "=&D" (__d0) \
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: "r"(size & 3), "0"(size / 4), "1"(addr), "a"(0)); \
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} while (0)
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/**
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* clear_user - Zero a block of memory in user space.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space.
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*
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* Return: number of bytes that could not be cleared.
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* On success, this will be zero.
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*/
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unsigned long
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clear_user(void __user *to, unsigned long n)
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{
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might_fault();
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if (access_ok(to, n))
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__do_clear_user(to, n);
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return n;
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}
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EXPORT_SYMBOL(clear_user);
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/**
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* __clear_user - Zero a block of memory in user space, with less checking.
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* @to: Destination address, in user space.
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* @n: Number of bytes to zero.
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*
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* Zero a block of memory in user space. Caller must check
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* the specified block with access_ok() before calling this function.
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*
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* Return: number of bytes that could not be cleared.
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* On success, this will be zero.
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*/
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unsigned long
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__clear_user(void __user *to, unsigned long n)
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{
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__do_clear_user(to, n);
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return n;
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}
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EXPORT_SYMBOL(__clear_user);
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#ifdef CONFIG_X86_INTEL_USERCOPY
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static unsigned long
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__copy_user_intel(void __user *to, const void *from, unsigned long size)
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{
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int d0, d1;
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__asm__ __volatile__(
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" .align 2,0x90\n"
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"1: movl 32(%4), %%eax\n"
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" cmpl $67, %0\n"
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" jbe 3f\n"
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"2: movl 64(%4), %%eax\n"
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" .align 2,0x90\n"
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"3: movl 0(%4), %%eax\n"
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"4: movl 4(%4), %%edx\n"
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"5: movl %%eax, 0(%3)\n"
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"6: movl %%edx, 4(%3)\n"
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"7: movl 8(%4), %%eax\n"
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"8: movl 12(%4),%%edx\n"
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"9: movl %%eax, 8(%3)\n"
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"10: movl %%edx, 12(%3)\n"
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"11: movl 16(%4), %%eax\n"
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"12: movl 20(%4), %%edx\n"
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"13: movl %%eax, 16(%3)\n"
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"14: movl %%edx, 20(%3)\n"
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"15: movl 24(%4), %%eax\n"
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"16: movl 28(%4), %%edx\n"
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"17: movl %%eax, 24(%3)\n"
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"18: movl %%edx, 28(%3)\n"
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"19: movl 32(%4), %%eax\n"
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"20: movl 36(%4), %%edx\n"
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"21: movl %%eax, 32(%3)\n"
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"22: movl %%edx, 36(%3)\n"
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"23: movl 40(%4), %%eax\n"
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"24: movl 44(%4), %%edx\n"
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"25: movl %%eax, 40(%3)\n"
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"26: movl %%edx, 44(%3)\n"
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"27: movl 48(%4), %%eax\n"
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"28: movl 52(%4), %%edx\n"
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"29: movl %%eax, 48(%3)\n"
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"30: movl %%edx, 52(%3)\n"
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"31: movl 56(%4), %%eax\n"
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"32: movl 60(%4), %%edx\n"
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"33: movl %%eax, 56(%3)\n"
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"34: movl %%edx, 60(%3)\n"
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" addl $-64, %0\n"
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" addl $64, %4\n"
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" addl $64, %3\n"
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" cmpl $63, %0\n"
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" ja 1b\n"
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"35: movl %0, %%eax\n"
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" shrl $2, %0\n"
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" andl $3, %%eax\n"
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" cld\n"
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"99: rep movsl\n"
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"36: movl %%eax, %0\n"
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"37: rep movsb\n"
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"100:\n"
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_ASM_EXTABLE_UA(1b, 100b)
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_ASM_EXTABLE_UA(2b, 100b)
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_ASM_EXTABLE_UA(3b, 100b)
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_ASM_EXTABLE_UA(4b, 100b)
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_ASM_EXTABLE_UA(5b, 100b)
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_ASM_EXTABLE_UA(6b, 100b)
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_ASM_EXTABLE_UA(7b, 100b)
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_ASM_EXTABLE_UA(8b, 100b)
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_ASM_EXTABLE_UA(9b, 100b)
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_ASM_EXTABLE_UA(10b, 100b)
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_ASM_EXTABLE_UA(11b, 100b)
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_ASM_EXTABLE_UA(12b, 100b)
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_ASM_EXTABLE_UA(13b, 100b)
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_ASM_EXTABLE_UA(14b, 100b)
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_ASM_EXTABLE_UA(15b, 100b)
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_ASM_EXTABLE_UA(16b, 100b)
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_ASM_EXTABLE_UA(17b, 100b)
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_ASM_EXTABLE_UA(18b, 100b)
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_ASM_EXTABLE_UA(19b, 100b)
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_ASM_EXTABLE_UA(20b, 100b)
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_ASM_EXTABLE_UA(21b, 100b)
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_ASM_EXTABLE_UA(22b, 100b)
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_ASM_EXTABLE_UA(23b, 100b)
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_ASM_EXTABLE_UA(24b, 100b)
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_ASM_EXTABLE_UA(25b, 100b)
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_ASM_EXTABLE_UA(26b, 100b)
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_ASM_EXTABLE_UA(27b, 100b)
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_ASM_EXTABLE_UA(28b, 100b)
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_ASM_EXTABLE_UA(29b, 100b)
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_ASM_EXTABLE_UA(30b, 100b)
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_ASM_EXTABLE_UA(31b, 100b)
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_ASM_EXTABLE_UA(32b, 100b)
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_ASM_EXTABLE_UA(33b, 100b)
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_ASM_EXTABLE_UA(34b, 100b)
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_ASM_EXTABLE_UA(35b, 100b)
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_ASM_EXTABLE_UA(36b, 100b)
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_ASM_EXTABLE_UA(37b, 100b)
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_ASM_EXTABLE_TYPE_REG(99b, 100b, EX_TYPE_UCOPY_LEN4, %%eax)
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: "=&c"(size), "=&D" (d0), "=&S" (d1)
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: "1"(to), "2"(from), "0"(size)
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: "eax", "edx", "memory");
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return size;
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}
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static unsigned long __copy_user_intel_nocache(void *to,
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const void __user *from, unsigned long size)
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{
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int d0, d1;
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__asm__ __volatile__(
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" .align 2,0x90\n"
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"0: movl 32(%4), %%eax\n"
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" cmpl $67, %0\n"
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" jbe 2f\n"
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"1: movl 64(%4), %%eax\n"
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" .align 2,0x90\n"
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"2: movl 0(%4), %%eax\n"
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"21: movl 4(%4), %%edx\n"
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" movnti %%eax, 0(%3)\n"
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" movnti %%edx, 4(%3)\n"
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"3: movl 8(%4), %%eax\n"
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"31: movl 12(%4),%%edx\n"
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" movnti %%eax, 8(%3)\n"
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" movnti %%edx, 12(%3)\n"
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"4: movl 16(%4), %%eax\n"
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"41: movl 20(%4), %%edx\n"
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" movnti %%eax, 16(%3)\n"
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" movnti %%edx, 20(%3)\n"
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"10: movl 24(%4), %%eax\n"
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"51: movl 28(%4), %%edx\n"
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" movnti %%eax, 24(%3)\n"
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" movnti %%edx, 28(%3)\n"
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"11: movl 32(%4), %%eax\n"
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"61: movl 36(%4), %%edx\n"
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" movnti %%eax, 32(%3)\n"
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" movnti %%edx, 36(%3)\n"
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"12: movl 40(%4), %%eax\n"
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"71: movl 44(%4), %%edx\n"
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" movnti %%eax, 40(%3)\n"
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" movnti %%edx, 44(%3)\n"
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"13: movl 48(%4), %%eax\n"
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"81: movl 52(%4), %%edx\n"
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" movnti %%eax, 48(%3)\n"
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" movnti %%edx, 52(%3)\n"
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"14: movl 56(%4), %%eax\n"
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"91: movl 60(%4), %%edx\n"
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" movnti %%eax, 56(%3)\n"
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" movnti %%edx, 60(%3)\n"
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" addl $-64, %0\n"
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" addl $64, %4\n"
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" addl $64, %3\n"
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" cmpl $63, %0\n"
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" ja 0b\n"
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" sfence \n"
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"5: movl %0, %%eax\n"
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" shrl $2, %0\n"
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" andl $3, %%eax\n"
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" cld\n"
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"6: rep movsl\n"
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" movl %%eax,%0\n"
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"7: rep movsb\n"
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"8:\n"
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_ASM_EXTABLE_UA(0b, 8b)
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_ASM_EXTABLE_UA(1b, 8b)
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_ASM_EXTABLE_UA(2b, 8b)
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_ASM_EXTABLE_UA(21b, 8b)
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_ASM_EXTABLE_UA(3b, 8b)
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_ASM_EXTABLE_UA(31b, 8b)
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_ASM_EXTABLE_UA(4b, 8b)
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_ASM_EXTABLE_UA(41b, 8b)
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_ASM_EXTABLE_UA(10b, 8b)
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_ASM_EXTABLE_UA(51b, 8b)
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_ASM_EXTABLE_UA(11b, 8b)
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_ASM_EXTABLE_UA(61b, 8b)
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_ASM_EXTABLE_UA(12b, 8b)
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_ASM_EXTABLE_UA(71b, 8b)
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_ASM_EXTABLE_UA(13b, 8b)
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_ASM_EXTABLE_UA(81b, 8b)
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_ASM_EXTABLE_UA(14b, 8b)
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_ASM_EXTABLE_UA(91b, 8b)
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_ASM_EXTABLE_TYPE_REG(6b, 8b, EX_TYPE_UCOPY_LEN4, %%eax)
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_ASM_EXTABLE_UA(7b, 8b)
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: "=&c"(size), "=&D" (d0), "=&S" (d1)
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: "1"(to), "2"(from), "0"(size)
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: "eax", "edx", "memory");
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return size;
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}
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#else
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/*
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* Leave these declared but undefined. They should not be any references to
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* them
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*/
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unsigned long __copy_user_intel(void __user *to, const void *from,
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unsigned long size);
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#endif /* CONFIG_X86_INTEL_USERCOPY */
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/* Generic arbitrary sized copy. */
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#define __copy_user(to, from, size) \
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do { \
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int __d0, __d1, __d2; \
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__asm__ __volatile__( \
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" cmp $7,%0\n" \
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" jbe 1f\n" \
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" movl %1,%0\n" \
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" negl %0\n" \
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" andl $7,%0\n" \
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" subl %0,%3\n" \
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"4: rep movsb\n" \
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" movl %3,%0\n" \
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" shrl $2,%0\n" \
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" andl $3,%3\n" \
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" .align 2,0x90\n" \
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"0: rep movsl\n" \
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" movl %3,%0\n" \
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"1: rep movsb\n" \
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"2:\n" \
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_ASM_EXTABLE_TYPE_REG(4b, 2b, EX_TYPE_UCOPY_LEN1, %3) \
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_ASM_EXTABLE_TYPE_REG(0b, 2b, EX_TYPE_UCOPY_LEN4, %3) \
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_ASM_EXTABLE_UA(1b, 2b) \
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: "=&c"(size), "=&D" (__d0), "=&S" (__d1), "=r"(__d2) \
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: "3"(size), "0"(size), "1"(to), "2"(from) \
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: "memory"); \
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} while (0)
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unsigned long __copy_user_ll(void *to, const void *from, unsigned long n)
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{
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__uaccess_begin_nospec();
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if (movsl_is_ok(to, from, n))
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__copy_user(to, from, n);
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else
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n = __copy_user_intel(to, from, n);
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__uaccess_end();
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return n;
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}
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EXPORT_SYMBOL(__copy_user_ll);
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unsigned long copy_from_user_inatomic_nontemporal(void *to, const void __user *from,
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unsigned long n)
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{
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if (!user_access_begin(from, n))
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return n;
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#ifdef CONFIG_X86_INTEL_USERCOPY
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if (n > 64 && static_cpu_has(X86_FEATURE_XMM2))
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n = __copy_user_intel_nocache(to, from, n);
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else
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__copy_user(to, from, n);
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#else
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__copy_user(to, from, n);
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#endif
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user_access_end();
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return n;
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}
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EXPORT_SYMBOL(copy_from_user_inatomic_nontemporal);
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