diff options
Diffstat (limited to 'arch/cris/arch-v32/lib/usercopy.c')
| -rw-r--r-- | arch/cris/arch-v32/lib/usercopy.c | 458 |
1 files changed, 0 insertions, 458 deletions
diff --git a/arch/cris/arch-v32/lib/usercopy.c b/arch/cris/arch-v32/lib/usercopy.c deleted file mode 100644 index 04e78b6ffa22..000000000000 --- a/arch/cris/arch-v32/lib/usercopy.c +++ /dev/null @@ -1,458 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0 -/* - * User address space access functions. - * The non-inlined parts of asm-cris/uaccess.h are here. - * - * Copyright (C) 2000, 2003 Axis Communications AB. - * - * Written by Hans-Peter Nilsson. - * Pieces used from memcpy, originally by Kenny Ranerup long time ago. - */ - -#include <linux/uaccess.h> - -/* Asm:s have been tweaked (within the domain of correctness) to give - satisfactory results for "gcc version 3.2.1 Axis release R53/1.53-v32". - - Check regularly... - - Note that for CRISv32, the PC saved at a bus-fault is the address - *at* the faulting instruction, with a special case for instructions - in delay slots: then it's the address of the branch. Note also that - in contrast to v10, a postincrement in the instruction is *not* - performed at a bus-fault; the register is seen having the original - value in fault handlers. */ - - -/* Copy to userspace. This is based on the memcpy used for - kernel-to-kernel copying; see "string.c". */ - -unsigned long __copy_user(void __user *pdst, const void *psrc, unsigned long pn) -{ - /* We want the parameters put in special registers. - Make sure the compiler is able to make something useful of this. - As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). - - FIXME: Comment for old gcc version. Check. - If gcc was alright, it really would need no temporaries, and no - stack space to save stuff on. */ - - register char *dst __asm__ ("r13") = pdst; - register const char *src __asm__ ("r11") = psrc; - register int n __asm__ ("r12") = pn; - register int retn __asm__ ("r10") = 0; - - - /* When src is aligned but not dst, this makes a few extra needless - cycles. I believe it would take as many to check that the - re-alignment was unnecessary. */ - if (((unsigned long) dst & 3) != 0 - /* Don't align if we wouldn't copy more than a few bytes; so we - don't have to check further for overflows. */ - && n >= 3) - { - if ((unsigned long) dst & 1) - { - __asm_copy_to_user_1 (dst, src, retn); - n--; - } - - if ((unsigned long) dst & 2) - { - __asm_copy_to_user_2 (dst, src, retn); - n -= 2; - } - } - - /* Movem is dirt cheap. The overheap is low enough to always use the - minimum possible block size as the threshold. */ - if (n >= 44) - { - /* For large copies we use 'movem'. */ - - /* It is not optimal to tell the compiler about clobbering any - registers; that will move the saving/restoring of those registers - to the function prologue/epilogue, and make non-movem sizes - suboptimal. */ - __asm__ volatile ("\ - ;; Check that the register asm declaration got right. \n\ - ;; The GCC manual explicitly says TRT will happen. \n\ - .ifnc %0%1%2%3,$r13$r11$r12$r10 \n\ - .err \n\ - .endif \n\ - \n\ - ;; Save the registers we'll use in the movem process \n\ - ;; on the stack. \n\ - subq 11*4,$sp \n\ - movem $r10,[$sp] \n\ - \n\ - ;; Now we've got this: \n\ - ;; r11 - src \n\ - ;; r13 - dst \n\ - ;; r12 - n \n\ - \n\ - ;; Update n for the first loop \n\ - subq 44,$r12 \n\ -0: \n\ - movem [$r11+],$r10 \n\ - subq 44,$r12 \n\ -1: bge 0b \n\ - movem $r10,[$r13+] \n\ -3: \n\ - addq 44,$r12 ;; compensate for last loop underflowing n \n\ - \n\ - ;; Restore registers from stack \n\ - movem [$sp+],$r10 \n\ -2: \n\ - .section .fixup,\"ax\" \n\ -4: \n\ -; When failing on any of the 1..44 bytes in a chunk, we adjust back the \n\ -; source pointer and just drop through to the by-16 and by-4 loops to \n\ -; get the correct number of failing bytes. This necessarily means a \n\ -; few extra exceptions, but invalid user pointers shouldn't happen in \n\ -; time-critical code anyway. \n\ - jump 3b \n\ - subq 44,$r11 \n\ - \n\ - .previous \n\ - .section __ex_table,\"a\" \n\ - .dword 1b,4b \n\ - .previous" - - /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n), "=r" (retn) - /* Inputs */ : "0" (dst), "1" (src), "2" (n), "3" (retn)); - - } - - while (n >= 16) - { - __asm_copy_to_user_16 (dst, src, retn); - n -= 16; - } - - /* Having a separate by-four loops cuts down on cache footprint. - FIXME: Test with and without; increasing switch to be 0..15. */ - while (n >= 4) - { - __asm_copy_to_user_4 (dst, src, retn); - n -= 4; - } - - switch (n) - { - case 0: - break; - case 1: - __asm_copy_to_user_1 (dst, src, retn); - break; - case 2: - __asm_copy_to_user_2 (dst, src, retn); - break; - case 3: - __asm_copy_to_user_3 (dst, src, retn); - break; - } - - return retn; -} -EXPORT_SYMBOL(__copy_user); - -/* Copy from user to kernel. The return-value is the number of bytes that were - inaccessible. */ -unsigned long __copy_user_in(void *pdst, const void __user *psrc, - unsigned long pn) -{ - /* We want the parameters put in special registers. - Make sure the compiler is able to make something useful of this. - As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). - - FIXME: Comment for old gcc version. Check. - If gcc was alright, it really would need no temporaries, and no - stack space to save stuff on. */ - - register char *dst __asm__ ("r13") = pdst; - register const char *src __asm__ ("r11") = psrc; - register int n __asm__ ("r12") = pn; - register int retn __asm__ ("r10") = 0; - - /* The best reason to align src is that we then know that a read-fault - was for aligned bytes; there's no 1..3 remaining good bytes to - pickle. */ - if (((unsigned long) src & 3) != 0) - { - if (((unsigned long) src & 1) && n != 0) - { - __asm_copy_from_user_1 (dst, src, retn); - n--; - if (retn != 0) - goto exception; - } - - if (((unsigned long) src & 2) && n >= 2) - { - __asm_copy_from_user_2 (dst, src, retn); - n -= 2; - if (retn != 0) - goto exception; - } - - } - - /* Movem is dirt cheap. The overheap is low enough to always use the - minimum possible block size as the threshold. */ - if (n >= 44) - { - /* It is not optimal to tell the compiler about clobbering any - registers; that will move the saving/restoring of those registers - to the function prologue/epilogue, and make non-movem sizes - suboptimal. */ - __asm__ volatile ("\ - .ifnc %0%1%2%3,$r13$r11$r12$r10 \n\ - .err \n\ - .endif \n\ - \n\ - ;; Save the registers we'll use in the movem process \n\ - ;; on the stack. \n\ - subq 11*4,$sp \n\ - movem $r10,[$sp] \n\ - \n\ - ;; Now we've got this: \n\ - ;; r11 - src \n\ - ;; r13 - dst \n\ - ;; r12 - n \n\ - \n\ - ;; Update n for the first loop \n\ - subq 44,$r12 \n\ -0: \n\ - movem [$r11+],$r10 \n\ - \n\ - subq 44,$r12 \n\ - bge 0b \n\ - movem $r10,[$r13+] \n\ - \n\ -4: \n\ - addq 44,$r12 ;; compensate for last loop underflowing n \n\ - \n\ - ;; Restore registers from stack \n\ - movem [$sp+],$r10 \n\ - .section .fixup,\"ax\" \n\ - \n\ -;; Do not jump back into the loop if we fail. For some uses, we get a \n\ -;; page fault somewhere on the line. Without checking for page limits, \n\ -;; we don't know where, but we need to copy accurately and keep an \n\ -;; accurate count; not just clear the whole line. To do that, we fall \n\ -;; down in the code below, proceeding with smaller amounts. It should \n\ -;; be kept in mind that we have to cater to code like what at one time \n\ -;; was in fs/super.c: \n\ -;; i = size - copy_from_user((void *)page, data, size); \n\ -;; which would cause repeated faults while clearing the remainder of \n\ -;; the SIZE bytes at PAGE after the first fault. \n\ -;; A caveat here is that we must not fall through from a failing page \n\ -;; to a valid page. \n\ - \n\ -3: \n\ - jump 4b ;; Fall through, pretending the fault didn't happen. \n\ - nop \n\ - \n\ - .previous \n\ - .section __ex_table,\"a\" \n\ - .dword 0b,3b \n\ - .previous" - - /* Outputs */ : "=r" (dst), "=r" (src), "=r" (n), "=r" (retn) - /* Inputs */ : "0" (dst), "1" (src), "2" (n), "3" (retn)); - } - - /* Either we directly start copying here, using dword copying in a loop, - or we copy as much as possible with 'movem' and then the last block - (<44 bytes) is copied here. This will work since 'movem' will have - updated src, dst and n. (Except with failing src.) - - Since we want to keep src accurate, we can't use - __asm_copy_from_user_N with N != (1, 2, 4); it updates dst and - retn, but not src (by design; it's value is ignored elsewhere). */ - - while (n >= 4) - { - __asm_copy_from_user_4 (dst, src, retn); - n -= 4; - - if (retn) - goto exception; - } - - /* If we get here, there were no memory read faults. */ - switch (n) - { - /* These copies are at least "naturally aligned" (so we don't have - to check each byte), due to the src alignment code before the - movem loop. The *_3 case *will* get the correct count for retn. */ - case 0: - /* This case deliberately left in (if you have doubts check the - generated assembly code). */ - break; - case 1: - __asm_copy_from_user_1 (dst, src, retn); - break; - case 2: - __asm_copy_from_user_2 (dst, src, retn); - break; - case 3: - __asm_copy_from_user_3 (dst, src, retn); - break; - } - - /* If we get here, retn correctly reflects the number of failing - bytes. */ - return retn; - -exception: - return retn + n; -} -EXPORT_SYMBOL(__copy_user_in); - -/* Zero userspace. */ -unsigned long __do_clear_user(void __user *pto, unsigned long pn) -{ - /* We want the parameters put in special registers. - Make sure the compiler is able to make something useful of this. - As it is now: r10 -> r13; r11 -> r11 (nop); r12 -> r12 (nop). - - FIXME: Comment for old gcc version. Check. - If gcc was alright, it really would need no temporaries, and no - stack space to save stuff on. */ - - register char *dst __asm__ ("r13") = pto; - register int n __asm__ ("r12") = pn; - register int retn __asm__ ("r10") = 0; - - - if (((unsigned long) dst & 3) != 0 - /* Don't align if we wouldn't copy more than a few bytes. */ - && n >= 3) - { - if ((unsigned long) dst & 1) - { - __asm_clear_1 (dst, retn); - n--; - } - - if ((unsigned long) dst & 2) - { - __asm_clear_2 (dst, retn); - n -= 2; - } - } - - /* Decide which copying method to use. - FIXME: This number is from the "ordinary" kernel memset. */ - if (n >= 48) - { - /* For large clears we use 'movem' */ - - /* It is not optimal to tell the compiler about clobbering any - call-saved registers; that will move the saving/restoring of - those registers to the function prologue/epilogue, and make - non-movem sizes suboptimal. - - This method is not foolproof; it assumes that the "asm reg" - declarations at the beginning of the function really are used - here (beware: they may be moved to temporary registers). - This way, we do not have to save/move the registers around into - temporaries; we can safely use them straight away. - - If you want to check that the allocation was right; then - check the equalities in the first comment. It should say - something like "r13=r13, r11=r11, r12=r12". */ - __asm__ volatile ("\ - .ifnc %0%1%2,$r13$r12$r10 \n\ - .err \n\ - .endif \n\ - \n\ - ;; Save the registers we'll clobber in the movem process \n\ - ;; on the stack. Don't mention them to gcc, it will only be \n\ - ;; upset. \n\ - subq 11*4,$sp \n\ - movem $r10,[$sp] \n\ - \n\ - clear.d $r0 \n\ - clear.d $r1 \n\ - clear.d $r2 \n\ - clear.d $r3 \n\ - clear.d $r4 \n\ - clear.d $r5 \n\ - clear.d $r6 \n\ - clear.d $r7 \n\ - clear.d $r8 \n\ - clear.d $r9 \n\ - clear.d $r10 \n\ - clear.d $r11 \n\ - \n\ - ;; Now we've got this: \n\ - ;; r13 - dst \n\ - ;; r12 - n \n\ - \n\ - ;; Update n for the first loop \n\ - subq 12*4,$r12 \n\ -0: \n\ - subq 12*4,$r12 \n\ -1: \n\ - bge 0b \n\ - movem $r11,[$r13+] \n\ - \n\ - addq 12*4,$r12 ;; compensate for last loop underflowing n \n\ - \n\ - ;; Restore registers from stack \n\ - movem [$sp+],$r10 \n\ -2: \n\ - .section .fixup,\"ax\" \n\ -3: \n\ - movem [$sp],$r10 \n\ - addq 12*4,$r10 \n\ - addq 12*4,$r13 \n\ - movem $r10,[$sp] \n\ - jump 0b \n\ - clear.d $r10 \n\ - \n\ - .previous \n\ - .section __ex_table,\"a\" \n\ - .dword 1b,3b \n\ - .previous" - - /* Outputs */ : "=r" (dst), "=r" (n), "=r" (retn) - /* Inputs */ : "0" (dst), "1" (n), "2" (retn) - /* Clobber */ : "r11"); - } - - while (n >= 16) - { - __asm_clear_16 (dst, retn); - n -= 16; - } - - /* Having a separate by-four loops cuts down on cache footprint. - FIXME: Test with and without; increasing switch to be 0..15. */ - while (n >= 4) - { - __asm_clear_4 (dst, retn); - n -= 4; - } - - switch (n) - { - case 0: - break; - case 1: - __asm_clear_1 (dst, retn); - break; - case 2: - __asm_clear_2 (dst, retn); - break; - case 3: - __asm_clear_3 (dst, retn); - break; - } - - return retn; -} -EXPORT_SYMBOL(__do_clear_user); |