1 /* 2 * Copyright 2011 Tilera Corporation. All Rights Reserved. 3 * 4 * This program is free software; you can redistribute it and/or 5 * modify it under the terms of the GNU General Public License 6 * as published by the Free Software Foundation, version 2. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or 11 * NON INFRINGEMENT. See the GNU General Public License for 12 * more details. 13 * 14 * Do memcpy(), but trap and return "n" when a load or store faults. 15 * 16 * Note: this idiom only works when memcpy() compiles to a leaf function. 17 * Here leaf function not only means it does not have calls, but also 18 * requires no stack operations (sp, stack frame pointer) and no 19 * use of callee-saved registers, else "jrp lr" will be incorrect since 20 * unwinding stack frame is bypassed. Since memcpy() is not complex so 21 * these conditions are satisfied here, but we need to be careful when 22 * modifying this file. This is not a clean solution but is the best 23 * one so far. 24 * 25 * Also note that we are capturing "n" from the containing scope here. 26 */ 27 28 #define _ST(p, inst, v) \ 29 ({ \ 30 asm("1: " #inst " %0, %1;" \ 31 ".pushsection .coldtext,\"ax\";" \ 32 "2: { move r0, %2; jrp lr };" \ 33 ".section __ex_table,\"a\";" \ 34 ".align 8;" \ 35 ".quad 1b, 2b;" \ 36 ".popsection" \ 37 : "=m" (*(p)) : "r" (v), "r" (n)); \ 38 }) 39 40 #define _LD(p, inst) \ 41 ({ \ 42 unsigned long __v; \ 43 asm("1: " #inst " %0, %1;" \ 44 ".pushsection .coldtext,\"ax\";" \ 45 "2: { move r0, %2; jrp lr };" \ 46 ".section __ex_table,\"a\";" \ 47 ".align 8;" \ 48 ".quad 1b, 2b;" \ 49 ".popsection" \ 50 : "=r" (__v) : "m" (*(p)), "r" (n)); \ 51 __v; \ 52 }) 53 54 #define USERCOPY_FUNC raw_copy_to_user 55 #define ST1(p, v) _ST((p), st1, (v)) 56 #define ST2(p, v) _ST((p), st2, (v)) 57 #define ST4(p, v) _ST((p), st4, (v)) 58 #define ST8(p, v) _ST((p), st, (v)) 59 #define LD1 LD 60 #define LD2 LD 61 #define LD4 LD 62 #define LD8 LD 63 #include "memcpy_64.c" 64 65 #define USERCOPY_FUNC raw_copy_from_user 66 #define ST1 ST 67 #define ST2 ST 68 #define ST4 ST 69 #define ST8 ST 70 #define LD1(p) _LD((p), ld1u) 71 #define LD2(p) _LD((p), ld2u) 72 #define LD4(p) _LD((p), ld4u) 73 #define LD8(p) _LD((p), ld) 74 #include "memcpy_64.c" 75 76 #define USERCOPY_FUNC raw_copy_in_user 77 #define ST1(p, v) _ST((p), st1, (v)) 78 #define ST2(p, v) _ST((p), st2, (v)) 79 #define ST4(p, v) _ST((p), st4, (v)) 80 #define ST8(p, v) _ST((p), st, (v)) 81 #define LD1(p) _LD((p), ld1u) 82 #define LD2(p) _LD((p), ld2u) 83 #define LD4(p) _LD((p), ld4u) 84 #define LD8(p) _LD((p), ld) 85 #include "memcpy_64.c" 86