1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #include <linux/linkage.h> 3 4 #define R0 0x00 5 #define R1 0x08 6 #define R2 0x10 7 #define R3 0x18 8 #define R4 0x20 9 #define R5 0x28 10 #define R6 0x30 11 #define R7 0x38 12 #define R8 0x40 13 #define R9 0x48 14 #define SL 0x50 15 #define FP 0x58 16 #define IP 0x60 17 #define SP 0x68 18 #define LR 0x70 19 #define PC 0x78 20 21 /* 22 * Implementation of void perf_regs_load(u64 *regs); 23 * 24 * This functions fills in the 'regs' buffer from the actual registers values, 25 * in the way the perf built-in unwinding test expects them: 26 * - the PC at the time at the call to this function. Since this function 27 * is called using a bl instruction, the PC value is taken from LR. 28 * The built-in unwinding test then unwinds the call stack from the dwarf 29 * information in unwind__get_entries. 30 * 31 * Notes: 32 * - the 8 bytes stride in the registers offsets comes from the fact 33 * that the registers are stored in an u64 array (u64 *regs), 34 * - the regs buffer needs to be zeroed before the call to this function, 35 * in this case using a calloc in dwarf-unwind.c. 36 */ 37 38 .text 39 .type perf_regs_load,%function 40 SYM_FUNC_START(perf_regs_load) 41 str r0, [r0, #R0] 42 str r1, [r0, #R1] 43 str r2, [r0, #R2] 44 str r3, [r0, #R3] 45 str r4, [r0, #R4] 46 str r5, [r0, #R5] 47 str r6, [r0, #R6] 48 str r7, [r0, #R7] 49 str r8, [r0, #R8] 50 str r9, [r0, #R9] 51 str sl, [r0, #SL] 52 str fp, [r0, #FP] 53 str ip, [r0, #IP] 54 str sp, [r0, #SP] 55 str lr, [r0, #LR] 56 str lr, [r0, #PC] // store pc as lr in order to skip the call 57 // to this function 58 mov pc, lr 59 SYM_FUNC_END(perf_regs_load) 60