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Diffstat (limited to '')
-rw-r--r-- | tools/perf/arch/arm/tests/regs_load.S | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/tools/perf/arch/arm/tests/regs_load.S b/tools/perf/arch/arm/tests/regs_load.S new file mode 100644 index 000000000..4284307d7 --- /dev/null +++ b/tools/perf/arch/arm/tests/regs_load.S @@ -0,0 +1,59 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/linkage.h> + +#define R0 0x00 +#define R1 0x08 +#define R2 0x10 +#define R3 0x18 +#define R4 0x20 +#define R5 0x28 +#define R6 0x30 +#define R7 0x38 +#define R8 0x40 +#define R9 0x48 +#define SL 0x50 +#define FP 0x58 +#define IP 0x60 +#define SP 0x68 +#define LR 0x70 +#define PC 0x78 + +/* + * Implementation of void perf_regs_load(u64 *regs); + * + * This functions fills in the 'regs' buffer from the actual registers values, + * in the way the perf built-in unwinding test expects them: + * - the PC at the time at the call to this function. Since this function + * is called using a bl instruction, the PC value is taken from LR. + * The built-in unwinding test then unwinds the call stack from the dwarf + * information in unwind__get_entries. + * + * Notes: + * - the 8 bytes stride in the registers offsets comes from the fact + * that the registers are stored in an u64 array (u64 *regs), + * - the regs buffer needs to be zeroed before the call to this function, + * in this case using a calloc in dwarf-unwind.c. + */ + +.text +.type perf_regs_load,%function +SYM_FUNC_START(perf_regs_load) + str r0, [r0, #R0] + str r1, [r0, #R1] + str r2, [r0, #R2] + str r3, [r0, #R3] + str r4, [r0, #R4] + str r5, [r0, #R5] + str r6, [r0, #R6] + str r7, [r0, #R7] + str r8, [r0, #R8] + str r9, [r0, #R9] + str sl, [r0, #SL] + str fp, [r0, #FP] + str ip, [r0, #IP] + str sp, [r0, #SP] + str lr, [r0, #LR] + str lr, [r0, #PC] // store pc as lr in order to skip the call + // to this function + mov pc, lr +SYM_FUNC_END(perf_regs_load) |