cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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arm64-frame-pointer-unwind-support.c (1856B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include "arm64-frame-pointer-unwind-support.h"
      3#include "callchain.h"
      4#include "event.h"
      5#include "perf_regs.h" // SMPL_REG_MASK
      6#include "unwind.h"
      7
      8#define perf_event_arm_regs perf_event_arm64_regs
      9#include "../../arch/arm64/include/uapi/asm/perf_regs.h"
     10#undef perf_event_arm_regs
     11
     12struct entries {
     13	u64 stack[2];
     14	size_t length;
     15};
     16
     17static bool get_leaf_frame_caller_enabled(struct perf_sample *sample)
     18{
     19	return callchain_param.record_mode == CALLCHAIN_FP && sample->user_regs.regs
     20		&& sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_LR);
     21}
     22
     23static int add_entry(struct unwind_entry *entry, void *arg)
     24{
     25	struct entries *entries = arg;
     26
     27	entries->stack[entries->length++] = entry->ip;
     28	return 0;
     29}
     30
     31u64 get_leaf_frame_caller_aarch64(struct perf_sample *sample, struct thread *thread, int usr_idx)
     32{
     33	int ret;
     34	struct entries entries = {};
     35	struct regs_dump old_regs = sample->user_regs;
     36
     37	if (!get_leaf_frame_caller_enabled(sample))
     38		return 0;
     39
     40	/*
     41	 * If PC and SP are not recorded, get the value of PC from the stack
     42	 * and set its mask. SP is not used when doing the unwinding but it
     43	 * still needs to be set to prevent failures.
     44	 */
     45
     46	if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_PC))) {
     47		sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_PC);
     48		sample->user_regs.cache_regs[PERF_REG_ARM64_PC] = sample->callchain->ips[usr_idx+1];
     49	}
     50
     51	if (!(sample->user_regs.mask & SMPL_REG_MASK(PERF_REG_ARM64_SP))) {
     52		sample->user_regs.cache_mask |= SMPL_REG_MASK(PERF_REG_ARM64_SP);
     53		sample->user_regs.cache_regs[PERF_REG_ARM64_SP] = 0;
     54	}
     55
     56	ret = unwind__get_entries(add_entry, &entries, thread, sample, 2, true);
     57	sample->user_regs = old_regs;
     58
     59	if (ret || entries.length != 2)
     60		return ret;
     61
     62	return callchain_param.order == ORDER_CALLER ? entries.stack[0] : entries.stack[1];
     63}