cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

unwind_guess.c (1823B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2#include <linux/sched.h>
      3#include <linux/ftrace.h>
      4#include <asm/ptrace.h>
      5#include <asm/bitops.h>
      6#include <asm/stacktrace.h>
      7#include <asm/unwind.h>
      8
      9unsigned long unwind_get_return_address(struct unwind_state *state)
     10{
     11	unsigned long addr;
     12
     13	if (unwind_done(state))
     14		return 0;
     15
     16	addr = READ_ONCE_NOCHECK(*state->sp);
     17
     18	return unwind_recover_ret_addr(state, addr, state->sp);
     19}
     20EXPORT_SYMBOL_GPL(unwind_get_return_address);
     21
     22unsigned long *unwind_get_return_address_ptr(struct unwind_state *state)
     23{
     24	return NULL;
     25}
     26
     27bool unwind_next_frame(struct unwind_state *state)
     28{
     29	struct stack_info *info = &state->stack_info;
     30
     31	if (unwind_done(state))
     32		return false;
     33
     34	do {
     35		for (state->sp++; state->sp < info->end; state->sp++) {
     36			unsigned long addr = READ_ONCE_NOCHECK(*state->sp);
     37
     38			if (__kernel_text_address(addr))
     39				return true;
     40		}
     41
     42		state->sp = PTR_ALIGN(info->next_sp, sizeof(long));
     43
     44	} while (!get_stack_info(state->sp, state->task, info,
     45				 &state->stack_mask));
     46
     47	return false;
     48}
     49EXPORT_SYMBOL_GPL(unwind_next_frame);
     50
     51void __unwind_start(struct unwind_state *state, struct task_struct *task,
     52		    struct pt_regs *regs, unsigned long *first_frame)
     53{
     54	memset(state, 0, sizeof(*state));
     55
     56	state->task = task;
     57	state->sp   = PTR_ALIGN(first_frame, sizeof(long));
     58
     59	get_stack_info(first_frame, state->task, &state->stack_info,
     60		       &state->stack_mask);
     61
     62	/*
     63	 * The caller can provide the address of the first frame directly
     64	 * (first_frame) or indirectly (regs->sp) to indicate which stack frame
     65	 * to start unwinding at.  Skip ahead until we reach it.
     66	 */
     67	if (!unwind_done(state) &&
     68	    (!on_stack(&state->stack_info, first_frame, sizeof(long)) ||
     69	    !__kernel_text_address(*first_frame)))
     70		unwind_next_frame(state);
     71}
     72EXPORT_SYMBOL_GPL(__unwind_start);