kernel/bpf/verifier.c

4730 /* When register 'dst_regno' is assigned some values from stack[min_off,
4741 				int min_off, int max_off, int dst_regno)
4762 		__mark_reg_const_zero(env, &state->regs[dst_regno]);
4765 		mark_reg_unknown(env, state->regs, dst_regno);
4767 	state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4771  * 'dst_regno'. It handles reg filling if the addressed stack slot is a
4774  * 'dst_regno' can be -1, meaning that the read value is not going to a
4782 				      int off, int size, int dst_regno)
4810 			if (dst_regno < 0)
4818 				s32 subreg_def = state->regs[dst_regno].subreg_def;
4820 				copy_register_state(&state->regs[dst_regno], reg);
4821 				state->regs[dst_regno].subreg_def = subreg_def;
4827 					state->regs[dst_regno].id = 0;
4852 					__mark_reg_const_zero(env, &state->regs[dst_regno]);
4856 					__mark_reg_const_zero(env, &state->regs[dst_regno]);
4859 					mark_reg_unknown(env, state->regs, dst_regno);
4863 			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4864 		} else if (dst_regno >= 0) {
4866 			copy_register_state(&state->regs[dst_regno], reg);
4871 			state->regs[dst_regno].live |= REG_LIVE_WRITTEN;
4873 			/* If dst_regno==-1, the caller is asking us whether
4898 		if (dst_regno >= 0)
4899 			mark_reg_stack_read(env, reg_state, off, off + size, dst_regno);
4924  * 'dst_regno'.
4931  * the offset is not fixed). We conservatively mark 'dst_regno' as containing
4937 				    int ptr_regno, int off, int size, int dst_regno)
4954 	mark_reg_stack_read(env, ptr_state, min_off, max_off + size, dst_regno);
4964  * 'dst_regno' is a register which will receive the value from the stack. It
4969 			    int dst_regno)
4981 	if (dst_regno < 0 && var_off) {
5001 						 dst_regno);
5004 		 * than fixed offset ones. Note that dst_regno >= 0 on this
5008 					       dst_regno);