lh-l4v/proof/infoflow/PasUpdates.thy

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(*
* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
*
* SPDX-License-Identifier: GPL-2.0-only
*)
text \<open>
Lemmas about updating the external flags of a PAS.
These flags are: pasSubject, pasMayEditReadyQueues and pasMayActivate.
\<close>
theory PasUpdates
imports
"Arch_IF"
"FinalCaps"
"AInvs.EmptyFail_AI"
begin
context begin interpretation Arch . (*FIXME: arch_split*)
section \<open>Separation lemmas for the idle thread and domain fields\<close>
abbreviation (input) domain_fields
where
"domain_fields P s \<equiv> P (domain_time s) (domain_index s) (domain_list s)"
lemma preemption_point_domain_fields[wp]:
"\<lbrace>domain_fields P\<rbrace> preemption_point \<lbrace>\<lambda>_. domain_fields P\<rbrace>"
by (simp add: preemption_point_def
| wp OR_choiceE_weak_wp modify_wp
| wpc
| simp add: reset_work_units_def update_work_units_def)+
crunch domain_fields[wp]: retype_region_ext,create_cap_ext,cap_insert_ext,ethread_set,
cap_move_ext,empty_slot_ext,cap_swap_ext,set_thread_state_ext,
tcb_sched_action,reschedule_required,cap_swap_for_delete,
finalise_cap,cap_move,cap_swap,cap_delete,cancel_badged_sends,
cap_insert
"domain_fields P"
( wp: syscall_valid select_wp crunch_wps rec_del_preservation cap_revoke_preservation modify_wp
simp: crunch_simps check_cap_at_def filterM_mapM unless_def
ignore: without_preemption filterM rec_del check_cap_at cap_revoke
ignore_del: retype_region_ext create_cap_ext cap_insert_ext ethread_set cap_move_ext
empty_slot_ext cap_swap_ext set_thread_state_ext tcb_sched_action reschedule_required)
lemma cap_revoke_domain_fields[wp]:"\<lbrace>domain_fields P\<rbrace> cap_revoke a \<lbrace>\<lambda>_. domain_fields P\<rbrace>"
by (rule cap_revoke_preservation2; wp)
lemma invoke_cnode_domain_fields[wp]: "\<lbrace>domain_fields P\<rbrace> invoke_cnode a \<lbrace>\<lambda>_. domain_fields P\<rbrace>"
unfolding invoke_cnode_def
by (wpsimp wp: get_cap_wp hoare_vcg_all_lift hoare_vcg_imp_lift
| rule conjI)+
crunch domain_fields[wp]:
set_domain,possible_switch_to,set_priority,set_extra_badge,
handle_send,handle_recv,handle_reply
"domain_fields P"
(wp: syscall_valid crunch_wps mapME_x_inv_wp
simp: crunch_simps check_cap_at_def detype_def detype_ext_def mapM_x_defsym
ignore: check_cap_at syscall
ignore_del: set_domain set_priority possible_switch_to
rule: transfer_caps_loop_pres)
section \<open>PAS wellformedness property for non-interference\<close>
definition pas_wellformed_noninterference where
"pas_wellformed_noninterference aag \<equiv>
(\<forall>l\<in>range (pasObjectAbs aag) \<union> \<Union>(range (pasDomainAbs aag)) - {SilcLabel}.
pas_wellformed (aag\<lparr> pasSubject := l \<rparr>)) \<and>
(\<forall>d. SilcLabel \<notin> pasDomainAbs aag d) \<and>
pas_domains_distinct aag"
lemma pas_wellformed_noninterference_domains_distinct:
"pas_wellformed_noninterference aag \<Longrightarrow> pas_domains_distinct aag"
by (simp add: pas_wellformed_noninterference_def)
lemma pas_wellformed_noninterference_silc[intro!]:
"pas_wellformed_noninterference aag \<Longrightarrow> SilcLabel \<notin> pasDomainAbs aag d"
apply (fastforce simp: pas_wellformed_noninterference_def)
done
section \<open>PAS subject update\<close>
lemma pasObjectAbs_pasSubject_update:
"pasObjectAbs (aag\<lparr> pasSubject := x \<rparr>) = pasObjectAbs aag"
apply simp
done
lemma pasASIDAbs_pasSubject_update:
"pasASIDAbs (aag\<lparr> pasSubject := x \<rparr>) = pasASIDAbs aag"
apply simp
done
lemma pasIRQAbs_pasSubject_update:
"pasIRQAbs (aag\<lparr> pasSubject := x \<rparr>) = pasIRQAbs aag"
apply simp
done
lemma state_asids_to_policy_pasSubject_update:
"state_asids_to_policy_aux (aag\<lparr> pasSubject := x \<rparr>) caps asid vrefs =
state_asids_to_policy_aux aag caps asid vrefs"
apply(rule equalityI)
apply(clarify)
apply(erule state_asids_to_policy_aux.cases
|simp
|fastforce intro: state_asids_to_policy_aux.intros)+
apply(clarify)
apply(erule state_asids_to_policy_aux.cases)
apply(simp,
subst pasObjectAbs_pasSubject_update[symmetric],
subst pasASIDAbs_pasSubject_update[symmetric],
rule state_asids_to_policy_aux.intros, assumption+)+
done
lemma state_irqs_to_policy_pasSubject_update:
"state_irqs_to_policy_aux (aag\<lparr> pasSubject := x \<rparr>) caps =
state_irqs_to_policy_aux aag caps"
apply(rule equalityI)
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases, simp,
blast intro: state_irqs_to_policy_aux.intros)
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases)
apply(simp)
apply(subst pasObjectAbs_pasSubject_update[symmetric])
apply(subst pasIRQAbs_pasSubject_update[symmetric])
apply(rule state_irqs_to_policy_aux.intros)
apply assumption+
done
lemma irq_map_wellformed_pasSubject_update:
"irq_map_wellformed_aux (aag\<lparr> pasSubject := x \<rparr>) irqn =
irq_map_wellformed_aux aag irqn"
by (clarsimp simp: irq_map_wellformed_aux_def)
lemma tcb_domain_map_wellformed_pasSubject_update:
"tcb_domain_map_wellformed_aux (aag\<lparr> pasSubject := x \<rparr>) irqn =
tcb_domain_map_wellformed_aux aag irqn"
by (clarsimp simp: tcb_domain_map_wellformed_aux_def)
lemma pas_refined_pasSubject_update':
"\<lbrakk>pas_refined aag s; pas_wellformed (aag\<lparr> pasSubject := x \<rparr>)\<rbrakk> \<Longrightarrow>
pas_refined (aag\<lparr> pasSubject := x \<rparr>) s"
apply(subst pas_refined_def)
apply(safe del: subsetI)
apply (simp add: irq_map_wellformed_pasSubject_update pas_refined_def)
apply (simp add: tcb_domain_map_wellformed_pasSubject_update pas_refined_def)
apply (clarsimp simp: pas_refined_def)
apply(fastforce intro: pas_refined_asid_mem simp: state_asids_to_policy_pasSubject_update)
apply(fastforce simp: pas_refined_def state_irqs_to_policy_pasSubject_update)
done
lemma pas_wellformed_pasSubject_update:
"\<lbrakk>pas_wellformed_noninterference aag; l \<in> pasDomainAbs aag d\<rbrakk> \<Longrightarrow>
pas_wellformed (aag\<lparr>pasSubject := l\<rparr>)"
by (auto simp: pas_wellformed_noninterference_def)
lemmas pas_refined_pasSubject_update =
pas_refined_pasSubject_update'[OF _ pas_wellformed_pasSubject_update]
lemma guarded_pas_domain_pasSubject_update[simp]:
"guarded_pas_domain (aag\<lparr>pasSubject := x\<rparr>) s = guarded_pas_domain aag s"
by (simp add: guarded_pas_domain_def)
lemma silc_inv_pasSubject_update':
"\<lbrakk>silc_inv aag st s; x \<noteq> SilcLabel\<rbrakk> \<Longrightarrow> silc_inv (aag\<lparr>pasSubject := x\<rparr>) st s"
by (auto simp: silc_inv_def silc_dom_equiv_def intra_label_cap_def cap_points_to_label_def)
lemma silc_inv_pasSubject_update:
"\<lbrakk>silc_inv aag st s; pas_wellformed_noninterference aag; l \<in> pasDomainAbs aag d\<rbrakk>
\<Longrightarrow> silc_inv (aag\<lparr>pasSubject := l\<rparr>) st s"
apply (fastforce intro: silc_inv_pasSubject_update' dest: pas_wellformed_noninterference_silc)
done
section \<open>PAS MayActivate update\<close>
lemma prop_of_pasMayActivate_update_idemp:
"\<lbrakk>P aag; pasMayActivate aag = v\<rbrakk> \<Longrightarrow> P (aag\<lparr> pasMayActivate := v \<rparr>)"
by (hypsubst, auto)
lemma pasObjectAbs_pasMayActivate_update:
"pasObjectAbs (aag\<lparr> pasMayActivate := x \<rparr>) = pasObjectAbs aag"
by simp
lemma pasASIDAbs_pasMayActivate_update:
"pasASIDAbs (aag\<lparr> pasMayActivate := x \<rparr>) = pasASIDAbs aag"
by simp
lemma pasIRQAbs_pasMayActivate_update:
"pasIRQAbs (aag\<lparr> pasMayActivate := x \<rparr>) = pasIRQAbs aag"
by simp
lemma state_asids_to_policy_pasMayActivate_update:
"state_asids_to_policy (aag\<lparr> pasMayActivate := x \<rparr>) s =
state_asids_to_policy aag s"
apply(rule equalityI)
apply(clarify)
apply(erule state_asids_to_policy_aux.cases
|simp
|fastforce intro: state_asids_to_policy_aux.intros)+
apply(clarify)
apply(erule state_asids_to_policy_aux.cases)
apply(simp,
subst pasObjectAbs_pasMayActivate_update[symmetric],
subst pasASIDAbs_pasMayActivate_update[symmetric],
rule state_asids_to_policy_aux.intros, assumption+)+
done
lemma state_irqs_to_policy_pasMayActivate_update:
"state_irqs_to_policy (aag\<lparr> pasMayActivate := x \<rparr>) s =
state_irqs_to_policy aag s"
apply(rule equalityI)
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases
|simp
|fastforce intro: state_irqs_to_policy_aux.intros)+
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases)
apply(simp,
subst pasObjectAbs_pasMayActivate_update[symmetric],
subst pasIRQAbs_pasMayActivate_update[symmetric],
rule state_irqs_to_policy_aux.intros, assumption+)+
done
lemma pas_refined_pasMayActivate_update:
"pas_refined aag s \<Longrightarrow>
pas_refined (aag\<lparr> pasMayActivate := x \<rparr>) s"
apply(simp add: pas_refined_def)
apply(clarsimp simp: irq_map_wellformed_aux_def state_asids_to_policy_pasMayActivate_update
state_irqs_to_policy_pasMayActivate_update tcb_domain_map_wellformed_aux_def)
done
lemma guarded_pas_domainMayActivate_update[simp]:
"guarded_pas_domain (aag\<lparr>pasMayActivate := False\<rparr>) = guarded_pas_domain aag"
by (simp add: guarded_pas_domain_def)
lemma cdt_change_allowedMayActivate_update[simp]:
"cdt_change_allowed (aag\<lparr>pasMayActivate := x\<rparr>) =
cdt_change_allowed aag "
by (simp add: cdt_change_allowed_def[abs_def] cdt_direct_change_allowed.simps direct_call_def)
section \<open>PAS MayEditReadyQueue update\<close>
lemma prop_of_pasMayEditReadyQueues_update_idemp:
"\<lbrakk>P aag; pasMayEditReadyQueues aag = v\<rbrakk> \<Longrightarrow> P (aag\<lparr> pasMayEditReadyQueues := v \<rparr>)"
by clarsimp
lemma pasObjectAbs_pasMayEditReadyQueues_update:
"pasObjectAbs (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) = pasObjectAbs aag"
by simp
lemma pasASIDAbs_pasMayEditReadyQueues_update:
"pasASIDAbs (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) = pasASIDAbs aag"
by simp
lemma pasIRQAbs_pasMayEditReadyQueues_update:
"pasIRQAbs (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) = pasIRQAbs aag"
by simp
lemma state_asids_to_policy_pasMayEditReadyQueues_update:
"state_asids_to_policy (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) s =
state_asids_to_policy aag s"
apply(rule equalityI)
apply(clarify)
apply(erule state_asids_to_policy_aux.cases
|simp
|fastforce intro: state_asids_to_policy_aux.intros)+
apply(clarify)
apply(erule state_asids_to_policy_aux.cases)
apply(simp,
subst pasObjectAbs_pasMayEditReadyQueues_update[symmetric],
subst pasASIDAbs_pasMayEditReadyQueues_update[symmetric],
rule state_asids_to_policy_aux.intros, assumption+)+
done
lemma state_irqs_to_policy_pasMayEditReadyQueues_update:
"state_irqs_to_policy (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) s =
state_irqs_to_policy aag s"
apply(rule equalityI)
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases
|simp
|fastforce intro: state_irqs_to_policy_aux.intros)+
apply(clarify)
apply(erule state_irqs_to_policy_aux.cases)
apply(simp,
subst pasObjectAbs_pasMayEditReadyQueues_update[symmetric],
subst pasIRQAbs_pasMayEditReadyQueues_update[symmetric],
rule state_irqs_to_policy_aux.intros, assumption+)+
done
lemma pas_refined_pasMayEditReadyQueues_update:
"pas_refined aag s \<Longrightarrow>
pas_refined (aag\<lparr> pasMayEditReadyQueues := x \<rparr>) s"
apply(simp add: pas_refined_def)
apply(clarsimp simp: irq_map_wellformed_aux_def
state_asids_to_policy_pasMayEditReadyQueues_update
state_irqs_to_policy_pasMayEditReadyQueues_update
tcb_domain_map_wellformed_aux_def)
done
lemma guarded_pas_domainMayEditReadyQueues_update[simp]:
"guarded_pas_domain (aag\<lparr>pasMayEditReadyQueues := False\<rparr>) = guarded_pas_domain aag"
by (simp add: guarded_pas_domain_def)
lemma cdt_change_allowedMayEditReadyQueues_update[simp]:
"cdt_change_allowed (aag\<lparr>pasMayEditReadyQueues := x\<rparr>) =
cdt_change_allowed aag"
by (simp add: cdt_change_allowed_def[abs_def] cdt_direct_change_allowed.simps direct_call_def)
end
end