cap_machine.rules.rules_Restrict
From iris.base_logic Require Export invariants gen_heap.
From iris.program_logic Require Export weakestpre ectx_lifting.
From iris.proofmode Require Import proofmode.
From iris.algebra Require Import frac.
From cap_machine Require Export rules_base.
Section cap_lang_rules.
Context `{memG Σ, regG Σ}.
Context `{MachineParameters}.
Implicit Types P Q : iProp Σ.
Implicit Types σ : ExecConf.
Implicit Types c : cap_lang.expr.
Implicit Types r : RegName.
Implicit Types v : cap_lang.val.
Implicit Types w : Word.
Implicit Types reg : gmap RegName Word.
Implicit Types ms : gmap Addr Word.
Inductive Restrict_failure (regs: Reg) (dst: RegName) (src: Z + RegName) :=
| Restrict_fail_src_nonz:
z_of_argument regs src = None →
Restrict_failure regs dst src
| Restrict_fail_allowed w:
regs !! dst = Some w →
is_mutable_range w = false →
Restrict_failure regs dst src
| Restrict_fail_invalid_perm_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E →
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = false →
Restrict_failure regs dst src
| Restrict_fail_PC_overflow_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E →
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = true →
incrementPC (<[ dst := WCap (decodePerm n) b e a ]> regs) = None →
Restrict_failure regs dst src
| Restrict_fail_invalid_perm_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = false →
Restrict_failure regs dst src
| Restrict_fail_PC_overflow_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = true →
incrementPC (<[ dst := WSealRange (decodeSealPerms n) b e a ]> regs) = None →
Restrict_failure regs dst src.
Inductive Restrict_spec (regs: Reg) (dst: RegName) (src: Z + RegName) (regs': Reg): cap_lang.val -> Prop :=
| Restrict_spec_success_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E ->
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = true →
incrementPC (<[ dst := WCap (decodePerm n) b e a ]> regs) = Some regs' →
Restrict_spec regs dst src regs' NextIV
| Restrict_spec_success_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = true →
incrementPC (<[ dst := WSealRange (decodeSealPerms n) b e a ]> regs) = Some regs' →
Restrict_spec regs dst src regs' NextIV
| Restrict_spec_failure:
Restrict_failure regs dst src →
Restrict_spec regs dst src regs' FailedV.
Lemma wp_Restrict Ep pc_p pc_b pc_e pc_a w dst src regs :
decodeInstrW w = Restrict dst src ->
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
regs !! PC = Some (WCap pc_p pc_b pc_e pc_a) →
regs_of (Restrict dst src) ⊆ dom regs →
{{{ ▷ pc_a ↦ₐ w ∗
▷ [∗ map] k↦y ∈ regs, k ↦ᵣ y }}}
Instr Executable @ Ep
{{{ regs' retv, RET retv;
⌜ Restrict_spec regs dst src regs' retv ⌝ ∗
pc_a ↦ₐ w ∗
[∗ map] k↦y ∈ regs', k ↦ᵣ y }}}.
Proof.
iIntros (Hinstr Hvpc HPC Dregs φ) "(>Hpc_a & >Hmap) Hφ".
iApply wp_lift_atomic_base_step_no_fork; auto.
iIntros (σ1 ns l1 l2 nt) "Hσ1 /=". destruct σ1; simpl.
iDestruct "Hσ1" as "[Hr Hm]".
iDestruct (gen_heap_valid_inclSepM with "Hr Hmap") as %Hregs.
have ? := lookup_weaken _ _ _ _ HPC Hregs.
iDestruct (@gen_heap_valid with "Hm Hpc_a") as %Hpc_a; auto.
iModIntro. iSplitR. by iPureIntro; apply normal_always_base_reducible.
iNext. iIntros (e2 σ2 efs Hpstep).
apply prim_step_exec_inv in Hpstep as (-> & -> & (c & -> & Hstep)).
iIntros "_".
iSplitR; auto. eapply step_exec_inv in Hstep; eauto.
specialize (indom_regs_incl _ _ _ Dregs Hregs) as Hri.
unfold regs_of in Hri, Dregs.
destruct (Hri dst) as [wdst [H'dst Hdst]]. by set_solver+.
rewrite /exec /= Hdst /= in Hstep.
destruct (z_of_argument regs src) as [wsrc|] eqn:Hwsrc;
pose proof Hwsrc as H'wsrc; cycle 1.
{ (* Failure: argument is not a constant (z_of_argument regs arg = None) *)
unfold z_of_argument in Hwsrc, Hstep. destruct src as [| r0]; [ congruence |].
odestruct (Hri r0) as [r0v [Hr'0 Hr0]].
{ unfold regs_of_argument. set_solver+. }
rewrite Hr0 Hr'0 in Hwsrc Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->).
{ destruct_word r0v; cbn in Hstep; try congruence; by simplify_pair_eq. }
iFailWP "Hφ" Restrict_fail_src_nonz. }
apply (z_of_arg_mono _ r) in Hwsrc; auto. rewrite Hwsrc in Hstep; simpl in Hstep.
destruct (is_mutable_range wdst) eqn:Hwdst.
2: { (* Failure: wdst is not of the right type *)
unfold is_mutable_range in Hwdst.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->).
{ destruct wdst as [ | [p b e a | ] | ]; try by inversion Hwdst.
all: try by simplify_pair_eq.
destruct p; try congruence.
simplify_pair_eq; auto. }
iFailWP "Hφ" Restrict_fail_allowed. }
(* Now the proof splits depending on the type of value in wdst *)
destruct wdst as [ | [p b e a | p b e a] | ].
1,4: inversion Hwdst.
(* First, the case where r1v is a capability *)
+ destruct (perm_eq_dec p E); [ subst p |].
{ rewrite /is_mutable_range in Hwdst; congruence. }
destruct (PermFlowsTo (decodePerm wsrc) p) eqn:Hflows; cycle 1.
{ destruct p; try congruence; inv Hstep ; iFailWP "Hφ" Restrict_fail_invalid_perm_cap. }
rewrite /update_reg /= in Hstep.
destruct (incrementPC (<[ dst := WCap (decodePerm wsrc) b e a ]> regs)) eqn:Hregs';
pose proof Hregs' as H'regs'; cycle 1.
{
assert (incrementPC (<[ dst := WCap( decodePerm wsrc) b e a ]> r) = None) as HH.
{ eapply incrementPC_overflow_mono; first eapply Hregs'.
by rewrite lookup_insert_is_Some'; eauto.
by apply insert_mono; eauto. }
apply (incrementPC_fail_updatePC _ m) in HH. rewrite HH in Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->)
by (destruct p; inversion Hstep; auto).
iFailWP "Hφ" Restrict_fail_PC_overflow_cap. }
eapply (incrementPC_success_updatePC _ m) in Hregs'
as (p' & g' & b' & e' & a'' & a_pc' & HPC'' & HuPC & ->).
eapply updatePC_success_incl with (m':=m) in HuPC. 2: by eapply insert_mono; eauto. rewrite HuPC in Hstep.
eassert ((c, σ2) = (NextI, _)) as HH.
{ destruct p; cbn in Hstep; eauto. congruence. }
simplify_pair_eq.
iFrame.
iMod ((gen_heap_update_inSepM _ _ dst) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iMod ((gen_heap_update_inSepM _ _ PC) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iFrame. iApply "Hφ". iFrame. iPureIntro. econstructor; eauto.
(* Now, the case where wsrc is a sealrange *)
+ destruct (SealPermFlowsTo (decodeSealPerms wsrc) p) eqn:Hflows; cycle 1.
{ destruct p; try congruence; inv Hstep ; iFailWP "Hφ" Restrict_fail_invalid_perm_sr. }
rewrite /update_reg /= in Hstep.
destruct (incrementPC (<[ dst := WSealRange (decodeSealPerms wsrc) b e a ]> regs)) eqn:Hregs';
pose proof Hregs' as H'regs'; cycle 1.
{
assert (incrementPC (<[ dst := WSealRange (decodeSealPerms wsrc) b e a ]> r) = None) as HH.
{ eapply incrementPC_overflow_mono; first eapply Hregs'.
by rewrite lookup_insert_is_Some'; eauto.
by apply insert_mono; eauto. }
apply (incrementPC_fail_updatePC _ m) in HH. rewrite HH in Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->)
by (destruct p; inversion Hstep; auto).
iFailWP "Hφ" Restrict_fail_PC_overflow_sr. }
eapply (incrementPC_success_updatePC _ m) in Hregs'
as (p' & g' & b' & e' & a'' & a_pc' & HPC'' & HuPC & ->).
eapply updatePC_success_incl with (m':=m) in HuPC. 2: by eapply insert_mono; eauto. rewrite HuPC in Hstep.
eassert ((c, σ2) = (NextI, _)) as HH.
{ destruct p; cbn in Hstep; eauto. }
simplify_pair_eq.
iFrame.
iMod ((gen_heap_update_inSepM _ _ dst) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iMod ((gen_heap_update_inSepM _ _ PC) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iFrame. iApply "Hφ". iFrame. iPureIntro. econstructor 2; eauto.
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_reg_PC Ep pc_p pc_b pc_e pc_a pc_a' w rv z:
decodeInstrW w = Restrict PC (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) pc_p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap (decodePerm z) pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hrv) Hφ".
iDestruct (map_of_regs_2 with "HPC Hrv") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite !insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame.
}
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct pc_p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_reg Ep pc_p pc_b pc_e pc_a pc_a' w r1 rv p b e a z :
decodeInstrW w = Restrict r1 (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) p = true →
p ≠ E →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WCap p b e a
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z
∗ r1 ↦ᵣ WCap (decodePerm z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows Hnp ϕ) "(>HPC & >Hpc_a & >Hr1 & >Hrv) Hφ".
iDestruct (map_of_regs_3 with "HPC Hr1 Hrv") as "[Hmap (%&%&%)]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_3 with "Hmap") as "(?&?&?)"; eauto; iFrame. }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z_PC Ep pc_p pc_b pc_e pc_a pc_a' w z :
decodeInstrW w = Restrict PC (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) pc_p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap (decodePerm z) pc_b pc_e pc_a'
∗ pc_a ↦ₐ w }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a) Hφ".
iDestruct (map_of_regs_1 with "HPC") as "Hmap".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)".
iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [ | | * Hfail ].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite !insert_insert.
iApply (regs_of_map_1 with "Hmap"). }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto.
destruct pc_p; congruence.
congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z Ep pc_p pc_b pc_e pc_a pc_a' w r1 p b e a z :
decodeInstrW w = Restrict r1 (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) p = true →
p ≠ E →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WCap p b e a }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ r1 ↦ᵣ WCap (decodePerm z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows HpE ϕ) "(>HPC & >Hpc_a & >Hr1) Hφ".
iDestruct (map_of_regs_2 with "HPC Hr1") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame. }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
(* Similar rules in case we have a SealRange instead of a capability, where some cases are impossible, because a SealRange is not a valid PC *)
Lemma wp_restrict_success_reg_sr Ep pc_p pc_b pc_e pc_a pc_a' w r1 rv p b e a z :
decodeInstrW w = Restrict r1 (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
SealPermFlowsTo (decodeSealPerms z) p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WSealRange p b e a
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z
∗ r1 ↦ᵣ WSealRange (decodeSealPerms z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hr1 & >Hrv) Hφ".
iDestruct (map_of_regs_3 with "HPC Hr1 Hrv") as "[Hmap (%&%&%)]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
destruct Hspec as [| | * Hfail].
{ (* Success with WCap (contradiction) *)
simplify_map_eq. }
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_3 with "Hmap") as "(?&?&?)"; eauto; iFrame. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z_sr Ep pc_p pc_b pc_e pc_a pc_a' w r1 p b e a z :
decodeInstrW w = Restrict r1 (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
SealPermFlowsTo (decodeSealPerms z) p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WSealRange p b e a }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ r1 ↦ᵣ WSealRange (decodeSealPerms z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hr1) Hφ".
iDestruct (map_of_regs_2 with "HPC Hr1") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
End cap_lang_rules.
From iris.program_logic Require Export weakestpre ectx_lifting.
From iris.proofmode Require Import proofmode.
From iris.algebra Require Import frac.
From cap_machine Require Export rules_base.
Section cap_lang_rules.
Context `{memG Σ, regG Σ}.
Context `{MachineParameters}.
Implicit Types P Q : iProp Σ.
Implicit Types σ : ExecConf.
Implicit Types c : cap_lang.expr.
Implicit Types r : RegName.
Implicit Types v : cap_lang.val.
Implicit Types w : Word.
Implicit Types reg : gmap RegName Word.
Implicit Types ms : gmap Addr Word.
Inductive Restrict_failure (regs: Reg) (dst: RegName) (src: Z + RegName) :=
| Restrict_fail_src_nonz:
z_of_argument regs src = None →
Restrict_failure regs dst src
| Restrict_fail_allowed w:
regs !! dst = Some w →
is_mutable_range w = false →
Restrict_failure regs dst src
| Restrict_fail_invalid_perm_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E →
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = false →
Restrict_failure regs dst src
| Restrict_fail_PC_overflow_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E →
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = true →
incrementPC (<[ dst := WCap (decodePerm n) b e a ]> regs) = None →
Restrict_failure regs dst src
| Restrict_fail_invalid_perm_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = false →
Restrict_failure regs dst src
| Restrict_fail_PC_overflow_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = true →
incrementPC (<[ dst := WSealRange (decodeSealPerms n) b e a ]> regs) = None →
Restrict_failure regs dst src.
Inductive Restrict_spec (regs: Reg) (dst: RegName) (src: Z + RegName) (regs': Reg): cap_lang.val -> Prop :=
| Restrict_spec_success_cap p b e a n:
regs !! dst = Some (WCap p b e a) →
p ≠ E ->
z_of_argument regs src = Some n →
PermFlowsTo (decodePerm n) p = true →
incrementPC (<[ dst := WCap (decodePerm n) b e a ]> regs) = Some regs' →
Restrict_spec regs dst src regs' NextIV
| Restrict_spec_success_sr p b e a n:
regs !! dst = Some (WSealRange p b e a) →
z_of_argument regs src = Some n →
SealPermFlowsTo (decodeSealPerms n) p = true →
incrementPC (<[ dst := WSealRange (decodeSealPerms n) b e a ]> regs) = Some regs' →
Restrict_spec regs dst src regs' NextIV
| Restrict_spec_failure:
Restrict_failure regs dst src →
Restrict_spec regs dst src regs' FailedV.
Lemma wp_Restrict Ep pc_p pc_b pc_e pc_a w dst src regs :
decodeInstrW w = Restrict dst src ->
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
regs !! PC = Some (WCap pc_p pc_b pc_e pc_a) →
regs_of (Restrict dst src) ⊆ dom regs →
{{{ ▷ pc_a ↦ₐ w ∗
▷ [∗ map] k↦y ∈ regs, k ↦ᵣ y }}}
Instr Executable @ Ep
{{{ regs' retv, RET retv;
⌜ Restrict_spec regs dst src regs' retv ⌝ ∗
pc_a ↦ₐ w ∗
[∗ map] k↦y ∈ regs', k ↦ᵣ y }}}.
Proof.
iIntros (Hinstr Hvpc HPC Dregs φ) "(>Hpc_a & >Hmap) Hφ".
iApply wp_lift_atomic_base_step_no_fork; auto.
iIntros (σ1 ns l1 l2 nt) "Hσ1 /=". destruct σ1; simpl.
iDestruct "Hσ1" as "[Hr Hm]".
iDestruct (gen_heap_valid_inclSepM with "Hr Hmap") as %Hregs.
have ? := lookup_weaken _ _ _ _ HPC Hregs.
iDestruct (@gen_heap_valid with "Hm Hpc_a") as %Hpc_a; auto.
iModIntro. iSplitR. by iPureIntro; apply normal_always_base_reducible.
iNext. iIntros (e2 σ2 efs Hpstep).
apply prim_step_exec_inv in Hpstep as (-> & -> & (c & -> & Hstep)).
iIntros "_".
iSplitR; auto. eapply step_exec_inv in Hstep; eauto.
specialize (indom_regs_incl _ _ _ Dregs Hregs) as Hri.
unfold regs_of in Hri, Dregs.
destruct (Hri dst) as [wdst [H'dst Hdst]]. by set_solver+.
rewrite /exec /= Hdst /= in Hstep.
destruct (z_of_argument regs src) as [wsrc|] eqn:Hwsrc;
pose proof Hwsrc as H'wsrc; cycle 1.
{ (* Failure: argument is not a constant (z_of_argument regs arg = None) *)
unfold z_of_argument in Hwsrc, Hstep. destruct src as [| r0]; [ congruence |].
odestruct (Hri r0) as [r0v [Hr'0 Hr0]].
{ unfold regs_of_argument. set_solver+. }
rewrite Hr0 Hr'0 in Hwsrc Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->).
{ destruct_word r0v; cbn in Hstep; try congruence; by simplify_pair_eq. }
iFailWP "Hφ" Restrict_fail_src_nonz. }
apply (z_of_arg_mono _ r) in Hwsrc; auto. rewrite Hwsrc in Hstep; simpl in Hstep.
destruct (is_mutable_range wdst) eqn:Hwdst.
2: { (* Failure: wdst is not of the right type *)
unfold is_mutable_range in Hwdst.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->).
{ destruct wdst as [ | [p b e a | ] | ]; try by inversion Hwdst.
all: try by simplify_pair_eq.
destruct p; try congruence.
simplify_pair_eq; auto. }
iFailWP "Hφ" Restrict_fail_allowed. }
(* Now the proof splits depending on the type of value in wdst *)
destruct wdst as [ | [p b e a | p b e a] | ].
1,4: inversion Hwdst.
(* First, the case where r1v is a capability *)
+ destruct (perm_eq_dec p E); [ subst p |].
{ rewrite /is_mutable_range in Hwdst; congruence. }
destruct (PermFlowsTo (decodePerm wsrc) p) eqn:Hflows; cycle 1.
{ destruct p; try congruence; inv Hstep ; iFailWP "Hφ" Restrict_fail_invalid_perm_cap. }
rewrite /update_reg /= in Hstep.
destruct (incrementPC (<[ dst := WCap (decodePerm wsrc) b e a ]> regs)) eqn:Hregs';
pose proof Hregs' as H'regs'; cycle 1.
{
assert (incrementPC (<[ dst := WCap( decodePerm wsrc) b e a ]> r) = None) as HH.
{ eapply incrementPC_overflow_mono; first eapply Hregs'.
by rewrite lookup_insert_is_Some'; eauto.
by apply insert_mono; eauto. }
apply (incrementPC_fail_updatePC _ m) in HH. rewrite HH in Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->)
by (destruct p; inversion Hstep; auto).
iFailWP "Hφ" Restrict_fail_PC_overflow_cap. }
eapply (incrementPC_success_updatePC _ m) in Hregs'
as (p' & g' & b' & e' & a'' & a_pc' & HPC'' & HuPC & ->).
eapply updatePC_success_incl with (m':=m) in HuPC. 2: by eapply insert_mono; eauto. rewrite HuPC in Hstep.
eassert ((c, σ2) = (NextI, _)) as HH.
{ destruct p; cbn in Hstep; eauto. congruence. }
simplify_pair_eq.
iFrame.
iMod ((gen_heap_update_inSepM _ _ dst) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iMod ((gen_heap_update_inSepM _ _ PC) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iFrame. iApply "Hφ". iFrame. iPureIntro. econstructor; eauto.
(* Now, the case where wsrc is a sealrange *)
+ destruct (SealPermFlowsTo (decodeSealPerms wsrc) p) eqn:Hflows; cycle 1.
{ destruct p; try congruence; inv Hstep ; iFailWP "Hφ" Restrict_fail_invalid_perm_sr. }
rewrite /update_reg /= in Hstep.
destruct (incrementPC (<[ dst := WSealRange (decodeSealPerms wsrc) b e a ]> regs)) eqn:Hregs';
pose proof Hregs' as H'regs'; cycle 1.
{
assert (incrementPC (<[ dst := WSealRange (decodeSealPerms wsrc) b e a ]> r) = None) as HH.
{ eapply incrementPC_overflow_mono; first eapply Hregs'.
by rewrite lookup_insert_is_Some'; eauto.
by apply insert_mono; eauto. }
apply (incrementPC_fail_updatePC _ m) in HH. rewrite HH in Hstep.
assert (c = Failed ∧ σ2 = (r, m)) as (-> & ->)
by (destruct p; inversion Hstep; auto).
iFailWP "Hφ" Restrict_fail_PC_overflow_sr. }
eapply (incrementPC_success_updatePC _ m) in Hregs'
as (p' & g' & b' & e' & a'' & a_pc' & HPC'' & HuPC & ->).
eapply updatePC_success_incl with (m':=m) in HuPC. 2: by eapply insert_mono; eauto. rewrite HuPC in Hstep.
eassert ((c, σ2) = (NextI, _)) as HH.
{ destruct p; cbn in Hstep; eauto. }
simplify_pair_eq.
iFrame.
iMod ((gen_heap_update_inSepM _ _ dst) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iMod ((gen_heap_update_inSepM _ _ PC) with "Hr Hmap") as "[Hr Hmap]"; eauto.
iFrame. iApply "Hφ". iFrame. iPureIntro. econstructor 2; eauto.
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_reg_PC Ep pc_p pc_b pc_e pc_a pc_a' w rv z:
decodeInstrW w = Restrict PC (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) pc_p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap (decodePerm z) pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hrv) Hφ".
iDestruct (map_of_regs_2 with "HPC Hrv") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite !insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame.
}
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct pc_p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_reg Ep pc_p pc_b pc_e pc_a pc_a' w r1 rv p b e a z :
decodeInstrW w = Restrict r1 (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) p = true →
p ≠ E →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WCap p b e a
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z
∗ r1 ↦ᵣ WCap (decodePerm z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows Hnp ϕ) "(>HPC & >Hpc_a & >Hr1 & >Hrv) Hφ".
iDestruct (map_of_regs_3 with "HPC Hr1 Hrv") as "[Hmap (%&%&%)]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_3 with "Hmap") as "(?&?&?)"; eauto; iFrame. }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z_PC Ep pc_p pc_b pc_e pc_a pc_a' w z :
decodeInstrW w = Restrict PC (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) pc_p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap (decodePerm z) pc_b pc_e pc_a'
∗ pc_a ↦ₐ w }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a) Hφ".
iDestruct (map_of_regs_1 with "HPC") as "Hmap".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)".
iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [ | | * Hfail ].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite !insert_insert.
iApply (regs_of_map_1 with "Hmap"). }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto.
destruct pc_p; congruence.
congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z Ep pc_p pc_b pc_e pc_a pc_a' w r1 p b e a z :
decodeInstrW w = Restrict r1 (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
PermFlowsTo (decodePerm z) p = true →
p ≠ E →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WCap p b e a }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ r1 ↦ᵣ WCap (decodePerm z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows HpE ϕ) "(>HPC & >Hpc_a & >Hr1) Hφ".
iDestruct (map_of_regs_2 with "HPC Hr1") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame. }
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
destruct p; congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
(* Similar rules in case we have a SealRange instead of a capability, where some cases are impossible, because a SealRange is not a valid PC *)
Lemma wp_restrict_success_reg_sr Ep pc_p pc_b pc_e pc_a pc_a' w r1 rv p b e a z :
decodeInstrW w = Restrict r1 (inr rv) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
SealPermFlowsTo (decodeSealPerms z) p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WSealRange p b e a
∗ ▷ rv ↦ᵣ WInt z }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ rv ↦ᵣ WInt z
∗ r1 ↦ᵣ WSealRange (decodeSealPerms z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hr1 & >Hrv) Hφ".
iDestruct (map_of_regs_3 with "HPC Hr1 Hrv") as "[Hmap (%&%&%)]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
destruct Hspec as [| | * Hfail].
{ (* Success with WCap (contradiction) *)
simplify_map_eq. }
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_3 with "Hmap") as "(?&?&?)"; eauto; iFrame. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
Lemma wp_restrict_success_z_sr Ep pc_p pc_b pc_e pc_a pc_a' w r1 p b e a z :
decodeInstrW w = Restrict r1 (inl z) →
isCorrectPC (WCap pc_p pc_b pc_e pc_a) →
(pc_a + 1)%a = Some pc_a' →
SealPermFlowsTo (decodeSealPerms z) p = true →
{{{ ▷ PC ↦ᵣ WCap pc_p pc_b pc_e pc_a
∗ ▷ pc_a ↦ₐ w
∗ ▷ r1 ↦ᵣ WSealRange p b e a }}}
Instr Executable @ Ep
{{{ RET NextIV;
PC ↦ᵣ WCap pc_p pc_b pc_e pc_a'
∗ pc_a ↦ₐ w
∗ r1 ↦ᵣ WSealRange (decodeSealPerms z) b e a }}}.
Proof.
iIntros (Hinstr Hvpc Hpca' Hflows ϕ) "(>HPC & >Hpc_a & >Hr1) Hφ".
iDestruct (map_of_regs_2 with "HPC Hr1") as "[Hmap %]".
iApply (wp_Restrict with "[$Hmap Hpc_a]"); eauto; simplify_map_eq; eauto.
by unfold regs_of; rewrite !dom_insert; set_solver+.
iNext. iIntros (regs' retv) "(#Hspec & Hpc_a & Hmap)". iDestruct "Hspec" as %Hspec.
assert (pc_p ≠ E).
{ intros ->. inversion Hvpc; subst. naive_solver. }
destruct Hspec as [| | * Hfail].
{ (* Success with WSealRange (contradiction) *)
simplify_map_eq. }
{ (* Success *)
iApply "Hφ". iFrame. incrementPC_inv; simplify_map_eq.
rewrite (insert_commute _ PC r1) // insert_insert
(insert_commute _ PC r1) // insert_insert.
iDestruct (regs_of_map_2 with "Hmap") as "(?&?)"; eauto; iFrame. }
{ (* Failure (contradiction) *)
destruct Hfail; simplify_map_eq; eauto; try congruence.
incrementPC_inv; simplify_map_eq; eauto. congruence. }
Unshelve. Fail idtac. Admitted.
End cap_lang_rules.