lh-l4v/spec/abstract/RISCV64/ArchDecode_A.thy

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(*
* Copyright 2020, Data61, CSIRO (ABN 41 687 119 230)
*
* SPDX-License-Identifier: GPL-2.0-only
*)
chapter "Decoding Architecture-specific System Calls"
theory ArchDecode_A
imports
Interrupt_A
InvocationLabels_A
"ExecSpec.InvocationLabels_H"
begin
context Arch begin global_naming RISCV64_A
section "Helper definitions"
definition check_vp_alignment :: "vmpage_size \<Rightarrow> machine_word \<Rightarrow> (unit,'z::state_ext) se_monad"
where
"check_vp_alignment sz vptr \<equiv>
unlessE (is_aligned vptr (pageBitsForSize sz)) $ throwError AlignmentError"
definition page_base :: "vspace_ref \<Rightarrow> vmpage_size \<Rightarrow> vspace_ref"
where
"page_base vaddr vmsize \<equiv> vaddr && ~~ mask (pageBitsForSize vmsize)"
section "Architecture-specific Decode Functions"
definition
arch_check_irq :: "data \<Rightarrow> (unit,'z::state_ext) se_monad"
where
"arch_check_irq irq \<equiv> whenE (irq > ucast maxIRQ \<or> irq = ucast irqInvalid) $
throwError (RangeError 1 (ucast maxIRQ))"
definition arch_decode_irq_control_invocation ::
"data \<Rightarrow> data list \<Rightarrow> cslot_ptr \<Rightarrow> cap list \<Rightarrow> (arch_irq_control_invocation,'z::state_ext) se_monad"
where
"arch_decode_irq_control_invocation label args src_slot cps \<equiv>
(if invocation_type label = ArchInvocationLabel RISCVIRQIssueIRQHandler
then if length args \<ge> 4 \<and> length cps \<ge> 1
then let irq_word = args ! 0;
trigger = args ! 1;
index = args ! 2;
depth = args ! 3;
cnode = cps ! 0;
irq = ucast irq_word
in doE
arch_check_irq irq_word;
irq_active \<leftarrow> liftE $ is_irq_active irq;
whenE irq_active $ throwError RevokeFirst;
dest_slot \<leftarrow> lookup_target_slot cnode (data_to_cptr index) (unat depth);
ensure_empty dest_slot;
returnOk $ RISCVIRQControlInvocation irq dest_slot src_slot (trigger \<noteq> 0)
odE
else throwError TruncatedMessage
else throwError IllegalOperation)"
definition attribs_from_word :: "machine_word \<Rightarrow> vm_attributes"
where
"attribs_from_word w \<equiv> if \<not> w!!0 then {Execute} else {}"
definition make_user_pte :: "vspace_ref \<Rightarrow> vm_attributes \<Rightarrow> vm_rights \<Rightarrow> pte"
where
"make_user_pte addr attr rights \<equiv>
if rights = {} \<and> attr = {}
then InvalidPTE
else PagePTE (ucast (addr >> pageBits)) (attr \<union> {User}) rights"
definition check_slot :: "obj_ref \<Rightarrow> (pte \<Rightarrow> bool) \<Rightarrow> (unit,'z::state_ext) se_monad"
where
"check_slot slot test = doE
pte \<leftarrow> liftE $ get_pte slot;
unlessE (test pte) $ throwError DeleteFirst
odE"
type_synonym 'z arch_decoder =
"data \<Rightarrow> data list \<Rightarrow> cslot_ptr \<Rightarrow> arch_cap \<Rightarrow> (cap \<times> cslot_ptr) list \<Rightarrow>
(arch_invocation,'z) se_monad"
definition decode_fr_inv_map :: "'z::state_ext arch_decoder"
where
"decode_fr_inv_map label args cte cap extra_caps \<equiv> case cap of
FrameCap p R pgsz dev mapped_address \<Rightarrow>
if length args > 2 \<and> length extra_caps > 0
then let
vaddr = args ! 0;
rights_mask = args ! 1;
attr = args ! 2;
vspace_cap = fst (extra_caps ! 0)
in doE
(pt, asid) \<leftarrow> case vspace_cap of
ArchObjectCap (PageTableCap pt (Some (asid, _))) \<Rightarrow> returnOk (pt, asid)
| _ \<Rightarrow> throwError $ InvalidCapability 1;
pt' \<leftarrow> lookup_error_on_failure False $ find_vspace_for_asid asid;
whenE (pt' \<noteq> pt) $ throwError $ InvalidCapability 1;
pg_bits \<leftarrow> returnOk $ pageBitsForSize pgsz;
vtop \<leftarrow> returnOk $ vaddr + mask (pageBitsForSize pgsz);
whenE (vtop \<ge> user_vtop) $ throwError $ InvalidArgument 0;
check_vp_alignment pgsz vaddr;
(level, slot) \<leftarrow> liftE $ gets_the $ pt_lookup_slot pt vaddr \<circ> ptes_of;
unlessE (pt_bits_left level = pg_bits) $
throwError $ FailedLookup False $ MissingCapability $ pt_bits_left level;
case mapped_address of
Some (asid', vaddr') \<Rightarrow> doE
whenE (asid' \<noteq> asid) (throwError $ InvalidCapability 1);
whenE (vaddr' \<noteq> vaddr) (throwError $ InvalidArgument 0);
check_slot slot (Not \<circ> is_PageTablePTE)
odE
| None \<Rightarrow> check_slot slot ((=) InvalidPTE);
vm_rights \<leftarrow> returnOk $ mask_vm_rights R (data_to_rights rights_mask);
attribs \<leftarrow> returnOk $ attribs_from_word attr;
pte \<leftarrow> returnOk $ make_user_pte (addrFromPPtr p) attribs vm_rights;
returnOk $ InvokePage $ PageMap (FrameCap p R pgsz dev (Some (asid,vaddr))) cte (pte,slot)
odE
else throwError TruncatedMessage
| _ \<Rightarrow> fail"
definition decode_frame_invocation :: "'z::state_ext arch_decoder"
where
"decode_frame_invocation label args cte cap extra_caps \<equiv>
if invocation_type label = ArchInvocationLabel RISCVPageMap
then decode_fr_inv_map label args cte cap extra_caps
else if invocation_type label = ArchInvocationLabel RISCVPageUnmap
then returnOk $ InvokePage $ PageUnmap cap cte
else if invocation_type label = ArchInvocationLabel RISCVPageGetAddress
then returnOk $ InvokePage $ PageGetAddr (acap_obj cap)
else throwError IllegalOperation"
definition decode_pt_inv_map :: "'z::state_ext arch_decoder"
where
"decode_pt_inv_map label args cte cap extra_caps \<equiv> case cap of
PageTableCap p mapped_address \<Rightarrow>
if length args > 1 \<and> length extra_caps > 0
then let
vaddr = args ! 0;
attr = args ! 1;
vspace_cap = fst (extra_caps ! 0)
in doE
whenE (mapped_address \<noteq> None) $ throwError $ InvalidCapability 0;
(pt, asid) \<leftarrow> case vspace_cap of
ArchObjectCap (PageTableCap pt (Some (asid,_))) \<Rightarrow> returnOk (pt, asid)
| _ \<Rightarrow> throwError $ InvalidCapability 1;
whenE (user_vtop \<le> vaddr) $ throwError $ InvalidArgument 0;
pt' \<leftarrow> lookup_error_on_failure False $ find_vspace_for_asid asid;
whenE (pt' \<noteq> pt) $ throwError $ InvalidCapability 1;
(level, slot) \<leftarrow> liftE $ gets_the $ pt_lookup_slot pt vaddr \<circ> ptes_of;
old_pte \<leftarrow> liftE $ get_pte slot;
whenE (pt_bits_left level = pageBits \<or> old_pte \<noteq> InvalidPTE) $ throwError DeleteFirst;
pte \<leftarrow> returnOk $ PageTablePTE (ucast (addrFromPPtr p >> pageBits)) {};
cap' <- returnOk $ PageTableCap p $ Some (asid, vaddr && ~~mask (pt_bits_left level));
returnOk $ InvokePageTable $ PageTableMap cap' cte pte slot
odE
else throwError TruncatedMessage
| _ \<Rightarrow> fail"
definition decode_page_table_invocation :: "'z::state_ext arch_decoder"
where
"decode_page_table_invocation label args cte cap extra_caps \<equiv>
if invocation_type label = ArchInvocationLabel RISCVPageTableMap
then decode_pt_inv_map label args cte cap extra_caps
else if invocation_type label = ArchInvocationLabel RISCVPageTableUnmap
then doE
final \<leftarrow> liftE $ is_final_cap (ArchObjectCap cap);
unlessE final $ throwError RevokeFirst;
case cap of
PageTableCap pt (Some (asid, _)) \<Rightarrow> doE
\<comment> \<open>cannot invoke unmap on top level page table\<close>
pt_opt \<leftarrow> liftE $ gets $ vspace_for_asid asid;
whenE (pt_opt = Some pt) $ throwError RevokeFirst
odE
| _ \<Rightarrow> returnOk ();
returnOk $ InvokePageTable $ PageTableUnmap cap cte
odE
else throwError IllegalOperation"
definition decode_asid_control_invocation :: "'z::state_ext arch_decoder"
where
"decode_asid_control_invocation label args cte cap extra_caps \<equiv>
if invocation_type label = ArchInvocationLabel RISCVASIDControlMakePool
then if length args > 1 \<and> length extra_caps > 1
then let
index = args ! 0;
depth = args ! 1;
(untyped, parent_slot) = extra_caps ! 0;
root = fst (extra_caps ! 1)
in doE
asid_table \<leftarrow> liftE $ gets (riscv_asid_table \<circ> arch_state);
free_set \<leftarrow> returnOk (- dom asid_table);
whenE (free_set = {}) $ throwError DeleteFirst;
free \<leftarrow> liftE $ select_ext (\<lambda>_. free_asid_select asid_table) free_set;
base \<leftarrow> returnOk (ucast free << asid_low_bits);
(p,n) \<leftarrow> case untyped of
UntypedCap False p n _ \<Rightarrow> returnOk (p,n)
| _ \<Rightarrow> throwError $ InvalidCapability 1;
frame \<leftarrow> if n = pageBits then doE
ensure_no_children parent_slot;
returnOk p
odE
else throwError $ InvalidCapability 1;
dest_slot \<leftarrow> lookup_target_slot root (to_bl index) (unat depth);
ensure_empty dest_slot;
returnOk $ InvokeASIDControl $ MakePool frame dest_slot parent_slot base
odE
else throwError TruncatedMessage
else throwError IllegalOperation"
definition decode_asid_pool_invocation :: "'z::state_ext arch_decoder"
where
"decode_asid_pool_invocation label args cte cap extra_caps \<equiv>
if invocation_type label = ArchInvocationLabel RISCVASIDPoolAssign
then if length extra_caps > 0
then let
(pt_cap, pt_cap_slot) = extra_caps ! 0;
p = acap_obj cap;
base = acap_asid_base cap
in case pt_cap of
ArchObjectCap (PageTableCap _ None) \<Rightarrow> doE
asid_table \<leftarrow> liftE $ gets (riscv_asid_table \<circ> arch_state);
pool_ptr \<leftarrow> returnOk (asid_table (asid_high_bits_of base));
whenE (pool_ptr = None) $ throwError $ FailedLookup False InvalidRoot;
whenE (p \<noteq> the pool_ptr) $ throwError $ InvalidCapability 0;
pool \<leftarrow> liftE $ get_asid_pool p;
free_set \<leftarrow> returnOk (- dom pool \<inter> {x. ucast x + base \<noteq> 0});
whenE (free_set = {}) $ throwError DeleteFirst;
offset \<leftarrow> liftE $ select_ext (\<lambda>_. free_asid_pool_select pool base) free_set;
returnOk $ InvokeASIDPool $ Assign (ucast offset + base) p pt_cap_slot
odE
| _ \<Rightarrow> throwError $ InvalidCapability 1
else throwError TruncatedMessage
else throwError IllegalOperation"
definition arch_decode_invocation ::
"data \<Rightarrow> data list \<Rightarrow> cap_ref \<Rightarrow> cslot_ptr \<Rightarrow> arch_cap \<Rightarrow> (cap \<times> cslot_ptr) list \<Rightarrow>
(arch_invocation,'z::state_ext) se_monad"
where
"arch_decode_invocation label args x_slot cte cap extra_caps \<equiv> case cap of
PageTableCap _ _ \<Rightarrow> decode_page_table_invocation label args cte cap extra_caps
| FrameCap _ _ _ _ _ \<Rightarrow> decode_frame_invocation label args cte cap extra_caps
| ASIDControlCap \<Rightarrow> decode_asid_control_invocation label args cte cap extra_caps
| ASIDPoolCap _ _ \<Rightarrow> decode_asid_pool_invocation label args cte cap extra_caps"
section "Interface Functions used in Decode"
definition arch_data_to_obj_type :: "nat \<Rightarrow> aobject_type option"
where
"arch_data_to_obj_type n \<equiv>
if n = 0 then Some HugePageObj
else if n = 1 then Some SmallPageObj
else if n = 2 then Some LargePageObj
else if n = 3 then Some PageTableObj
else None"
end
end