From: Maria Celeste Cesario <maria.celeste.cesario@xxxxxxxxxxx>
Add JSON file containing properties.
Add rst file containing explanation on how to update properties.json.
Add instruction to eclair_analysis/prepare.sh to parse the JSON file.
Signed-off-by: Maria Celeste Cesario <maria.celeste.cesario@xxxxxxxxxxx>
Signed-off-by: Simone Ballarin <simone.ballarin@xxxxxxxxxxx>
---
.../eclair_analysis/ECLAIR/analysis.ecl | 1 +
automation/eclair_analysis/prepare.sh | 2 +
docs/properties.json | 841 ++++++++++++++++++
docs/properties.rst | 58 ++
4 files changed, 902 insertions(+)
create mode 100644 docs/properties.json
create mode 100644 docs/properties.rst
diff --git a/automation/eclair_analysis/ECLAIR/analysis.ecl
b/automation/eclair_analysis/ECLAIR/analysis.ecl
index a604582da3..684c5b0b39 100644
--- a/automation/eclair_analysis/ECLAIR/analysis.ecl
+++ b/automation/eclair_analysis/ECLAIR/analysis.ecl
@@ -30,6 +30,7 @@ if(not(scheduled_analysis),
-eval_file=deviations.ecl
-eval_file=call_properties.ecl
-eval_file=tagging.ecl
+-eval_file=properties.ecl
-eval_file=concat(set,".ecl")
-doc="Hide reports in external code."
diff --git a/automation/eclair_analysis/prepare.sh
b/automation/eclair_analysis/prepare.sh
index fe9d16e48e..47b2a2f32a 100755
--- a/automation/eclair_analysis/prepare.sh
+++ b/automation/eclair_analysis/prepare.sh
@@ -43,4 +43,6 @@ fi
make -f "${script_dir}/Makefile.prepare" prepare
# Translate the /* SAF-n-safe */ comments into ECLAIR CBTs
scripts/xen-analysis.py --run-eclair --no-build --no-clean
+ # Translate function-properties.json into ECLAIR properties
+ python3 ${script_dir}/propertyparser.py
)
diff --git a/docs/properties.json b/docs/properties.json
new file mode 100644
index 0000000000..74058297b5
--- /dev/null
+++ b/docs/properties.json
@@ -0,0 +1,841 @@
+{
+ "version": "1.0",
+ "content": [
+ {
+ "type": "function",
+ "value": "^printk.*$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^debugtrace_printk.*$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^panic.*$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^domain_crash$",
+ "properties":{
+ "pointee_write": "2..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^(g?d|mm_)?printk$",
+ "properties":{
+ "pointee_write": "2..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^guest_bug_on_failed$",
+ "properties":{
+ "pointee_write": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^spin_lock_init_prof$",
+ "properties":{
+ "pointee_write": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^sched_test_func$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^dev_(info|warn)$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^PAGING_DEBUG$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^ACPI_(WARNING|ERROR|INFO)$",
+ "properties":{
+ "pointee_write": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^fdt_get_property_by_offset_.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^read_atomic_size.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^device_tree_get_reg.*$",
+ "properties":{
+ "pointee_write": "4..=always",
+ "pointee_read": "4..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^dt_get_range.*$",
+ "properties":{
+ "pointee_write": "3..=always",
+ "pointee_read": "3..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^parse_static_mem_prop.*$",
+ "properties":{
+ "pointee_write": "2..=always",
+ "pointee_read": "2..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_ttbr_and_gran_64bit.*$",
+ "properties":{
+ "pointee_write": "1..2=always",
+ "pointee_read": "1..2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^hvm_emulate_init_once.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^__vmread.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^hvm_pci_decode_addr.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^vpci_mmcfg_decode_addr.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^x86emul_decode.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^unmap_grant_ref.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^arm_smmu_cmdq_build_cmd.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^pci_size_mem_bar.*$",
+ "properties":{
+ "pointee_write": "4=always",
+ "pointee_read": "4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^_hvm_read_entry.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^hvm_map_guest_frame_rw.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^guest_cpuid.*$",
+ "properties":{
+ "pointee_write": "4=always",
+ "pointee_read": "4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^epte_get_entry_emt.*$",
+ "properties":{
+ "pointee_write": "5=always",
+ "pointee_read": "5=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^mcheck_mca_logout.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^set_field_in_reg_u32.*$",
+ "properties":{
+ "pointee_write": "5=always",
+ "pointee_read": "5=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^alloc_affinity_masks.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^xasprintf.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^find_non_smt.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^call_rcu.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^getdomaininfo.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^MAPPING_(INSERT|SEARCH)\\(.*$",
+ "properties":{
+ "pointee_write": "2..=always",
+ "pointee_read": "2..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^FormatDec.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^FormatHex.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^p2m_get_ioreq_server.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^elf_memset_unchecked.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^set_iommu_pte_present.*$",
+ "properties":{
+ "pointee_write": "7=always",
+ "pointee_read": "7=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^clear_iommu_pte_present.*$",
+ "properties":{
+ "pointee_write": "4=always",
+ "pointee_read": "4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^vcpu_runstate_get.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^va_start.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^sgi_target_init.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_hw_residencies.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^x86_cpu_policy_to_featureset.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^simple_strtou?ll?\\(.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^msi_compose_msg.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^print_tainted.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_hvm_registers.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^x86_insn_modrm.*$",
+ "properties":{
+ "pointee_write": "2..3=always",
+ "pointee_read": "2..3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^cpuid_count_leaf.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^rcu_lock_remote_domain_by_id.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^cpuid_count.*$",
+ "properties":{
+ "pointee_write": "3..=always",
+ "pointee_read": "3..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^.*efi_boot_mem_unused.*$",
+ "properties":{
+ "pointee_write": "1..=always",
+ "pointee_read": "1..=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^collect_time_info.*$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^setup_xstate_comp.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^map_domain_gfn.*$",
+ "properties":{
+ "pointee_read": "5=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^fdt_getprop.*$",
+ "properties":{
+ "pointee_read": "4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^fdt_get_name.*$",
+ "properties":{
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^fdt_get_property.*$",
+ "properties":{
+ "pointee_read": "4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^pci_get_host_bridge_segment.*$",
+ "properties":{
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^dt_get_property.*$",
+ "properties":{
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^dt_property_read_u32.*$",
+ "properties":{
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^dt_device_get_paddr.*$",
+ "properties":{
+ "pointee_read": "3..4=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_evtchn_dt_property.*$",
+ "properties":{
+ "pointee_write": "2..3=maybe",
+ "pointee_read": "2..3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^setup_chosen_node.*$",
+ "properties":{
+ "pointee_write": "2..3=maybe",
+ "pointee_read": "2..3=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^queue_remove_raw.*$",
+ "properties":{
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^memset$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^va_start$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^memcmp$",
+ "properties":{
+ "pointee_write": "1..2=never",
+ "taken": ""
+ }
+ },
+ {
+ "type": "macro",
+ "value": "^memcpy$",
+ "properties":{
+ "pointee_write": "1=always&&2..=never",
+ "pointee_read": "1=never&&2..=always",
+ "taken": ""
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_cpu_info.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^pdx_to_pfn.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^is_pci_passthrough_enabled.*$",
+ "properties":{
+ "attribute": "const"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_cycles.*$",
+ "properties":{
+ "attribute": "noeffect"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^msi_gflags.*$",
+ "properties":{
+ "attribute": "const"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^hvm_save_size.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^cpu_has.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^boot_cpu_has.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^get_cpu_info.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^put_pte_flags.*$",
+ "properties":{
+ "attribute": "const"
+ }
+ },
+ {
+ "type": "function",
+ "value": "^is_pv_cpu.*$",
+ "properties":{
+ "attribute": "pure"
+ }
+ },
+ {
+ "description": "Property inferred as a consequence of the semantics of
device_tree_get_reg",
+ "type": "function",
+ "value": "^acquire_static_memory_bank.*$",
+ "properties":{
+ "pointee_write": "4..=always",
+ "pointee_read": "4..=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "Property inferred as a consequence of the semantics of
dt_set_cell",
+ "type": "function",
+ "value": "^set_interrupt.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description":"Property inferred as a consequence of the semantics of
__p2m_get_mem_access",
+ "type": "function",
+ "value": "^p2m_get_mem_access.*$",
+ "properties":{
+ "pointee_write": "3=always",
+ "pointee_read": "3=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "This function has alternative definitions with props
{write=always,read=never} and {write=never,read=never}",
+ "type": "function",
+ "value": "^alloc_cpumask_var.*$",
+ "properties":{
+ "pointee_write": "1=maybe",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "Property inferred as a consequence of the semantics of
alloc_cpumask_var",
+ "type": "function",
+ "value": "^xenctl_bitmap_to_cpumask.*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "The call to bitmap_and causes the pointee of dstp to be
always written",
+ "type": "function",
+ "value": "^cpumask_(and|andnot|clear|copy|complement).*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "The call to bitmap_and causes the pointee of dstp to be
always written",
+ "type": "function",
+ "value": "^bitmap_(andnot|complement|fill).*$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "The .*copy_(to|from).* helpers all have a memcpy-like
expectation that the destination is a copy of the source. Furthermore, their uses do initialize the
involved variables as needed by futher uses in the caller.",
+ "type": "macro",
+ "value": "^(__)?(raw_)?copy_from_(paddr|guest|compat)(_offset)?$",
+ "properties":{
+ "pointee_write": "1=always",
+ "pointee_read": "1=never",
+ "taken": ""
+ }
+ },
+ {
+ "description":"The .*copy_(to|from).* helpers all have a memcpy-like
expectation that the destination is a copy of the source. Furthermore, their uses do initialize the
involved variables as needed by futher uses in the caller.",
+ "type": "macro",
+ "value": "^(__)?copy_to_(guest|compat)(_offset)?$",
+ "properties":{
+ "pointee_write": "2=always",
+ "pointee_read": "2=never",
+ "taken": ""
+ }
+ },
+ {
+ "description": "Functions generated by build_atomic_read cannot be
considered pure since the input pointer is volatile, but they do not produce any persistent side
effect.",
+ "type": "function",
+ "value": "^read_u(8|16|32|64|int)_atomic.*$",
+ "properties":{
+ "attribute": "noeffect"
+ }
+ },
+ {
+ "description": "Functions generated by TYPE_SAFE are const.",
+ "type": "function",
+ "value": "^(mfn|gfn|pfn)_x\\(.*$",
+ "properties":{
+ "attribute": "const"
+ }
+ },
+ {
+ "description": "Functions generated by TYPE_SAFE are const.",
+ "type": "function",
+ "value": "^_(mfn|gfn|pfn)\\(.*$",
+ "properties":{
+ "attribute": "const"
+ }
+ }
+ ]
+}
diff --git a/docs/properties.rst b/docs/properties.rst
new file mode 100644
index 0000000000..790f1ede1e
--- /dev/null
+++ b/docs/properties.rst
@@ -0,0 +1,58 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
+Properties list for Xen
+=======================
+
+Some functions and macros are found to have properties relevant to
+the Xen codebase. For this reason, the file docs/properties.json
+contains all the needed properties.
+
+Here is an example of the properties.json file::
+
+ {
+ "version": "1.0",
+ "content": [
+ {
+ "description": ""
+ "type": "function", // required
+ "value:": "^printk*.$", // required
+ "properties":{
+ "pointee_write": "1..2=never",
+ "pointee_read": "",
+ "taken": ""
+ "attribute": ""
+ }
+ }
+ ]
+ }
+
+Here is an explanation of the fields inside an object of the "content" array:
+
+ - description: a brief description of why the properties apply
+ - type: this is the kind of the element called: it may be either ``macro`` or
``function``
+ - value: must be a regex, starting with ^ and ending with $ and matching
function fully
+ qualified name or macro name.
+ - properties: a list of properties applied to said function.
+ Possible values are:
+
+ - pointee_write: indicate the write use for call arguments that correspond
to
+ parameters whose pointee types are non-const
+ - pointee_read: indicate the read use for call arguments that correspond to
+ parameters whose pointee types are non-const
+ - taken: indicates that the specified address arguments may be stored in
objects
+ that persist after the function has ceased to exist (excluding the
returned value);
+ address arguments not listed are never taken
+ - attribute: attributes a function may have. Possible values are pure,
const and noeffect.
+
+ pointee_read and pointee_write use a specific kind of argument, structured
as pointee_arg=rw:
+
+ - pointee_arg: argument index for callee. Index 0 refers to the return
value,
+ the indices of the arguments start from 1. It can be either a single
value or a range.
+ - rw: a value that's either always, maybe or never
+
+ - always: for pointee_read: argument pointee is expected to be fully
initialized at function enter,
+ for pointee_write: argument pointee is fully initialized at function
exit
+ - maybe: for pointee_read: argument pointee may be expected to be
initialized at function enter,
+ for pointee_write: argument pointee may be written by function body
+ - never: for pointee_read: argument pointee is not expected to be read
in the functions's body,
+ for pointee_write: argument pointee is never written by function body
