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The ACPI PRM address space handler calls efi_call_virt_pointer() to
execute PRM firmware code, but doing so is only permitted when the EFI
runtime environment is available. Otherwise, such calls are guaranteed
to result in a crash, and must therefore be avoided.
Given that the EFI runtime services may become unavailable after a crash
occurring in the firmware, we need to check this each time the PRM
address space handler is invoked. If the EFI runtime services were not
available at registration time to being with, don't install the address
space handler at all.
Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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handler_addr is a virtual address passed to efi_call_virt_pointer.
While x86 currently type cast it into the pointer in it's arch specific
arch_efi_call_virt() implementation, ARM64 is restrictive for right
reasons.
Convert the handler_addr type from u64 to void pointer.
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
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Handle memory allocation and memory remap failure in acpi_parse_prmt()
when system runs out of memory to avoid the potential NULL pointer
dereference errors.
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Just remove unnecessary blank lines, no other code changes
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Find and verify PRMT before parsing it, which eliminates a
warning on machines without PRMT:
[ 7.197173] ACPI: PRMT not present
Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: 5.14+ <stable@vger.kernel.org> # 5.14+
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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On the system PRMT table is not present, dmesg output:
$ dmesg | grep PRM
[ 1.532237] ACPI: PRMT not present
[ 1.532237] PRM: found 4294967277 modules
The result of acpi_table_parse_entries need to be checked and return
immediately if PRMT table is not present or no PRM module found.
Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The sparse tool complains as follows:
drivers/acpi/prmt.c:53:1: warning:
symbol 'prm_module_list' was not declared. Should it be static?
This symbol is not used outside of prmt.c, so marks it static.
Fixes: cefc7ca46235 ("ACPI: PRM: implement OperationRegion handler for the PlatformRtMechanism subtype")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Platform Runtime Mechanism (PRM) is a firmware interface that exposes
a set of binary executables that can either be called from the AML
interpreter or device drivers by bypassing the AML interpreter.
This change implements the AML interpreter path.
According to the specification [1], PRM services are listed in an
ACPI table called the PRMT. This patch parses module and handler
information listed in the PRMT and registers the PlatformRtMechanism
OpRegion handler before ACPI tables are loaded.
Each service is defined by a 16-byte GUID and called from writing a
26-byte ASL buffer containing the identifier to a FieldUnit object
defined inside a PlatformRtMechanism OperationRegion.
OperationRegion (PRMR, PlatformRtMechanism, 0, 26)
Field (PRMR, BufferAcc, NoLock, Preserve)
{
PRMF, 208 // Write to this field to invoke the OperationRegion Handler
}
The 26-byte ASL buffer is defined as the following:
Byte Offset Byte Length Description
=============================================================
0 1 PRM OperationRegion handler status
1 8 PRM service status
9 1 PRM command
10 16 PRM handler GUID
The ASL caller fills out a 26-byte buffer containing the PRM command
and the PRM handler GUID like so:
/* Local0 is the PRM data buffer */
Local0 = buffer (26){}
/* Create byte fields over the buffer */
CreateByteField (Local0, 0x9, CMD)
CreateField (Local0, 0x50, 0x80, GUID)
/* Fill in the command and data fields of the data buffer */
CMD = 0 // run command
GUID = ToUUID("xxxx-xx-xxx-xxxx")
/*
* Invoke PRM service with an ID that matches GUID and save the
* result.
*/
Local0 = (\_SB.PRMT.PRMF = Local0)
Byte offset 0 - 8 are written by the handler as a status passed back to AML
and used by ASL like so:
/* Create byte fields over the buffer */
CreateByteField (Local0, 0x0, PSTA)
CreateQWordField (Local0, 0x1, USTA)
In this ASL code, PSTA contains a status from the OperationRegion and
USTA contains a status from the PRM service.
The 26-byte buffer is recieved by acpi_platformrt_space_handler. This
handler will look at the command value and the handler guid and take
the approperiate actions.
Command value Action
=====================================================================
0 Run the PRM service indicated by the PRM handler
GUID (bytes 10-26)
1 Prevent PRM runtime updates from happening to the
service's parent module
2 Allow PRM updates from happening to the service's parent module
This patch enables command value 0.
Link: https://uefi.org/sites/default/files/resources/Platform%20Runtime%20Mechanism%20-%20with%20legal%20notice.pdf # [1]
Signed-off-by: Erik Kaneda <erik.kaneda@intel.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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