[PATCH 2/6] efi_loader: Add headers for EDK2 StandAloneMM communication
Ilias Apalodimas
ilias.apalodimas at linaro.org
Mon May 11 12:25:22 CEST 2020
On Sat, May 09, 2020 at 10:12:25AM +0200, Heinrich Schuchardt wrote:
> On 5/6/20 9:12 PM, Ilias Apalodimas wrote:
> > From: Sughosh Ganu <sughosh.ganu at linaro.org>
> >
> > In Arm devices OP-TEE has the ability to run StandAloneMM (from EDK2)
> > in a separate partition and handle UEFI variables.
> > A following patch introduces this functionality.
> >
> > Add the headers needed for OP-TEE <--> StandAloneMM communication
> >
> > Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > ---
> > include/mm_communication.h | 28 ++++++++++++++
> > include/mm_variable.h | 78 ++++++++++++++++++++++++++++++++++++++
> > 2 files changed, 106 insertions(+)
> > create mode 100644 include/mm_communication.h
> > create mode 100644 include/mm_variable.h
> >
> > diff --git a/include/mm_communication.h b/include/mm_communication.h
> > new file mode 100644
> > index 000000000000..fb4c91103400
> > --- /dev/null
> > +++ b/include/mm_communication.h
> > @@ -0,0 +1,28 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
>
> BSD-2-Clause-Patent is compatible with GPL-2. So relicensing as GPL
> should be ok.
>
> > +/*
> > + * Headers for EFI variable service via StandAloneMM, EDK2 application running
> > + * in OP-TEE
> > + *
> > + * Copyright (C) 2020 Linaro Ltd. <sughosh.ganu at linaro.org>
> > + * Copyright (C) 2020 Linaro Ltd. <ilias.apalodimas at linaro.org>
>
> EDK2, MdePkg/Include/Protocol/MmCommunication.h has:
> Copyright (c) 2017, Intel Corporation. All rights reserved.
>
> Why did you replace their copyright by yours?
> Who is the original copyright holder of the MM module?
Oops sorry will add the original Copyright as well.
>
> > + */
> > +
> > +#if !defined _MM_COMMUNICATION_H_
>
> I would use #ifndef here.
>
> > +#define _MM_COMMUNICATION_H_
> > +
> > +/* defined in EDK2 MmCommunication.h */
>
> Please, add a description of the structure, cf.
> https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#structure-union-and-enumeration-documentation
>
> > +struct mm_communicate_header {
> > + efi_guid_t header_guid;
> > + size_t message_len;
> > + u8 data[1];
>
> In C11 you can use data[].
>
Yes see below
> > +};
> > +
> > +#define MM_COMMUNICATE_HEADER_SIZE \
> > + (offsetof(struct mm_communicate_header, data))
>
> SMM_COMMUNICATE_HEADER_SIZE?
> Why not simply use data[] and sizeof(struct mm_communicate_header)
> instead of defining this constant.
>
Because it would make future porting easier. This is not exactly speed critical
code.
I'll change it to C11.
> > +
> > +#define MM_RET_SUCCESS 0
>
> Why don't you use the same names as in EDK2, e.g.
> ARM_SMC_MM_RET_SUCCESS?
>
> Please, add ARM_SMC_MM_RET_NOT_SUPPORTED.
Ok
Makes sense to keep the original naming.
>
> > +#define MM_RET_INVALID_PARAMS -2
> > +#define MM_RET_DENIED -3
> > +#define MM_RET_NO_MEMORY -4
> > +
> > +#endif /* _MM_COMMUNICATION_H_*/
> > diff --git a/include/mm_variable.h b/include/mm_variable.h
> > new file mode 100644
> > index 000000000000..f56c52597629
> > --- /dev/null
> > +++ b/include/mm_variable.h
> > @@ -0,0 +1,78 @@
> > +/* SPDX-License-Identifier: GPL-2.0+ */
> > +/*
> > + * Headers for EFI variable service via StandAloneMM, EDK2 application running
> > + * in OP-TEE
> > + *
> > + * Copyright (C) 2020 Linaro Ltd. <sughosh.ganu at linaro.org>
> > + * Copyright (C) 2020 Linaro Ltd. <ilias.apalodimas at linaro.org>
>
> If you copied this from SmmVariableCommon.h shouldn't you mention:
> Copyright (c) 2011 - 2019, Intel Corporation. All rights reserved.
>
Ok
> > + */
> > +
> > +#if !defined _MM_VARIABLE_H_
>
> #ifndef would be shorter.
>
Ok
> > +#define _MM_VARIABLE_H_
> > +
> > +#include <part_efi.h>
> > +
> > +/* defined in EDK2 SmmVariableCommon.h */
>
> Please, add a description of the structure, cf.
> https://www.kernel.org/doc/html/latest/doc-guide/kernel-doc.html#structure-union-and-enumeration-documentation
>
> > +struct mm_variable_communicate_header {
> > + efi_uintn_t function;
> > + efi_status_t ret_status;
> > + u8 data[1];
> > +};
> > +
> > +#define MM_VARIABLE_COMMUNICATE_SIZE \
> > + (offsetof(struct mm_variable_communicate_header, data))
>
> Why not the original name SMM_VARIABLE_COMMUNICATE_HEADER_SIZE?
Ok
>
> > +
> > +#define MM_VARIABLE_FUNCTION_GET_VARIABLE 1
>
> MdeModulePkg/Include/Guid/SmmVariableCommon.h uses
> SMM_VARIABLE_FUNCTION_GET_VARIABLE. Why invent a new name?
>
> > +
> > +#define MM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME 2
> > +
> > +#define MM_VARIABLE_FUNCTION_SET_VARIABLE 3
> > +
> > +#define MM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO 4
> > +
> > +#define MM_VARIABLE_FUNCTION_READY_TO_BOOT 5
> > +
> > +#define MM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE 6
> > +
> > +#define MM_VARIABLE_FUNCTION_GET_STATISTICS 7
> > +
> > +#define MM_VARIABLE_FUNCTION_LOCK_VARIABLE 8
> > +
> > +#define MM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_SET 9
> > +
> > +#define MM_VARIABLE_FUNCTION_VAR_CHECK_VARIABLE_PROPERTY_GET 10
> > +
> > +#define MM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE 11
>
> Values 12 - 14 are missing. I think we should provide all values.
>
Ok
> > +
>
> Missing structure description.
>
> > +struct mm_variable_access {
>
> smm_variable_access?
>
> > + efi_guid_t guid;
> > + efi_uintn_t data_size;
> > + efi_uintn_t name_size;
> > + u32 attr;
> > + u16 name[1];
>
> This name[1] was needed in old compilers. It is not needed anymore in
> C11. For a variable length structure component, please, use name[].
>
> > +};
> > +
> > +#define MM_VARIABLE_ACCESS_HEADER_SIZE \
> > + (offsetof(struct mm_variable_access, name))
>
> If you have name[] as component, you can use sizeof(struct
> smm_variable_access) instead of this define.
>
> > +
>
> Structure description missing.
>
> > +struct mm_variable_payload_size {
> > + efi_uintn_t size;
> > +};
>
> In EDK2 PayloadSize is simply UINTN.
>
> Isn't this structure superfluous? Can't we directly pass a type UINTN
> variable instead and get rid of a level of indirection?
This is defined as SMM_VARIABLE_COMMUNICATE_GET_PAYLOAD_SIZE which is what we
define here.
>
> > +
>
> Structure description missing.
>
> > +struct mm_variable_getnext {
> > + efi_guid_t guid;
> > + efi_uintn_t name_size;
> > + u16 name[1];
>
> name[]?
>
> > +};
> > +
> > +#define MM_VARIABLE_GET_NEXT_HEADER_SIZE \
> > + (offsetof(struct mm_variable_getnext, name))
> > +
>
> Structure description missing.
>
> You could think about merging the two include files into one.
Agreed
Regards
/Ilias
>
> Best regards
>
> Heinrich
>
> > +struct mm_variable_query_info {
> > + u64 max_variable_storage;
> > + u64 remaining_variable_storage;
> > + u64 max_variable_size;
> > + u32 attr;
> > +};
> > +
> > +#endif /* _MM_VARIABLE_H_ */
> >
>
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