u-boot.git/lib/efi_loader/efi_variable_tee.c, branch v2021.04

efi_loader: Avoid emitting efi_var_buf to .GOT

2021-01-20T07:17:17+00:00

Atish reports that on RISC-V, accessing the EFI variables causes
a kernel panic. An objdump of the file verifies that, since the
global pointer for efi_var_buf ends up in .GOT section which is
not mapped in virtual address space for Linux.



0000000000000084 :
  84:   715d                    addi    sp,sp,-80

* objdump -dr
0000000000000086 <.LCFI2>:
  86:   e0a2                    sd  s0,64(sp)
  88:   fc26                    sd  s1,56(sp)
  8a:   e486                    sd  ra,72(sp)
  8c:   f84a                    sd  s2,48(sp)
  8e:   f44e                    sd  s3,40(sp)
  90:   f052                    sd  s4,32(sp)
  92:   ec56                    sd  s5,24(sp)
  94:   00000497            auipc   s1,0x0
            94: R_RISCV_GOT_HI20    efi_var_buf
  98:   0004b483            ld  s1,0(s1) # 94 <.LCFI2+0xe>
            98: R_RISCV_PCREL_LO12_I    .L0
            98: R_RISCV_RELAX   *ABS*

* objdump -t
0000000000000084 g     F .text.efi_runtime  00000000000000b8 efi_var_mem_find

With the patch applied:

* objdump -dr
0000000000000086 <.LCFI2>:
  86:   e0a2                    sd  s0,64(sp)
  88:   fc26                    sd  s1,56(sp)
  8a:   e486                    sd  ra,72(sp)
  8c:   f84a                    sd  s2,48(sp)
  8e:   f44e                    sd  s3,40(sp)
  90:   f052                    sd  s4,32(sp)
  92:   ec56                    sd  s5,24(sp)
  94:   00000497            auipc   s1,0x0
            94: R_RISCV_PCREL_HI20  .LANCHOR0
            94: R_RISCV_RELAX   *ABS*
  98:   00048493            mv  s1,s1
            98: R_RISCV_PCREL_LO12_I    .L0
            98: R_RISCV_RELAX   *ABS*

* objdump -t
0000000000000008 l     O .data.efi_runtime  0000000000000008 efi_var_buf

On arm64 this works, because there's no .GOT entries for this
and everything is converted to relative references.

* objdump -dr (identical pre-post patch, only the new function shows up)
00000000000000b4 :
  b4:   aa0003ee    mov x14, x0
  b8:   9000000a    adrp    x10, 0 
            b8: R_AARCH64_ADR_PREL_PG_HI21  .data.efi_runtime
  bc:   91000140    add x0, x10, #0x0
            bc: R_AARCH64_ADD_ABS_LO12_NC   .data.efi_runtime
  c0:   aa0103ed    mov x13, x1
  c4:   79400021    ldrh    w1, [x1]
  c8:   aa0203eb    mov x11, x2
  cc:   f9400400    ldr x0, [x0, #8]
  d0:   b940100c    ldr w12, [x0, #16]
  d4:   8b0c000c    add x12, x0, x12

So let's switch efi_var_buf to static and create a helper function for
anyone that needs to update it.

Fixes: e01aed47d6a0 ("efi_loader: Enable run-time variable support for tee based variables")
Reported-by: Atish Patra 
Tested-by: Atish Patra 
Signed-off-by: Ilias Apalodimas 
Reviewed-by: Heinrich Schuchardt

efi_loader: Extra checks while opening an OPTEE session

2020-12-26T11:47:46+00:00

When opening an OP-TEE session we need to check the internal return
value of OP-TEE call arguments as well the return code of the
function itself.
The code was also ignoring to close the OP-TEE session in case the
shared memory registration failed.

Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
Signed-off-by: Ilias Apalodimas 
Signed-off-by: Heinrich Schuchardt

efi_loader: Enable run-time variable support for tee based variables

2020-08-01T09:57:41+00:00

We recently added functions for storing/restoring variables
from a file to a memory backed buffer marked as __efi_runtime_data
commit f1f990a8c958 ("efi_loader: memory buffer for variables")
commit 5f7dcf079de8 ("efi_loader: UEFI variable persistence")

Using the same idea we now can support GetVariable() and GetNextVariable()
on the OP-TEE based variables as well.

So let's re-arrange the code a bit and move the commmon code for
accessing variables out of efi_variable.c. Create common functions for
reading variables from memory that both implementations can use on
run-time. Then just use those functions in the run-time variants of the
OP-TEE based EFI variable implementation and initialize the memory
buffer on ExitBootServices()

Signed-off-by: Ilias Apalodimas 
Reviewed-by: Heinrich Schuchardt

efi_loader: Trim output buffer size correctly for tee variables

2020-08-01T09:57:41+00:00

The current code does not trim the output buffer correctly.
In fact it doesn't trim the buffer at all, since it calculates a wrong
value for it, which isn't even applied.
So let's remove the unused temporary size variable and trim the buffer
correctly.
Since we are editing efi_get_next_variable_name_int(), fix an indentation
error along the way.

Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
Signed-off-by: Ilias Apalodimas 

Remove superfluous conversion to (u8 *) for memcpy argument.
Reviewed-by: Heinrich Schuchardt

efi_loader: Check for the native OP-TEE result on mm_communicate calls

2020-07-22T10:32:41+00:00

Currently we only check for the return value of tee_invoke_func().
Although OP-TEE and StMM will correctly set param[1].u.value.a and we'll
eventually return an error, the correct thing to do is check for the
OP_TEE return code as well.
So let's check for that and move tee_shm_free() and tee_close_session()
before exiting with an error to make sure we always clear the registered
memory.

Fixes: f042e47e8fb43 ("efi_loader: Implement EFI variable handling via OP-TEE")
Signed-off-by: Ilias Apalodimas 
Use EFI_DEVICE_ERROR for TEE communication problems.
Reviewed-by: Heinrich Schuchardt

efi_loader: Rename and correct values for ARM_SMC_MM_*

2020-07-22T10:32:41+00:00

Instead of adding the definition for the specific MM SVC used in
StandAloneMM we added the one used in the standard SMC calls.
So change the value from -4 to -5 to match the correct one defined in
EDK2 and rename them to avoid future confusion

Fixes 23a397d2e2fb: ("efi_loader: Add headers for EDK2 StandAloneMM communication")
Signed-off-by: Ilias Apalodimas 
Reviewed-by: Heinrich Schuchardt

efi_loader: update secure state

2020-07-16T10:37:02+00:00

Update the UEFI secure state when variable 'PK' is updated in the TEE
variables implementation.

Signed-off-by: Heinrich Schuchardt 
Reviewed-by: Ilias Apalodimas

efi_loader: display RO attribute with TEE-backed variables

2020-07-16T10:37:02+00:00

A previous commit adds support for displaying variables RO flag.
Let's add it on the TEE backed variable storage as well.

Signed-off-by: Ilias Apalodimas 
Reviewed-by: Heinrich Schuchardt

efi_loader: separate UEFI variable API from implemementation

2020-07-11T21:14:16+00:00

Separate the remaining UEFI variable API functions GetNextVariableName and
QueryVariableInfo() from internal functions implementing them.

Signed-off-by: Heinrich Schuchardt

efi_loader: prepare for read only OP-TEE variables

2020-07-11T21:14:16+00:00

We currently have two implementations of UEFI variables:

* variables provided via an OP-TEE module
* variables stored in the U-Boot environment

Read only variables are up to now only implemented in the U-Boot
environment implementation.

Provide a common interface for both implementations that allows handling
read-only variables.

As variable access is limited to very few source files put variable
related definitions into new include efi_variable.h instead of efi_loader.

Signed-off-by: Heinrich Schuchardt