mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
47 lines
1.1 KiB
47 lines
1.1 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
|
/* |
|
* Copyright (C) 2018 Linaro Ltd <ard.biesheuvel@linaro.org> |
|
*/ |
|
|
|
#include <linux/linkage.h> |
|
|
|
SYM_FUNC_START(__efi_rt_asm_wrapper) |
|
stp x29, x30, [sp, #-32]! |
|
mov x29, sp |
|
|
|
/* |
|
* Register x18 is designated as the 'platform' register by the AAPCS, |
|
* which means firmware running at the same exception level as the OS |
|
* (such as UEFI) should never touch it. |
|
*/ |
|
stp x1, x18, [sp, #16] |
|
|
|
/* |
|
* We are lucky enough that no EFI runtime services take more than |
|
* 5 arguments, so all are passed in registers rather than via the |
|
* stack. |
|
*/ |
|
mov x8, x0 |
|
mov x0, x2 |
|
mov x1, x3 |
|
mov x2, x4 |
|
mov x3, x5 |
|
mov x4, x6 |
|
blr x8 |
|
|
|
ldp x1, x2, [sp, #16] |
|
cmp x2, x18 |
|
ldp x29, x30, [sp], #32 |
|
b.ne 0f |
|
ret |
|
0: |
|
/* |
|
* With CONFIG_SHADOW_CALL_STACK, the kernel uses x18 to store a |
|
* shadow stack pointer, which we need to restore before returning to |
|
* potentially instrumented code. This is safe because the wrapper is |
|
* called with preemption disabled and a separate shadow stack is used |
|
* for interrupts. |
|
*/ |
|
mov x18, x2 |
|
b efi_handle_corrupted_x18 // tail call |
|
SYM_FUNC_END(__efi_rt_asm_wrapper)
|
|
|