1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3 * Copyright (C) 2018 Linaro Ltd <ard.biesheuve
4 */
5
6 #include <linux/linkage.h>
7 #include <asm/assembler.h>
8
9 SYM_FUNC_START(__efi_rt_asm_wrapper)
10 stp x29, x30, [sp, #-112]!
11 mov x29, sp
12
13 /*
14 * Register x18 is designated as the '
15 * which means firmware running at the
16 * (such as UEFI) should never touch i
17 */
18 stp x1, x18, [sp, #16]
19
20 /*
21 * Preserve all callee saved registers
22 * value at the base of the EFI runtim
23 * synchronous exceptions occurring wh
24 * routines.
25 */
26 stp x19, x20, [sp, #32]
27 stp x21, x22, [sp, #48]
28 stp x23, x24, [sp, #64]
29 stp x25, x26, [sp, #80]
30 stp x27, x28, [sp, #96]
31
32 ldr_l x16, efi_rt_stack_top
33 mov sp, x16
34 stp x18, x29, [sp, #-16]!
35
36 /*
37 * We are lucky enough that no EFI run
38 * 5 arguments, so all are passed in r
39 * stack.
40 */
41 mov x8, x0
42 mov x0, x2
43 mov x1, x3
44 mov x2, x4
45 mov x3, x5
46 mov x4, x6
47 blr x8
48
49 mov x16, sp
50 mov sp, x29
51 str xzr, [x16, #8]
52
53 ldp x1, x2, [sp, #16]
54 cmp x2, x18
55 ldp x29, x30, [sp], #112
56 b.ne 0f
57 ret
58 0:
59 /*
60 * With CONFIG_SHADOW_CALL_STACK, the
61 * shadow stack pointer, which we need
62 * potentially instrumented code. This
63 * called with preemption disabled and
64 * for interrupts.
65 */
66 #ifdef CONFIG_SHADOW_CALL_STACK
67 ldr_l x18, efi_rt_stack_top
68 ldr x18, [x18, #-16]
69 #endif
70
71 b efi_handle_corrupted_x18
72 SYM_FUNC_END(__efi_rt_asm_wrapper)
73
74 SYM_CODE_START(__efi_rt_asm_recover)
75 mov sp, x30
76
77 ldr_l x16, efi_rt_stack_top
78 str xzr, [x16, #-8]
79
80 ldp x19, x20, [sp, #32]
81 ldp x21, x22, [sp, #48]
82 ldp x23, x24, [sp, #64]
83 ldp x25, x26, [sp, #80]
84 ldp x27, x28, [sp, #96]
85 ldp x29, x30, [sp], #112
86 ret
87 SYM_CODE_END(__efi_rt_asm_recover)
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