1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/errno.h>
3 #include <linux/linkage.h>
4 #include <asm/asm-offsets.h>
5 #include <asm/assembler.h>
6 #include <asm/smp.h>
7
8 .text
9 /*
10 * Implementation of MPIDR_EL1 hash algorithm through shifting
11 * and OR'ing.
12 *
13 * @dst: register containing hash result
14 * @rs0: register containing affinity level 0 bit shift
15 * @rs1: register containing affinity level 1 bit shift
16 * @rs2: register containing affinity level 2 bit shift
17 * @rs3: register containing affinity level 3 bit shift
18 * @mpidr: register containing MPIDR_EL1 value
19 * @mask: register containing MPIDR mask
20 *
21 * Pseudo C-code:
22 *
23 *u32 dst;
24 *
25 *compute_mpidr_hash(u32 rs0, u32 rs1, u32 rs2, u32 rs3, u64 mpidr, u64 mask) {
26 * u32 aff0, aff1, aff2, aff3;
27 * u64 mpidr_masked = mpidr & mask;
28 * aff0 = mpidr_masked & 0xff;
29 * aff1 = mpidr_masked & 0xff00;
30 * aff2 = mpidr_masked & 0xff0000;
31 * aff3 = mpidr_masked & 0xff00000000;
32 * dst = (aff0 >> rs0 | aff1 >> rs1 | aff2 >> rs2 | aff3 >> rs3);
33 *}
34 * Input registers: rs0, rs1, rs2, rs3, mpidr, mask
35 * Output register: dst
36 * Note: input and output registers must be disjoint register sets
37 (eg: a macro instance with mpidr = x1 and dst = x1 is invalid)
38 */
39 .macro compute_mpidr_hash dst, rs0, rs1, rs2, rs3, mpidr, mask
40 and \mpidr, \mpidr, \mask // mask out MPIDR bits
41 and \dst, \mpidr, #0xff // mask=aff0
42 lsr \dst ,\dst, \rs0 // dst=aff0>>rs0
43 and \mask, \mpidr, #0xff00 // mask = aff1
44 lsr \mask ,\mask, \rs1
45 orr \dst, \dst, \mask // dst|=(aff1>>rs1)
46 and \mask, \mpidr, #0xff0000 // mask = aff2
47 lsr \mask ,\mask, \rs2
48 orr \dst, \dst, \mask // dst|=(aff2>>rs2)
49 and \mask, \mpidr, #0xff00000000 // mask = aff3
50 lsr \mask ,\mask, \rs3
51 orr \dst, \dst, \mask // dst|=(aff3>>rs3)
52 .endm
53 /*
54 * Save CPU state in the provided sleep_stack_data area, and publish its
55 * location for cpu_resume()'s use in sleep_save_stash.
56 *
57 * cpu_resume() will restore this saved state, and return. Because the
58 * link-register is saved and restored, it will appear to return from this
59 * function. So that the caller can tell the suspend/resume paths apart,
60 * __cpu_suspend_enter() will always return a non-zero value, whereas the
61 * path through cpu_resume() will return 0.
62 *
63 * x0 = struct sleep_stack_data area
64 */
65 SYM_FUNC_START(__cpu_suspend_enter)
66 stp x29, lr, [x0, #SLEEP_STACK_DATA_CALLEE_REGS]
67 stp x19, x20, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+16]
68 stp x21, x22, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+32]
69 stp x23, x24, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+48]
70 stp x25, x26, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+64]
71 stp x27, x28, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+80]
72
73 /* save the sp in cpu_suspend_ctx */
74 mov x2, sp
75 str x2, [x0, #SLEEP_STACK_DATA_SYSTEM_REGS + CPU_CTX_SP]
76
77 /* find the mpidr_hash */
78 ldr_l x1, sleep_save_stash
79 mrs x7, mpidr_el1
80 adr_l x9, mpidr_hash
81 ldr x10, [x9, #MPIDR_HASH_MASK]
82 /*
83 * Following code relies on the struct mpidr_hash
84 * members size.
85 */
86 ldp w3, w4, [x9, #MPIDR_HASH_SHIFTS]
87 ldp w5, w6, [x9, #(MPIDR_HASH_SHIFTS + 8)]
88 compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10
89 add x1, x1, x8, lsl #3
90
91 str x0, [x1]
92 add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
93 stp x29, lr, [sp, #-16]!
94 bl cpu_do_suspend
95 ldp x29, lr, [sp], #16
96 mov x0, #1
97 ret
98 SYM_FUNC_END(__cpu_suspend_enter)
99
100 .pushsection ".idmap.text", "a"
101 SYM_CODE_START(cpu_resume)
102 mov x0, xzr
103 bl init_kernel_el
104 mov x19, x0 // preserve boot mode
105 bl __cpu_setup
106 /* enable the MMU early - so we can access sleep_save_stash by va */
107 adrp x1, swapper_pg_dir
108 adrp x2, idmap_pg_dir
109 bl __enable_mmu
110 ldr x8, =_cpu_resume
111 br x8
112 SYM_CODE_END(cpu_resume)
113 .ltorg
114 .popsection
115
116 SYM_FUNC_START(_cpu_resume)
117 mov x0, x19
118 bl finalise_el2
119
120 mrs x1, mpidr_el1
121 adr_l x8, mpidr_hash // x8 = struct mpidr_hash virt address
122
123 /* retrieve mpidr_hash members to compute the hash */
124 ldr x2, [x8, #MPIDR_HASH_MASK]
125 ldp w3, w4, [x8, #MPIDR_HASH_SHIFTS]
126 ldp w5, w6, [x8, #(MPIDR_HASH_SHIFTS + 8)]
127 compute_mpidr_hash x7, x3, x4, x5, x6, x1, x2
128
129 /* x7 contains hash index, let's use it to grab context pointer */
130 ldr_l x0, sleep_save_stash
131 ldr x0, [x0, x7, lsl #3]
132 add x29, x0, #SLEEP_STACK_DATA_CALLEE_REGS
133 add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS
134 /* load sp from context */
135 ldr x2, [x0, #CPU_CTX_SP]
136 mov sp, x2
137 /*
138 * cpu_do_resume expects x0 to contain context address pointer
139 */
140 bl cpu_do_resume
141
142 #if defined(CONFIG_KASAN) && defined(CONFIG_KASAN_STACK)
143 mov x0, sp
144 bl kasan_unpoison_task_stack_below
145 #endif
146
147 ldp x19, x20, [x29, #16]
148 ldp x21, x22, [x29, #32]
149 ldp x23, x24, [x29, #48]
150 ldp x25, x26, [x29, #64]
151 ldp x27, x28, [x29, #80]
152 ldp x29, lr, [x29]
153 mov x0, #0
154 ret
155 SYM_FUNC_END(_cpu_resume)
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