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 */
 65SYM_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
 98SYM_FUNC_END(__cpu_suspend_enter)
 99
100	.pushsection ".idmap.text", "a"
101SYM_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
112SYM_CODE_END(cpu_resume)
113	.ltorg
114	.popsection
115
116SYM_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
155SYM_FUNC_END(_cpu_resume)