diff options
Diffstat (limited to 'arch/arm64/kernel/sleep.S')
| -rw-r--r-- | arch/arm64/kernel/sleep.S | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S new file mode 100644 index 000000000..ba40d5775 --- /dev/null +++ b/arch/arm64/kernel/sleep.S @@ -0,0 +1,149 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#include <linux/errno.h> +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/assembler.h> +#include <asm/smp.h> + + .text +/* + * Implementation of MPIDR_EL1 hash algorithm through shifting + * and OR'ing. + * + * @dst: register containing hash result + * @rs0: register containing affinity level 0 bit shift + * @rs1: register containing affinity level 1 bit shift + * @rs2: register containing affinity level 2 bit shift + * @rs3: register containing affinity level 3 bit shift + * @mpidr: register containing MPIDR_EL1 value + * @mask: register containing MPIDR mask + * + * Pseudo C-code: + * + *u32 dst; + * + *compute_mpidr_hash(u32 rs0, u32 rs1, u32 rs2, u32 rs3, u64 mpidr, u64 mask) { + * u32 aff0, aff1, aff2, aff3; + * u64 mpidr_masked = mpidr & mask; + * aff0 = mpidr_masked & 0xff; + * aff1 = mpidr_masked & 0xff00; + * aff2 = mpidr_masked & 0xff0000; + * aff3 = mpidr_masked & 0xff00000000; + * dst = (aff0 >> rs0 | aff1 >> rs1 | aff2 >> rs2 | aff3 >> rs3); + *} + * Input registers: rs0, rs1, rs2, rs3, mpidr, mask + * Output register: dst + * Note: input and output registers must be disjoint register sets + (eg: a macro instance with mpidr = x1 and dst = x1 is invalid) + */ + .macro compute_mpidr_hash dst, rs0, rs1, rs2, rs3, mpidr, mask + and \mpidr, \mpidr, \mask // mask out MPIDR bits + and \dst, \mpidr, #0xff // mask=aff0 + lsr \dst ,\dst, \rs0 // dst=aff0>>rs0 + and \mask, \mpidr, #0xff00 // mask = aff1 + lsr \mask ,\mask, \rs1 + orr \dst, \dst, \mask // dst|=(aff1>>rs1) + and \mask, \mpidr, #0xff0000 // mask = aff2 + lsr \mask ,\mask, \rs2 + orr \dst, \dst, \mask // dst|=(aff2>>rs2) + and \mask, \mpidr, #0xff00000000 // mask = aff3 + lsr \mask ,\mask, \rs3 + orr \dst, \dst, \mask // dst|=(aff3>>rs3) + .endm +/* + * Save CPU state in the provided sleep_stack_data area, and publish its + * location for cpu_resume()'s use in sleep_save_stash. + * + * cpu_resume() will restore this saved state, and return. Because the + * link-register is saved and restored, it will appear to return from this + * function. So that the caller can tell the suspend/resume paths apart, + * __cpu_suspend_enter() will always return a non-zero value, whereas the + * path through cpu_resume() will return 0. + * + * x0 = struct sleep_stack_data area + */ +SYM_FUNC_START(__cpu_suspend_enter) + stp x29, lr, [x0, #SLEEP_STACK_DATA_CALLEE_REGS] + stp x19, x20, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+16] + stp x21, x22, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+32] + stp x23, x24, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+48] + stp x25, x26, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+64] + stp x27, x28, [x0,#SLEEP_STACK_DATA_CALLEE_REGS+80] + + /* save the sp in cpu_suspend_ctx */ + mov x2, sp + str x2, [x0, #SLEEP_STACK_DATA_SYSTEM_REGS + CPU_CTX_SP] + + /* find the mpidr_hash */ + ldr_l x1, sleep_save_stash + mrs x7, mpidr_el1 + adr_l x9, mpidr_hash + ldr x10, [x9, #MPIDR_HASH_MASK] + /* + * Following code relies on the struct mpidr_hash + * members size. + */ + ldp w3, w4, [x9, #MPIDR_HASH_SHIFTS] + ldp w5, w6, [x9, #(MPIDR_HASH_SHIFTS + 8)] + compute_mpidr_hash x8, x3, x4, x5, x6, x7, x10 + add x1, x1, x8, lsl #3 + + str x0, [x1] + add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS + stp x29, lr, [sp, #-16]! + bl cpu_do_suspend + ldp x29, lr, [sp], #16 + mov x0, #1 + ret +SYM_FUNC_END(__cpu_suspend_enter) + + .pushsection ".idmap.text", "awx" +SYM_CODE_START(cpu_resume) + bl el2_setup // if in EL2 drop to EL1 cleanly + bl __cpu_setup + /* enable the MMU early - so we can access sleep_save_stash by va */ + adrp x1, swapper_pg_dir + bl __enable_mmu + ldr x8, =_cpu_resume + br x8 +SYM_CODE_END(cpu_resume) + .ltorg + .popsection + +SYM_FUNC_START(_cpu_resume) + mrs x1, mpidr_el1 + adr_l x8, mpidr_hash // x8 = struct mpidr_hash virt address + + /* retrieve mpidr_hash members to compute the hash */ + ldr x2, [x8, #MPIDR_HASH_MASK] + ldp w3, w4, [x8, #MPIDR_HASH_SHIFTS] + ldp w5, w6, [x8, #(MPIDR_HASH_SHIFTS + 8)] + compute_mpidr_hash x7, x3, x4, x5, x6, x1, x2 + + /* x7 contains hash index, let's use it to grab context pointer */ + ldr_l x0, sleep_save_stash + ldr x0, [x0, x7, lsl #3] + add x29, x0, #SLEEP_STACK_DATA_CALLEE_REGS + add x0, x0, #SLEEP_STACK_DATA_SYSTEM_REGS + /* load sp from context */ + ldr x2, [x0, #CPU_CTX_SP] + mov sp, x2 + /* + * cpu_do_resume expects x0 to contain context address pointer + */ + bl cpu_do_resume + +#ifdef CONFIG_KASAN + mov x0, sp + bl kasan_unpoison_task_stack_below +#endif + + ldp x19, x20, [x29, #16] + ldp x21, x22, [x29, #32] + ldp x23, x24, [x29, #48] + ldp x25, x26, [x29, #64] + ldp x27, x28, [x29, #80] + ldp x29, lr, [x29] + mov x0, #0 + ret +SYM_FUNC_END(_cpu_resume) |