diff options
Diffstat (limited to 'arch/arm64/kernel/sleep.S')
| -rw-r--r-- | arch/arm64/kernel/sleep.S | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/arm64/kernel/sleep.S b/arch/arm64/kernel/sleep.S new file mode 100644 index 00000000000..b1925729c69 --- /dev/null +++ b/arch/arm64/kernel/sleep.S @@ -0,0 +1,184 @@ +#include <linux/errno.h> +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/assembler.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; + * aff2 = 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 for a suspend. This saves callee registers, and allocates + * space on the kernel stack to save the CPU specific registers + some + * other data for resume. + * + * x0 = suspend finisher argument + */ +ENTRY(__cpu_suspend) + stp x29, lr, [sp, #-96]! + stp x19, x20, [sp,#16] + stp x21, x22, [sp,#32] + stp x23, x24, [sp,#48] + stp x25, x26, [sp,#64] + stp x27, x28, [sp,#80] + mov x2, sp + sub sp, sp, #CPU_SUSPEND_SZ // allocate cpu_suspend_ctx + mov x1, sp + /* + * x1 now points to struct cpu_suspend_ctx allocated on the stack + */ + str x2, [x1, #CPU_CTX_SP] + ldr x2, =sleep_save_sp + ldr x2, [x2, #SLEEP_SAVE_SP_VIRT] +#ifdef CONFIG_SMP + mrs x7, mpidr_el1 + ldr 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 x2, x2, x8, lsl #3 +#endif + bl __cpu_suspend_finisher + /* + * Never gets here, unless suspend fails. + * Successful cpu_suspend should return from cpu_resume, returning + * through this code path is considered an error + * If the return value is set to 0 force x0 = -EOPNOTSUPP + * to make sure a proper error condition is propagated + */ + cmp x0, #0 + mov x3, #-EOPNOTSUPP + csel x0, x3, x0, eq + add sp, sp, #CPU_SUSPEND_SZ // rewind stack pointer + ldp x19, x20, [sp, #16] + ldp x21, x22, [sp, #32] + ldp x23, x24, [sp, #48] + ldp x25, x26, [sp, #64] + ldp x27, x28, [sp, #80] + ldp x29, lr, [sp], #96 + ret +ENDPROC(__cpu_suspend) + .ltorg + +/* + * x0 must contain the sctlr value retrieved from restored context + */ +ENTRY(cpu_resume_mmu) + ldr x3, =cpu_resume_after_mmu + msr sctlr_el1, x0 // restore sctlr_el1 + isb + br x3 // global jump to virtual address +ENDPROC(cpu_resume_mmu) +cpu_resume_after_mmu: + mov x0, #0 // return zero on success + ldp x19, x20, [sp, #16] + ldp x21, x22, [sp, #32] + ldp x23, x24, [sp, #48] + ldp x25, x26, [sp, #64] + ldp x27, x28, [sp, #80] + ldp x29, lr, [sp], #96 + ret +ENDPROC(cpu_resume_after_mmu) + + .data +ENTRY(cpu_resume) + bl el2_setup // if in EL2 drop to EL1 cleanly +#ifdef CONFIG_SMP + mrs x1, mpidr_el1 + adr x4, mpidr_hash_ptr + ldr x5, [x4] + add x8, x4, x5 // x8 = struct mpidr_hash phys 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 */ +#else + mov x7, xzr +#endif + adr x0, sleep_save_sp + ldr x0, [x0, #SLEEP_SAVE_SP_PHYS] + ldr x0, [x0, x7, lsl #3] + /* load sp from context */ + ldr x2, [x0, #CPU_CTX_SP] + adr x1, sleep_idmap_phys + /* load physical address of identity map page table in x1 */ + ldr x1, [x1] + mov sp, x2 + /* + * cpu_do_resume expects x0 to contain context physical address + * pointer and x1 to contain physical address of 1:1 page tables + */ + bl cpu_do_resume // PC relative jump, MMU off + b cpu_resume_mmu // Resume MMU, never returns +ENDPROC(cpu_resume) + + .align 3 +mpidr_hash_ptr: + /* + * offset of mpidr_hash symbol from current location + * used to obtain run-time mpidr_hash address with MMU off + */ + .quad mpidr_hash - . +/* + * physical address of identity mapped page tables + */ + .type sleep_idmap_phys, #object +ENTRY(sleep_idmap_phys) + .quad 0 +/* + * struct sleep_save_sp { + * phys_addr_t *save_ptr_stash; + * phys_addr_t save_ptr_stash_phys; + * }; + */ + .type sleep_save_sp, #object +ENTRY(sleep_save_sp) + .space SLEEP_SAVE_SP_SZ // struct sleep_save_sp |