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#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
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