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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 and execute the suspend finisher.
* On success it will return 0 through cpu_resume - ie through a CPU
* soft/hard reboot from the reset vector.
* On failure it returns the suspend finisher return value or force
* -EOPNOTSUPP if the finisher erroneously returns 0 (the suspend finisher
* is not allowed to return, if it does this must be considered failure).
* It 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
* x1 = suspend finisher function pointer
*/
ENTRY(__cpu_suspend_enter)
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]
/*
* Stash suspend finisher and its argument in x20 and x19
*/
mov x19, x0
mov x20, x1
mov x2, sp
sub sp, sp, #CPU_SUSPEND_SZ // allocate cpu_suspend_ctx
mov x0, sp
/*
* x0 now points to struct cpu_suspend_ctx allocated on the stack
*/
str x2, [x0, #CPU_CTX_SP]
ldr x1, =sleep_save_sp
ldr x1, [x1, #SLEEP_SAVE_SP_VIRT]
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 x1, x1, x8, lsl #3
bl __cpu_suspend_save
/*
* Grab suspend finisher in x20 and its argument in x19
*/
mov x0, x19
mov x1, x20
/*
* We are ready for power down, fire off the suspend finisher
* in x1, with argument in x0
*/
blr x1
/*
* Never gets here, unless suspend finisher 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_enter)
.ltorg
/*
* x0 must contain the sctlr value retrieved from restored context
*/
.pushsection ".idmap.text", "ax"
ENTRY(cpu_resume_mmu)
ldr x3, =cpu_resume_after_mmu
msr sctlr_el1, x0 // restore sctlr_el1
isb
/*
* Invalidate the local I-cache so that any instructions fetched
* speculatively from the PoC are discarded, since they may have
* been dynamically patched at the PoU.
*/
ic iallu
dsb nsh
isb
br x3 // global jump to virtual address
ENDPROC(cpu_resume_mmu)
.popsection
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)
ENTRY(cpu_resume)
bl el2_setup // if in EL2 drop to EL1 cleanly
mrs x1, mpidr_el1
adrp x8, mpidr_hash
add x8, x8, #:lo12:mpidr_hash // 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 */
ldr_l x0, sleep_save_sp + SLEEP_SAVE_SP_PHYS
ldr x0, [x0, x7, lsl #3]
/* load sp from context */
ldr x2, [x0, #CPU_CTX_SP]
/* load physical address of identity map page table in x1 */
adrp x1, idmap_pg_dir
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)
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