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/*
* This file is part of the coreboot project.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* Optimized assembly for low-level CPU operations on ARM64 processors.
*/
#include <arch/asm.h>
#include <arch/cache.h>
.macro dcache_apply_all crm
dsb sy
mrs x0, clidr_el1 // read CLIDR
and w3, w0, #0x07000000 // narrow to LoC
lsr w3, w3, #23 // left align LoC (low 4 bits)
cbz w3, 5f //done
mov w10, #0 // w10 = 2 * cache level
mov w8, #1 // w8 = constant 0b1
1: //next_level
add w2, w10, w10, lsr #1 // calculate 3 * cache level
lsr w1, w0, w2 // extract 3-bit cache type for this level
and w1, w1, #0x7 // w1 = cache type
cmp w1, #2 // is it data or i&d?
b.lt 4f //skip
msr csselr_el1, x10 // select current cache level
isb // sync change of csselr
mrs x1, ccsidr_el1 // w1 = read ccsidr
and w2, w1, #7 // w2 = log2(linelen_bytes) - 4
add w2, w2, #4 // w2 = log2(linelen_bytes)
ubfx w4, w1, #3, #10 // w4 = associativity - 1 (also
// max way number)
clz w5, w4 // w5 = 32 - log2(ways)
// (bit position of way in DC)
lsl w9, w4, w5 // w9 = max way number
// (aligned for DC)
lsl w16, w8, w5 // w16 = amount to decrement (way
// number per iteration)
2: //next_way
ubfx w7, w1, #13, #15 // w7 = max set #, right aligned
lsl w7, w7, w2 // w7 = max set #, DC aligned
lsl w17, w8, w2 // w17 = amount to decrement (set
// number per iteration)
3: //next_set
orr w11, w10, w9 // w11 = combine way # & cache #
orr w11, w11, w7 // ... and set #
dc \crm, x11 // clean and/or invalidate line
subs w7, w7, w17 // decrement set number
b.ge 3b //next_set
subs x9, x9, x16 // decrement way number
b.ge 2b //next_way
4: //skip
add w10, w10, #2 // increment 2 *cache level
cmp w3, w10 // Went beyond LoC?
b.gt 1b //next_level
5: //done
dsb sy
isb
ret
.endm
ENTRY(dcache_invalidate_all)
dcache_apply_all crm=isw
ENDPROC(dcache_invalidate_all)
ENTRY(dcache_clean_all)
dcache_apply_all crm=csw
ENDPROC(dcache_clean_all)
ENTRY(dcache_clean_invalidate_all)
dcache_apply_all crm=cisw
ENDPROC(dcache_clean_invalidate_all)
/* This must be implemented in assembly to ensure there are no accesses to
memory (e.g. the stack) in between disabling and flushing the cache. */
ENTRY(mmu_disable)
str x30, [sp, #-0x8]
mrs x0, sctlr_el3
mov x1, #~(SCTLR_C | SCTLR_M)
and x0, x0, x1
msr sctlr_el3, x0
isb
bl dcache_clean_invalidate_all
ldr x30, [sp, #-0x8]
ret
ENDPROC(mmu_disable)
/*
* Bring an ARMv8 processor we just gained control of (e.g. from IROM) into a
* known state regarding caches/SCTLR/PSTATE. Completely invalidates
* icache/dcache, disables MMU and dcache (if active), and enables unaligned
* accesses, icache and branch prediction (if inactive). Seeds the stack and
* initializes SP_EL0. Clobbers R22 and R23.
*/
ENTRY(arm64_init_cpu)
/* Initialize PSTATE (unmask all exceptions, select SP_EL0). */
msr SPSel, #0
msr DAIFClr, #0xf
/* TODO: This is where we'd put non-boot CPUs into WFI if needed. */
/* x22: SCTLR, return address: x23 (callee-saved by subroutine) */
mov x23, x30
/* TODO: Assert that we always start running at EL3 */
mrs x22, sctlr_el3
/* Activate ICache (12) already for speed during cache flush below. */
orr x22, x22, #(1 << 12)
msr sctlr_el3, x22
isb
/* Invalidate dcache */
bl dcache_invalidate_all
/* Deactivate MMU (0), Alignment Check (1) and DCache (2) */
and x22, x22, # ~(1 << 0) & ~(1 << 1) & ~(1 << 2)
/* Activate Stack Alignment (3) because why not */
orr x22, x22, #(1 << 3)
/* Set to little-endian (25) */
and x22, x22, # ~(1 << 25)
/* Deactivate write-xor-execute enforcement (19) */
and x22, x22, # ~(1 << 19)
msr sctlr_el3, x22
/* Invalidate icache and TLB for good measure */
ic iallu
tlbi alle3
dsb sy
isb
/* Initialize stack with sentinel value to later check overflow. */
ldr x2, =0xdeadbeefdeadbeef
ldr x0, =_stack
ldr x1, =_estack
1:
stp x2, x2, [x0], #16
cmp x0, x1
bne 1b
/* Leave a line of beef dead for easier visibility in stack dumps. */
sub sp, x0, #16
ret x23
ENDPROC(arm64_init_cpu)
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