mirror of
https://github.com/Atmosphere-NX/Atmosphere
synced 2024-12-23 12:51:13 +00:00
283 lines
11 KiB
ArmAsm
283 lines
11 KiB
ArmAsm
/*
|
|
* Copyright (c) Atmosphère-NX
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms and conditions of the GNU General Public License,
|
|
* version 2, as published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope 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.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include <mesosphere/kern_select_assembly_macros.h>
|
|
|
|
/* ams::kern::KScheduler::ScheduleImpl() */
|
|
.section .text._ZN3ams4kern10KScheduler12ScheduleImplEv, "ax", %progbits
|
|
.global _ZN3ams4kern10KScheduler12ScheduleImplEv
|
|
.type _ZN3ams4kern10KScheduler12ScheduleImplEv, %function
|
|
|
|
/* Ensure ScheduleImpl is aligned to 0x40 bytes. */
|
|
.balign 0x40
|
|
|
|
_ZN3ams4kern10KScheduler12ScheduleImplEv:
|
|
/* Right now, x0 contains (this). We want x1 to point to the scheduling state, */
|
|
/* KScheduler layout has state at +0x0, this is guaranteed statically by assembly offsets. */
|
|
mov x1, x0
|
|
|
|
/* First, clear the need's scheduling bool (and dmb ish after, as it's an atomic). */
|
|
strb wzr, [x1]
|
|
dmb ish
|
|
|
|
/* Check whether there are runnable interrupt tasks. */
|
|
ldrb w8, [x1, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
|
|
cbnz w8, 0f
|
|
|
|
/* If it isn't, we want to check if the highest priority thread is the same as the current thread. */
|
|
ldr x7, [x1, #(KSCHEDULER_HIGHEST_PRIORITY_THREAD)]
|
|
cmp x7, x18
|
|
b.ne 1f
|
|
|
|
/* If they're the same, then we can just issue a memory barrier and return. */
|
|
dmb ish
|
|
ret
|
|
|
|
0: /* The interrupt task thread is runnable. */
|
|
/* We want to switch to the interrupt task/idle thread. */
|
|
mov x7, #0
|
|
|
|
1: /* The highest priority thread is not the same as the current thread. */
|
|
/* Get a reference to the current thread's stack parameters. */
|
|
add x2, sp, #0x1000
|
|
and x2, x2, #~(0x1000-1)
|
|
sub x2, x2, #(THREAD_STACK_PARAMETERS_SIZE)
|
|
|
|
/* Get a reference to the current thread's context. */
|
|
add x3, x2, #(THREAD_STACK_PARAMETERS_THREAD_CONTEXT)
|
|
|
|
/* Save the callee-save registers + SP. */
|
|
stp x19, x20, [x3, #(THREAD_CONTEXT_X19_X20)]
|
|
stp x21, x22, [x3, #(THREAD_CONTEXT_X21_X22)]
|
|
stp x23, x24, [x3, #(THREAD_CONTEXT_X23_X24)]
|
|
stp x25, x26, [x3, #(THREAD_CONTEXT_X25_X26)]
|
|
stp x27, x28, [x3, #(THREAD_CONTEXT_X27_X28)]
|
|
stp x29, x30, [x3, #(THREAD_CONTEXT_X29_X30)]
|
|
|
|
mov x4, sp
|
|
str x4, [x3, #(THREAD_CONTEXT_SP)]
|
|
|
|
/* Check if the fpu is enabled; if it is, we need to save it. */
|
|
mrs x5, cpacr_el1
|
|
and x4, x5, #0x300000
|
|
cbz x4, 8f
|
|
|
|
/* We need to save the fpu state; save fpsr/fpcr. */
|
|
mrs x4, fpcr
|
|
mrs x6, fpsr
|
|
stp w4, w6, [x3, #(THREAD_CONTEXT_FPCR_FPSR)]
|
|
|
|
/* Set fpu-restore-needed in our exception flags. */
|
|
ldrb w4, [x2, #(THREAD_STACK_PARAMETERS_EXCEPTION_FLAGS)]
|
|
orr w4, w4, #(THREAD_EXCEPTION_FLAG_IS_FPU_CONTEXT_RESTORE_NEEDED)
|
|
strb w4, [x2, #(THREAD_STACK_PARAMETERS_EXCEPTION_FLAGS)]
|
|
|
|
/* We need to save fpu state based on whether we're a 64-bit or 32-bit thread. */
|
|
tbz w4, #(THREAD_EXCEPTION_FLAG_BIT_INDEX_IS_FPU_64_BIT), 4f
|
|
|
|
/* We have a 64-bit fpu. */
|
|
|
|
/* If we're in a usermode exception, we need to save the caller-save fpu registers. */
|
|
tbz w4, #(THREAD_EXCEPTION_FLAG_BIT_INDEX_IS_IN_USERMODE_EXCEPTION_HANDLER), 2f
|
|
|
|
/* If we're in an SVC (and not a usermode exception), we only need to save the callee-save fpu registers. */
|
|
tbz w4, #(THREAD_EXCEPTION_FLAG_BIT_INDEX_IS_CALLING_SVC), 3f
|
|
|
|
2: /* Save the 64-bit caller-save fpu registers. */
|
|
ldr x6, [x2, #(THREAD_STACK_PARAMETERS_CALLER_SAVE_FPU_REGISTERS)]
|
|
stp q0, q1, [x6, #(THREAD_FPU64_CONTEXT_Q0_Q1)]
|
|
stp q2, q3, [x6, #(THREAD_FPU64_CONTEXT_Q2_Q3)]
|
|
stp q4, q5, [x6, #(THREAD_FPU64_CONTEXT_Q4_Q5)]
|
|
stp q6, q7, [x6, #(THREAD_FPU64_CONTEXT_Q6_Q7)]
|
|
stp q16, q17, [x6, #(THREAD_FPU64_CONTEXT_Q16_Q17)]
|
|
stp q18, q19, [x6, #(THREAD_FPU64_CONTEXT_Q18_Q19)]
|
|
stp q20, q21, [x6, #(THREAD_FPU64_CONTEXT_Q20_Q21)]
|
|
stp q22, q23, [x6, #(THREAD_FPU64_CONTEXT_Q22_Q23)]
|
|
stp q24, q25, [x6, #(THREAD_FPU64_CONTEXT_Q24_Q25)]
|
|
stp q26, q27, [x6, #(THREAD_FPU64_CONTEXT_Q26_Q27)]
|
|
stp q28, q29, [x6, #(THREAD_FPU64_CONTEXT_Q28_Q29)]
|
|
stp q30, q31, [x6, #(THREAD_FPU64_CONTEXT_Q30_Q31)]
|
|
|
|
3: /* Save the 64-bit callee-save fpu registers. */
|
|
stp q8, q9, [x3, #(THREAD_CONTEXT_FPU64_Q8_Q9)]
|
|
stp q10, q11, [x3, #(THREAD_CONTEXT_FPU64_Q10_Q11)]
|
|
stp q12, q13, [x3, #(THREAD_CONTEXT_FPU64_Q12_Q13)]
|
|
stp q14, q15, [x3, #(THREAD_CONTEXT_FPU64_Q14_Q15)]
|
|
b 7f
|
|
|
|
4: /* We have a 32-bit fpu. */
|
|
|
|
/* If we're in a usermode exception, we need to save the caller-save fpu registers. */
|
|
tbz w4, #(THREAD_EXCEPTION_FLAG_BIT_INDEX_IS_IN_USERMODE_EXCEPTION_HANDLER), 5f
|
|
|
|
/* If we're in an SVC (and not a usermode exception), we only need to save the callee-save fpu registers. */
|
|
tbz w4, #(THREAD_EXCEPTION_FLAG_BIT_INDEX_IS_CALLING_SVC), 6f
|
|
|
|
5: /* Save the 32-bit caller-save fpu registers. */
|
|
ldr x6, [x2, #(THREAD_STACK_PARAMETERS_CALLER_SAVE_FPU_REGISTERS)]
|
|
stp q0, q1, [x6, #(THREAD_FPU32_CONTEXT_Q0_Q1)]
|
|
stp q2, q3, [x6, #(THREAD_FPU32_CONTEXT_Q2_Q3)]
|
|
stp q8, q9, [x6, #(THREAD_FPU32_CONTEXT_Q8_Q9)]
|
|
stp q10, q11, [x6, #(THREAD_FPU32_CONTEXT_Q10_Q11)]
|
|
stp q12, q13, [x6, #(THREAD_FPU32_CONTEXT_Q12_Q13)]
|
|
stp q14, q15, [x6, #(THREAD_FPU32_CONTEXT_Q14_Q15)]
|
|
|
|
6: /* Save the 32-bit callee-save fpu registers. */
|
|
stp q4, q5, [x3, #(THREAD_CONTEXT_FPU32_Q4_Q5)]
|
|
stp q6, q7, [x3, #(THREAD_CONTEXT_FPU32_Q6_Q7)]
|
|
|
|
7: /* With the fpu state saved, disable the fpu. */
|
|
and x5, x5, #(~0x300000)
|
|
msr cpacr_el1, x5
|
|
|
|
8: /* We're done saving this thread's context. */
|
|
|
|
/* Check if the thread is terminated by checking the DPC flags for DpcFlag_Terminated. */
|
|
ldrb w4, [x2, #(THREAD_STACK_PARAMETERS_DPC_FLAGS)]
|
|
tbnz w4, #1, 9f
|
|
|
|
/* The thread isn't terminated, so we want to unlock it. */
|
|
/* Write atomically to the context's locked member. */
|
|
add x3, x3, #(THREAD_CONTEXT_LOCKED)
|
|
stlrb wzr, [x3]
|
|
|
|
9: /* The current thread's context has been entirely taken care of. */
|
|
/* Now we want to loop until we successfully switch the thread context. */
|
|
/* Start by saving all the values we care about in callee-save registers. */
|
|
mov x19, x0 /* this */
|
|
mov x20, x1 /* this->state */
|
|
mov x21, x7 /* highest priority thread */
|
|
|
|
/* Set our stack to the idle thread stack. */
|
|
ldr x3, [x20, #(KSCHEDULER_IDLE_THREAD_STACK)]
|
|
mov sp, x3
|
|
b 11f
|
|
|
|
10: /* We failed to successfully do the context switch, and need to retry. */
|
|
/* Clear the exclusive monitor. */
|
|
clrex
|
|
|
|
/* Clear the need's scheduling bool (and dmb ish after, as it's an atomic). */
|
|
strb wzr, [x20]
|
|
dmb ish
|
|
|
|
/* Refresh the highest priority thread. */
|
|
ldr x21, [x20, #(KSCHEDULER_HIGHEST_PRIORITY_THREAD)]
|
|
|
|
11: /* We're starting to try to do the context switch. */
|
|
/* Check if the highest priority thread if null. */
|
|
/* If it is, we want to branch to a special idle thread loop. */
|
|
cbz x21, 16f
|
|
|
|
/* Get the highest priority thread's context, and save it. */
|
|
/* ams::kern::KThread::GetContextForSchedulerLoop() */
|
|
ldr x22, [x21, #(THREAD_KERNEL_STACK_TOP)]
|
|
sub x22, x22, #(THREAD_STACK_PARAMETERS_SIZE - THREAD_STACK_PARAMETERS_THREAD_CONTEXT)
|
|
|
|
/* Prepare to try to acquire the context lock. */
|
|
add x1, x22, #(THREAD_CONTEXT_LOCKED)
|
|
mov w2, #1
|
|
|
|
12: /* We want to try to lock the highest priority thread's context. */
|
|
/* Check if the lock is already held. */
|
|
ldaxrb w3, [x1]
|
|
cbnz w3, 13f
|
|
|
|
/* If it's not, try to take it. */
|
|
stxrb w3, w2, [x1]
|
|
cbnz w3, 12b
|
|
|
|
/* We hold the lock, so we can now switch the thread. */
|
|
b 14f
|
|
|
|
13: /* The highest priority thread's context is already locked. */
|
|
/* Check if we need scheduling. If we don't, we can retry directly. */
|
|
ldarb w3, [x20] // ldarb w3, [x20, #(KSCHEDULER_NEEDS_SCHEDULING)]
|
|
cbz w3, 12b
|
|
|
|
/* If we do, another core is interfering, and we must start from the top. */
|
|
b 10b
|
|
|
|
14: /* It's time to switch the thread. */
|
|
/* Switch to the highest priority thread. */
|
|
mov x0, x19
|
|
mov x1, x21
|
|
|
|
/* Call ams::kern::KScheduler::SwitchThread(ams::kern::KThread *) */
|
|
bl _ZN3ams4kern10KScheduler12SwitchThreadEPNS0_7KThreadE
|
|
|
|
/* Check if we need scheduling. If we do, then we can't complete the switch and should retry. */
|
|
ldarb w1, [x20] // ldarb w1, [x20, #(KSCHEDULER_NEEDS_SCHEDULING)]
|
|
cbnz w1, 15f
|
|
|
|
/* Restore the thread context. */
|
|
mov x0, x22
|
|
ldp x19, x20, [x0, #(THREAD_CONTEXT_X19_X20)]
|
|
ldp x21, x22, [x0, #(THREAD_CONTEXT_X21_X22)]
|
|
ldp x23, x24, [x0, #(THREAD_CONTEXT_X23_X24)]
|
|
ldp x25, x26, [x0, #(THREAD_CONTEXT_X25_X26)]
|
|
ldp x27, x28, [x0, #(THREAD_CONTEXT_X27_X28)]
|
|
ldp x29, x30, [x0, #(THREAD_CONTEXT_X29_X30)]
|
|
|
|
ldr x1, [x0, #(THREAD_CONTEXT_SP)]
|
|
mov sp, x1
|
|
|
|
/* Return. */
|
|
ret
|
|
|
|
15: /* Our switch failed. */
|
|
/* We should unlock the thread context, and then retry. */
|
|
add x1, x22, #(THREAD_CONTEXT_LOCKED)
|
|
stlrb wzr, [x1]
|
|
b 10b
|
|
|
|
16: /* The next thread is nullptr! */
|
|
/* Switch to nullptr. This will actually switch to the idle thread. */
|
|
mov x0, x19
|
|
mov x1, #0
|
|
|
|
/* Call ams::kern::KScheduler::SwitchThread(ams::kern::KThread *) */
|
|
bl _ZN3ams4kern10KScheduler12SwitchThreadEPNS0_7KThreadE
|
|
|
|
17: /* We've switched to the idle thread, so we want to process interrupt tasks until we schedule a non-idle thread. */
|
|
/* Check whether there are runnable interrupt tasks. */
|
|
ldrb w3, [x20, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
|
|
cbnz w3, 18f
|
|
|
|
/* Check if we need scheduling. */
|
|
ldarb w3, [x20] // ldarb w3, [x20, #(KSCHEDULER_NEEDS_SCHEDULING)]
|
|
cbnz w3, 10b
|
|
|
|
/* Clear the previous thread. */
|
|
str xzr, [x20, #(KSCHEDULER_PREVIOUS_THREAD)]
|
|
|
|
/* Wait for an interrupt and check again. */
|
|
wfi
|
|
|
|
msr daifclr, #2
|
|
msr daifset, #2
|
|
|
|
b 17b
|
|
|
|
18: /* We have interrupt tasks to execute! */
|
|
/* Execute any pending interrupt tasks. */
|
|
ldr x0, [x20, #(KSCHEDULER_INTERRUPT_TASK_MANAGER)]
|
|
bl _ZN3ams4kern21KInterruptTaskManager7DoTasksEv
|
|
|
|
/* Clear the interrupt task thread as runnable. */
|
|
strb wzr, [x20, #(KSCHEDULER_INTERRUPT_TASK_RUNNABLE)]
|
|
|
|
/* Retry the scheduling loop. */
|
|
b 10b
|