Atmosphere-libs/libmesosphere/source/arch/arm64/kern_k_thread_context_asm.s

/*
 * Copyright (c) 2018-2020 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/>.
 */

/* ams::kern::arm64::UserModeThreadStarter() */
.section    .text._ZN3ams4kern5arm6421UserModeThreadStarterEv, "ax", %progbits
.global     _ZN3ams4kern5arm6421UserModeThreadStarterEv
.type       _ZN3ams4kern5arm6421UserModeThreadStarterEv, %function
_ZN3ams4kern5arm6421UserModeThreadStarterEv:
    /* NOTE: Stack layout on entry looks like following:                         */
    /* SP                                                                        */
    /* |                                                                         */
    /* v                                                                         */
    /* | KExceptionContext (size 0x120) | KThread::StackParameters (size 0x30) | */

    /* Clear the disable count for this thread's stack parameters. */
    str wzr, [sp, #(0x120 + 0x18)]

    /* Call ams::kern::arm64::OnThreadStart() */
    bl _ZN3ams4kern5arm6413OnThreadStartEv

    /* Restore thread state from the KExceptionContext on stack  */
    ldp x30, x19, [sp, #(8 * 30)]       /* x30 = lr,   x19 = sp  */
    ldp x20, x21, [sp, #(8 * 30 + 16)]  /* x20 = pc,   x21 = psr */
    ldr x22,      [sp, #(8 * 30 + 32)]  /* x22 = tpidr           */

    msr sp_el0,    x19
    msr elr_el1,   x20
    msr spsr_el1,  x21
    msr tpidr_el1, x22

    ldp x0,  x1,  [sp, #(8 *  0)]
    ldp x2,  x3,  [sp, #(8 *  2)]
    ldp x4,  x5,  [sp, #(8 *  4)]
    ldp x6,  x7,  [sp, #(8 *  6)]
    ldp x8,  x9,  [sp, #(8 *  8)]
    ldp x10, x11, [sp, #(8 * 10)]
    ldp x12, x13, [sp, #(8 * 12)]
    ldp x14, x15, [sp, #(8 * 14)]
    ldp x16, x17, [sp, #(8 * 16)]
    ldp x18, x19, [sp, #(8 * 18)]
    ldp x20, x21, [sp, #(8 * 20)]
    ldp x22, x23, [sp, #(8 * 22)]
    ldp x24, x25, [sp, #(8 * 24)]
    ldp x26, x27, [sp, #(8 * 26)]
    ldp x28, x29, [sp, #(8 * 28)]

    /* Increment stack pointer above the KExceptionContext */
    add sp, sp, #0x120

    /* Return to EL0 */
    eret

/* ams::kern::arm64::SupervisorModeThreadStarter() */
.section    .text._ZN3ams4kern5arm6427SupervisorModeThreadStarterEv, "ax", %progbits
.global     _ZN3ams4kern5arm6427SupervisorModeThreadStarterEv
.type       _ZN3ams4kern5arm6427SupervisorModeThreadStarterEv, %function
_ZN3ams4kern5arm6427SupervisorModeThreadStarterEv:
    /* NOTE: Stack layout on entry looks like following:                        */
    /* SP                                                                       */
    /* |                                                                        */
    /* v                                                                        */
    /* | u64 argument | u64 entrypoint | KThread::StackParameters (size 0x30) | */

    /* Load the argument and entrypoint. */
    ldp x0, x1, [sp], #0x10

    /* Clear the disable count for this thread's stack parameters. */
    str wzr, [sp, #(0x18)]

    /*  Mask I bit in DAIF */
    msr daifclr, #2
    br x1

    /* This should never execute, but Nintendo includes an ERET here. */
    eret


/* ams::kern::arm64::KThreadContext::RestoreFpuRegisters64(const KThreadContext &) */
.section    .text._ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters64ERKS2_, "ax", %progbits
.global     _ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters64ERKS2_
.type       _ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters64ERKS2_, %function
_ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters64ERKS2_:
    /* Load and restore FPCR and FPSR from the context. */
    ldr x1, [x0, #0x70]
    msr fpcr, x1
    ldr x1, [x0, #0x78]
    msr fpsr, x1

    /* Restore the FPU registers. */
    ldp q0,  q1,  [sp, #(16 *  0 + 0x80)]
    ldp q2,  q3,  [sp, #(16 *  2 + 0x80)]
    ldp q4,  q5,  [sp, #(16 *  4 + 0x80)]
    ldp q6,  q7,  [sp, #(16 *  6 + 0x80)]
    ldp q8,  q9,  [sp, #(16 *  8 + 0x80)]
    ldp q10, q11, [sp, #(16 * 10 + 0x80)]
    ldp q12, q13, [sp, #(16 * 12 + 0x80)]
    ldp q14, q15, [sp, #(16 * 14 + 0x80)]
    ldp q16, q17, [sp, #(16 * 16 + 0x80)]
    ldp q18, q19, [sp, #(16 * 18 + 0x80)]
    ldp q20, q21, [sp, #(16 * 20 + 0x80)]
    ldp q22, q23, [sp, #(16 * 22 + 0x80)]
    ldp q24, q25, [sp, #(16 * 24 + 0x80)]
    ldp q26, q27, [sp, #(16 * 26 + 0x80)]
    ldp q28, q29, [sp, #(16 * 28 + 0x80)]
    ldp q30, q31, [sp, #(16 * 30 + 0x80)]

    ret

/* ams::kern::arm64::KThreadContext::RestoreFpuRegisters32(const KThreadContext &) */
.section    .text._ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters32ERKS2_, "ax", %progbits
.global     _ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters32ERKS2_
.type       _ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters32ERKS2_, %function
_ZN3ams4kern5arm6414KThreadContext21RestoreFpuRegisters32ERKS2_:
    /* Load and restore FPCR and FPSR from the context. */
    ldr x1, [x0, #0x70]
    msr fpcr, x1
    ldr x1, [x0, #0x78]
    msr fpsr, x1

    /* Restore the FPU registers. */
    ldp q0,  q1,  [sp, #(16 *  0 + 0x80)]
    ldp q2,  q3,  [sp, #(16 *  2 + 0x80)]
    ldp q4,  q5,  [sp, #(16 *  4 + 0x80)]
    ldp q6,  q7,  [sp, #(16 *  6 + 0x80)]
    ldp q8,  q9,  [sp, #(16 *  8 + 0x80)]
    ldp q10, q11, [sp, #(16 * 10 + 0x80)]
    ldp q12, q13, [sp, #(16 * 12 + 0x80)]
    ldp q14, q15, [sp, #(16 * 14 + 0x80)]

    ret