alexvoste
157 lines
2.7 KiB
NASM
157 lines
2.7 KiB
NASM
section .text
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extern task_exit
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global context_switch
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global first_task_start
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global fpu_save
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global fpu_restore
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global task_trampoline
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global task_trampoline_user
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global task_trampoline_fork
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TASK_ENTRY_OFFSET equ 120
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TASK_ARG_OFFSET equ 128
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TASK_USER_RSP_OFFSET equ 144
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TASK_CR3_OFFSET equ 24
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TASK_USER_SAVED_RIP_OFFSET equ 272
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TASK_USER_SAVED_RBP_OFFSET equ 280
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TASK_USER_SAVED_RBX_OFFSET equ 288
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TASK_USER_SAVED_R12_OFFSET equ 296
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TASK_USER_SAVED_R13_OFFSET equ 304
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TASK_USER_SAVED_R14_OFFSET equ 312
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TASK_USER_SAVED_R15_OFFSET equ 320
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TASK_USER_SAVED_R11_OFFSET equ 328
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PERCPU_CURRENT_TASK equ 24
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TASK_ON_CPU_OFFSET equ 0x158
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context_switch:
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push rbp
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push rbx
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push r12
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push r13
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push r14
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push r15
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mov [rdi], rsp
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mov [rdx], rsi
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mov [gs:PERCPU_CURRENT_TASK], rsi
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mov rsp, [rsi]
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test rcx, rcx
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jz .skip_cr3
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mov cr3, rcx
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.skip_cr3:
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lock add dword [rsp], 0
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mov byte [rdi + TASK_ON_CPU_OFFSET], 0
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pop r15
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pop r14
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pop r13
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pop r12
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pop rbx
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pop rbp
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ret
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first_task_start:
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mov [gs:PERCPU_CURRENT_TASK], rdi
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mov rsi, [rdi + TASK_CR3_OFFSET]
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mov rsp, [rdi]
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test rsi, rsi
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jz .skip_cr3_fts
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mov cr3, rsi
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.skip_cr3_fts:
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pop r15
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pop r14
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pop r13
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pop r12
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pop rbx
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pop rbp
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ret
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fpu_save:
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fxsave [rdi]
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ret
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fpu_restore:
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fxrstor [rdi]
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ret
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task_trampoline:
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mov rdi, [rbp + TASK_ARG_OFFSET]
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mov rax, [rbp + TASK_ENTRY_OFFSET]
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xor rbp, rbp
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sti
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call rax
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call task_exit
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.hang:
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cli
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hlt
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jmp .hang
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task_trampoline_user:
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mov rax, [rbp + TASK_ENTRY_OFFSET]
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mov rcx, [rbp + TASK_USER_RSP_OFFSET]
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xor rbp, rbp
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push qword 0x1B
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push rcx
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pushfq
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pop rdx
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or rdx, (1 << 9)
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and rdx, ~(3 << 12)
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push rdx
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push qword 0x23
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push rax
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xor rax, rax
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xor rbx, rbx
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xor rcx, rcx
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xor rdx, rdx
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xor rdi, rdi
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xor rsi, rsi
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xor r8, r8
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xor r9, r9
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xor r10, r10
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xor r11, r11
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xor r12, r12
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xor r13, r13
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xor r14, r14
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xor r15, r15
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swapgs
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iretq
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task_trampoline_fork:
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cli
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mov rax, [rbp + TASK_USER_SAVED_RIP_OFFSET]
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mov rcx, [rbp + TASK_USER_RSP_OFFSET]
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mov r11, [rbp + TASK_USER_SAVED_R11_OFFSET]
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mov rbx, [rbp + TASK_USER_SAVED_RBX_OFFSET]
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mov r12, [rbp + TASK_USER_SAVED_R12_OFFSET]
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mov r13, [rbp + TASK_USER_SAVED_R13_OFFSET]
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mov r14, [rbp + TASK_USER_SAVED_R14_OFFSET]
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mov r15, [rbp + TASK_USER_SAVED_R15_OFFSET]
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mov rbp, [rbp + TASK_USER_SAVED_RBP_OFFSET]
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or r11, (1 << 9)
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push qword 0x1B
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push rcx
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push r11
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push qword 0x23
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push rax
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xor rax, rax
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swapgs
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iretq |