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c666ebb1f8
Whatever was in the frame pointer register prior to clone() will no longer be valid in the child process, so zero it to protect FP-based unwinders. This is just an extension of what was already done for i386 and x86_64. Only applied to architectures where the _start() code also zeroes the frame pointer.
36 lines
762 B
ArmAsm
Vendored
36 lines
762 B
ArmAsm
Vendored
.set noreorder
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.global __clone
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.hidden __clone
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.type __clone,@function
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__clone:
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# Save function pointer and argument pointer on new thread stack
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and $5, $5, -16 # aligning stack to double word
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subu $5, $5, 16
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sw $4, 0($5) # save function pointer
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sw $7, 4($5) # save argument pointer
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# Shuffle (fn,sp,fl,arg,ptid,tls,ctid) to (fl,sp,ptid,tls,ctid)
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# sys_clone(u64 flags, u64 ustack_base, u64 parent_tidptr, u64 child_tidptr, u64 tls)
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move $4, $6
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move $6, $8
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move $7, $9
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move $8, $10
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li $2, 6055
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syscall
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beq $7, $0, 1f
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nop
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jr $ra
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subu $2, $0, $2
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1: beq $2, $0, 1f
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nop
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jr $ra
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nop
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1: move $fp, $0
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lw $25, 0($sp) # function pointer
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lw $4, 4($sp) # argument pointer
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jalr $25 # call the user's function
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nop
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move $4, $2
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li $2, 6058
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syscall
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