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// Mark stack as non-executable
#if defined(__linux__) && defined(__ELF__)
.section .note.GNU-stack, "", @progbits
#endif
.text
.globl upcall_new_stack
.globl upcall_del_stack
.globl __morestack
.hidden __morestack
.cfi_startproc
.set nomips16
.ent __morestack
__morestack:
.set noreorder
.set nomacro
addiu $29, $29, -12
sw $31, 8($29)
sw $30, 4($29)
sw $23, 0($29)
// 24 = 12 (current) + 12 (previous)
.cfi_def_cfa_offset 24
.cfi_offset 31, -4
.cfi_offset 30, -20
.cfi_offset 23, -24
move $23, $28
move $30, $29
.cfi_def_cfa_register 30
// Save argument registers of the original function
addiu $29, $29, -32
sw $4, 16($29)
sw $5, 20($29)
sw $6, 24($29)
sw $7, 28($29)
move $4, $14 // Size of stack arguments
addu $5, $30, 24 // Address of stack arguments
move $6, $15 // The amount of stack needed
move $28, $23
lw $25, %call16(upcall_new_stack)($23)
jalr $25
nop
// Pop the saved arguments
lw $4, 16($29)
lw $5, 20($29)
lw $6, 24($29)
lw $7, 28($29)
addiu $29, $29, 32
lw $24, 8($30) // Grab the return pointer.
addiu $24, $24, 12 // Skip past the `lw`, `jr`, `addiu` in our parent frame
move $29, $2 // Switch to the new stack.
// for PIC
lw $2, 12($30)
lw $25, 16($30)
move $28, $23
jalr $24 // Reenter the caller function
nop
// Switch back to the rust stack
move $29, $30
// Save the return value
addiu $29, $29, -24
sw $2, 16($29)
sw $3, 20($29)
move $28, $23
lw $25, %call16(upcall_del_stack)($23)
jalr $25
nop
// Restore the return value
lw $2, 16($29)
lw $3, 20($29)
addiu $29, $29, 24
lw $31, 8($29)
lw $30, 4($29)
lw $23, 0($29)
addiu $29, $29, 12
jr $31
nop
.end __morestack
.cfi_endproc
|
