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VM_MAP_STACK (9) | Kernel routines | Unix Manual Pages | :man


vm_map_stack, vm_map_growstack - manage process stacks


Implementation Notes
Return Values
See Also


.In sys/param.h
.In vm/vm.h
.In vm/vm_map.h int
.Fo vm_map_stack "vm_map_t map" "vm_offset_t addrbos" "vm_size_t max_ssize" "vm_prot_t prot" "vm_prot_t max" "int cow"
.Fc int vm_map_growstack "struct proc *p" "vm_offset_t addr"


The vm_map_stack function maps a process stack for a new process image. The stack is mapped addrbos in map, with a maximum size of max_ssize. Copy-on-write flags passed in cow are also applied to the new mapping. Protection bits are supplied by prot and max.

It is typically called by execve(2).

The vm_map_growstack function is responsible for growing a stack for the process p to the desired address addr, similar to the legacy sbrk(2) call.


The vm_map_stack function calls vm_map_insert(9) to create its mappings.

The vm_map_growstack function acquires the Giant lock, and the process lock on p, for the duration of the call.


The vm_map_stack function returns KERN_SUCCESS if the mapping was allocated successfully.

Otherwise, if mapping the stack would exceed the process’s VMEM resource limit, or if the specified bottom-of-stack address is out of range for the map, or if there is already a mapping at the address which would result, or if max_ssize could not be accomodated within the current mapping, KERN_NO_SPACE is returned.

Other possible return values for this function are documented in vm_map_insert(9).

The vm_map_growstack function returns KERN_SUCCESS if addr is already mapped, or if the stack was grown successfully.

It also returns KERN_SUCCESS if addr is outside the stack range; this is done in order to preserve compatibility with the deprecated grow function previously located in the file vm_machdep.c.


vm_map(9), vm_map_insert(9)


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