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//+build linux
//+private
package mem_virtual
import "core:sys/linux"
_reserve :: proc "contextless" (size: uint) -> (data: []byte, err: Allocator_Error) {
addr, errno := linux.mmap(0, size, {}, {.PRIVATE, .ANONYMOUS})
if errno == .ENOMEM {
return nil, .Out_Of_Memory
} else if errno == .EINVAL {
return nil, .Invalid_Argument
}
return (cast([^]byte)addr)[:size], nil
}
_commit :: proc "contextless" (data: rawptr, size: uint) -> Allocator_Error {
errno := linux.mprotect(data, size, {.READ, .WRITE})
if errno == .EINVAL {
return .Invalid_Pointer
} else if errno == .ENOMEM {
return .Out_Of_Memory
}
return nil
}
_decommit :: proc "contextless" (data: rawptr, size: uint) {
_ = linux.mprotect(data, size, {})
_ = linux.madvise(data, size, .FREE)
}
_release :: proc "contextless" (data: rawptr, size: uint) {
_ = linux.munmap(data, size)
}
_protect :: proc "contextless" (data: rawptr, size: uint, flags: Protect_Flags) -> bool {
pflags: linux.Mem_Protection
pflags = {}
if .Read in flags { pflags |= {.READ} }
if .Write in flags { pflags |= {.WRITE} }
if .Execute in flags { pflags |= {.EXEC} }
errno := linux.mprotect(data, size, pflags)
return errno != .NONE
}
_platform_memory_init :: proc() {
DEFAULT_PAGE_SIZE = 4096
// is power of two
assert(DEFAULT_PAGE_SIZE != 0 && (DEFAULT_PAGE_SIZE & (DEFAULT_PAGE_SIZE-1)) == 0)
}
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