diff --git a/src/unix/bsd/netbsdlike/openbsd/aarch64.rs b/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
index 6a8cbb5c..99350ec8 100644
--- a/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/aarch64.rs
@@ -12,3 +12,5 @@ cfg_if! {
         pub const _ALIGNBYTES: usize = 8 - 1;
     }
 }
+
+pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/mod.rs b/src/unix/bsd/netbsdlike/openbsd/mod.rs
index a397d58c..51b1bf14 100644
--- a/src/unix/bsd/netbsdlike/openbsd/mod.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/mod.rs
@@ -1297,8 +1297,9 @@ pub const IFF_LINK1: ::c_int = 0x2000; // per link layer defined bit
 pub const IFF_LINK2: ::c_int = 0x4000; // per link layer defined bit
 pub const IFF_MULTICAST: ::c_int = 0x8000; // supports multicast
 
-pub const PTHREAD_STACK_MIN : ::size_t = 4096;
-pub const SIGSTKSZ : ::size_t = 28672;
+pub const PTHREAD_STACK_MIN: ::size_t = (1_usize << _MAX_PAGE_SHIFT);
+pub const MINSIGSTKSZ: ::size_t = (3_usize << _MAX_PAGE_SHIFT);
+pub const SIGSTKSZ: ::size_t = MINSIGSTKSZ + (1_usize << _MAX_PAGE_SHIFT) * 4;
 
 pub const PT_FIRSTMACH: ::c_int = 32;
 
@@ -1437,6 +1438,9 @@ cfg_if! {
     } else if #[cfg(target_arch = "aarch64")] {
         mod aarch64;
         pub use self::aarch64::*;
+    } else if #[cfg(target_arch = "sparc64")] {
+        mod sparc64;
+        pub use self::sparc64::*;
     } else {
         // Unknown target_arch
     }
diff --git a/src/unix/bsd/netbsdlike/openbsd/sparc64.rs b/src/unix/bsd/netbsdlike/openbsd/sparc64.rs
new file mode 100644
index 00000000..070fc938
--- /dev/null
+++ b/src/unix/bsd/netbsdlike/openbsd/sparc64.rs
@@ -0,0 +1,8 @@
+pub type c_long = i64;
+pub type c_ulong = u64;
+pub type c_char = i8;
+
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = 0xf;
+
+pub const _MAX_PAGE_SHIFT: u32 = 13;
diff --git a/src/unix/bsd/netbsdlike/openbsd/x86.rs b/src/unix/bsd/netbsdlike/openbsd/x86.rs
index 05538cd0..e87d0ff1 100644
--- a/src/unix/bsd/netbsdlike/openbsd/x86.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/x86.rs
@@ -12,3 +12,5 @@ cfg_if! {
         pub const _ALIGNBYTES: usize = 4 - 1;
     }
 }
+
+pub const _MAX_PAGE_SHIFT: u32 = 12;
diff --git a/src/unix/bsd/netbsdlike/openbsd/x86_64.rs b/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
index 7daa9d83..263b6e13 100644
--- a/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
+++ b/src/unix/bsd/netbsdlike/openbsd/x86_64.rs
@@ -15,6 +15,8 @@ cfg_if! {
     }
 }
 
+pub const _MAX_PAGE_SHIFT: u32 = 12;
+
 pub const PT_STEP: ::c_int = PT_FIRSTMACH + 0;
 pub const PT_GETREGS: ::c_int = PT_FIRSTMACH + 1;
 pub const PT_SETREGS: ::c_int = PT_FIRSTMACH + 2;