diff --git a/newsfragments/6038.added.md b/newsfragments/6038.added.md
new file mode 100644
index 00000000000..62a29b3f123
--- /dev/null
+++ b/newsfragments/6038.added.md
@@ -0,0 +1 @@
+Add FFI definitions `PyEval_SetProfileAllThreads` and `PyEval_SetTraceAllThreads`.
diff --git a/newsfragments/6038.changed.md b/newsfragments/6038.changed.md
new file mode 100644
index 00000000000..a4d21f0361e
--- /dev/null
+++ b/newsfragments/6038.changed.md
@@ -0,0 +1 @@
+FFI definitions `_PyCode_GetExtra`, `_PyCode_SetExtra`, and `_PyEval_RequestCodeExtraIndex` have been updated to `PyUnstable_Code_GetExtra`, `PyUnstable_Code_SetExtra`, and `PyUnstable_Eval_RequestCodeExtraIndex`.
diff --git a/newsfragments/6038.removed.md b/newsfragments/6038.removed.md
new file mode 100644
index 00000000000..cfa1f7fdf57
--- /dev/null
+++ b/newsfragments/6038.removed.md
@@ -0,0 +1 @@
+Remove private FFI definition `_PyEval_EvalFrameDefault`.
diff --git a/pyo3-ffi-check/macro/src/lib.rs b/pyo3-ffi-check/macro/src/lib.rs
index 7151e938c2a..9363f0fabec 100644
--- a/pyo3-ffi-check/macro/src/lib.rs
+++ b/pyo3-ffi-check/macro/src/lib.rs
@@ -424,6 +424,9 @@ const MACRO_EXCLUSIONS: &[(&str, &str)] = &[
     ("Py_TYPE", "not(Py_3_14)"),
     ("Py_XDECREF", ""),
     ("Py_XINCREF", ""),
+    ("_PyCode_GetExtra", "Py_3_12"),
+    ("_PyCode_SetExtra", "Py_3_12"),
+    ("_PyEval_RequestCodeExtraIndex", "Py_3_12"),
     // These functions were only added in 3.10, but pyo3-ffi defines them for
     // all versions. Technically not macros but the machinery happens to work
     // the same way.
@@ -435,10 +438,11 @@ const MACRO_EXCLUSIONS: &[(&str, &str)] = &[
 
 // TODO: probably need to clean these up
 const EXCLUDED_SYMBOLS: &[&str] = &[
-    // CPython deprecated these but the symbols still exist, pyo3-ffi will probably clean them up anyway
-    "_PyCode_GetExtra",
-    "_PyCode_SetExtra",
-    "_PyEval_RequestCodeExtraIndex",
+    // CPython moved these to the unstable API in 3.12, we exposed these for all versions just
+    // to keep it simpler to migrate
+    "PyUnstable_Code_GetExtra",
+    "PyUnstable_Code_SetExtra",
+    "PyUnstable_Eval_RequestCodeExtraIndex",
     // FIXME: probably outdated definitions that fail to build, need investigation,
     // temporarily here to make the build pass to get CI running
     "_PyFloat_CAST",
@@ -483,10 +487,6 @@ const EXCLUDED_SYMBOLS: &[&str] = &[
     "PyObject_Vectorcall",
     "PyVectorcall_Function",
     "PyObject_VectorcallDict",
-    // Needs fixing: since 3.9 it takes thread state as first argument
-    "_PyEval_EvalFrameDefault",
-    // Needs fixing: argument count is wrong on 3.13 against headers
-    "_PyLong_AsByteArray",
     // CPython gates these on a HAVE_FORK macro, pyo3-ffi needs to replicate this?
     "PyOS_BeforeFork",
     "PyOS_AfterFork_Parent",
diff --git a/pyo3-ffi/src/cpython/ceval.rs b/pyo3-ffi/src/cpython/ceval.rs
index 682280b6c15..ea12ccfc338 100644
--- a/pyo3-ffi/src/cpython/ceval.rs
+++ b/pyo3-ffi/src/cpython/ceval.rs
@@ -1,21 +1,46 @@
 use crate::cpython::pystate::Py_tracefunc;
 use crate::object::{freefunc, PyObject};
-use core::ffi::c_int;
+use crate::Py_ssize_t;
 
 extern_libpython! {
-    // skipped non-limited _PyEval_CallTracing
+    pub fn PyEval_SetProfile(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
+    #[cfg(Py_3_12)]
+    pub fn PyEval_SetProfileAllThreads(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
+    pub fn PyEval_SetTrace(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
+    #[cfg(Py_3_12)]
+    pub fn PyEval_SetTraceAllThreads(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
 
-    #[cfg(not(Py_3_11))]
-    pub fn _PyEval_EvalFrameDefault(arg1: *mut crate::PyFrameObject, exc: c_int) -> *mut PyObject;
+    // skipped PyEval_MergeCompilerFlags
 
-    #[cfg(Py_3_11)]
-    pub fn _PyEval_EvalFrameDefault(
-        tstate: *mut crate::PyThreadState,
-        frame: *mut crate::_PyInterpreterFrame,
-        exc: c_int,
-    ) -> *mut crate::PyObject;
+    // skipped private _PyEval_EvalFrameDefault
+
+    // was moved to the unstable API tier on Py_3_12, use link_name for older versions
+    #[cfg_attr(Py_3_12, link_name = "_PyEval_RequestCodeExtraIndex")]
+    pub fn PyUnstable_Eval_RequestCodeExtraIndex(func: freefunc) -> Py_ssize_t;
+}
+
+#[deprecated(
+    since = "0.29.0",
+    note = "renamed to PyUnstable_Eval_RequestCodeExtraIndex"
+)]
+#[inline]
+pub unsafe extern "C" fn _PyEval_RequestCodeExtraIndex(func: freefunc) -> Py_ssize_t {
+    PyUnstable_Eval_RequestCodeExtraIndex(func)
+}
+
+extern_libpython! {
+
+    // skipped private _PyEval_SliceIndex
+    // skipped private _PyEval_SliceIndexNotNone
+    // skipped private _PyEval_UnpackIndices
+
+    // skipped PerfMapState
+
+    // skipped PyUnstable_PerfMapState_Init
+    // skipped PyUnstable_WritePerfMapEntry
+    // skipped PyUnstable_PerfMapState_Fini
+    // skipped PyUnstable_CopyPerfMapFile
+    // skipped PyUnstable_PerfTrampoline_CompileCode
+    // skipped PyUnstable_PerfTrampoline_SetPersistAfterFork
 
-    pub fn _PyEval_RequestCodeExtraIndex(func: freefunc) -> c_int;
-    pub fn PyEval_SetProfile(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
-    pub fn PyEval_SetTrace(trace_func: Option<Py_tracefunc>, arg1: *mut PyObject);
 }
diff --git a/pyo3-ffi/src/cpython/code.rs b/pyo3-ffi/src/cpython/code.rs
index 9744256002a..10c25cad9cd 100644
--- a/pyo3-ffi/src/cpython/code.rs
+++ b/pyo3-ffi/src/cpython/code.rs
@@ -140,10 +140,38 @@ extern_libpython! {
         names: *mut PyObject,
         lnotab: *mut PyObject,
     ) -> *mut PyObject;
-    pub fn _PyCode_GetExtra(
+
+    #[cfg_attr(not(Py_3_12), link_name = "_PyCode_GetExtra")]
+    pub fn PyUnstable_Code_GetExtra(
+        code: *mut PyObject,
+        index: Py_ssize_t,
+        extra: *mut *mut c_void,
+    ) -> c_int;
+
+    #[cfg_attr(not(Py_3_12), link_name = "_PyCode_SetExtra")]
+    pub fn PyUnstable_Code_SetExtra(
         code: *mut PyObject,
         index: Py_ssize_t,
-        extra: *const *mut c_void,
+        extra: *mut c_void,
     ) -> c_int;
-    pub fn _PyCode_SetExtra(code: *mut PyObject, index: Py_ssize_t, extra: *mut c_void) -> c_int;
+}
+
+#[deprecated(since = "0.29.0", note = "renamed to PyUnstable_Code_GetExtra")]
+#[inline]
+pub unsafe extern "C" fn _PyCode_GetExtra(
+    code: *mut PyObject,
+    index: Py_ssize_t,
+    extra: *mut *mut c_void,
+) -> c_int {
+    PyUnstable_Code_GetExtra(code, index, extra)
+}
+
+#[deprecated(since = "0.29.0", note = "renamed to PyUnstable_Code_SetExtra")]
+#[inline]
+pub unsafe extern "C" fn _PyCode_SetExtra(
+    code: *mut PyObject,
+    index: Py_ssize_t,
+    extra: *mut c_void,
+) -> c_int {
+    PyUnstable_Code_SetExtra(code, index, extra)
 }
diff --git a/pyo3-ffi/src/cpython/longobject.rs b/pyo3-ffi/src/cpython/longobject.rs
index ef0e2c465b1..f5d50979ea5 100644
--- a/pyo3-ffi/src/cpython/longobject.rs
+++ b/pyo3-ffi/src/cpython/longobject.rs
@@ -1,10 +1,13 @@
+#[cfg(not(Py_3_13))]
 use crate::longobject::*;
 use crate::object::*;
 #[cfg(Py_3_13)]
 use crate::pyport::Py_ssize_t;
+use core::ffi::c_int;
+#[cfg(not(Py_3_13))]
+use core::ffi::c_uchar;
 #[cfg(Py_3_13)]
 use core::ffi::c_void;
-use core::ffi::{c_int, c_uchar};
 use libc::size_t;
 
 #[cfg(Py_3_13)]
@@ -53,7 +56,9 @@ extern_libpython! {
     // skipped PyUnstable_Long_IsCompact
     // skipped PyUnstable_Long_CompactValue
 
+    #[cfg(not(Py_3_13))]
     #[cfg_attr(PyPy, link_name = "_PyPyLong_FromByteArray")]
+    #[doc(hidden)] // used in PyO3's older bytes conversions, but not otherwise public API
     pub fn _PyLong_FromByteArray(
         bytes: *const c_uchar,
         n: size_t,
@@ -61,6 +66,8 @@ extern_libpython! {
         is_signed: c_int,
     ) -> *mut PyObject;
 
+    #[cfg(not(Py_3_13))]
+    #[doc(hidden)] // used in PyO3's older bytes conversions, but not otherwise public API
     #[cfg_attr(PyPy, link_name = "_PyPyLong_AsByteArrayO")]
     pub fn _PyLong_AsByteArray(
         v: *mut PyLongObject,
diff --git a/pyo3-ffi/src/cpython/pyframe.rs b/pyo3-ffi/src/cpython/pyframe.rs
index b672ad103b9..1e244c14abe 100644
--- a/pyo3-ffi/src/cpython/pyframe.rs
+++ b/pyo3-ffi/src/cpython/pyframe.rs
@@ -5,7 +5,6 @@ use crate::{PyObject, PyTypeObject, Py_IS_TYPE};
 use core::ffi::c_char;
 use core::ffi::c_int;
 
-// NB used in `_PyEval_EvalFrameDefault`, maybe we remove this too.
 #[cfg(all(Py_3_11, not(PyPy)))]
 opaque_struct!(pub _PyInterpreterFrame);
 
diff --git a/pyo3-ffi/src/impl_/macros.rs b/pyo3-ffi/src/impl_/macros.rs
index 466fbb8f4de..66dfb4920f9 100644
--- a/pyo3-ffi/src/impl_/macros.rs
+++ b/pyo3-ffi/src/impl_/macros.rs
@@ -56,30 +56,6 @@ macro_rules! extern_libpython_maybe_private_fn {
     ) => {
         extern_libpython_cpython_private_fn! { $(#[$attrs])* $vis $name($($args)*) $(-> $ret)? }
     };
-    (
-        [_PyEval_EvalFrameDefault]
-        $(#[$attrs:meta])* $vis:vis fn $name:ident($($args:tt)*) $(-> $ret:ty)?
-    ) => {
-        extern_libpython_cpython_private_fn! { $(#[$attrs])* $vis $name($($args)*) $(-> $ret)? }
-    };
-    (
-        [_PyEval_RequestCodeExtraIndex]
-        $(#[$attrs:meta])* $vis:vis fn $name:ident($($args:tt)*) $(-> $ret:ty)?
-    ) => {
-        extern_libpython_cpython_private_fn! { $(#[$attrs])* $vis $name($($args)*) $(-> $ret)? }
-    };
-    (
-        [_PyCode_GetExtra]
-        $(#[$attrs:meta])* $vis:vis fn $name:ident($($args:tt)*) $(-> $ret:ty)?
-    ) => {
-        extern_libpython_cpython_private_fn! { $(#[$attrs])* $vis $name($($args)*) $(-> $ret)? }
-    };
-    (
-        [_PyCode_SetExtra]
-        $(#[$attrs:meta])* $vis:vis fn $name:ident($($args:tt)*) $(-> $ret:ty)?
-    ) => {
-        extern_libpython_cpython_private_fn! { $(#[$attrs])* $vis $name($($args)*) $(-> $ret)? }
-    };
     (
         [_PyLong_AsByteArray]
         $(#[$attrs:meta])* $vis:vis fn $name:ident($($args:tt)*) $(-> $ret:ty)?