Remove references to seL4_IPCBuffer.userData

This field is no longer needed to store a reference to the IPC buffer.

libsel4platsupport/src/bootinfo.c

diff --git a/libsel4platsupport/src/bootinfo.c b/libsel4platsupport/src/bootinfo.c
index 7320e33..d8d099c 100644
--- a/libsel4platsupport/src/bootinfo.c
+++ b/libsel4platsupport/src/bootinfo.c
@@ -24,8 +24,6 @@
         ZF_LOGE("Attempted %s in an environment without bootinfo.", __FUNCTION__);
         return NULL;
     }
-    /* Save the address of the IPC buffer for seL4_GetIPCBuffer on IA32. */
-    seL4_SetUserData((seL4_Word)bootinfo->ipcBuffer);
     return bootinfo;
 }
 

libsel4utils/src/thread.c

diff --git a/libsel4utils/src/thread.c b/libsel4utils/src/thread.c
index 14a91c6..13e94a2 100644
--- a/libsel4utils/src/thread.c
+++ b/libsel4utils/src/thread.c
@@ -31,17 +31,6 @@
 #include <sel4utils/helpers.h>
 #include <utils/stack.h>
 
-static int write_ipc_buffer_user_data(vka_t *vka, vspace_t *vspace, seL4_CPtr ipc_buf, uintptr_t buf_loc)
-{
-    void *mapping = sel4utils_dup_and_map(vka, vspace, ipc_buf, seL4_PageBits);
-    if (!mapping) {
-        return -1;
-    }
-    seL4_IPCBuffer *buffer = mapping;
-    buffer->userData = buf_loc;
-    sel4utils_unmap_dup(vka, vspace, mapping, seL4_PageBits);
-    return 0;
-}
 
 int sel4utils_configure_thread(vka_t *vka, vspace_t *parent, vspace_t *alloc, seL4_CPtr fault_endpoint,
                                seL4_CNode cspace, seL4_Word cspace_root_data, sel4utils_thread_t *res)
@@ -73,11 +62,6 @@
             ZF_LOGE("ipc buffer allocation failed");
             return -1;
         }
-
-        if (write_ipc_buffer_user_data(vka, parent, res->ipc_buffer, res->ipc_buffer_addr)) {
-            ZF_LOGE("failed to set user data word in IPC buffer");
-            return -1;
-        }
     }
 
     if (config_set(CONFIG_KERNEL_RT) && config.create_reply) {