Merge pull request #3808 from LemonBoy/i386-for-ya

linux-i386 support

1 files changed, 29 insertions, 2 deletions

diff --git a/lib/std/thread.zig b/lib/std/thread.zig
index fe976a6839..571773dcae 100644
--- a/lib/std/thread.zig
+++ b/lib/std/thread.zig
@@ -314,11 +314,38 @@ pub const Thread = struct {
                 os.CLONE_THREAD | os.CLONE_SYSVSEM | os.CLONE_PARENT_SETTID | os.CLONE_CHILD_CLEARTID |
                 os.CLONE_DETACHED;
             var newtls: usize = undefined;
+            // This structure is only needed when targeting i386
+            var user_desc: if (builtin.arch == .i386) os.linux.user_desc else void = undefined;
+
             if (os.linux.tls.tls_image) |tls_img| {
-                newtls = os.linux.tls.copyTLS(mmap_addr + tls_start_offset);
+                if (builtin.arch == .i386) {
+                    user_desc = os.linux.user_desc{
+                        .entry_number = tls_img.gdt_entry_number,
+                        .base_addr = os.linux.tls.copyTLS(mmap_addr + tls_start_offset),
+                        .limit = 0xfffff,
+                        .seg_32bit = 1,
+                        .contents = 0, // Data
+                        .read_exec_only = 0,
+                        .limit_in_pages = 1,
+                        .seg_not_present = 0,
+                        .useable = 1,
+                    };
+                    newtls = @ptrToInt(&user_desc);
+                } else {
+                    newtls = os.linux.tls.copyTLS(mmap_addr + tls_start_offset);
+                }
                 flags |= os.CLONE_SETTLS;
             }
-            const rc = os.linux.clone(MainFuncs.linuxThreadMain, mmap_addr + stack_end_offset, flags, arg, &thread_ptr.data.handle, newtls, &thread_ptr.data.handle);
+
+            const rc = os.linux.clone(
+                MainFuncs.linuxThreadMain,
+                mmap_addr + stack_end_offset,
+                flags,
+                arg,
+                &thread_ptr.data.handle,
+                newtls,
+                &thread_ptr.data.handle,
+            );
             switch (os.errno(rc)) {
                 0 => return thread_ptr,
                 os.EAGAIN => return error.ThreadQuotaExceeded,