From 513b63201d667366feb69ad7de2ffcb373f2f515 Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Sun, 9 Sep 2018 18:09:08 +0200
Subject: extra/sbcl: introduce the necessary patch(es)

---
 extra/sbcl/x86-linux-os.patch | 112 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 extra/sbcl/x86-linux-os.patch

(limited to 'extra/sbcl/x86-linux-os.patch')

diff --git a/extra/sbcl/x86-linux-os.patch b/extra/sbcl/x86-linux-os.patch
new file mode 100644
index 00000000..c1fd12b7
--- /dev/null
+++ b/extra/sbcl/x86-linux-os.patch
@@ -0,0 +1,112 @@
+--- sbcl-1.4.10/src/runtime/x86-linux-os.c.orig	2018-09-07 03:07:10.927918139 +0000
++++ sbcl-1.4.10/src/runtime/x86-linux-os.c	2018-09-07 03:05:10.471896471 +0000
+@@ -45,73 +45,43 @@
+ #include <linux/version.h>
+ #include "thread.h"             /* dynamic_values_bytes */
+ 
+-#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,0)
+-#define user_desc  modify_ldt_ldt_s
+-#endif
+-
+-static inline int modify_ldt(int func, void *ptr, unsigned long bytecount)
++static inline int set_thread_area(struct user_desc *u_info)
+ {
+-  return syscall(SYS_modify_ldt, func, ptr, bytecount);
++    return syscall(SYS_set_thread_area, u_info);
+ }
+ 
+ #include "validate.h"
+ size_t os_vm_page_size;
+ 
+-u32 local_ldt_copy[LDT_ENTRIES*LDT_ENTRY_SIZE/sizeof(u32)];
+-
+-/* This is never actually called, but it's great for calling from gdb when
+- * users have thread-related problems that maintainers can't duplicate */
+-
+-void debug_get_ldt()
+-{
+-    int n=modify_ldt (0, local_ldt_copy, sizeof local_ldt_copy);
+-    printf("%d bytes in ldt: print/x local_ldt_copy\n", n);
+-}
+-
+-#ifdef LISP_FEATURE_SB_THREAD
+-pthread_mutex_t modify_ldt_lock = PTHREAD_MUTEX_INITIALIZER;
+-#endif
+-
+ int arch_os_thread_init(struct thread *thread) {
+     stack_t sigstack;
+ #ifdef LISP_FEATURE_SB_THREAD
+-    struct user_desc ldt_entry = {
+-        1, 0, 0, /* index, address, length filled in later */
+-        1, MODIFY_LDT_CONTENTS_DATA, 0, 0, 0, 1
++    struct user_desc desc = {
++        0, (unsigned long) thread, dynamic_values_bytes,
++        1, 0, 0, 1, 0, 1
+     };
+-    int n;
+-    thread_mutex_lock(&modify_ldt_lock);
+-    n=modify_ldt(0,local_ldt_copy,sizeof local_ldt_copy);
+-    /* get next free ldt entry */
+-
+-    if(n) {
+-        u32 *p;
+-        for(n=0,p=local_ldt_copy;*p;p+=LDT_ENTRY_SIZE/sizeof(u32))
+-            n++;
+-    }
+-    ldt_entry.entry_number=n;
+-    ldt_entry.base_addr=(unsigned long) thread;
+-    ldt_entry.limit=dynamic_values_bytes;
+-    ldt_entry.limit_in_pages=0;
+-    if (modify_ldt (1, &ldt_entry, sizeof (ldt_entry)) != 0) {
+-        thread_mutex_unlock(&modify_ldt_lock);
+-        /* modify_ldt call failed: something magical is not happening */
++
++    static int entry_number = -1;
++
++    desc.entry_number = entry_number;
++
++    if (set_thread_area(&desc) != 0) {
+         return 0;
+     }
++
++    entry_number = desc.entry_number;
++
+     __asm__ __volatile__ ("movw %w0, %%fs" : : "q"
+-                          ((n << 3) /* selector number */
+-                           + (1 << 2) /* TI set = LDT */
+-                           + 3)); /* privilege level */
+-    thread->tls_cookie=n;
+-    pthread_mutex_unlock(&modify_ldt_lock);
++                          ((entry_number << 3) + 3));
+ 
+-    if(n<0) return 0;
++    if(entry_number < 0) return 0;
+ #ifdef LISP_FEATURE_GCC_TLS
+     current_thread = thread;
+ #else
+     pthread_setspecific(specials,thread);
+ #endif
+ #endif
++
+ #ifdef LISP_FEATURE_C_STACK_IS_CONTROL_STACK
+     /* Signal handlers are run on the control stack, so if it is exhausted
+      * we had better use an alternate stack for whatever signal tells us
+@@ -136,17 +106,7 @@
+  */
+ 
+ int arch_os_thread_cleanup(struct thread *thread) {
+-    struct user_desc ldt_entry = {
+-        0, 0, 0,
+-        0, MODIFY_LDT_CONTENTS_DATA, 0, 0, 0, 0
+-    };
+-    int result;
+-
+-    ldt_entry.entry_number=thread->tls_cookie;
+-    thread_mutex_lock(&modify_ldt_lock);
+-    result = modify_ldt(1, &ldt_entry, sizeof (ldt_entry));
+-    thread_mutex_unlock(&modify_ldt_lock);
+-    return result;
++    return 1;
+ }
+ 
+ 
-- 
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