From a79cec095d20bca36305211ce36b6f92a96b1245 Mon Sep 17 00:00:00 2001
From: Manuel Novoa III <mjn3@codepoet.org>
Date: Wed, 27 Jun 2001 17:59:13 +0000
Subject: Make these PIC and _LIBC_REENTRANT compatible.

---
 libc/sysdeps/linux/i386/__uClibc_syscall.S | 50 +++++++++++++++++++++++++++---
 libc/sysdeps/linux/i386/vfork.S            | 47 +++++++++++++++++++++++++---
 2 files changed, 89 insertions(+), 8 deletions(-)

(limited to 'libc')

diff --git a/libc/sysdeps/linux/i386/__uClibc_syscall.S b/libc/sysdeps/linux/i386/__uClibc_syscall.S
index cc785efd7..b79d2666e 100644
--- a/libc/sysdeps/linux/i386/__uClibc_syscall.S
+++ b/libc/sysdeps/linux/i386/__uClibc_syscall.S
@@ -1,3 +1,21 @@
+/*
+ * June 27, 2001             Manuel Novoa III
+ *
+ * This is a heavily modified version of gcc's output for the syscall5 macro.
+ * The idea (originally from dietlibc) is that all syscall functions simply
+ * set the syscall number in %al (since <= 255) and then jump here.  All the
+ * common work is done by __uClibc_syscall, saving a fair amount of generated
+ * code where a number of syscalls are used.  The (potential) cost is some 
+ * unnecessary pushes, pops, and movs but the execution time penalty should
+ * be relatively small compared to the cost of the syscall itself.
+ *
+ * WARNING: If the startup code for uClibc changes, I suppose it is possible
+ *          that this code might try to access memory under the bottom of
+ *          the stack.
+ * WARNING: This will need to be modified if the number of syscalls ever
+ *          exceeds 255.  So will the associated syscall macros.
+ */
+	
 .text
 	.align 4
 .globl __uClibc_syscall
@@ -16,15 +34,39 @@ __uClibc_syscall:
 	int $0x80
 #NO_APP
 	cmpl $-4095,%eax
-	jbe .L5
+	jbe .Ldone
+
+#ifdef PIC
+	call Lhere
+Lhere:
+	popl %ebx
+	addl $_GLOBAL_OFFSET_TABLE_+[.-Lhere],%ebx
+	negl %eax
+	movl %eax,%ecx
+#ifdef _LIBC_REENTRANT
+	call __errno_location@PLT
+#else
+	movl errno@GOT(%ebx),%eax
+#endif /* _LIBC_REENTRANT */
+	movl %ecx,(%eax)
+#else
 	negl %eax
+#ifdef _LIBC_REENTRANT
+	movl %eax,%ecx
+	call __errno_location
+	movl %ecx,(%eax)
+#else
 	movl %eax,errno
+#endif /* _LIBC_REENTRANT */
+
+#endif /* PIC */
+
 	movl $-1,%eax
 	.p2align 4,,7
-.L5:
+.Ldone:
 	popl %ebx
 	popl %esi
 	popl %edi
 	ret
-.Lfe1:
-	.size	 __uClibc_syscall,.Lfe1-__uClibc_syscall
+.Lsize:
+	.size	 __uClibc_syscall,.Lsize-__uClibc_syscall
diff --git a/libc/sysdeps/linux/i386/vfork.S b/libc/sysdeps/linux/i386/vfork.S
index 5775daee3..10e95b170 100644
--- a/libc/sysdeps/linux/i386/vfork.S
+++ b/libc/sysdeps/linux/i386/vfork.S
@@ -1,3 +1,10 @@
+/*
+ * June 27, 2001             Manuel Novoa III
+ *
+ * Modified to (hopefully) be PIC and REENTRANT safe.
+ *
+ */
+	
 .text
 	.align 4
 .globl vfork
@@ -5,18 +12,50 @@
 vfork:
 	popl %ecx
 	movl $190,%eax
+#ifdef PIC
+	pushl %ebx
+#endif
 #APP
 	int $0x80
 #NO_APP
+#ifdef PIC
+	popl %ebx
+#endif
 	cmpl $-4095,%eax
-	jae .L5
+	jae .Lerror
 	jmp *%ecx
 	.p2align 4,,7
-.L5:
+.Lerror:
 	pushl %ecx
+
+#ifdef PIC
+	pushl %ebx
+	call .Lhere
+.Lhere:
+	popl %ebx
+	addl $_GLOBAL_OFFSET_TABLE_+[.-.Lhere],%ebx
 	negl %eax
+	movl %eax,%ecx
+#ifdef _LIBC_REENTRANT
+	call __errno_location@PLT
+#else
+	movl errno@GOT(%ebx),%eax
+#endif /* _LIBC_REENTRANT */
+	movl %ecx,(%eax)
+	popl %ebx
+#else
+	negl %eax
+#ifdef _LIBC_REENTRANT
+	movl %eax,%ecx
+	call __errno_location
+	movl %ecx,(%eax)
+#else
 	movl %eax,errno
+#endif /* _LIBC_REENTRANT */
+
+#endif /* PIC */
+	
 	movl $-1,%eax
 	ret
-.Lfe1:
-	.size	 vfork,.Lfe1-vfork
+.Lsize:
+	.size	 vfork,.Lsize-vfork
-- 
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