[PATCH] uml: Use klibc setjmp/longjmp
This patch adds an implementation of setjmp and longjmp to UML, allowing
access to the inside of a jmpbuf without needing the access macros formerly
provided by libc.
The implementation is stolen from klibc. I copy the relevant files into
arch/um. I have another patch which avoids the copying, but requires klibc be
in the tree.
setjmp and longjmp users required some tweaking. Includes of <setjmp.h> were
removed and includes of the UML longjmp.h were added where necessary. There
are also replacements of siglongjmp with UML_LONGJMP which I somehow missed
earlier.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/sys-i386/setjmp.S b/arch/um/sys-i386/setjmp.S
new file mode 100644
index 0000000..b766792
--- /dev/null
+++ b/arch/um/sys-i386/setjmp.S
@@ -0,0 +1,58 @@
+#
+# arch/i386/setjmp.S
+#
+# setjmp/longjmp for the i386 architecture
+#
+
+#
+# The jmp_buf is assumed to contain the following, in order:
+# %ebx
+# %esp
+# %ebp
+# %esi
+# %edi
+# <return address>
+#
+
+ .text
+ .align 4
+ .globl setjmp
+ .type setjmp, @function
+setjmp:
+#ifdef _REGPARM
+ movl %eax,%edx
+#else
+ movl 4(%esp),%edx
+#endif
+ popl %ecx # Return address, and adjust the stack
+ xorl %eax,%eax # Return value
+ movl %ebx,(%edx)
+ movl %esp,4(%edx) # Post-return %esp!
+ pushl %ecx # Make the call/return stack happy
+ movl %ebp,8(%edx)
+ movl %esi,12(%edx)
+ movl %edi,16(%edx)
+ movl %ecx,20(%edx) # Return address
+ ret
+
+ .size setjmp,.-setjmp
+
+ .text
+ .align 4
+ .globl longjmp
+ .type longjmp, @function
+longjmp:
+#ifdef _REGPARM
+ xchgl %eax,%edx
+#else
+ movl 4(%esp),%edx # jmp_ptr address
+ movl 8(%esp),%eax # Return value
+#endif
+ movl (%edx),%ebx
+ movl 4(%edx),%esp
+ movl 8(%edx),%ebp
+ movl 12(%edx),%esi
+ movl 16(%edx),%edi
+ jmp *20(%edx)
+
+ .size longjmp,.-longjmp