[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>

14 files changed, 173 insertions, 23 deletions

diff --git a/arch/um/include/longjmp.h b/arch/um/include/longjmp.h
index 1b5c0131a12e..e93c6d3e893b 100644
--- a/arch/um/include/longjmp.h
+++ b/arch/um/include/longjmp.h
@@ -1,9 +1,12 @@
 #ifndef __UML_LONGJMP_H
 #define __UML_LONGJMP_H
 
-#include <setjmp.h>
+#include "sysdep/archsetjmp.h"
 #include "os.h"
 
+extern int setjmp(jmp_buf);
+extern void longjmp(jmp_buf, int);
+
 #define UML_LONGJMP(buf, val) do { \
         longjmp(*buf, val);     \
 } while(0)
diff --git a/arch/um/include/sysdep-i386/archsetjmp.h b/arch/um/include/sysdep-i386/archsetjmp.h
new file mode 100644
index 000000000000..ea1ba3d42aee
--- /dev/null
+++ b/arch/um/include/sysdep-i386/archsetjmp.h
@@ -0,0 +1,19 @@
+/*
+ * arch/i386/include/klibc/archsetjmp.h
+ */
+
+#ifndef _KLIBC_ARCHSETJMP_H
+#define _KLIBC_ARCHSETJMP_H
+
+struct __jmp_buf {
+        unsigned int __ebx;
+        unsigned int __esp;
+        unsigned int __ebp;
+        unsigned int __esi;
+        unsigned int __edi;
+        unsigned int __eip;
+};
+
+typedef struct __jmp_buf jmp_buf[1];
+
+#endif                          /* _SETJMP_H */
diff --git a/arch/um/include/sysdep-x86_64/archsetjmp.h b/arch/um/include/sysdep-x86_64/archsetjmp.h
new file mode 100644
index 000000000000..454fc60aff6d
--- /dev/null
+++ b/arch/um/include/sysdep-x86_64/archsetjmp.h
@@ -0,0 +1,21 @@
+/*
+ * arch/x86_64/include/klibc/archsetjmp.h
+ */
+
+#ifndef _KLIBC_ARCHSETJMP_H
+#define _KLIBC_ARCHSETJMP_H
+
+struct __jmp_buf {
+        unsigned long __rbx;
+        unsigned long __rsp;
+        unsigned long __rbp;
+        unsigned long __r12;
+        unsigned long __r13;
+        unsigned long __r14;
+        unsigned long __r15;
+        unsigned long __rip;
+};
+
+typedef struct __jmp_buf jmp_buf[1];
+
+#endif                          /* _SETJMP_H */
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index b98d3ca2cd1b..3afde92ad2c0 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -7,7 +7,6 @@
 #include <stdio.h>
 #include <errno.h>
 #include <signal.h>
-#include <setjmp.h>
 #include <linux/unistd.h>
 #include <sys/mman.h>
 #include <sys/wait.h>
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index 7baf90fda58b..50418a5e7134 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -8,7 +8,6 @@
 #include <unistd.h>
 #include <errno.h>
 #include <signal.h>
-#include <setjmp.h>
 #include <sched.h>
 #include "ptrace_user.h"
 #include <sys/wait.h>
@@ -470,7 +469,7 @@ void thread_wait(void *sw, void *fb)
         *switch_buf = &buf;
         fork_buf = fb;
         if(UML_SETJMP(&buf) == 0)
-                siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK);
+                UML_LONGJMP(fork_buf, INIT_JMP_REMOVE_SIGSTACK);
 }
 
 void switch_threads(void *me, void *next)
diff --git a/arch/um/os-Linux/sys-i386/registers.c b/arch/um/os-Linux/sys-i386/registers.c
index 516f66dd87e3..1f90a2d71386 100644
--- a/arch/um/os-Linux/sys-i386/registers.c
+++ b/arch/um/os-Linux/sys-i386/registers.c
@@ -5,12 +5,12 @@
 
 #include <errno.h>
 #include <string.h>
-#include <setjmp.h>
 #include "sysdep/ptrace_user.h"
 #include "sysdep/ptrace.h"
 #include "uml-config.h"
 #include "skas_ptregs.h"
 #include "registers.h"
+#include "longjmp.h"
 #include "user.h"
 
 /* These are set once at boot time and not changed thereafter */
@@ -132,9 +132,9 @@ void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
 
 void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer)
 {
-        struct __jmp_buf_tag *jmpbuf = buffer;
+        struct __jmp_buf *jmpbuf = buffer;
 
-        UPT_SET(uml_regs, EIP, jmpbuf->__jmpbuf[JB_PC]);
-        UPT_SET(uml_regs, UESP, jmpbuf->__jmpbuf[JB_SP]);
-        UPT_SET(uml_regs, EBP, jmpbuf->__jmpbuf[JB_BP]);
+        UPT_SET(uml_regs, EIP, jmpbuf->__eip);
+        UPT_SET(uml_regs, UESP, jmpbuf->__esp);
+        UPT_SET(uml_regs, EBP, jmpbuf->__ebp);
 }
diff --git a/arch/um/os-Linux/sys-x86_64/registers.c b/arch/um/os-Linux/sys-x86_64/registers.c
index becd898d9398..e730447d6c02 100644
--- a/arch/um/os-Linux/sys-x86_64/registers.c
+++ b/arch/um/os-Linux/sys-x86_64/registers.c
@@ -5,11 +5,11 @@
 
 #include <errno.h>
 #include <string.h>
-#include <setjmp.h>
 #include "ptrace_user.h"
 #include "uml-config.h"
 #include "skas_ptregs.h"
 #include "registers.h"
+#include "longjmp.h"
 #include "user.h"
 
 /* These are set once at boot time and not changed thereafter */
@@ -80,9 +80,9 @@ void get_safe_registers(unsigned long *regs, unsigned long *fp_regs)
 
 void get_thread_regs(union uml_pt_regs *uml_regs, void *buffer)
 {
-        struct __jmp_buf_tag *jmpbuf = buffer;
+        struct __jmp_buf *jmpbuf = buffer;
 
-        UPT_SET(uml_regs, RIP, jmpbuf->__jmpbuf[JB_PC]);
-        UPT_SET(uml_regs, RSP, jmpbuf->__jmpbuf[JB_RSP]);
-        UPT_SET(uml_regs, RBP, jmpbuf->__jmpbuf[JB_RBP]);
+        UPT_SET(uml_regs, RIP, jmpbuf->__rip);
+        UPT_SET(uml_regs, RSP, jmpbuf->__rsp);
+        UPT_SET(uml_regs, RBP, jmpbuf->__rbp);
 }
diff --git a/arch/um/os-Linux/trap.c b/arch/um/os-Linux/trap.c
index 90b29ae9af46..1df231a26244 100644
--- a/arch/um/os-Linux/trap.c
+++ b/arch/um/os-Linux/trap.c
@@ -5,7 +5,6 @@
 
 #include <stdlib.h>
 #include <signal.h>
-#include <setjmp.h>
 #include "kern_util.h"
 #include "user_util.h"
 #include "os.h"
diff --git a/arch/um/os-Linux/uaccess.c b/arch/um/os-Linux/uaccess.c
index 865f6a6a2590..bbb73a650370 100644
--- a/arch/um/os-Linux/uaccess.c
+++ b/arch/um/os-Linux/uaccess.c
@@ -4,8 +4,7 @@
  * Licensed under the GPL
  */
 
-#include <setjmp.h>
-#include <string.h>
+#include <stddef.h>
 #include "longjmp.h"
 
 unsigned long __do_user_copy(void *to, const void *from, int n,
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index c47a2a7ce70e..3f5b1514e8a7 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -7,7 +7,6 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <limits.h>
-#include <setjmp.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/utsname.h>
@@ -107,11 +106,11 @@ int setjmp_wrapper(void (*proc)(void *, void *), ...)
         jmp_buf buf;
         int n;
 
-        n = sigsetjmp(buf, 1);
+        n = UML_SETJMP(&buf);
         if(n == 0){
                 va_start(args, proc);
                 (*proc)(&buf, &args);
         }
         va_end(args);
-        return(n);
+        return n;
 }
diff --git a/arch/um/sys-i386/Makefile b/arch/um/sys-i386/Makefile
index 374d61a19439..59cc70275754 100644
--- a/arch/um/sys-i386/Makefile
+++ b/arch/um/sys-i386/Makefile
@@ -1,5 +1,5 @@
 obj-y = bugs.o checksum.o delay.o fault.o ksyms.o ldt.o ptrace.o \
-        ptrace_user.o signal.o sigcontext.o syscalls.o sysrq.o \
+        ptrace_user.o setjmp.o signal.o sigcontext.o syscalls.o sysrq.o \
         sys_call_table.o tls.o
 
 obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
diff --git a/arch/um/sys-i386/setjmp.S b/arch/um/sys-i386/setjmp.S
new file mode 100644
index 000000000000..b766792c9933
--- /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
diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile
index c19794d435d6..f41768b8e25e 100644
--- a/arch/um/sys-x86_64/Makefile
+++ b/arch/um/sys-x86_64/Makefile
@@ -5,8 +5,8 @@
 #
 
 obj-y = bugs.o delay.o fault.o ldt.o mem.o ptrace.o ptrace_user.o \
-        sigcontext.o signal.o syscalls.o syscall_table.o sysrq.o ksyms.o \
-        tls.o
+        setjmp.o sigcontext.o signal.o syscalls.o syscall_table.o sysrq.o \
+        ksyms.o tls.o
 
 obj-$(CONFIG_MODE_SKAS) += stub.o stub_segv.o
 obj-$(CONFIG_MODULES) += um_module.o
diff --git a/arch/um/sys-x86_64/setjmp.S b/arch/um/sys-x86_64/setjmp.S
new file mode 100644
index 000000000000..45f547b4043e
--- /dev/null
+++ b/arch/um/sys-x86_64/setjmp.S
@@ -0,0 +1,54 @@
+#
+# arch/x86_64/setjmp.S
+#
+# setjmp/longjmp for the x86-64 architecture
+#
+
+#
+# The jmp_buf is assumed to contain the following, in order:
+#       %rbx
+#       %rsp (post-return)
+#       %rbp
+#       %r12
+#       %r13
+#       %r14
+#       %r15
+#       <return address>
+#
+
+        .text
+        .align 4
+        .globl setjmp
+        .type setjmp, @function
+setjmp:
+        pop  %rsi                       # Return address, and adjust the stack
+        xorl %eax,%eax                  # Return value
+        movq %rbx,(%rdi)
+        movq %rsp,8(%rdi)               # Post-return %rsp!
+        push %rsi                       # Make the call/return stack happy
+        movq %rbp,16(%rdi)
+        movq %r12,24(%rdi)
+        movq %r13,32(%rdi)
+        movq %r14,40(%rdi)
+        movq %r15,48(%rdi)
+        movq %rsi,56(%rdi)              # Return address
+        ret
+
+        .size setjmp,.-setjmp
+
+        .text
+        .align 4
+        .globl longjmp
+        .type longjmp, @function
+longjmp:
+        movl %esi,%eax                  # Return value (int)
+        movq (%rdi),%rbx
+        movq 8(%rdi),%rsp
+        movq 16(%rdi),%rbp
+        movq 24(%rdi),%r12
+        movq 32(%rdi),%r13
+        movq 40(%rdi),%r14
+        movq 48(%rdi),%r15
+        jmp *56(%rdi)
+
+        .size longjmp,.-longjmp