[PATCH 7/11] UML - Move libc-dependent skas process handling

From: Jeff Dike
Date: Sun Jan 15 2006 - 15:50:28 EST

From: Gennady Sharapov <Gennady.V.Sharapov@xxxxxxxxx>

The serial UML OS-abstraction layer patch (um/kernel/skas dir).

This moves all systemcalls from skas/process.c file under
os-Linux dir and join skas/process.c and skas/process_kern.c files.

Signed-off-by: Gennady Sharapov <gennady.v.sharapov@xxxxxxxxx>
Signed-off-by: Jeff Dike <jdike@xxxxxxxxxxx>

Index: linux-2.6.15-mm/arch/um/include/os.h
===================================================================
--- linux-2.6.15-mm.orig/arch/um/include/os.h 2006-01-09 11:30:10.000000000 -0500
+++ linux-2.6.15-mm/arch/um/include/os.h 2006-01-09 11:35:10.000000000 -0500
@@ -232,6 +232,7 @@ extern void block_signals(void);
extern void unblock_signals(void);
extern int get_signals(void);
extern int set_signals(int enable);
+extern void os_usr1_signal(int on);

/* trap.c */
extern void os_fill_handlinfo(struct kern_handlers h);
@@ -272,4 +273,22 @@ extern int protect(struct mm_id * mm_idp
unsigned long len, int r, int w, int x, int done,
void **data);

+/* skas/process.c */
+extern int is_skas_winch(int pid, int fd, void *data);
+extern int start_userspace(unsigned long stub_stack);
+extern int copy_context_skas0(unsigned long stack, int pid);
+extern void userspace(union uml_pt_regs *regs);
+extern void map_stub_pages(int fd, unsigned long code,
+ unsigned long data, unsigned long stack);
+extern void new_thread(void *stack, void **switch_buf_ptr,
+ void **fork_buf_ptr, void (*handler)(int));
+extern void thread_wait(void *sw, void *fb);
+extern void switch_threads(void *me, void *next);
+extern int start_idle_thread(void *stack, void *switch_buf_ptr,
+ void **fork_buf_ptr);
+extern void initial_thread_cb_skas(void (*proc)(void *),
+ void *arg);
+extern void halt_skas(void);
+extern void reboot_skas(void);
+
#endif
Index: linux-2.6.15-mm/arch/um/include/skas/mode-skas.h
===================================================================
--- linux-2.6.15-mm.orig/arch/um/include/skas/mode-skas.h 2006-01-09 11:26:24.000000000 -0500
+++ linux-2.6.15-mm/arch/um/include/skas/mode-skas.h 2006-01-09 11:35:10.000000000 -0500
@@ -14,9 +14,6 @@ extern unsigned long exec_fpx_regs[];
extern int have_fpx_regs;

extern void sig_handler_common_skas(int sig, void *sc_ptr);
-extern void halt_skas(void);
-extern void reboot_skas(void);
extern void kill_off_processes_skas(void);
-extern int is_skas_winch(int pid, int fd, void *data);

#endif
Index: linux-2.6.15-mm/arch/um/include/skas/mode_kern_skas.h
===================================================================
--- linux-2.6.15-mm.orig/arch/um/include/skas/mode_kern_skas.h 2006-01-09 11:26:24.000000000 -0500
+++ linux-2.6.15-mm/arch/um/include/skas/mode_kern_skas.h 2006-01-09 11:35:10.000000000 -0500
@@ -18,7 +18,6 @@ extern int copy_thread_skas(int nr, unsi
unsigned long sp, unsigned long stack_top,
struct task_struct *p, struct pt_regs *regs);
extern void release_thread_skas(struct task_struct *task);
-extern void initial_thread_cb_skas(void (*proc)(void *), void *arg);
extern void init_idle_skas(void);
extern void flush_tlb_kernel_range_skas(unsigned long start,
unsigned long end);
Index: linux-2.6.15-mm/arch/um/include/skas/skas.h
===================================================================
--- linux-2.6.15-mm.orig/arch/um/include/skas/skas.h 2006-01-09 11:30:10.000000000 -0500
+++ linux-2.6.15-mm/arch/um/include/skas/skas.h 2006-01-09 11:35:37.000000000 -0500
@@ -13,21 +13,12 @@ extern int userspace_pid[];
extern int proc_mm, ptrace_faultinfo, ptrace_ldt;
extern int skas_needs_stub;

-extern void switch_threads(void *me, void *next);
-extern void thread_wait(void *sw, void *fb);
-extern void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
- void (*handler)(int));
-extern int start_idle_thread(void *stack, void *switch_buf_ptr,
- void **fork_buf_ptr);
extern int user_thread(unsigned long stack, int flags);
-extern void userspace(union uml_pt_regs *regs);
extern void new_thread_proc(void *stack, void (*handler)(int sig));
extern void new_thread_handler(int sig);
extern void handle_syscall(union uml_pt_regs *regs);
extern void user_signal(int sig, union uml_pt_regs *regs, int pid);
extern int new_mm(unsigned long stack);
-extern int start_userspace(unsigned long stub_stack);
-extern int copy_context_skas0(unsigned long stack, int pid);
extern void get_skas_faultinfo(int pid, struct faultinfo * fi);
extern long execute_syscall_skas(void *r);
extern unsigned long current_stub_stack(void);
Index: linux-2.6.15-mm/arch/um/kernel/skas/Makefile
===================================================================
--- linux-2.6.15-mm.orig/arch/um/kernel/skas/Makefile 2006-01-09 11:30:10.000000000 -0500
+++ linux-2.6.15-mm/arch/um/kernel/skas/Makefile 2006-01-09 11:35:10.000000000 -0500
@@ -3,10 +3,10 @@
# Licensed under the GPL
#

-obj-y := clone.o exec_kern.o mem.o mmu.o process.o process_kern.o \
+obj-y := clone.o exec_kern.o mem.o mmu.o process_kern.o \
syscall.o tlb.o uaccess.o

-USER_OBJS := process.o clone.o
+USER_OBJS := clone.o

include arch/um/scripts/Makefile.rules

Index: linux-2.6.15-mm/arch/um/kernel/skas/process_kern.c
===================================================================
--- linux-2.6.15-mm.orig/arch/um/kernel/skas/process_kern.c 2006-01-09 11:26:24.000000000 -0500
+++ linux-2.6.15-mm/arch/um/kernel/skas/process_kern.c 2006-01-09 11:40:19.000000000 -0500
@@ -1,4 +1,4 @@
-/*
+/*
* Copyright (C) 2002 Jeff Dike (jdike@xxxxxxxxxx)
* Licensed under the GPL
*/
@@ -32,7 +32,7 @@ void switch_to_skas(void *prev, void *ne
if(current->pid == 0)
switch_timers(0);

- switch_threads(&from->thread.mode.skas.switch_buf,
+ switch_threads(&from->thread.mode.skas.switch_buf,
to->thread.mode.skas.switch_buf);

if(current->pid == 0)
@@ -48,8 +48,8 @@ void new_thread_handler(int sig)

fn = current->thread.request.u.thread.proc;
arg = current->thread.request.u.thread.arg;
- change_sig(SIGUSR1, 1);
- thread_wait(&current->thread.mode.skas.switch_buf,
+ os_usr1_signal(1);
+ thread_wait(&current->thread.mode.skas.switch_buf,
current->thread.mode.skas.fork_buf);

if(current->thread.prev_sched != NULL)
@@ -80,8 +80,8 @@ void release_thread_skas(struct task_str

void fork_handler(int sig)
{
- change_sig(SIGUSR1, 1);
- thread_wait(&current->thread.mode.skas.switch_buf,
+ os_usr1_signal(1);
+ thread_wait(&current->thread.mode.skas.switch_buf,
current->thread.mode.skas.fork_buf);

force_flush_all();
@@ -91,13 +91,13 @@ void fork_handler(int sig)
schedule_tail(current->thread.prev_sched);
current->thread.prev_sched = NULL;

- /* Handle any immediate reschedules or signals */
+/* Handle any immediate reschedules or signals */
interrupt_end();
userspace(&current->thread.regs.regs);
}

int copy_thread_skas(int nr, unsigned long clone_flags, unsigned long sp,
- unsigned long stack_top, struct task_struct * p,
+ unsigned long stack_top, struct task_struct * p,
struct pt_regs *regs)
{
void (*handler)(int);
@@ -121,8 +121,6 @@ int copy_thread_skas(int nr, unsigned lo
return(0);
}

-extern void map_stub_pages(int fd, unsigned long code,
- unsigned long data, unsigned long stack);
int new_mm(unsigned long stack)
{
int fd;
Index: linux-2.6.15-mm/arch/um/os-Linux/signal.c
===================================================================
--- linux-2.6.15-mm.orig/arch/um/os-Linux/signal.c 2006-01-09 11:26:24.000000000 -0500
+++ linux-2.6.15-mm/arch/um/os-Linux/signal.c 2006-01-09 11:35:10.000000000 -0500
@@ -194,3 +194,8 @@ int set_signals(int enable)

return(ret);
}
+
+void os_usr1_signal(int on)
+{
+ change_sig(SIGUSR1, on);
+}
Index: linux-2.6.15-mm/arch/um/os-Linux/skas/Makefile
===================================================================
--- linux-2.6.15-mm.orig/arch/um/os-Linux/skas/Makefile 2006-01-09 11:30:10.000000000 -0500
+++ linux-2.6.15-mm/arch/um/os-Linux/skas/Makefile 2006-01-09 11:35:10.000000000 -0500
@@ -3,8 +3,8 @@
# Licensed under the GPL
#

-obj-y := mem.o trap.o
+obj-y := mem.o process.o trap.o

-USER_OBJS := mem.o trap.o
+USER_OBJS := mem.o process.o trap.o

include arch/um/scripts/Makefile.rules
Index: linux-2.6.15-mm/arch/um/os-Linux/skas/process.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.15-mm/arch/um/os-Linux/skas/process.c 2006-01-09 11:39:54.000000000 -0500
@@ -0,0 +1,565 @@
+/*
+ * Copyright (C) 2002- 2004 Jeff Dike (jdike@xxxxxxxxxxx)
+ * Licensed under the GPL
+ */
+
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <setjmp.h>
+#include <sched.h>
+#include "ptrace_user.h"
+#include <sys/wait.h>
+#include <sys/mman.h>
+#include <sys/user.h>
+#include <sys/time.h>
+#include <asm/unistd.h>
+#include <asm/types.h>
+#include "user.h"
+#include "sysdep/ptrace.h"
+#include "user_util.h"
+#include "kern_util.h"
+#include "skas.h"
+#include "stub-data.h"
+#include "mm_id.h"
+#include "sysdep/sigcontext.h"
+#include "sysdep/stub.h"
+#include "os.h"
+#include "proc_mm.h"
+#include "skas_ptrace.h"
+#include "chan_user.h"
+#include "registers.h"
+#include "mem.h"
+#include "uml-config.h"
+#include "process.h"
+
+int is_skas_winch(int pid, int fd, void *data)
+{
+ if(pid != os_getpgrp())
+ return(0);
+
+ register_winch_irq(-1, fd, -1, data);
+ return(1);
+}
+
+void wait_stub_done(int pid, int sig, char * fname)
+{
+ int n, status, err;
+
+ do {
+ if ( sig != -1 ) {
+ err = ptrace(PTRACE_CONT, pid, 0, sig);
+ if(err)
+ panic("%s : continue failed, errno = %d\n",
+ fname, errno);
+ }
+ sig = 0;
+
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ } while((n >= 0) && WIFSTOPPED(status) &&
+ ((WSTOPSIG(status) == SIGVTALRM) ||
+ /* running UML inside a detached screen can cause
+ * SIGWINCHes
+ */
+ (WSTOPSIG(status) == SIGWINCH)));
+
+ if((n < 0) || !WIFSTOPPED(status) ||
+ (WSTOPSIG(status) != SIGUSR1 && WSTOPSIG(status) != SIGTRAP)){
+ unsigned long regs[HOST_FRAME_SIZE];
+
+ if(ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
+ printk("Failed to get registers from stub, "
+ "errno = %d\n", errno);
+ else {
+ int i;
+
+ printk("Stub registers -\n");
+ for(i = 0; i < HOST_FRAME_SIZE; i++)
+ printk("\t%d - %lx\n", i, regs[i]);
+ }
+ panic("%s : failed to wait for SIGUSR1/SIGTRAP, "
+ "pid = %d, n = %d, errno = %d, status = 0x%x\n",
+ fname, pid, n, errno, status);
+ }
+}
+
+extern unsigned long current_stub_stack(void);
+
+void get_skas_faultinfo(int pid, struct faultinfo * fi)
+{
+ int err;
+
+ if(ptrace_faultinfo){
+ err = ptrace(PTRACE_FAULTINFO, pid, 0, fi);
+ if(err)
+ panic("get_skas_faultinfo - PTRACE_FAULTINFO failed, "
+ "errno = %d\n", errno);
+
+ /* Special handling for i386, which has different structs */
+ if (sizeof(struct ptrace_faultinfo) < sizeof(struct faultinfo))
+ memset((char *)fi + sizeof(struct ptrace_faultinfo), 0,
+ sizeof(struct faultinfo) -
+ sizeof(struct ptrace_faultinfo));
+ }
+ else {
+ wait_stub_done(pid, SIGSEGV, "get_skas_faultinfo");
+
+ /* faultinfo is prepared by the stub-segv-handler at start of
+ * the stub stack page. We just have to copy it.
+ */
+ memcpy(fi, (void *)current_stub_stack(), sizeof(*fi));
+ }
+}
+
+static void handle_segv(int pid, union uml_pt_regs * regs)
+{
+ get_skas_faultinfo(pid, &regs->skas.faultinfo);
+ segv(regs->skas.faultinfo, 0, 1, NULL);
+}
+
+/*To use the same value of using_sysemu as the caller, ask it that value (in local_using_sysemu)*/
+static void handle_trap(int pid, union uml_pt_regs *regs, int local_using_sysemu)
+{
+ int err, status;
+
+ /* Mark this as a syscall */
+ UPT_SYSCALL_NR(regs) = PT_SYSCALL_NR(regs->skas.regs);
+
+ if (!local_using_sysemu)
+ {
+ err = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
+ __NR_getpid);
+ if(err < 0)
+ panic("handle_trap - nullifying syscall failed errno = %d\n",
+ errno);
+
+ err = ptrace(PTRACE_SYSCALL, pid, 0, 0);
+ if(err < 0)
+ panic("handle_trap - continuing to end of syscall failed, "
+ "errno = %d\n", errno);
+
+ CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
+ if((err < 0) || !WIFSTOPPED(status) ||
+ (WSTOPSIG(status) != SIGTRAP + 0x80))
+ panic("handle_trap - failed to wait at end of syscall, "
+ "errno = %d, status = %d\n", errno, status);
+ }
+
+ handle_syscall(regs);
+}
+
+extern int __syscall_stub_start;
+int stub_code_fd = -1;
+__u64 stub_code_offset;
+
+static int userspace_tramp(void *stack)
+{
+ void *addr;
+
+ ptrace(PTRACE_TRACEME, 0, 0, 0);
+
+ init_new_thread_signals(1);
+ enable_timer();
+
+ if(!proc_mm){
+ /* This has a pte, but it can't be mapped in with the usual
+ * tlb_flush mechanism because this is part of that mechanism
+ */
+ addr = mmap64((void *) UML_CONFIG_STUB_CODE, page_size(),
+ PROT_EXEC, MAP_FIXED | MAP_PRIVATE,
+ stub_code_fd, stub_code_offset);
+ if(addr == MAP_FAILED){
+ printk("mapping stub code failed, errno = %d\n",
+ errno);
+ exit(1);
+ }
+
+ if(stack != NULL){
+ int fd;
+ __u64 offset;
+ fd = phys_mapping(to_phys(stack), &offset);
+ addr = mmap((void *) UML_CONFIG_STUB_DATA, page_size(),
+ PROT_READ | PROT_WRITE,
+ MAP_FIXED | MAP_SHARED, fd, offset);
+ if(addr == MAP_FAILED){
+ printk("mapping stub stack failed, "
+ "errno = %d\n", errno);
+ exit(1);
+ }
+ }
+ }
+ if(!ptrace_faultinfo){
+ unsigned long v = UML_CONFIG_STUB_CODE +
+ (unsigned long) stub_segv_handler -
+ (unsigned long) &__syscall_stub_start;
+
+ set_sigstack((void *) UML_CONFIG_STUB_DATA, page_size());
+ set_handler(SIGSEGV, (void *) v, SA_ONSTACK,
+ SIGIO, SIGWINCH, SIGALRM, SIGVTALRM,
+ SIGUSR1, -1);
+ }
+
+ os_stop_process(os_getpid());
+ return(0);
+}
+
+/* Each element set once, and only accessed by a single processor anyway */
+#undef NR_CPUS
+#define NR_CPUS 1
+int userspace_pid[NR_CPUS];
+
+int start_userspace(unsigned long stub_stack)
+{
+ void *stack;
+ unsigned long sp;
+ int pid, status, n, flags;
+
+ if ( stub_code_fd == -1 )
+ stub_code_fd = phys_mapping(to_phys(&__syscall_stub_start),
+ &stub_code_offset);
+
+ stack = mmap(NULL, PAGE_SIZE, PROT_READ | PROT_WRITE | PROT_EXEC,
+ MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ if(stack == MAP_FAILED)
+ panic("start_userspace : mmap failed, errno = %d", errno);
+ sp = (unsigned long) stack + PAGE_SIZE - sizeof(void *);
+
+ flags = CLONE_FILES | SIGCHLD;
+ if(proc_mm) flags |= CLONE_VM;
+ pid = clone(userspace_tramp, (void *) sp, flags, (void *) stub_stack);
+ if(pid < 0)
+ panic("start_userspace : clone failed, errno = %d", errno);
+
+ do {
+ CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
+ if(n < 0)
+ panic("start_userspace : wait failed, errno = %d",
+ errno);
+ } while(WIFSTOPPED(status) && (WSTOPSIG(status) == SIGVTALRM));
+
+ if(!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
+ panic("start_userspace : expected SIGSTOP, got status = %d",
+ status);
+
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL, (void *)PTRACE_O_TRACESYSGOOD) < 0)
+ panic("start_userspace : PTRACE_OLDSETOPTIONS failed, errno=%d\n",
+ errno);
+
+ if(munmap(stack, PAGE_SIZE) < 0)
+ panic("start_userspace : munmap failed, errno = %d\n", errno);
+
+ return(pid);
+}
+
+void userspace(union uml_pt_regs *regs)
+{
+ int err, status, op, pid = userspace_pid[0];
+ int local_using_sysemu; /*To prevent races if using_sysemu changes under us.*/
+
+ while(1){
+ restore_registers(pid, regs);
+
+ /* Now we set local_using_sysemu to be used for one loop */
+ local_using_sysemu = get_using_sysemu();
+
+ op = SELECT_PTRACE_OPERATION(local_using_sysemu, singlestepping(NULL));
+
+ err = ptrace(op, pid, 0, 0);
+ if(err)
+ panic("userspace - could not resume userspace process, "
+ "pid=%d, ptrace operation = %d, errno = %d\n",
+ op, errno);
+
+ CATCH_EINTR(err = waitpid(pid, &status, WUNTRACED));
+ if(err < 0)
+ panic("userspace - waitpid failed, errno = %d\n",
+ errno);
+
+ regs->skas.is_user = 1;
+ save_registers(pid, regs);
+ UPT_SYSCALL_NR(regs) = -1; /* Assume: It's not a syscall */
+
+ if(WIFSTOPPED(status)){
+ switch(WSTOPSIG(status)){
+ case SIGSEGV:
+ if(PTRACE_FULL_FAULTINFO || !ptrace_faultinfo)
+ user_signal(SIGSEGV, regs, pid);
+ else handle_segv(pid, regs);
+ break;
+ case SIGTRAP + 0x80:
+ handle_trap(pid, regs, local_using_sysemu);
+ break;
+ case SIGTRAP:
+ relay_signal(SIGTRAP, regs);
+ break;
+ case SIGIO:
+ case SIGVTALRM:
+ case SIGILL:
+ case SIGBUS:
+ case SIGFPE:
+ case SIGWINCH:
+ user_signal(WSTOPSIG(status), regs, pid);
+ break;
+ default:
+ printk("userspace - child stopped with signal "
+ "%d\n", WSTOPSIG(status));
+ }
+ again:
+ pid = userspace_pid[0];
+ interrupt_end();
+
+ /* Avoid -ERESTARTSYS handling in host */
+ if(PT_SYSCALL_NR_OFFSET != PT_SYSCALL_RET_OFFSET)
+ PT_SYSCALL_NR(regs->skas.regs) = -1;
+ }
+ }
+}
+#define INIT_JMP_NEW_THREAD 0
+#define INIT_JMP_REMOVE_SIGSTACK 1
+#define INIT_JMP_CALLBACK 2
+#define INIT_JMP_HALT 3
+#define INIT_JMP_REBOOT 4
+
+int copy_context_skas0(unsigned long new_stack, int pid)
+{
+ int err;
+ unsigned long regs[MAX_REG_NR];
+ unsigned long current_stack = current_stub_stack();
+ struct stub_data *data = (struct stub_data *) current_stack;
+ struct stub_data *child_data = (struct stub_data *) new_stack;
+ __u64 new_offset;
+ int new_fd = phys_mapping(to_phys((void *)new_stack), &new_offset);
+
+ /* prepare offset and fd of child's stack as argument for parent's
+ * and child's mmap2 calls
+ */
+ *data = ((struct stub_data) { .offset = MMAP_OFFSET(new_offset),
+ .fd = new_fd,
+ .timer = ((struct itimerval)
+ { { 0, 1000000 / hz() },
+ { 0, 1000000 / hz() }})});
+ get_safe_registers(regs);
+
+ /* Set parent's instruction pointer to start of clone-stub */
+ regs[REGS_IP_INDEX] = UML_CONFIG_STUB_CODE +
+ (unsigned long) stub_clone_handler -
+ (unsigned long) &__syscall_stub_start;
+ regs[REGS_SP_INDEX] = UML_CONFIG_STUB_DATA + PAGE_SIZE -
+ sizeof(void *);
+#ifdef __SIGNAL_FRAMESIZE
+ regs[REGS_SP_INDEX] -= __SIGNAL_FRAMESIZE;
+#endif
+ err = ptrace_setregs(pid, regs);
+ if(err < 0)
+ panic("copy_context_skas0 : PTRACE_SETREGS failed, "
+ "pid = %d, errno = %d\n", pid, errno);
+
+ /* set a well known return code for detection of child write failure */
+ child_data->err = 12345678;
+
+ /* Wait, until parent has finished its work: read child's pid from
+ * parent's stack, and check, if bad result.
+ */
+ wait_stub_done(pid, 0, "copy_context_skas0");
+
+ pid = data->err;
+ if(pid < 0)
+ panic("copy_context_skas0 - stub-parent reports error %d\n",
+ pid);
+
+ /* Wait, until child has finished too: read child's result from
+ * child's stack and check it.
+ */
+ wait_stub_done(pid, -1, "copy_context_skas0");
+ if (child_data->err != UML_CONFIG_STUB_DATA)
+ panic("copy_context_skas0 - stub-child reports error %d\n",
+ child_data->err);
+
+ if (ptrace(PTRACE_OLDSETOPTIONS, pid, NULL,
+ (void *)PTRACE_O_TRACESYSGOOD) < 0)
+ panic("copy_context_skas0 : PTRACE_OLDSETOPTIONS failed, "
+ "errno = %d\n", errno);
+
+ return pid;
+}
+
+/*
+ * This is used only, if stub pages are needed, while proc_mm is
+ * availabl. Opening /proc/mm creates a new mm_context, which lacks
+ * the stub-pages. Thus, we map them using /proc/mm-fd
+ */
+void map_stub_pages(int fd, unsigned long code,
+ unsigned long data, unsigned long stack)
+{
+ struct proc_mm_op mmop;
+ int n;
+
+ mmop = ((struct proc_mm_op) { .op = MM_MMAP,
+ .u =
+ { .mmap =
+ { .addr = code,
+ .len = PAGE_SIZE,
+ .prot = PROT_EXEC,
+ .flags = MAP_FIXED | MAP_PRIVATE,
+ .fd = stub_code_fd,
+ .offset = stub_code_offset
+ } } });
+ n = os_write_file(fd, &mmop, sizeof(mmop));
+ if(n != sizeof(mmop))
+ panic("map_stub_pages : /proc/mm map for code failed, "
+ "err = %d\n", -n);
+
+ if ( stack ) {
+ __u64 map_offset;
+ int map_fd = phys_mapping(to_phys((void *)stack), &map_offset);
+ mmop = ((struct proc_mm_op)
+ { .op = MM_MMAP,
+ .u =
+ { .mmap =
+ { .addr = data,
+ .len = PAGE_SIZE,
+ .prot = PROT_READ | PROT_WRITE,
+ .flags = MAP_FIXED | MAP_SHARED,
+ .fd = map_fd,
+ .offset = map_offset
+ } } });
+ n = os_write_file(fd, &mmop, sizeof(mmop));
+ if(n != sizeof(mmop))
+ panic("map_stub_pages : /proc/mm map for data failed, "
+ "err = %d\n", -n);
+ }
+}
+
+void new_thread(void *stack, void **switch_buf_ptr, void **fork_buf_ptr,
+ void (*handler)(int))
+{
+ unsigned long flags;
+ sigjmp_buf switch_buf, fork_buf;
+
+ *switch_buf_ptr = &switch_buf;
+ *fork_buf_ptr = &fork_buf;
+
+ /* Somewhat subtle - siglongjmp restores the signal mask before doing
+ * the longjmp. This means that when jumping from one stack to another
+ * when the target stack has interrupts enabled, an interrupt may occur
+ * on the source stack. This is bad when starting up a process because
+ * it's not supposed to get timer ticks until it has been scheduled.
+ * So, we disable interrupts around the sigsetjmp to ensure that
+ * they can't happen until we get back here where they are safe.
+ */
+ flags = get_signals();
+ block_signals();
+ if(sigsetjmp(fork_buf, 1) == 0)
+ new_thread_proc(stack, handler);
+
+ remove_sigstack();
+
+ set_signals(flags);
+}
+
+void thread_wait(void *sw, void *fb)
+{
+ sigjmp_buf buf, **switch_buf = sw, *fork_buf;
+
+ *switch_buf = &buf;
+ fork_buf = fb;
+ if(sigsetjmp(buf, 1) == 0)
+ siglongjmp(*fork_buf, INIT_JMP_REMOVE_SIGSTACK);
+}
+
+void switch_threads(void *me, void *next)
+{
+ sigjmp_buf my_buf, **me_ptr = me, *next_buf = next;
+
+ *me_ptr = &my_buf;
+ if(sigsetjmp(my_buf, 1) == 0)
+ siglongjmp(*next_buf, 1);
+}
+
+static sigjmp_buf initial_jmpbuf;
+
+/* XXX Make these percpu */
+static void (*cb_proc)(void *arg);
+static void *cb_arg;
+static sigjmp_buf *cb_back;
+
+int start_idle_thread(void *stack, void *switch_buf_ptr, void **fork_buf_ptr)
+{
+ sigjmp_buf **switch_buf = switch_buf_ptr;
+ int n;
+
+ set_handler(SIGWINCH, (__sighandler_t) sig_handler,
+ SA_ONSTACK | SA_RESTART, SIGUSR1, SIGIO, SIGALRM,
+ SIGVTALRM, -1);
+
+ *fork_buf_ptr = &initial_jmpbuf;
+ n = sigsetjmp(initial_jmpbuf, 1);
+ switch(n){
+ case INIT_JMP_NEW_THREAD:
+ new_thread_proc((void *) stack, new_thread_handler);
+ break;
+ case INIT_JMP_REMOVE_SIGSTACK:
+ remove_sigstack();
+ break;
+ case INIT_JMP_CALLBACK:
+ (*cb_proc)(cb_arg);
+ siglongjmp(*cb_back, 1);
+ break;
+ case INIT_JMP_HALT:
+ kmalloc_ok = 0;
+ return(0);
+ case INIT_JMP_REBOOT:
+ kmalloc_ok = 0;
+ return(1);
+ default:
+ panic("Bad sigsetjmp return in start_idle_thread - %d\n", n);
+ }
+ siglongjmp(**switch_buf, 1);
+}
+
+void initial_thread_cb_skas(void (*proc)(void *), void *arg)
+{
+ sigjmp_buf here;
+
+ cb_proc = proc;
+ cb_arg = arg;
+ cb_back = &here;
+
+ block_signals();
+ if(sigsetjmp(here, 1) == 0)
+ siglongjmp(initial_jmpbuf, INIT_JMP_CALLBACK);
+ unblock_signals();
+
+ cb_proc = NULL;
+ cb_arg = NULL;
+ cb_back = NULL;
+}
+
+void halt_skas(void)
+{
+ block_signals();
+ siglongjmp(initial_jmpbuf, INIT_JMP_HALT);
+}
+
+void reboot_skas(void)
+{
+ block_signals();
+ siglongjmp(initial_jmpbuf, INIT_JMP_REBOOT);
+}
+
+void switch_mm_skas(struct mm_id *mm_idp)
+{
+ int err;
+
+#warning need cpu pid in switch_mm_skas
+ if(proc_mm){
+ err = ptrace(PTRACE_SWITCH_MM, userspace_pid[0], 0,
+ mm_idp->u.mm_fd);
+ if(err)
+ panic("switch_mm_skas - PTRACE_SWITCH_MM failed, "
+ "errno = %d\n", errno);
+ }
+ else userspace_pid[0] = mm_idp->u.pid;
+}

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