v4.19.13 snapshot.
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
new file mode 100644
index 0000000..b3e0d40
--- /dev/null
+++ b/arch/um/os-Linux/process.c
@@ -0,0 +1,287 @@
+/*
+ * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+#include <sys/ptrace.h>
+#include <sys/wait.h>
+#include <asm/unistd.h>
+#include <init.h>
+#include <longjmp.h>
+#include <os.h>
+
+#define ARBITRARY_ADDR -1
+#define FAILURE_PID -1
+
+#define STAT_PATH_LEN sizeof("/proc/#######/stat\0")
+#define COMM_SCANF "%*[^)])"
+
+unsigned long os_process_pc(int pid)
+{
+ char proc_stat[STAT_PATH_LEN], buf[256];
+ unsigned long pc = ARBITRARY_ADDR;
+ int fd, err;
+
+ sprintf(proc_stat, "/proc/%d/stat", pid);
+ fd = open(proc_stat, O_RDONLY, 0);
+ if (fd < 0) {
+ printk(UM_KERN_ERR "os_process_pc - couldn't open '%s', "
+ "errno = %d\n", proc_stat, errno);
+ goto out;
+ }
+ CATCH_EINTR(err = read(fd, buf, sizeof(buf)));
+ if (err < 0) {
+ printk(UM_KERN_ERR "os_process_pc - couldn't read '%s', "
+ "err = %d\n", proc_stat, errno);
+ goto out_close;
+ }
+ os_close_file(fd);
+ pc = ARBITRARY_ADDR;
+ if (sscanf(buf, "%*d " COMM_SCANF " %*c %*d %*d %*d %*d %*d %*d %*d "
+ "%*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d %*d "
+ "%*d %*d %*d %*d %*d %lu", &pc) != 1)
+ printk(UM_KERN_ERR "os_process_pc - couldn't find pc in '%s'\n",
+ buf);
+ out_close:
+ close(fd);
+ out:
+ return pc;
+}
+
+int os_process_parent(int pid)
+{
+ char stat[STAT_PATH_LEN];
+ char data[256];
+ int parent = FAILURE_PID, n, fd;
+
+ if (pid == -1)
+ return parent;
+
+ snprintf(stat, sizeof(stat), "/proc/%d/stat", pid);
+ fd = open(stat, O_RDONLY, 0);
+ if (fd < 0) {
+ printk(UM_KERN_ERR "Couldn't open '%s', errno = %d\n", stat,
+ errno);
+ return parent;
+ }
+
+ CATCH_EINTR(n = read(fd, data, sizeof(data)));
+ close(fd);
+
+ if (n < 0) {
+ printk(UM_KERN_ERR "Couldn't read '%s', errno = %d\n", stat,
+ errno);
+ return parent;
+ }
+
+ parent = FAILURE_PID;
+ n = sscanf(data, "%*d " COMM_SCANF " %*c %d", &parent);
+ if (n != 1)
+ printk(UM_KERN_ERR "Failed to scan '%s'\n", data);
+
+ return parent;
+}
+
+void os_alarm_process(int pid)
+{
+ kill(pid, SIGALRM);
+}
+
+void os_stop_process(int pid)
+{
+ kill(pid, SIGSTOP);
+}
+
+void os_kill_process(int pid, int reap_child)
+{
+ kill(pid, SIGKILL);
+ if (reap_child)
+ CATCH_EINTR(waitpid(pid, NULL, __WALL));
+}
+
+/* Kill off a ptraced child by all means available. kill it normally first,
+ * then PTRACE_KILL it, then PTRACE_CONT it in case it's in a run state from
+ * which it can't exit directly.
+ */
+
+void os_kill_ptraced_process(int pid, int reap_child)
+{
+ kill(pid, SIGKILL);
+ ptrace(PTRACE_KILL, pid);
+ ptrace(PTRACE_CONT, pid);
+ if (reap_child)
+ CATCH_EINTR(waitpid(pid, NULL, __WALL));
+}
+
+/* Don't use the glibc version, which caches the result in TLS. It misses some
+ * syscalls, and also breaks with clone(), which does not unshare the TLS.
+ */
+
+int os_getpid(void)
+{
+ return syscall(__NR_getpid);
+}
+
+int os_getpgrp(void)
+{
+ return getpgrp();
+}
+
+int os_map_memory(void *virt, int fd, unsigned long long off, unsigned long len,
+ int r, int w, int x)
+{
+ void *loc;
+ int prot;
+
+ prot = (r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
+ (x ? PROT_EXEC : 0);
+
+ loc = mmap64((void *) virt, len, prot, MAP_SHARED | MAP_FIXED,
+ fd, off);
+ if (loc == MAP_FAILED)
+ return -errno;
+ return 0;
+}
+
+int os_protect_memory(void *addr, unsigned long len, int r, int w, int x)
+{
+ int prot = ((r ? PROT_READ : 0) | (w ? PROT_WRITE : 0) |
+ (x ? PROT_EXEC : 0));
+
+ if (mprotect(addr, len, prot) < 0)
+ return -errno;
+
+ return 0;
+}
+
+int os_unmap_memory(void *addr, int len)
+{
+ int err;
+
+ err = munmap(addr, len);
+ if (err < 0)
+ return -errno;
+ return 0;
+}
+
+#ifndef MADV_REMOVE
+#define MADV_REMOVE KERNEL_MADV_REMOVE
+#endif
+
+int os_drop_memory(void *addr, int length)
+{
+ int err;
+
+ err = madvise(addr, length, MADV_REMOVE);
+ if (err < 0)
+ err = -errno;
+ return err;
+}
+
+int __init can_drop_memory(void)
+{
+ void *addr;
+ int fd, ok = 0;
+
+ printk(UM_KERN_INFO "Checking host MADV_REMOVE support...");
+ fd = create_mem_file(UM_KERN_PAGE_SIZE);
+ if (fd < 0) {
+ printk(UM_KERN_ERR "Creating test memory file failed, "
+ "err = %d\n", -fd);
+ goto out;
+ }
+
+ addr = mmap64(NULL, UM_KERN_PAGE_SIZE, PROT_READ | PROT_WRITE,
+ MAP_SHARED, fd, 0);
+ if (addr == MAP_FAILED) {
+ printk(UM_KERN_ERR "Mapping test memory file failed, "
+ "err = %d\n", -errno);
+ goto out_close;
+ }
+
+ if (madvise(addr, UM_KERN_PAGE_SIZE, MADV_REMOVE) != 0) {
+ printk(UM_KERN_ERR "MADV_REMOVE failed, err = %d\n", -errno);
+ goto out_unmap;
+ }
+
+ printk(UM_KERN_CONT "OK\n");
+ ok = 1;
+
+out_unmap:
+ munmap(addr, UM_KERN_PAGE_SIZE);
+out_close:
+ close(fd);
+out:
+ return ok;
+}
+
+static int os_page_mincore(void *addr)
+{
+ char vec[2];
+ int ret;
+
+ ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
+ if (ret < 0) {
+ if (errno == ENOMEM || errno == EINVAL)
+ return 0;
+ else
+ return -errno;
+ }
+
+ return vec[0] & 1;
+}
+
+int os_mincore(void *addr, unsigned long len)
+{
+ char *vec;
+ int ret, i;
+
+ if (len <= UM_KERN_PAGE_SIZE)
+ return os_page_mincore(addr);
+
+ vec = calloc(1, (len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE);
+ if (!vec)
+ return -ENOMEM;
+
+ ret = mincore(addr, UM_KERN_PAGE_SIZE, vec);
+ if (ret < 0) {
+ if (errno == ENOMEM || errno == EINVAL)
+ ret = 0;
+ else
+ ret = -errno;
+
+ goto out;
+ }
+
+ for (i = 0; i < ((len + UM_KERN_PAGE_SIZE - 1) / UM_KERN_PAGE_SIZE); i++) {
+ if (!(vec[i] & 1)) {
+ ret = 0;
+ goto out;
+ }
+ }
+
+ ret = 1;
+out:
+ free(vec);
+ return ret;
+}
+
+void init_new_thread_signals(void)
+{
+ set_handler(SIGSEGV);
+ set_handler(SIGTRAP);
+ set_handler(SIGFPE);
+ set_handler(SIGILL);
+ set_handler(SIGBUS);
+ signal(SIGHUP, SIG_IGN);
+ set_handler(SIGIO);
+ signal(SIGWINCH, SIG_IGN);
+}