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linux/arch/um/include/os.h
Jeff Dike 5d33e4d7fd uml: random driver fixes 
The random driver would essentially hang if the host's /dev/random returned
-EAGAIN.  There was a test of need_resched followed by a schedule inside the
loop, but that didn't help and it's the wrong way to work anyway.

The right way is to ask for an interrupt when there is input available from
the host and handle it then rather than polling.

Now, when the host's /dev/random returns -EAGAIN, the driver asks for a wakeup
when there's randomness available again and sleeps.  The interrupt routine
just wakes up whatever processes are sleeping on host_read_wait.

There is an atomic_t, host_sleep_count, which counts the number of processes
waiting for randomness.  When this reaches zero, the interrupt is disabled.

An added complication is that async I/O notification was only recently added
to /dev/random (by me), so essentially all hosts will lack it.  So, we use the
sigio workaround here, which is to have a separate thread poll on the
descriptor and send an interrupt when there is input on it.  This mechanism is
activated when a process gets -EAGAIN (activating this multiple times is
harmless, if a bit wasteful) and deactivated by the last process still
waiting.

The module name was changed from "random" to "hw_random" in order for udev to
recognize it.

The sigio workaround needed some changes.  sigio_broken was added for cases
when we know that async notification doesn't work.  This is now called from
maybe_sigio_broken, which deals with pts devices.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-13 08:02:22 -07:00

305 lines
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/*
* Copyright (C) 2002 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#ifndef __OS_H__
#define __OS_H__
#include <stdarg.h>
#include "irq_user.h"
#include "longjmp.h"
#include "mm_id.h"
#include "sysdep/tls.h"
#include "../os/include/file.h"
#define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR))
#define OS_TYPE_FILE 1
#define OS_TYPE_DIR 2
#define OS_TYPE_SYMLINK 3
#define OS_TYPE_CHARDEV 4
#define OS_TYPE_BLOCKDEV 5
#define OS_TYPE_FIFO 6
#define OS_TYPE_SOCK 7
/* os_access() flags */
#define OS_ACC_F_OK 0 /* Test for existence. */
#define OS_ACC_X_OK 1 /* Test for execute permission. */
#define OS_ACC_W_OK 2 /* Test for write permission. */
#define OS_ACC_R_OK 4 /* Test for read permission. */
#define OS_ACC_RW_OK (OS_ACC_W_OK | OS_ACC_R_OK) /* Test for RW permission */
/*
* types taken from stat_file() in hostfs_user.c
* (if they are wrong here, they are wrong there...).
*/
struct uml_stat {
int ust_dev; /* device */
unsigned long long ust_ino; /* inode */
int ust_mode; /* protection */
int ust_nlink; /* number of hard links */
int ust_uid; /* user ID of owner */
int ust_gid; /* group ID of owner */
unsigned long long ust_size; /* total size, in bytes */
int ust_blksize; /* blocksize for filesystem I/O */
unsigned long long ust_blocks; /* number of blocks allocated */
unsigned long ust_atime; /* time of last access */
unsigned long ust_mtime; /* time of last modification */
unsigned long ust_ctime; /* time of last change */
};
struct openflags {
unsigned int r : 1;
unsigned int w : 1;
unsigned int s : 1; /* O_SYNC */
unsigned int c : 1; /* O_CREAT */
unsigned int t : 1; /* O_TRUNC */
unsigned int a : 1; /* O_APPEND */
unsigned int e : 1; /* O_EXCL */
unsigned int cl : 1; /* FD_CLOEXEC */
};
#define OPENFLAGS() ((struct openflags) { .r = 0, .w = 0, .s = 0, .c = 0, \
.t = 0, .a = 0, .e = 0, .cl = 0 })
static inline struct openflags of_read(struct openflags flags)
{
flags.r = 1;
return flags;
}
static inline struct openflags of_write(struct openflags flags)
{
flags.w = 1;
return flags;
}
static inline struct openflags of_rdwr(struct openflags flags)
{
return of_read(of_write(flags));
}
static inline struct openflags of_set_rw(struct openflags flags, int r, int w)
{
flags.r = r;
flags.w = w;
return flags;
}
static inline struct openflags of_sync(struct openflags flags)
{
flags.s = 1;
return flags;
}
static inline struct openflags of_create(struct openflags flags)
{
flags.c = 1;
return flags;
}
static inline struct openflags of_trunc(struct openflags flags)
{
flags.t = 1;
return flags;
}
static inline struct openflags of_append(struct openflags flags)
{
flags.a = 1;
return flags;
}
static inline struct openflags of_excl(struct openflags flags)
{
flags.e = 1;
return flags;
}
static inline struct openflags of_cloexec(struct openflags flags)
{
flags.cl = 1;
return flags;
}
/* file.c */
extern int os_stat_file(const char *file_name, struct uml_stat *buf);
extern int os_stat_fd(const int fd, struct uml_stat *buf);
extern int os_access(const char *file, int mode);
extern int os_set_exec_close(int fd);
extern int os_ioctl_generic(int fd, unsigned int cmd, unsigned long arg);
extern int os_get_ifname(int fd, char *namebuf);
extern int os_set_slip(int fd);
extern int os_mode_fd(int fd, int mode);
extern int os_seek_file(int fd, unsigned long long offset);
extern int os_open_file(const char *file, struct openflags flags, int mode);
extern int os_read_file(int fd, void *buf, int len);
extern int os_write_file(int fd, const void *buf, int count);
extern int os_file_size(const char *file, unsigned long long *size_out);
extern int os_file_modtime(const char *file, unsigned long *modtime);
extern int os_pipe(int *fd, int stream, int close_on_exec);
extern int os_set_fd_async(int fd);
extern int os_clear_fd_async(int fd);
extern int os_set_fd_block(int fd, int blocking);
extern int os_accept_connection(int fd);
extern int os_create_unix_socket(const char *file, int len, int close_on_exec);
extern int os_shutdown_socket(int fd, int r, int w);
extern void os_close_file(int fd);
extern int os_rcv_fd(int fd, int *helper_pid_out);
extern int create_unix_socket(char *file, int len, int close_on_exec);
extern int os_connect_socket(const char *name);
extern int os_file_type(char *file);
extern int os_file_mode(const char *file, struct openflags *mode_out);
extern int os_lock_file(int fd, int excl);
extern void os_flush_stdout(void);
extern int os_stat_filesystem(char *path, long *bsize_out,
long long *blocks_out, long long *bfree_out,
long long *bavail_out, long long *files_out,
long long *ffree_out, void *fsid_out,
int fsid_size, long *namelen_out,
long *spare_out);
extern int os_change_dir(char *dir);
extern int os_fchange_dir(int fd);
/* start_up.c */
extern void os_early_checks(void);
extern void can_do_skas(void);
extern void os_check_bugs(void);
extern void check_host_supports_tls(int *supports_tls, int *tls_min);
/* mem.c */
extern int create_mem_file(unsigned long long len);
/* process.c */
extern unsigned long os_process_pc(int pid);
extern int os_process_parent(int pid);
extern void os_stop_process(int pid);
extern void os_kill_process(int pid, int reap_child);
extern void os_kill_ptraced_process(int pid, int reap_child);
extern long os_ptrace_ldt(long pid, long addr, long data);
extern int os_getpid(void);
extern int os_getpgrp(void);
extern void init_new_thread_signals(void);
extern int run_kernel_thread(int (*fn)(void *), void *arg, jmp_buf **jmp_ptr);
extern int os_map_memory(void *virt, int fd, unsigned long long off,
unsigned long len, int r, int w, int x);
extern int os_protect_memory(void *addr, unsigned long len,
int r, int w, int x);
extern int os_unmap_memory(void *addr, int len);
extern int os_drop_memory(void *addr, int length);
extern int can_drop_memory(void);
extern void os_flush_stdout(void);
/* uaccess.c */
extern unsigned long __do_user_copy(void *to, const void *from, int n,
void **fault_addr, jmp_buf **fault_catcher,
void (*op)(void *to, const void *from,
int n), int *faulted_out);
/* execvp.c */
extern int execvp_noalloc(char *buf, const char *file, char *const argv[]);
/* helper.c */
extern int run_helper(void (*pre_exec)(void *), void *pre_data, char **argv);
extern int run_helper_thread(int (*proc)(void *), void *arg,
unsigned int flags, unsigned long *stack_out);
extern int helper_wait(int pid);
/* tls.c */
extern int os_set_thread_area(user_desc_t *info, int pid);
extern int os_get_thread_area(user_desc_t *info, int pid);
/* umid.c */
extern int umid_file_name(char *name, char *buf, int len);
extern int set_umid(char *name);
extern char *get_umid(void);
/* signal.c */
extern void timer_init(void);
extern void set_sigstack(void *sig_stack, int size);
extern void remove_sigstack(void);
extern void set_handler(int sig, void (*handler)(int), int flags, ...);
extern int change_sig(int signal, int on);
extern void block_signals(void);
extern void unblock_signals(void);
extern int get_signals(void);
extern int set_signals(int enable);
/* util.c */
extern void stack_protections(unsigned long address);
extern int raw(int fd);
extern void setup_machinename(char *machine_out);
extern void setup_hostinfo(char *buf, int len);
extern void os_dump_core(void) __attribute__ ((noreturn));
/* time.c */
extern void idle_sleep(unsigned long long nsecs);
extern int set_interval(void);
extern int timer_one_shot(int ticks);
extern long long disable_timer(void);
extern void uml_idle_timer(void);
extern long long os_nsecs(void);
/* skas/mem.c */
extern long run_syscall_stub(struct mm_id * mm_idp,
int syscall, unsigned long *args, long expected,
void **addr, int done);
extern long syscall_stub_data(struct mm_id * mm_idp,
unsigned long *data, int data_count,
void **addr, void **stub_addr);
extern int map(struct mm_id * mm_idp, unsigned long virt,
unsigned long len, int prot, int phys_fd,
unsigned long long offset, int done, void **data);
extern int unmap(struct mm_id * mm_idp, unsigned long addr, unsigned long len,
int done, void **data);
extern int protect(struct mm_id * mm_idp, unsigned long addr,
unsigned long len, unsigned int prot, 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(struct uml_pt_regs *regs);
extern int map_stub_pages(int fd, unsigned long code, unsigned long data,
unsigned long stack);
extern void new_thread(void *stack, jmp_buf *buf, void (*handler)(void));
extern void switch_threads(jmp_buf *me, jmp_buf *you);
extern int start_idle_thread(void *stack, jmp_buf *switch_buf);
extern void initial_thread_cb_skas(void (*proc)(void *),
void *arg);
extern void halt_skas(void);
extern void reboot_skas(void);
/* irq.c */
extern int os_waiting_for_events(struct irq_fd *active_fds);
extern int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds);
extern void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2);
extern void os_free_irq_later(struct irq_fd *active_fds,
int irq, void *dev_id);
extern int os_get_pollfd(int i);
extern void os_set_pollfd(int i, int fd);
extern void os_set_ioignore(void);
/* sigio.c */
extern int add_sigio_fd(int fd);
extern int ignore_sigio_fd(int fd);
extern void maybe_sigio_broken(int fd, int read);
extern void sigio_broken(int fd, int read);
/* sys-x86_64/prctl.c */
extern int os_arch_prctl(int pid, int code, unsigned long *addr);
/* tty.c */
extern int get_pty(void);
/* sys-$ARCH/task_size.c */
extern unsigned long os_get_task_size(void);
#endif
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