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  1. 08 5月, 2007 6 次提交
    • J
      uml: speed page fault path · 64f60841
      由 Jeff Dike 提交于 
      Give the page fault code a specialized path.  There is only one page to look
at, so there's no point in going into the general page table walking code.
There's only going to be one host operation, so there are no opportunities for
merging.  So, we go straight to the pte we want, figure out what needs doing,
and do it.

While I was in here, I fixed the wart where the address passed to unmap was a
void *, but an unsigned long to map and protect.

This gives me just under 10% on a kernel build.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      64f60841
    • J
      uml: rename os_{read_write}_file_k back to os_{read_write}_file · a6ea4cce
      由 Jeff Dike 提交于 
      Rename os_{read_write}_file_k back to os_{read_write}_file, delete
the originals and their bogus infrastructure, and fix all the callers.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a6ea4cce
    • J
      uml: dump core on panic · 63843c26
      由 Jeff Dike 提交于 
      Dump core after a panic.  This will provide better debugging information than
is currently available.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      63843c26
    • J
      uml: start fixing os_read_file and os_write_file · 3d564047
      由 Jeff Dike 提交于 
      This patch starts the removal of a very old, very broken piece of code.  This
stems from the problem of passing a userspace buffer into read() or write() on
the host.  If that buffer had not yet been faulted in, read and write will
return -EFAULT.

To avoid this problem, the solution was to fault the buffer in before the
system call by touching the pages that hold the buffer by doing a copy-user of
a byte to each page.  This is obviously bogus, but it does usually work, in tt
mode, since the kernel and process are in the same address space and userspace
addresses can be accessed directly in the kernel.

In skas mode, where the kernel and process are in separate address spaces, it
is completely bogus because the userspace address, which is invalid in the
kernel, is passed into the system call instead of the corresponding physical
address, which would be valid.  Here, it appears that this code, on every host
read() or write(), tries to fault in a random process page.  This doesn't seem
to cause any correctness problems, but there is a performance impact.  This
patch, and the ones following, result in a 10-15% performance gain on a kernel
build.

This code can't be immediately tossed out because when it is, you can't log
in.  Apparently, there is some code in the console driver which depends on
this somehow.

However, we can start removing it by switching the code which does I/O using
kernel addresses to using plain read() and write().  This patch introduces
os_read_file_k and os_write_file_k for use with kernel buffers and converts
all call locations which use obvious kernel buffers to use them.  These
include I/O using buffers which are local variables which are on the stack or
kmalloc-ed.  Later patches will handle the less obvious cases, followed by a
mass conversion back to the original interface.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3d564047
    • J
      uml: move remaining useful contents of user_util.h · 24fa6c08
      由 Jeff Dike 提交于 
      Rescue the useful contents of the soon-to-be-gone user-util.h.

pty.c now gets ptsname from stdlib.h like it should have always done.

CATCH_EINTR is now in os.h, although perhaps all usage should be under
os-Linux at some point.

get_pty is also in os.h.

This patch restores the old definition of ARRAY_SIZE in user.h.  This file is
included only in userspace files, so there will be no conflict with the
kernel's new ARRAY_SIZE.  The copy of the kernel's ARRAY_SIZE and associated
infrastructure is now gone.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      24fa6c08
    • J
      uml: host_info tidying · b4ffb6ad
      由 Jeff Dike 提交于 
      Move the host_info string from util.c to um_arch.c, where it is
actually initialized and used.  Also document its lack of locking.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b4ffb6ad
  3. 08 3月, 2007 1 次提交
  5. 12 2月, 2007 2 次提交
  7. 26 11月, 2006 1 次提交
    • P
      [PATCH] uml: make execvp safe for our usage · 5d48545e
      由 Paolo 'Blaisorblade' Giarrusso 提交于 
      Reimplement execvp for our purposes - after we call fork() it is fundamentally
unsafe to use the kernel allocator - current is not valid there.  So we simply
pass to our modified execvp() a preallocated buffer.  This fixes a real bug
and works very well in testing (I've seen indirectly warning messages from the
forked thread - they went on the pipe connected to its stdout and where read
as a number by UML, when calling read_output().  I verified the obtained
number corresponded to "BUG:").

The added use of __cant_sleep() is not a new bug since __cant_sleep() is
already used in the same function - passing an atomicity parameter would be
better but it would require huge change, stating that this function must not
be called in atomic context and can sleep is a better idea (will make sure of
this gradually).
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      5d48545e
  9. 12 10月, 2006 1 次提交
  11. 27 9月, 2006 2 次提交
    • J
      [PATCH] uml: thread creation tidying · 3c917350
      由 Jeff Dike 提交于 
      fork on UML has always somewhat subtle.  The underlying cause has been the
need to initialize a stack for the new process.  The only portable way to
initialize a new stack is to set it as the alternate signal stack and take a
signal.  The signal handler does whatever initialization is needed and jumps
back to the original stack, where the fork processing is finished.  The basic
context switching mechanism is a jmp_buf for each process.  You switch to a
new process by longjmping to its jmp_buf.

Now that UML has its own implementation of setjmp and longjmp, and I can poke
around inside a jmp_buf without fear that libc will change the structure, a
much simpler mechanism is possible.  The jmpbuf can simply be initialized by
hand.

This eliminates -
	the need to set up and remove the alternate signal stack
	sending and handling a signal
	the signal blocking needed around the stack switching, since
there is no stack switching
	setting up the jmp_buf needed to jump back to the original
stack after the new one is set up

In addition, since jmp_buf is now defined by UML, and not by libc, it can be
embedded in the thread struct.  This makes it unnecessary to have it exist on
the stack, where it used to be.  It also simplifies interfaces, since the
switch jmp_buf used to be a void * inside the thread struct, and functions
which took it as an argument needed to define a jmp_buf variable and assign it
from the void *.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3c917350
    • J
      [PATCH] uml: mark some tt-mode code · 0915ee38
      由 Jeff Dike 提交于 
      Mark a symbol and file as being tt-mode only.  This shrinks the binary
slightly when tt mode support is compiled out and makes it easier to identity
stuff when tt mode is removed.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      0915ee38
  13. 26 9月, 2006 2 次提交
    • J
      [PATCH] uml: timer cleanups · 537ae946
      由 Jeff Dike 提交于 
      set_interval returns an error instead of panicing if setitimer fails.  Some of
its callers now check the return.

enable_timer is largely tt-mode-specific, so it is marked as such, and the
only skas-mode caller is made to call set-interval instead.

user_time_init was a no-value-added wrapper around set_interval, so it is
gone.

Since set_interval is now called from kernel code, callers no longer pass
ITIMER_* to it.  Instead, they pass a flag which is converted into ITIMER_REAL
or ITIMER_VIRTUAL.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      537ae946
    • J
      [PATCH] uml: SIGIO cleanups · 19bdf040
      由 Jeff Dike 提交于 
      - Various cleanups in the sigio code.

- Removed explicit zero-initializations of a few structures.

- Improved some error messages.

- An API change - there was an asymmetry between reactivate_fd calling
  maybe_sigio_broken, which goes through all the machinery of figuring out if
  a file descriptor supports SIGIO and applying the workaround to it if not,
  and deactivate_fd, which just turns off the descriptor.

  This is changed so that only activate_fd calls maybe_sigio_broken, when
  the descriptor is first seen.  reactivate_fd now calls add_sigio_fd, which
  is symmetric with ignore_sigio_fd.

  This removes a recursion which makes a critical section look more critical
  than it really was, obsoleting a big comment to that effect.  This requires
  keeping track of all descriptors which are getting the SIGIO treatment, not
  just the ones being polled at any given moment, so that reactivate_fd,
  through add_sigio_fd, doesn't try to tell the SIGIO thread about descriptors
  it doesn't care about.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      19bdf040
  15. 15 7月, 2006 1 次提交
  17. 11 7月, 2006 3 次提交
  19. 01 4月, 2006 4 次提交
  21. 28 3月, 2006 4 次提交
  23. 25 2月, 2006 1 次提交
  25. 19 1月, 2006 4 次提交
  27. 09 1月, 2006 2 次提交
  29. 07 1月, 2006 2 次提交
    • J
      [PATCH] uml: umid cleanup · 7eebe8a9
      由 Jeff Dike 提交于 
      This patch cleans up the umid code:

- The only_if_set argument to get_umid is gone.

- get_umid returns an empty string rather than NULL if there is no umid.

- umid_is_random is gone since its users went away.

- Some printfs were turned into printks because the code runs late enough
  that printk is working.

- Error paths were cleaned up.

- Some functions now return an error and let the caller print the error
  message rather than printing it themselves.  This eliminates the practice of
  passing a pointer to printf or printk in, depending on where in the boot
  process we are.

- Major tidying of not_dead_yet - mostly error path cleanup, plus a comment
  explaining why it doesn't react to errors the way you might expect.

- Calls to os_* interfaces that were moved under os are changed back to
  their native libc forms.

- snprintf, strlcpy, and their bounds-checking friends are used more often,
  replacing by-hand bounds checking in some places.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      7eebe8a9
    • J
      [PATCH] uml: separate libc-dependent umid code · 2264c475
      由 Jeff Dike 提交于 
      I reworked Gennady's umid OS abstraction patch because the code shouldn't
be moved entirely to os.  As it turns out, I moved most of it anyway.  This
patch is the minimal one needed to move the code and have it work.
It turns out that the concept of the umid is OS-independent, but
almost everything else about the implementation is OS-dependent.

This is code movement without cleanup - a follow-on patch tidies
everything up without shuffling code around.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      2264c475
  31. 07 11月, 2005 3 次提交
  33. 12 10月, 2005 1 次提交