Commit Graph

218 Commits

Author SHA1 Message Date
Jeff Dike
18badddaa8 uml: rename pt_regs general-purpose register file
Before the removal of tt mode, access to a register on the skas-mode side of a
pt_regs struct looked like pt_regs.regs.skas.regs.regs[FOO].  This was bad
enough, but it became pt_regs.regs.regs.regs[FOO] with the removal of the
union from the middle.  To get rid of the run of three "regs", the last field
is renamed to "gp".

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>
2007-10-16 09:43:06 -07:00
Jeff Dike
6c738ffa9f uml: fold mmu_context_skas into mm_context
This patch folds mmu_context_skas into struct mm_context, changing all users
of these structures as needed.

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>
2007-10-16 09:43:06 -07:00
Jeff Dike
fab95c55e3 uml: get rid of do_longjmp
do_longjmp used to be needed when UML didn't have its own implementation of
setjmp and longjmp.  They came from libc, and couldn't be called directly from
kernel code, as the libc jmp_buf couldn't be imported there.  do_longjmp was a
userspace function which served to provide longjmp access to kernel code.

This is gone, and a number of void * pointers can now be jmp_buf *.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
0a7675aa20 uml: remove __u64 usage from physical memory subsystem
Eliminate some uses of __u64 in the physical memory support.  It's hard to get
a definition of __u64 in both kernel and userspace code on x86_64, so this
changes them to unsigned long long.

There are also a copyright update and formatting comment removal from the
affected header.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
ba180fd437 uml: style fixes pass 3
Formatting changes in the files which have been changed in the course
of folding foo_skas functions into their callers.  These include:
	copyright updates
	header file trimming
	style fixes
	adding severity to printks

These changes should be entirely non-functional.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
77bf440031 uml: remove code made redundant by CHOOSE_MODE removal
This patch makes a number of simplifications enabled by the removal of
CHOOSE_MODE.  There were lots of functions that looked like

	int foo(args){
		foo_skas(args);
	}

The bodies of foo_skas are now folded into foo, and their declarations (and
sometimes entire header files) are deleted.

In addition, the union uml_pt_regs, which was a union between the tt and skas
register formats, is now a struct, with the tt-mode arm of the union being
removed.

It turns out that usr2_handler was unused, so it is gone.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
ae2587e412 uml: style fixes pass 2
Formatting changes in the files which have been changed in the course
of removing CHOOSE_MODE.  These include:
	copyright updates
	header file trimming
	style fixes
	adding severity to printks

These changes should be entirely non-functional.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
6aa802ce6a uml: throw out CHOOSE_MODE
The next stage after removing code which depends on CONFIG_MODE_TT is removing
the CHOOSE_MODE abstraction, which provided both compile-time and run-time
branching to either tt-mode or skas-mode code.

This patch removes choose-mode.h and all inclusions of it, and replaces all
CHOOSE_MODE invocations with the skas branch.  This leaves a number of trivial
functions which will be dealt with in a later patch.

There are some changes in the uaccess and tls support which go somewhat beyond
this and eliminate some of the now-redundant functions.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
4c9e138513 uml: style fixes pass 1
Formatting changes in the files which have been changed in the
tt-removal patchset so far.  These include:
	copyright updates
	header file trimming
	style fixes
	adding severity to printks
	indenting Kconfig help according to the predominant kernel style

These changes should be entirely non-functional.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
c28b59d477 uml: remove sysdep/thread.h
This patch removes thread.h, which turns out not to be needed any more.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
42fda66387 uml: throw out CONFIG_MODE_TT
This patchset throws out tt mode, which has been non-functional for a while.

This is done in phases, interspersed with code cleanups on the affected files.

The removal is done as follows:
	remove all code, config options, and files which depend on
CONFIG_MODE_TT
	get rid of the CHOOSE_MODE macro, which decided whether to
call tt-mode or skas-mode code, and replace invocations with their
skas portions
	replace all now-trivial procedures with their skas equivalents

There are now a bunch of now-redundant pieces of data structures, including
mode-specific pieces of the thread structure, pt_regs, and mm_context.  These
are all replaced with their skas-specific contents.

As part of the ongoing style compliance project, I made a style pass over all
files that were changed.  There are three such patches, one for each phase,
covering the files affected by that phase but no later ones.

I noticed that we weren't freeing the LDT state associated with a process when
it exited, so that's fixed in one of the later patches.

The last patch is a tidying patch which I've had for a while, but which caused
inexplicable crashes under tt mode.  Since that is no longer a problem, this
can now go in.

This patch:

Start getting rid of tt mode support.

This patch throws out CONFIG_MODE_TT and all config options, code, and files
which depend on it.

CONFIG_MODE_SKAS is gone and everything that depends on it is included
unconditionally.

The few changed lines are in re-written Kconfig help, lines which needed
something skas-related removed from them, and a few more which weren't
strictly deletions.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
6d536e4b59 uml: physmem code tidying
Tidying of the UML physical memory system.  These are mostly style fixes,
however the includes were cleaned as well.  This uncovered a need for
mem_user.h to be included in mode_kern_skas.h.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
42daba3165 uml: stop saving process FP state
Throw out a lot of code dealing with saving and restoring floating-point
state.  In skas mode, where processes run in a restoring floating-point state
on kernel entry and exit is pointless.

This eliminates most of arch/um/os-Linux/sys-{i386,x86_64}/registers.c.  Most
of what remained is now arch-indpendent, and can be moved up to
arch/um/os-Linux/registers.c.  Both arches need the jmp_buf accessor
get_thread_reg, and i386 needs {save,restore}_fp_regs because it cheats during
sigreturn by getting the fp state using ptrace rather than copying it out of
the process sigcontext.

After this, it turns out that arch/um/include/skas/mode-skas.h is almost
completely unneeded.  The declarations in it are variables which either don't
exist or which don't have global scope.  The one exception is
kill_off_processes_skas.  If that's removed, this header can be deleted.

This uncovered a bug in user.h, which wasn't correctly making sure that a
size_t definition was available to both userspace and kernelspace files.

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>
2007-10-16 09:43:05 -07:00
Jeff Dike
5c8aaceab8 uml: stop specially protecting kernel stacks
Map all of physical memory as executable to avoid having to change stack
protections during fork and exit.

unprotect_stack is now called only from MODE_TT code, so it is marked as such.

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>
2007-10-16 09:43:04 -07:00
Jeff Dike
71f926f2ea uml: stop using libc asm/page.h
Remove includes of asm/page.h from libc code.  This header seems to be
disappearing, and UML doesn't make much use of it anyway.

The one use, PAGE_SHIFT in stub.h, is handled by copying the constant from the
kernel side of the house in common_offsets.h.

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>
2007-10-16 09:43:04 -07:00
Jeff Dike
8e2d10e1e7 uml: tidy recently-moved code
Now that the generic console operations are in a userspace file, we
can do the following:
	directly call into libc instead of through the os_* wrappers
	eliminate os_window_size since it has only one user

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16 09:43:04 -07:00
Jeff Dike
508a92741a uml: fix irqstack crash
This patch fixes a crash caused by an interrupt coming in when an IRQ stack
is being torn down.  When this happens, handle_signal will loop, setting up
the IRQ stack again because the tearing down had finished, and handling
whatever signals had come in.

However, to_irq_stack returns a mask of pending signals to be handled, plus
bit zero is set if the IRQ stack was already active, and thus shouldn't be
torn down.  This causes a problem because when handle_signal goes around
the loop, sig will be zero, and to_irq_stack will duly set bit zero in the
returned mask, faking handle_signal into believing that it shouldn't tear
down the IRQ stack and return thread_info pointers back to their original
values.

This will eventually cause a crash, as the IRQ stack thread_info will
continue pointing to the original task_struct and an interrupt will look
into it after it has been freed.

The fix is to stop passing a signal number into to_irq_stack.  Rather, the
pending signals mask is initialized beforehand with the bit for sig already
set.  References to sig in to_irq_stack can be replaced with references to
the mask.

[akpm@linux-foundation.org: use UL]
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>
2007-09-19 11:24:18 -07:00
Jeff Dike
e4c4bf9968 uml: Eliminate kernel allocator wrappers
UML had two wrapper procedures for kmalloc, um_kmalloc and um_kmalloc_atomic
because the flag constants weren't available in userspace code.
kern_constants.h had made kernel constants available for a long time, so there
is no need for these wrappers any more.  Rather, userspace code calls kmalloc
directly with the userspace versions of the gfp flags.

kmalloc isn't a real procedure, so I had to essentially copy the inline
wrapper around __kmalloc.

vmalloc also had its own wrapper for no good reason.  This is now gone.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:38 -07:00
Jeff Dike
c43990162f uml: simplify helper stack handling
run_helper and run_helper_thread had arguments which were the same in all
callers.  run_helper's stack_out was always NULL and run_helper_thread's
stack_order was always 0.  These are now gone, and the constants folded
into the code.

Also fixed leaks of the helper stack in the AIO and SIGIO code.

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>
2007-07-16 09:05:38 -07:00
Jeff Dike
42a359e31a uml: SIGIO support cleanup
Cleanup of the SIGWINCH support.

Some code and comment reformatting.

The stack used for SIGWINCH threads was leaked.  This is now fixed by storing
it with the pid and other information, and freeing it when the thread is
killed.

If something goes wrong with a WIGWINCH thread, and this is discovered in the
interrupt handler, the winch record would leak.  It is now freed, except that
the IRQ isn't freed.  This is hard to do from interrupt context.  This has the
side-effect that the IRQ system maintains a reference to the freed structure,
but that shouldn't cause a problem since the descriptor is disabled.

register_winch_irq is now much better about cleaning up after an
initialization failure.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:38 -07:00
Jeff Dike
d14ad81f80 uml: handle errors on opening host side of consoles
If the host side of a console can't be opened, this will now produce visible
error messages.

enable_chan now returns a status and this is passed up to con_open and
ssl_open, which will complain if anything went wrong.

The default host device for the serial line driver is now a pts device rather
than a pty device since lots of hosts have LEGACY_PTYS disabled.  This had
always been failing on such hosts, but silently.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16 09:05:38 -07:00
Jeff Dike
63920f4717 uml: xterm driver tidying
Major tidying of the xterm console driver:
	got rid of the tt-mode gdb support
	tidied up the includes
	fixed lots of style violations
	replaced os_* calls with glibc calls in xterm.c
	all printk calls now have a severity indicator
	the error paths of xterm_open are closer to being right

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>
2007-07-16 09:05:38 -07:00
Jeff Dike
c539ab7307 uml: remove PAGE_SIZE from libc code
Distros seem to be removing PAGE_SIZE from asm/page.h.  So, the libc side of
UML should stop using it.

I replace it with UM_KERN_PAGE_SIZE, which is defined to be the same as
PAGE_SIZE on the kernel side of the house.  I could also use getpagesize(),
but it's more important that UML have the same value of PAGE_SIZE everywhere.
It's conceivable that it could be built with a larger PAGE_SIZE, and use of
getpagesize() would break that badly.

PAGE_MASK got the same treatment, as it is closely tied to PAGE_SIZE.

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>
2007-06-16 13:16:16 -07:00
Al Viro
ecec5ba681 fix uml-x86_64
__NR_syscall_max is done in x86_64 asm-offsets; do an equivalent in
uml kern_constants.h

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-15 18:56:37 -07:00
Jeff Dike
c14b84949e uml: iRQ stacks
Add a separate IRQ stack.  This differs from i386 in having the entire
interrupt run on a separate stack rather than starting on the normal kernel
stack and switching over once some preparation has been done.  The underlying
mechanism, is of course, sigaltstack.

Another difference is that interrupts that happen in userspace are handled on
the normal kernel stack.  These cause a wait wakeup instead of a signal
delivery so there is no point in trying to switch stacks for these.  There's
no other stuff on the stack, so there is no extra stack consumption.

This quirk makes it possible to have the entire interrupt run on a separate
stack - process preemption (and calls to schedule()) happens on a normal
kernel stack.  If we enable CONFIG_PREEMPT, this will need to be rethought.

The IRQ stack for CPU 0 is declared in the same way as the initial kernel
stack.  IRQ stacks for other CPUs will be allocated dynamically.

An extra field was added to the thread_info structure.  When the active
thread_info is copied to the IRQ stack, the real_thread field points back to
the original stack.  This makes it easy to tell where to copy the thread_info
struct back to when the interrupt is finished.  It also serves as a marker of
a nested interrupt.  It is NULL for the first interrupt on the stack, and
non-NULL for any nested interrupts.

Care is taken to behave correctly if a second interrupt comes in when the
thread_info structure is being set up or taken down.  I could just disable
interrupts here, but I don't feel like giving up any of the performance gained
by not flipping signals on and off.

If an interrupt comes in during these critical periods, the handler can't run
because it has no idea what shape the stack is in.  So, it sets a bit for its
signal in a global mask and returns.  The outer handler will deal with this
signal itself.

Atomicity is had with xchg.  A nested interrupt that needs to bail out will
xchg its signal mask into pending_mask and repeat in case yet another
interrupt hit at the same time, until the mask stabilizes.

The outermost interrupt will set up the thread_info and xchg a zero into
pending_mask when it is done.  At this point, nested interrupts will look at
->real_thread and see that no setup needs to be done.  They can just continue
normally.

Similar care needs to be taken when exiting the outer handler.  If another
interrupt comes in while it is copying the thread_info, it will drop a bit
into pending_mask.  The outer handler will check this and if it is non-zero,
will loop, set up the stack again, and handle the interrupt.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:34 -07:00
Jeff Dike
57598fd7b3 uml: remove task_protections
Replaced task_protections with stack_protections since they do the same
thing, and task_protections was misnamed anyway.

This needs THREAD_SIZE, so that's imported via common-offsets.h

Also tidied up the code in the vicinity.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-11 08:29:33 -07:00
Uwe Kleine-König
5886269962 fix file specification in comments
Many files include the filename at the beginning, serveral used a wrong one.

Signed-off-by: Uwe Kleine-König <ukleinek@informatik.uni-freiburg.de>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
2007-05-09 08:58:16 +02:00
Paolo 'Blaisorblade' Giarrusso
c2f239d93e uml: fix prototypes
Declare strlcpy and strlcat more correctly.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:04 -07:00
Jeff Dike
16dd07bc64 uml: more page fault path trimming
More trimming of the page fault path.

Permissions are passed around in a single int rather than one bit per
int.  The permission values are copied from libc so that they can be
passed to mmap and mprotect without any further conversion.

The register sets used by do_syscall_stub and copy_context_skas0 are
initialized once, at boot time, rather than once per call.

wait_stub_done checks whether it is getting the signals it expects by
comparing the wait status to a mask containing bits for the signals of
interest rather than comparing individually to the signal numbers.  It
also has one check for a wait failure instead of two.  The caller is
expected to do the initial continue of the stub.  This gets rid of an
argument and some logic.  The fname argument is gone, as that can be
had from a stack trace.

user_signal() is collapsed into userspace() as it is basically one or
two lines of code afterwards.

The physical memory remapping stuff is gone, as it is unused.

flush_tlb_page is inlined.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:04 -07:00
Jeff Dike
64f60841c0 uml: speed page fault path
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: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:04 -07:00
Jeff Dike
a6ea4cceed uml: rename os_{read_write}_file_k back to os_{read_write}_file
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: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:03 -07:00
Jeff Dike
63843c265f uml: dump core on panic
Dump core after a panic.  This will provide better debugging information than
is currently available.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:03 -07:00
Jeff Dike
3d564047a5 uml: start fixing os_read_file and os_write_file
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: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:03 -07:00
Jeff Dike
377fad3acb uml: kernel segfaults should dump proper registers
If there's a segfault inside the kernel, we want a dump of the registers at
the point of the segfault, not the registers at the point of calling panic or
the last userspace registers.

sig_handler_common_skas now uses a static register set in the case of a
SIGSEGV to avoid messing up the process registers if the segfault turns out to
be non-fatal.

The architecture sigcontext-to-pt_regs copying code was repurposed to copy
data out of the SEGV stack frame.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:02 -07:00
Jeff Dike
5d86456d38 uml: tidy fault code
Tidying in preparation for the segfault register dumping patch which follows.

void * pointers are changed to union uml_pt_regs *.  This makes the types
match reality, except in arch_fixup, which is changed to operate on a union
uml_pt_regs.  This fixes a bug in the call from segv_handler, which passes a
union uml_pt_regs, to segv, which expects to pass a struct sigcontext to
arch_fixup.

Whitespace and other style fixes.

There's also a errno printk fix.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:02 -07:00
Jeff Dike
1ffb9164f5 uml: remove page_size()
userspace code used to have to call the kernelspace function page_size() in
order to determine the value of the kernel's PAGE_SIZE.  Since this is now
available directly from kern_constants.h as UM_KERN_PAGE_SIZE, page_size() can
be deleted and calls changed to use the constant.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:02 -07:00
Jeff Dike
6e21aec3fc uml: tidy process.c
Clean up arch/um/kernel/process.c:

- lots of return(x); -> return x; conversions

- a number of the small functions are either unused, in which case they are
  gone, along any declarations in a header, or could be made static.

- current_pid is ifdefed on CONFIG_MODE_TT and its declaration is ifdefed on
  both CONFIG_MODE_TT and UML_CONFIG_MODE_TT because we don't know whether
  it's being used in a userspace or kernel file.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:02 -07:00
Paolo 'Blaisorblade' Giarrusso
c74c69b442 uml: Replace one-element array with zero-element array
To look at users I did:
$ find arch/um/ include/asm-um -name '*.[ch]'|xargs grep -r 'net_kern\.h'
+-l|xargs grep '\<user\>'

Most users just cast user to the appropriate pointer, the remaining ones are
fixed here.  In net_kern.c, I'm almost sure that save trick is not needed
anymore, but I've not verified it.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
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>
2007-05-07 12:13:02 -07:00
Jeff Dike
9218b17149 uml: remove user_util.h
user_util.h isn't needed any more, so delete it and remove all includes of it.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:01 -07:00
Jeff Dike
24fa6c0832 uml: move remaining useful contents of user_util.h
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: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:01 -07:00
Jeff Dike
4ff83ce111 uml: create as-layout.h
This patch moves all the the symbols defined in um_arch.c, which are mostly
boundaries between different parts of the UML kernel address space, to a new
header, as-layout.h.  There are also a few things here which aren't really
related to address space layout, but which don't really have a better place to
go.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:01 -07:00
Jeff Dike
eb8307595b uml: create arch.h
This patch moves the declarations of the architecture hooks from user_util.h
to a new header, arch.c, and adds the necessary includes to files which need
those declarations.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:01 -07:00
Jeff Dike
c65badbdf5 uml: move SIGIO testing to sigio.c
This patch narrows the sigio interface.  The boot-time SIGIO testing used to
be in start_up.c, which meant that pty_output_sigio and pty_close_sigio needed
to be global.  By moving that code here, those can become static and the
declarations moved from user_util.h.

os_check_bugs is also here because it only does the SIGIO checking.  If it
does more, it'll probably move back to start_up.c.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:01 -07:00
Rusty Russell
c5e631cf65 ARRAY_SIZE: check for type
We can use a gcc extension to ensure that ARRAY_SIZE() is handed an array,
not a pointer.  This is especially important when code is changed from a
fixed array to a pointer.  I assume the Intel compiler doesn't support
__builtin_types_compatible_p.

[jdike@addtoit.com: uml: update UML definition of ARRAY_SIZE]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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>
2007-05-07 12:13:00 -07:00
Jeff Dike
f34d9d2dcb uml: network interface hotplug error handling
This fixes a number of problems associated with network interface hotplug.

The userspace initialization function can fail in some cases, but the
failure was never passed back to eth_configure, which proceeded with the
configuration.  This results in a zombie device that is present, but can't
work.  This is fixed by allowing the initialization routines to return an
error, which is checked, and the configuration aborted on failure.

eth_configure failed to check for many failures.  Even when it did check,
it didn't undo whatever initializations has already happened, so a present,
but partially initialized and non-working device could result.  It now
checks everything that can fail, and bails out, undoing whatever had been
done.

The return value of eth_configure was always ignored, so it is now just
void.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:00 -07:00
Jeff Dike
b4ffb6ad8d uml: host_info tidying
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: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:00 -07:00
Jeff Dike
11100b1dfb uml: delete unused code
Get rid of a bunch of unused stuff -
	cpu_feature had no users
	linux_prog is little-used, so its declaration is moved to the
user for easy deletion when the whole file goes away
	a long-unused debugging aid in helper.c is gone

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-07 12:13:00 -07:00
Jeff Dike
622e696938 [PATCH] uml: fix compilation problems
Fix a few miscellaneous compilation problems -
	an assignment with mismatched types in ldt.c
	a missing include in mconsole.h which needs a definition of uml_pt_regs
	I missed removing an include of user_util.h in hostfs

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-29 08:22:25 -07:00
Jeff Dike
b92c4f922b [PATCH] uml: use correct register file size everywhere
This patch uses MAX_REG_NR consistently to refer to the register file size.
 FRAME_SIZE isn't sufficient because on x86_64, it is smaller than the
ptrace register file size.  MAX_REG_NR was introduced as a consistent way
to get the number of registers, but wasn't used everywhere it should be.

When this causes a problem, it makes PTRACE_SETREGS fail on x86_64 because
of a corrupted segment register value in the known-good register file.  The
patch also adds a register dump at that point in case there are any future
problems here.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-27 09:05:15 -07:00
Paolo 'Blaisorblade' Giarrusso
9ff1d36cf4 [PATCH] um: remove dead code about os_usr1_signal() and os_usr1_process()
os_usr1_signal() is totally unused, os_usr1_process() is used only by TT mode.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-03-08 07:38:21 -08:00