| Age | Commit message (Collapse) | Author |
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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: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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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: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch simplifies the opening and closing of host console devices and the
registration and deregistration of IRQs. The intent is to make it obvious
that an IRQ can't exist without an open file descriptor.
chan_enable will now open the channel, and when both opening and IRQ
registration are desired, this should be used. Opening only is done for the
initial console, so that interface still needs to exist.
The free_irqs_later interface is now gone. It was intended to avoid freeing
an IRQ while it was being processed. It did this, but it didn't eliminate the
possiblity of free_irq being called from an interrupt, which is bad. In its
place is a list of irqs to be freed, which is processed by the signal handler
just before exiting. close_one_chan now disables irqs.
When a host device disappears, it is just closed, and that disables IRQs.
The device id registered with the IRQ is now the chan structure, not the tty.
This is because the interrupt arrives on a descriptor associated with the
channel. This caused equivalent changes in the arguments to line_timer_cb.
line_disable is gone since it is not used any more.
The count field in the line structure is gone. tty->count is used instead.
The complicated logic in sigio_handler with freeing IRQs when necessary and
making sure its idea of the next irq is correct is now much simpler. The irq
list can't be rearranged underneath it, so it is now a simple list walk.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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There are a few functions which are declared to return something, but don't.
These are actually infinite loops which are forced to be declared as non-void.
This makes them all return 0.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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With Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
UML skas0 stub has been miscompiling for many people (incidentally not
the authors), depending on the used GCC versions.
I think (and testing on some GCC versions shows) this patch avoids the
fundamental issue which is behind this, namely gcc using the stack when
we have just replaced it, behind gcc's back. The remapping and storage
of the return value is hidden in a blob of asm, hopefully giving gcc no
room for creativity.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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arch/um/kernel/tt/uaccess.c: In function `copy_from_user_tt':
arch/um/kernel/tt/uaccess.c:11: error: `FIXADDR_USER_START' undeclared (first use in this function)
arch/um/kernel/tt/uaccess.c:11: error: (Each undeclared identifier is reported only once
arch/um/kernel/tt/uaccess.c:11: error: for each function it appears in.)
I get the compile error when I disable CONFIG_MODE_SKAS.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Acked-by: Paolo Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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On some systems, libc PAGE_SIZE calls getpagesize, which can't happen from a
stub. So, I use UM_KERN_PAGE_SIZE, which is less variable in its definition,
instead.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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We have a bug in the i386 stub_syscall6 which pushes ebp before the system
call and pops it afterwards. Because we use syscall6 to remap the stack, the
old contents of the stack (and the former value of ebp) are no longer
available. Some versions of gcc make from a real local, accessed through ebp,
despite my efforts to make it obvious that references to from are really
constants. This patch attempts to make it even more obvious by eliminating
from and using a macro to access the stub's data explicitly with constants.
My original thinking on this was to replace syscall6 with a remap_stack
interface which saved ebp someplace and restored it afterwards. The problem
is that there are no registers to put it in, except for esp. That could work,
since we can store a constant in esp after the mmap because we just replaced
the stack. However, this approach seems a tad cleaner.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The access_ok_tt() macro is bogus, in that a read access is unconditionally
considered valid.
I couldn't find in SCM logs the introduction of this check, but I went back to
2.4.20-1um and the definition was the same.
Possibly this was done to avoid problems with missing set_fs() calls, but
there can't be any I think because they would fail with SKAS mode.
TT-specific code is still to check.
Also, this patch joins common code together, and makes the "address range
wrapping" check happen for all cases, rather than for only some.
This may, possibly, be reoptimized at some time, but the current code doesn't
seem clever, just confused.
* Important: I've also had to change references to access_ok_{tt,skas} back to
access_ok - the kernel wasn't that happy otherwise.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The below warning was added in place of pte_mkyoung(); if (is_write)
pte_mkdirty();
In fact, if the PTE is not marked young/dirty, our dirty/accessed bit
emulation would cause the TLB permission not to be changed, and so we'd loop,
and given we don't support preemption yet, we'd busy-hang here.
However, I've seen this warning trigger without crashes during a loop of
concurrent kernel builds, at random times (i.e. like a race condition), and I
realized that two concurrent faults on the same page, one on read and one on
write, can trigger it. The read fault gets serviced and the PTE gets marked
writable but clean (it's possible on a shared-writable mapping), while the
generic code sees the PTE was already installed and returns without action. In
this case, we'll see another fault and service it normally.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This is the arch/ part of the big kfree cleanup patch.
Remove pointless checks for NULL prior to calling kfree() in arch/.
Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
Acked-by: Grant Grundler <grundler@parisc-linux.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The sys_ptrace boilerplate code (everything outside the big switch
statement for the arch-specific requests) is shared by most architectures.
This patch moves it to kernel/ptrace.c and leaves the arch-specific code as
arch_ptrace.
Some architectures have a too different ptrace so we have to exclude them.
They continue to keep their implementations. For sh64 I had to add a
sh64_ptrace wrapper because it does some initialization on the first call.
For um I removed an ifdefed SUBARCH_PTRACE_SPECIAL block, but
SUBARCH_PTRACE_SPECIAL isn't defined anywhere in the tree.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Paul Mackerras <paulus@samba.org>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-By: David Howells <dhowells@redhat.com>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Remove usage of hardcoded constants in paging_init().
By chance I spotted a bug in zones_setup involving a change to ZONE_*
constants, due to the ZONE_DMA32 patch from Andi Kleen (which is in -mm).
So, possibly, instead of zones_size[2] you will find zones_size[3] in the
code, but that change is wrong and this patch is still correct.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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A number of fixes to improve behavior when large physical memory sizes
are specified:
- libc files need -D_FILE_OFFSET_BITS=64 because there are unavoidable uses
of non-64 interfaces in libc
- some %d need to be %u
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Patch imlements full LDT handling in SKAS:
* UML holds it's own LDT table, used to deliver data on
modify_ldt(READ)
* UML disables the default_ldt, inherited from the host (SKAS3)
or resets LDT entries, set by host's clib and inherited in
SKAS0
* A new global variable skas_needs_stub is inserted, that
can be used to decide, whether stub-pages must be supported
or not.
* Uses the syscall-stub to replace missing PTRACE_LDT (therefore,
write_ldt_entry needs to be modified)
Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all systemcalls from helper.c file under os-Linux dir
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all systemcalls from main.c file under os-Linux dir and joins mem.c
and um_arch.c files.
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all systemcalls from uaccess_user.c file under os-Linux dir
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Add some more debugging information when a stub does something unexpected,
usually segfaulting. Now, it dumps out the stub's registers as well as the
signal.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Define jiffies_64 in kernel/timer.c rather than having 24 duplicated
defines in each architecture.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
a many-threaded application which concurrently initializes different parts of
a large anonymous area.
This patch corrects that, by using a separate spinlock per page table page, to
guard the page table entries in that page, instead of using the mm's single
page_table_lock. (But even then, page_table_lock is still used to guard page
table allocation, and anon_vma allocation.)
In this implementation, the spinlock is tucked inside the struct page of the
page table page: with a BUILD_BUG_ON in case it overflows - which it would in
the case of 32-bit PA-RISC with spinlock debugging enabled.
Splitting the lock is not quite for free: another cacheline access. Ideally,
I suppose we would use split ptlock only for multi-threaded processes on
multi-cpu machines; but deciding that dynamically would have its own costs.
So for now enable it by config, at some number of cpus - since the Kconfig
language doesn't support inequalities, let preprocessor compare that with
NR_CPUS. But I don't think it's worth being user-configurable: for good
testing of both split and unsplit configs, split now at 4 cpus, and perhaps
change that to 8 later.
There is a benefit even for singly threaded processes: kswapd can be attacking
one part of the mm while another part is busy faulting.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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In worrying over the various pte operations in different architectures, I came
across some unused functions in UML: remove mprotect_kernel_vm,
protect_vm_page and addr_pte.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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There's usually a good reason when a pte is examined without the lock; but it
makes me nervous when the pointer is dereferenced more than once.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Convert those few architectures which are calling pud_alloc, pmd_alloc,
pte_alloc_map on a user mm, not to take the page_table_lock first, nor drop it
after. Each of these can continue to use pte_alloc_map, no need to change
over to pte_alloc_map_lock, they're neither racy nor swappable.
In the sparc64 io_remap_pfn_range, flush_tlb_range then falls outside of the
page_table_lock: that's okay, on sparc64 it's like flush_tlb_mm, and that has
always been called from outside of page_table_lock in dup_mmap.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The old code had the IP and SP coming from the registers in the thread
struct, which are completely wrong since those are the userspace
registers. This fixes that by pulling the correct values from the
jmp_buf in which the kernel state of each thread is stored.
Signed-off-by: Allan Graves <allan.graves@oracle.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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SEGV_MAYBE_FIXABLE tests ptrace_faultinfo, and depends on it being 1 only in
SKAS3 mode, while currently when running with mode=tt it will be 1 anyway.
Fix this, and do the same for proc_mm.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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I hadn't been running a SKAS3 host when testing the "uml: fix hang in TT mode
on fault" patch (commit 546fe1cbf91d4d62e3849517c31a2327c992e5c5), and I
didn't think enough to the missing trap_no in SKAS3 mode.
In fact, the resulting kernel doesn't work at all in SKAS3 mode.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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UML makefiles sanitized:
- number of generated headers reduced to 2 (from user-offsets.c and
kernel-offsets.c resp.). The rest is made constant and simply
includes those two.
- mk_... helpers are gone now that we don't need to generate these
headers
- arch/um/include2 removed since everything under arch/um/include/sysdep
is constant now and symlink can point straight to source tree.
- dependencies seriously simplified.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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setup_initial_poll is only called with sigio_lock() held, so use appropriate
allocation.
Also, parse_chan() can also be called when holding a spinlock (see line_open()
-> parse_chan_pair()).
I have sporadic problems (spinlock taken twice, with spinlock debugging on UP)
which could be caused by a sequence like "take spinlock, alloc and go to
sleep, take again the spinlock in the other thread".
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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GFP_ATOMIC | GFP_KERNEL is meaningless and won't work. Actually it never
worked, even in 2.4.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Following i386, we should maybe refuse trying to fault in pages when we're
doing atomic operations, because to handle the fault we could need to take
already taken spinlocks.
Also, if we're doing an atomic operation (in the sense of in_atomic()) we're
surely in kernel mode and we're surely going to handle adequately the failed
fault, so it's safe to behave this way.
Currently, on UML SMP is rarely used, and we don't support PREEMPT, so this is
unlikely to create problems right now, but it might in the future.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Avoid setting w = 0 twice. Spotted this (trivial) thing which is needed for
another patch.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The current code doesn't handle well general protection faults on the host -
it thinks that cr2 is always the address of a page fault. While actually, on
general protection faults, that address is not accessible, so we'd better
assume we couldn't satisfy the fault. Currently instead we think we've fixed
it, so we go back, retry the instruction and fault again endlessly.
This leads to the kernel hanging when doing copy_from_user(dest, -1, ...) in
TT mode, since reading *(-1) causes a GFP, and we don't support kernel
preemption.
Thanks to Luo Xin for testing UML with LTP and reporting the failures he got.
Cc: Luo Xin <luothing@sina.com>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Simplify the code by using strlcat() instead of strncat() and manual
appending.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Only remove the UML pidfile and management socket if we created them.
Currently in case two UMLs are started with the same umid, the second will
remove the first's ones.
Probably we should also panic() at that point, not sure however.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The header declaring this function wasn't included, so the function declaration
was totally bogus wrt. the proto - even if this wasn't going to fail at all.
It was so bad that the compile warning I got was "control reaches end of
non-void function", i.e. missing return. Actually, this has been there for ages,
the consolidation patch just added the warning which was needed to clean it up.
Nice. Really.
Cc: Allan Graves <allan.graves@gmail.com>
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Translate uname output taken from the host if needed.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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When removing verify_area, verify_area_{tt,skas} were forgotten.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This joins mem_user.c and mem.c files.
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The serial UML OS-abstraction layer patch (um/kernel dir).
This moves all system calls from mem_user.c and tempfile.c files under
os-Linux dir.
Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The poster child for this patch is the third tuntap_user hunk. When an ioctl
fails, it properly closes the opened file descriptor and returns. However,
the close resets errno to 0, and the 'return errno' that follows returns 0
rather than the value that ioctl set. This caused the caller to believe that
the device open succeeded and had opened file descriptor 0, which caused no
end of interesting behavior.
The rest of this patch is a pass through the UML sources looking for places
where errno could be reset before being passed back out. A common culprit is
printk, which could call write, being called before errno is returned.
In some cases, where the code ends up being much smaller, I just deleted the
printk.
There was another case where a caller of run_helper looked at errno after a
failure, rather than the return value of run_helper, which was the errno value
that it wanted.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch implements a stack trace for a thread, not unlike sysrq-t does.
The advantage to this is that a break point can be placed on showreqs, so that
upon showing the stack, you jump immediately into the debugger. While sysrq-t
does the same thing, sysrq-t shows *all* threads stacks. It also doesn't work
right now. In the future, I thought it might be acceptable to make this show
all pids stacks, but perhaps leaving well enough alone and just using sysrq-t
would be okay. For now, upon receiving the stack command, UML switches
context to that thread, dumps its registers, and then switches context back to
the original thread. Since UML compacts all threads into one of 4 host
threads, this sort of mechanism could be expanded in the future to include
other debugging helpers that sysrq does not cover.
Note by jdike - The main benefit to this is that it brings an arbitrary thread
back into context, where it can be examined by gdb. The fact that it dumps it
stack is secondary. This provides the capability to examine a sleeping
thread, which has existed in tt mode, but not in skas mode until now.
Also, the other threads, that sysrq doesn't cover, can be gdb-ed directly
anyway.
Signed-off-by: Allan Graves<allan.graves@gmail.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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This patch moves code that is in both switch_to_tt and switch_to_skas to the
top level _switch_to function, keeping us from duplicating code. It is
required for the stack trace patch to work properly.
Signed-off-by: Allan Graves <allan.graves@gmail.com>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Cc: Paolo Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The PTE returned from handle_mm_fault is already marked as dirty and accessed
if needed.
Also, since this is not set with set_pte() (which sets NEWPAGE and NEWPROT as
needed), this wouldn't work anyway.
This version has been updated and fixed, thanks to some feedback from Jeff Dike.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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The UML fault handler was recently changed to enforce PROT_NONE protections,
by requiring VM_READ or VM_EXEC on VMA's.
However, by mistake, things were changed such that VM_READ is always checked,
also on write faults; so a VMA mapped with only PROT_WRITE is not readable
(unless it's prefaulted with MAP_POPULATE or with a write), which is different
from i386.
Discovered while testing remap_file_pages protection support.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Turns out that, for UML, a *lot* of VM-related trivial functions are not
inlined but rather normal functions.
In other sections of UML code, this is justified by having files which
interact with the host and cannot therefore include kernel headers, but in
this case there's no such justification.
I've had to turn many of them to macros because of missing declarations. While
doing this, I've decided to reuse some already existing macros.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Inside the linker script, insert the code for DWARF debug info sections. This
may help GDB'ing a Uml binary. Actually, it seems that ld is able to guess
what I added correctly, but normal linker scripts include this section so it
should be correct anyway adding it.
On request by Sam Ravnborg <sam@ravnborg.org>, I've added it to
asm-generic/vmlinux.lds.s. I've also moved there the stabs debug section,
used the new macro in i386 linker script and added DWARF debug section to
that.
In the truth, I've not been able to verify the difference in GDB behaviour
after this change (I've seen large improvements with another patch). This
may depend on my binutils version, older one may have worse defaults.
However, this section is present in normal linker script, so add it at
least for the sake of cleanness.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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