The userspace part of UML uses the asm-offsets.h generator mechanism to
create definitions for UM_KERN_<LEVEL> that match the in-kernel
KERN_<LEVEL> constant definitions.

As of commit 04d2c8c83d0e3ac5f78aeede51babb3236200112 ("printk: convert
the format for KERN_<LEVEL> to a 2 byte pattern"), KERN_<LEVEL> is no
longer expanded to the literal '"<LEVEL>"', but to '"\001" "LEVEL"', i.e.
it contains two parts.

However, the combo of DEFINE_STR() in
arch/x86/um/shared/sysdep/kernel-offsets.h and sed-y in Kbuild doesn't
support string literals consisting of multiple parts. Hence for all
UM_KERN_<LEVEL> definitions, only the SOH character is retained in the actual
definition, while the remainder ends up in the comment. E.g. in
include/generated/asm-offsets.h we get

    #define UM_KERN_INFO "\001" /* "6" KERN_INFO */

instead of

    #define UM_KERN_INFO "\001" "6" /* KERN_INFO */

This causes spurious '^A' output in some kernel messages:

    Calibrating delay loop... 4640.76 BogoMIPS (lpj=23203840)
    pid_max: default: 32768 minimum: 301
    Mount-cache hash table entries: 256
    ^AChecking that host ptys support output SIGIO...Yes
    ^AChecking that host ptys support SIGIO on close...No, enabling workaround
    ^AUsing 2.6 host AIO
    NET: Registered protocol family 16
    bio: create slab <bio-0> at 0
    Switching to clocksource itimer

To fix this:
  - Move the mapping from UM_KERN_<LEVEL> to KERN_<LEVEL> from
    arch/um/include/shared/common-offsets.h to
    arch/um/include/shared/user.h, which is preincluded for all userspace
    parts,
  - Preinclude include/linux/kern_levels.h for all userspace parts, to
    obtain the in-kernel KERN_<LEVEL> constant definitions. This doesn't
    violate the kernel/userspace separation, as include/linux/kern_levels.h
    is self-contained and doesn't expose any other kernel internals.
  - Remove the now unused STR() and DEFINE_STR() macros.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Richard Weinberger <richard@nod.at>

UML guest processes now get correct siginfo_t for SIGTRAP, SIGFPE,
SIGILL and SIGBUS. Specifically, si_addr and si_code are now correct
where previously they were si_addr = NULL and si_code = 128.

Signed-off-by: Martin Pärtel <martin.partel@gmail.com>
Signed-off-by: Richard Weinberger <richard@nod.at>

Only 3 out of 63 do not.  Renamed the current variant to __set_current_blocked(),
added set_current_blocked() that will exclude unblockable signals, switched
open-coded instances to it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Instead of using chip->release() we can achieve the same
using a simple wrapper for free_irq().
We have already um_request_irq(), so um_free_irq() is the perfect
counterpart.

Signed-off-by: Richard Weinberger <richard@nod.at>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

just provide get_current_pid() to the userland side of things
instead of get_current() + manual poking in its results

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

it's x86-only and we have no business playing with it in asm/mmu.h; make
the latter have
	struct uml_arch_mm_context arch;
instead of
	struct uml_ldt ldt;
and let arch/<subarch>/um/asm/mm_context.h decide what'll be in there.
While we are at it, kill host_ldt.h - it's not needed in part of places
that include it (we want asm/ldt.h in those) and it can be trivially
expanded into the single remaining one.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

it's i386-specific; moreover, analogs on other targets have
incompatible interface - PTRACE_GET_THREAD_AREA does exist
elsewhere, but struct user_desc does *not*

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>