The earlier crash dump fix on x86_64 depended on patches in -mm which
are intended for post-2.6.23.  Without those, it broke the build when
it went into 2.6.23-rc5.

This changes the field references in ELF_CORE_COPY_REGS back to those
still used in mainline.

Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Stop UML crashing when trying to dump a process core on x86_64.  This is the
minimal fix to stop the crash - more things are broken here, and patches are
forthcoming.

The immediate thing to do is define ELF_CORE_COPY_REGS and
ELF_CORE_COPY_FPREGS.  Defining ELF_CORE_COPY_FPREGS allows dump_fpu to go
away.  It is defined in terms of save_fp_registers, so that needs to be added.

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>

Fix a class of bugs in the UML linker scripts which caused section boundary
variables to sometimes not line up with their sections.

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>

New arch macro STACK_TOP_MAX it gives the larges valid stack address for the
architecture in question.

It differs from STACK_TOP in that it will not distinguish between
personalities but will always return the largest possible address.

This is used to create the initial stack on execve, which we will move down to
the proper location once the binfmt code has figured out where that is.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ollie Wild <aaw@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add generic exit-time stack-depth checking to CONFIG_DEBUG_STACK_USAGE.

This also adds UML support.

Tested on UML and i386.

[akpm@linux-foundation.org: cleanups, speedups, tweaks]
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For some reason, I was using kmalloc instead of get_free_pages for kernel
stacks.

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>

Kill pte_rdprotect(), pte_exprotect(), pte_mkread(), pte_mkexec(), pte_read(),
pte_exec(), and pte_user() except where arch-specific code is making use of
them.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add asm-um/paravirt.h so that i386 headers that get pulled into UML
don't cause build failures when they want asm/paravirt.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>

Get UML to use the generic bug support rather than arch specific one.

If I insert an artificial bug right before loading init, I get this:

 Kernel panic - not syncing: Kernel mode signal 4

 EIP: 0023:[<0819d501>] CPU: 0 Not tainted ESP: 002b:f7fd4fbc EFLAGS: 00000246
    Not tainted
    EAX: 00000000 EBX: 00007870 ECX: 00000013 EDX: 00007870
    ESI: 0000786d EDI: 00000011 EBP: f7fd4fd8 DS: 002b ES: 002b
    08273bec:  [<0806e814>] show_regs+0x104/0x106
    08273c08:  [<08058927>] panic_exit+0x2c/0x4b
    08273c18:  [<08080ee7>] notifier_call_chain+0x32/0x5b
    08273c38:  [<08080fbd>] __atomic_notifier_call_chain+0x30/0x32
    08273c54:  [<08080fee>] atomic_notifier_call_chain+0x2f/0x31
    08273c70:  [<08073b88>] panic+0x75/0x131
    08273c94:  [<080586c7>] relay_signal+0x87/0x95
    08273cb0:  [<0806b9ee>] sig_handler_common_skas+0x9e/0x120
    08273cd8:  [<08067738>] sig_handler+0x28/0x4f
    08273cec:  [<0806792e>] handle_signal+0x53/0x89
    08273d0c:  [<08069f60>] hard_handler+0x18/0x28
    08273d1c:  [<ffffe500>] transitions+0xf7d598b8/0xfffffff0

With this patch in place, this is how it looks:

 BUG: failure at init/main.c:779/init_post()!
 Kernel panic - not syncing: BUG!

 EIP: 0023:[<081a65d1>] CPU: 0 Not tainted ESP: 002b:f7f0dfbc EFLAGS: 00000246
    Not tainted
    EAX: 00000000 EBX: 000069db ECX: 00000013 EDX: 000069db
    ESI: 000069d8 EDI: 00000011 EBP: f7f0dfd8 DS: 002b ES: 002b
    098efedc:  [<0806e9a4>] show_regs+0x104/0x106
    098efef8:  [<080589c7>] panic_exit+0x2c/0x4b
    098eff08:  [<080818d7>] notifier_call_chain+0x32/0x5b
    098eff28:  [<080819ad>] __atomic_notifier_call_chain+0x30/0x32
    098eff44:  [<080819de>] atomic_notifier_call_chain+0x2f/0x31
    098eff60:  [<08073f28>] panic+0x75/0x131
    098eff84:  [<080541d5>] init_post+0xcd/0xe8
    098eff9c:  [<08048ad4>] kernel_init+0x8e/0x9a
    098effb4:  [<08066dee>] run_kernel_thread+0x41/0x53
    098effe0:  [<08058e75>] new_thread_handler+0x62/0x8b
    098efffc:  [<a55a5a5a>] 0xa55a5a5a

[ jdike - added BUG_TABLE to linker script ]

Signed-off-by: Nick Piggin <npiggin@suse.de>
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>

The x86_64 a.out.h got a definition of STACK_TOP_MAX, which interferes with
the UML version.  So, just undef it like STACK_TOP.

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>