Commit e41f501d ("vmlinux.lds: account for destructor sections")
added '.text.exit' to EXIT_TEXT which is discarded at link time by default.
This breaks compilation of UML:
     `.text.exit' referenced in section `.fini_array' of
     /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/libc.a(sdlerror.o):
     defined in discarded section `.text.exit' of
     /usr/lib/gcc/x86_64-linux-gnu/6/../../../x86_64-linux-gnu/libc.a(sdlerror.o)

Apparently UML doesn't want to discard exit text, so let's place all EXIT_TEXT
sections in .exit.text.

Fixes: e41f501d ("vmlinux.lds: account for destructor sections")
Reported-by: NStefan Traby <stefan@hello-penguin.com>
Signed-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: <stable@vger.kernel.org>
Acked-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NRichard Weinberger <richard@nod.at>

Normalize global variables exported by vmlinux.lds to conform usage
guidelines from include/asm-generic/sections.h.

1) Use _text to mark the start of the kernel image including the head
text, and _stext to mark the start of the .text section.
2) Export mandatory global variables __bss_stop.
3) Adjust __init_begin and __init_end to avoid acrossing .text and
   .data sections.
Signed-off-by: NJiang Liu <jiang.liu@huawei.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Percpu allocator honors alignment request upto PAGE_SIZE and both the
percpu addresses in the percpu address space and the translated kernel
addresses should be aligned accordingly.  The calculation of the
former depends on the alignment of percpu output section in the kernel
image.

The linker script macros PERCPU_VADDR() and PERCPU() are used to
define this output section and the latter takes @align parameter.
Several architectures are using @align smaller than PAGE_SIZE breaking
percpu memory alignment.

This patch removes @align parameter from PERCPU(), renames it to
PERCPU_SECTION() and makes it always align to PAGE_SIZE.  While at it,
add PCPU_SETUP_BUG_ON() checks such that alignment problems are
reliably detected and remove percpu alignment comment recently added
in workqueue.c as the condition would trigger BUG way before reaching
there.

For um, this patch raises the alignment of percpu area.  As the area
is in .init, there shouldn't be any noticeable difference.

This problem was discovered by David Howells while debugging boot
failure on mn10300.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Cc: uclinux-dist-devel@blackfin.uclinux.org
Cc: David Howells <dhowells@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net

Currently percpu readmostly subsection may share cachelines with other
percpu subsections which may result in unnecessary cacheline bounce
and performance degradation.

This patch adds @cacheline parameter to PERCPU() and PERCPU_VADDR()
linker macros, makes each arch linker scripts specify its cacheline
size and use it to align percpu subsections.

This is based on Shaohua's x86 only patch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Shaohua Li <shaohua.li@intel.com>

Signed-off-by: NTim Abbott <tabbott@ksplice.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: user-mode-linux-devel@lists.sourceforge.net
Acked-by: NSam Ravnborg <sam@ravnborg.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Discarded sections in different archs share some commonality but have
considerable differences.  This led to linker script for each arch
implementing its own /DISCARD/ definition, which makes maintaining
tedious and adding new entries error-prone.

This patch makes all linker scripts to move discard definitions to the
end of the linker script and use the common DISCARDS macro.  As ld
uses the first matching section definition, archs can include default
discarded sections by including them earlier in the linker script.

ia64 is notable because it first throws away some ia64 specific
subsections and then include the rest of the sections into the final
image, so those sections must be discarded before the inclusion.

defconfig compile tested for x86, x86-64, powerpc, powerpc64, ia64,
alpha, sparc, sparc64 and s390.  Michal Simek tested microblaze.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NMike Frysinger <vapier@gentoo.org>
Tested-by: NMichal Simek <monstr@monstr.eu>
Cc: linux-arch@vger.kernel.org
Cc: Michal Simek <monstr@monstr.eu>
Cc: microblaze-uclinux@itee.uq.edu.au
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Tony Luck <tony.luck@intel.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

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: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus 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: NNick Piggin <npiggin@suse.de>
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There was a typo in commit 7632fc8f,
preventing it from working - 32bit binaries crashed hopelessly before
the below fix and work perfectly now.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During a static link, ld has started putting a .note section in the
.uml.setup.init section.  This has the result that the UML setups begin
with 32 bytes of garbage and UML crashes immediately on boot.

This patch creates a specific .note section for ld to drop this stuff
into.
Signed-off-by: NJeff Dike <jdike@linux.intel.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the UML piece of the INITCALLS tidying.
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>

      Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

Prevent the kernel from oopsing during the extable sorting, as it can do
now, because the extable is in the readonly section of the binary.

Jeff says: The exception table turned RO in 2.6.11-rc3-mm1 for some reason.
Moving it causes it to land in the writable data section of the binary.

Paolo says: This patch fixes a oops on startup, which can be easily
triggered by compiling with CONFIG_MODE_TT disabled, and STATIC_LINK either
disabled or enabled.  The resulting kernel will always Oops on startup,
after printing this simple output:

I've verified, by binary search on the BitKeeper repository (synced up as
of 2.6.12-rc2), starting from the range 2.6.11-2.6.12-rc1, that this bug
shows up on BitKeeper revisions in the range [@1.1994.11.168,+inf), i.e.
starting from this:

[PATCH] lib/sort: Replace insertion sort in exception tables

Since UML does not use the exception table, it's likely that insertion sort
didn't happen to write anything on the table.
Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!