linux.git/arch/s390/kernel/vmlinux.lds.S, branch v5.1.18

s390: avoid vmlinux segments overlap

2018-10-26T08:19:40+00:00

Currently .vmlinux.info section of uncompressed vmlinux elf image is
included into the data segment and load address specified as 0. That
extends data segment to address 0 and makes "text" and "data" segments
overlap.
Program Headers:
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000000001000 0x0000000000100000 0x0000000000100000
                 0x0000000000ead03c 0x0000000000ead03c  R E    0x1000
  LOAD           0x0000000000eaf000 0x0000000000000000 0x0000000000000000
                 0x0000000001a13400 0x000000000233b520  RWE    0x1000
  NOTE           0x0000000000eae000 0x0000000000fad000 0x0000000000fad000
                 0x000000000000003c 0x000000000000003c         0x4

 Section to Segment mapping:
  Segment Sections...
   00     .text .notes
   01     .rodata __ksymtab __ksymtab_gpl __ksymtab_strings __param
   __modver .data..ro_after_init __ex_table .data __bug_table .init.text
   .exit.text .exit.data .altinstructions .altinstr_replacement
   .nospec_call_table .nospec_return_table .boot.data .init.data
   .data..percpu .bss .vmlinux.info
   02     .notes

Later when vmlinux.bin is produced from vmlinux, .vmlinux.info section
is removed. But elf vmlinux file, even though it is not bootable anymore,
used for debugging and loadable segments overlap should be avoided.

Utilize special ":NONE" phdr specification to avoid adding .vmlinux.info
into loadable data segment. Also set .vmlinux.info section type to INFO,
which allows to get a not-loadable info CONTENTS section.

Since minimal supported version of binutils 2.20 does not have
--dump-section objcopy option, make .vmlinux.info section loadable during
info.bin creation to get actual section contents.

Reported-by: Philipp Rudo 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2018-10-23T12:08:53+00:00

Pull locking and misc x86 updates from Ingo Molnar:
 "Lots of changes in this cycle - in part because locking/core attracted
  a number of related x86 low level work which was easier to handle in a
  single tree:

   - Linux Kernel Memory Consistency Model updates (Alan Stern, Paul E.
     McKenney, Andrea Parri)

   - lockdep scalability improvements and micro-optimizations (Waiman
     Long)

   - rwsem improvements (Waiman Long)

   - spinlock micro-optimization (Matthew Wilcox)

   - qspinlocks: Provide a liveness guarantee (more fairness) on x86.
     (Peter Zijlstra)

   - Add support for relative references in jump tables on arm64, x86
     and s390 to optimize jump labels (Ard Biesheuvel, Heiko Carstens)

   - Be a lot less permissive on weird (kernel address) uaccess faults
     on x86: BUG() when uaccess helpers fault on kernel addresses (Jann
     Horn)

   - macrofy x86 asm statements to un-confuse the GCC inliner. (Nadav
     Amit)

   - ... and a handful of other smaller changes as well"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits)
  locking/lockdep: Make global debug_locks* variables read-mostly
  locking/lockdep: Fix debug_locks off performance problem
  locking/pvqspinlock: Extend node size when pvqspinlock is configured
  locking/qspinlock_stat: Count instances of nested lock slowpaths
  locking/qspinlock, x86: Provide liveness guarantee
  x86/asm: 'Simplify' GEN_*_RMWcc() macros
  locking/qspinlock: Rework some comments
  locking/qspinlock: Re-order code
  locking/lockdep: Remove duplicated 'lock_class_ops' percpu array
  x86/defconfig: Enable CONFIG_USB_XHCI_HCD=y
  futex: Replace spin_is_locked() with lockdep
  locking/lockdep: Make class->ops a percpu counter and move it under CONFIG_DEBUG_LOCKDEP=y
  x86/jump-labels: Macrofy inline assembly code to work around GCC inlining bugs
  x86/cpufeature: Macrofy inline assembly code to work around GCC inlining bugs
  x86/extable: Macrofy inline assembly code to work around GCC inlining bugs
  x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops
  x86/bug: Macrofy the BUG table section handling, to work around GCC inlining bugs
  x86/alternatives: Macrofy lock prefixes to work around GCC inlining bugs
  x86/refcount: Work around GCC inlining bug
  x86/objtool: Use asm macros to work around GCC inlining bugs
  ...

s390: introduce .boot.data section

2018-10-09T09:21:06+00:00

Introduce .boot.data section which is "shared" between the decompressor
code and the decompressed kernel. The decompressor will store values in
it, and copy over to the decompressed image before starting it. This
method allows to avoid using pre-defined addresses and other hacks to
pass values between those boot phases.

.boot.data section is a part of init data, and will be freed after kernel
initialization is complete.

For uncompressed kernel image, .boot.data section is basically the same
as .init.data

Reviewed-by: Martin Schwidefsky 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390: rescue initrd as early as possible

2018-10-09T09:21:05+00:00

To avoid multi-stage initrd rescue operation and to simplify
assumptions during early memory allocations move initrd at some final
safe destination as early as possible. This would also allow us to
drop .bss usage restrictions for some files.

Reviewed-by: Martin Schwidefsky 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390/decompressor: rework uncompressed image info collection

2018-10-09T09:21:02+00:00

The kernel decompressor has to know several bits of information about
uncompressed image. Currently this info is collected by running "nm" on
uncompressed vmlinux + "sed" and producing sizes.h file. This method
worked well, but it has several disadvantages. Obscure symbols name
pattern matching is fragile. Adding new values makes pattern even
longer. Logic is spread across code and make file. Limited ability to
adjust symbols values (currently magic lma value of 0x100000 is always
subtracted). Apart from that same pieces of information (and more)
would be needed for early memory detection and features like KASLR
outside of boot/compressed/ folder where sizes.h is generated.

To overcome limitations new "struct vmlinux_info" has been introduced
to include values needed for the decompressor and the rest of the
boot code. The only static instance of vmlinux_info is produced during
vmlinux link step by filling in struct fields by the linker (like it is
done with input_data in boot/compressed/vmlinux.scr.lds.S). This way
individual values could be adjusted with all the knowledge linker has
and arithmetic it supports. Later .vmlinux.info section (which contains
struct vmlinux_info) is transplanted into the decompressor image and
dropped from uncompressed image altogether.

While doing that replace "compressed/vmlinux.scr.lds.S" linker
script (whose purpose is to rename .data section in piggy.o to
.rodata.compressed) with plain objcopy command. And simplify
decompressor's linker script.

Reviewed-by: Martin Schwidefsky 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390/vmlinux.lds: Move JUMP_TABLE_DATA into output section

2018-10-02T06:08:08+00:00

Commit e872267b8bcbb179 ("jump_table: move entries into ro_after_init
region") moved the __jump_table input section into the __ro_after_init
output section, but inadvertently put the macro in the wrong place in
the s390 linker script. Let's fix that.

Fixes: e872267b8bcbb179 ("jump_table: move entries into ro_after_init region")
Reported-by: Guenter Roeck 
Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Acked-by: Heiko Carstens 
Tested-by: Guenter Roeck 
Cc: linux-s390@vger.kernel.org
Cc: Martin Schwidefsky 
Cc: Jessica Yu 
Cc: Peter Zijlstra 
Link: https://lkml.kernel.org/r/20180930164950.3841-1-ard.biesheuvel@linaro.org

jump_table: Move entries into ro_after_init region

2018-09-27T15:56:49+00:00

The __jump_table sections emitted into the core kernel and into
each module consist of statically initialized references into
other parts of the code, and with the exception of entries that
point into init code, which are defused at post-init time, these
data structures are never modified.

So let's move them into the ro_after_init section, to prevent them
from being corrupted inadvertently by buggy code, or deliberately
by an attacker.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Kees Cook 
Acked-by: Jessica Yu 
Acked-by: Peter Zijlstra (Intel) 
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-s390@vger.kernel.org
Cc: Arnd Bergmann 
Cc: Heiko Carstens 
Cc: Will Deacon 
Cc: Catalin Marinas 
Cc: Steven Rostedt 
Cc: Martin Schwidefsky 
Link: https://lkml.kernel.org/r/20180919065144.25010-9-ard.biesheuvel@linaro.org

s390: move _text to an actual .text start

2018-07-02T09:25:00+00:00

Since the uncompressed image .text section starts at 0x100000 now there
is no need to redefine _text to something else to make perf happy.

Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390: correct _stext offset

2018-07-02T09:24:59+00:00

Avoid unnecessary rewrite of psw and merge _stext into
startup_continue. This allows to move _stext definition to vmlinux.lds.S,
where _etext is also defined and set _stext to the actual beginning of
.text at 0x100000.

This fixes the problem with setting the last .text page as
not-executable due to vmem_map_init relying on page alinged _stext and
_etext.

Fixes: bd79d6632958 ("s390/decompressor: trim the kernel image up to 1M")
Reported-by: Nils Hoppmann 
Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky

s390: get rid of the first mb of uncompressed image

2018-07-02T09:24:58+00:00

Instead of generating uncompressed kernel image starting at 0, filling
first mb with zeros (with ".org 0x100000") and then trimming it off
from vmlinux.bin before compression, simply generate a kernel image
starting from 0x100000.

Reviewed-by: Heiko Carstens 
Signed-off-by: Vasily Gorbik 
Signed-off-by: Martin Schwidefsky