linux-stable.git/arch/x86/kernel/vmlinux.lds.S, branch v5.3

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-07-11T20:54:00+00:00

Pull x86 fixes from Thomas Gleixner:
 "A collection of assorted fixes:

   - Fix for the pinned cr0/4 fallout which escaped all testing efforts
     because the kvm-intel module was never loaded when the kernel was
     compiled with CONFIG_PARAVIRT=n. The cr0/4 accessors are moved out
     of line and static key is now solely used in the core code and
     therefore can stay in the RO after init section. So the kvm-intel
     and other modules do not longer reference the (read only) static
     key which the module loader tried to update.

   - Prevent an infinite loop in arch_stack_walk_user() by breaking out
     of the loop once the return address is detected to be 0.

   - Prevent the int3_emulate_call() selftest from corrupting the stack
     when KASAN is enabled. KASASN clobbers more registers than covered
     by the emulated call implementation. Convert the int3_magic()
     selftest to a ASM function so the compiler cannot KASANify it.

   - Unbreak the build with old GCC versions and with the Gold linker by
     reverting the 'Move of _etext to the actual end of .text'. In both
     cases the build fails with 'Invalid absolute R_X86_64_32S
     relocation: _etext'

   - Initialize the context lock for init_mm, which was never an issue
     until the alternatives code started to use a temporary mm for
     patching.

   - Fix a build warning vs. the LOWMEM_PAGES constant where clang
     complains rightfully about a signed integer overflow in the shift
     operation by converting the operand to an ULL.

   - Adjust the misnamed ENDPROC() of common_spurious in the 32bit entry
     code"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/stacktrace: Prevent infinite loop in arch_stack_walk_user()
  x86/asm: Move native_write_cr0/4() out of line
  x86/pgtable/32: Fix LOWMEM_PAGES constant
  x86/alternatives: Fix int3_emulate_call() selftest stack corruption
  x86/entry/32: Fix ENDPROC of common_spurious
  Revert "x86/build: Move _etext to actual end of .text"
  x86/ldt: Initialize the context lock for init_mm

Revert "x86/build: Move _etext to actual end of .text"

2019-07-09T11:57:31+00:00

This reverts commit 392bef709659abea614abfe53cf228e7a59876a4.

Per the discussion here:

  https://lkml.kernel.org/r/201906201042.3BF5CD6@keescook

the above referenced commit breaks kernel compilation with old GCC
toolchains as well as current versions of the Gold linker.

Revert it to fix the regression and to keep the ability to compile the
kernel with these tools.

Signed-off-by: Ross Zwisler 
Signed-off-by: Thomas Gleixner 
Reviewed-by: Guenter Roeck 
Cc: 
Cc: "H. Peter Anvin" 
Cc: Borislav Petkov 
Cc: Kees Cook 
Cc: Johannes Hirte 
Cc: Klaus Kusche 
Cc: samitolvanen@google.com
Cc: Guenter Roeck 
Link: https://lkml.kernel.org/r/20190701155208.211815-1-zwisler@google.com
Signed-off-by: Ingo Molnar

x86/mm: Create a workarea in the kernel for SME early encryption

2019-06-20T07:44:26+00:00

In order for the kernel to be encrypted "in place" during boot, a workarea
outside of the kernel must be used. This SME workarea used during early
encryption of the kernel is situated on a 2MB boundary after the end of
the kernel text, data, etc. sections (_end).

This works well during initial boot of a compressed kernel because of
the relocation used for decompression of the kernel. But when performing
a kexec boot, there's a chance that the SME workarea may not be mapped
by the kexec pagetables or that some of the other data used by kexec
could exist in this range.

Create a section for SME in vmlinux.lds.S. Position it after "_end", which
is after "__end_of_kernel_reserve", so that the memory will be reclaimed
during boot and since this area is all zeroes, it compresses well. This
new section will be part of the kernel image, so kexec will account for it
in pagetable mappings and placement of data after the kernel.

Here's an example of a kernel size without and with the SME section:

	without:
		vmlinux:	36,501,616
		bzImage:	 6,497,344

		100000000-47f37ffff : System RAM
		  1e4000000-1e47677d4 : Kernel code	(0x7677d4)
		  1e47677d5-1e4e2e0bf : Kernel data	(0x6c68ea)
		  1e5074000-1e5372fff : Kernel bss	(0x2fefff)

	with:
		vmlinux:	44,419,408
		bzImage:	 6,503,136

		880000000-c7ff7ffff : System RAM
		  8cf000000-8cf7677d4 : Kernel code	(0x7677d4)
		  8cf7677d5-8cfe2e0bf : Kernel data	(0x6c68ea)
		  8d0074000-8d0372fff : Kernel bss	(0x2fefff)

Signed-off-by: Tom Lendacky 
Signed-off-by: Borislav Petkov 
Reviewed-by: Baoquan He 
Reviewed-by: Dave Hansen 
Tested-by: Lianbo Jiang 
Cc: Andy Lutomirski 
Cc: Brijesh Singh 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Joerg Roedel 
Cc: Kees Cook 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: "Rafael Ávila de Espíndola" 
Cc: Sami Tolvanen 
Cc: Thomas Gleixner 
Cc: "x86@kernel.org" 
Link: https://lkml.kernel.org/r/3c483262eb4077b1654b2052bd14a8d011bffde3.1560969363.git.thomas.lendacky@amd.com

x86/mm: Identify the end of the kernel area to be reserved

2019-06-20T07:22:47+00:00

The memory occupied by the kernel is reserved using memblock_reserve()
in setup_arch(). Currently, the area is from symbols _text to __bss_stop.
Everything after __bss_stop must be specifically reserved otherwise it
is discarded. This is not clearly documented.

Add a new symbol, __end_of_kernel_reserve, that more readily identifies
what is reserved, along with comments that indicate what is reserved,
what is discarded and what needs to be done to prevent a section from
being discarded.

Signed-off-by: Tom Lendacky 
Signed-off-by: Borislav Petkov 
Reviewed-by: Baoquan He 
Reviewed-by: Dave Hansen 
Tested-by: Lianbo Jiang 
Cc: Andy Lutomirski 
Cc: Brijesh Singh 
Cc: Dave Young 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Joerg Roedel 
Cc: Juergen Gross 
Cc: Kees Cook 
Cc: Nick Desaulniers 
Cc: Pavel Tatashin 
Cc: Peter Zijlstra 
Cc: Robert Richter 
Cc: Sami Tolvanen 
Cc: Sinan Kaya 
Cc: Thomas Gleixner 
Cc: "x86@kernel.org" 
Link: https://lkml.kernel.org/r/7db7da45b435f8477f25e66f292631ff766a844c.1560969363.git.thomas.lendacky@amd.com

Merge branch 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-06T23:13:31+00:00

Pull x86 mm updates from Ingo Molnar:
 "The changes in here are:

   - text_poke() fixes and an extensive set of executability lockdowns,
     to (hopefully) eliminate the last residual circumstances under
     which we are using W|X mappings even temporarily on x86 kernels.
     This required a broad range of surgery in text patching facilities,
     module loading, trampoline handling and other bits.

   - tweak page fault messages to be more informative and more
     structured.

   - remove DISCONTIGMEM support on x86-32 and make SPARSEMEM the
     default.

   - reduce KASLR granularity on 5-level paging kernels from 512 GB to
     1 GB.

   - misc other changes and updates"

* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (36 commits)
  x86/mm: Initialize PGD cache during mm initialization
  x86/alternatives: Add comment about module removal races
  x86/kprobes: Use vmalloc special flag
  x86/ftrace: Use vmalloc special flag
  bpf: Use vmalloc special flag
  modules: Use vmalloc special flag
  mm/vmalloc: Add flag for freeing of special permsissions
  mm/hibernation: Make hibernation handle unmapped pages
  x86/mm/cpa: Add set_direct_map_*() functions
  x86/alternatives: Remove the return value of text_poke_*()
  x86/jump-label: Remove support for custom text poker
  x86/modules: Avoid breaking W^X while loading modules
  x86/kprobes: Set instruction page as executable
  x86/ftrace: Set trampoline pages as executable
  x86/kgdb: Avoid redundant comparison of patched code
  x86/alternatives: Use temporary mm for text poking
  x86/alternatives: Initialize temporary mm for patching
  fork: Provide a function for copying init_mm
  uprobes: Initialize uprobes earlier
  x86/mm: Save debug registers when loading a temporary mm
  ...

Merge branch 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-05-06T22:56:41+00:00

Pull x86 irq updates from Ingo Molnar:
 "Here are the main changes in this tree:

   - Introduce x86-64 IRQ/exception/debug stack guard pages to detect
     stack overflows immediately and deterministically.

   - Clean up over a decade worth of cruft accumulated.

  The outcome of this should be more clear-cut faults/crashes when any
  of the low level x86 CPU stacks overflow, instead of silent memory
  corruption and sporadic failures much later on"

* 'x86-irq-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
  x86/irq: Fix outdated comments
  x86/irq/64: Remove stack overflow debug code
  x86/irq/64: Remap the IRQ stack with guard pages
  x86/irq/64: Split the IRQ stack into its own pages
  x86/irq/64: Init hardirq_stack_ptr during CPU hotplug
  x86/irq/32: Handle irq stack allocation failure proper
  x86/irq/32: Invoke irq_ctx_init() from init_IRQ()
  x86/irq/64: Rename irq_stack_ptr to hardirq_stack_ptr
  x86/irq/32: Rename hard/softirq_stack to hard/softirq_stack_ptr
  x86/irq/32: Make irq stack a character array
  x86/irq/32: Define IRQ_STACK_SIZE
  x86/dumpstack/64: Speedup in_exception_stack()
  x86/exceptions: Split debug IST stack
  x86/exceptions: Enable IST guard pages
  x86/exceptions: Disconnect IST index and stack order
  x86/cpu: Remove orig_ist array
  x86/cpu: Prepare TSS.IST setup for guard pages
  x86/dumpstack/64: Use cpu_entry_area instead of orig_ist
  x86/irq/64: Use cpu entry area instead of orig_ist
  x86/traps: Use cpu_entry_area instead of orig_ist
  ...

Merge branch 'linus' into x86/mm, to pick up dependent fix

2019-04-26T10:01:33+00:00

Signed-off-by: Ingo Molnar

x86/build: Move _etext to actual end of .text

2019-04-24T10:27:47+00:00

When building x86 with Clang LTO and CFI, CFI jump regions are
automatically added to the end of the .text section late in linking. As a
result, the _etext position was being labelled before the appended jump
regions, causing confusion about where the boundaries of the executable
region actually are in the running kernel, and broke at least the fault
injection code. This moves the _etext mark to outside (and immediately
after) the .text area, as it already the case on other architectures
(e.g. arm64, arm).

Reported-and-tested-by: Sami Tolvanen 
Signed-off-by: Kees Cook 
Cc: Borislav Petkov 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20190423183827.GA4012@beast
Signed-off-by: Ingo Molnar

x86/irq/64: Split the IRQ stack into its own pages

2019-04-17T13:37:02+00:00

Currently, the IRQ stack is hardcoded as the first page of the percpu
area, and the stack canary lives on the IRQ stack. The former gets in
the way of adding an IRQ stack guard page, and the latter is a potential
weakness in the stack canary mechanism.

Split the IRQ stack into its own private percpu pages.

[ tglx: Make 64 and 32 bit share struct irq_stack ]

Signed-off-by: Andy Lutomirski 
Signed-off-by: Thomas Gleixner 
Signed-off-by: Borislav Petkov 
Cc: Alexey Dobriyan 
Cc: Andrew Morton 
Cc: Ard Biesheuvel 
Cc: Boris Ostrovsky 
Cc: Brijesh Singh 
Cc: "Chang S. Bae" 
Cc: Dominik Brodowski 
Cc: Feng Tang 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Jan Beulich 
Cc: Jiri Kosina 
Cc: Joerg Roedel 
Cc: Jordan Borgner 
Cc: Josh Poimboeuf 
Cc: Juergen Gross 
Cc: Konrad Rzeszutek Wilk 
Cc: Maran Wilson 
Cc: Masahiro Yamada 
Cc: Michal Hocko 
Cc: Mike Rapoport 
Cc: Nick Desaulniers 
Cc: Nicolai Stange 
Cc: Peter Zijlstra 
Cc: Pu Wen 
Cc: "Rafael Ávila de Espíndola" 
Cc: Sean Christopherson 
Cc: Stefano Stabellini 
Cc: Vlastimil Babka 
Cc: x86-ml 
Cc: xen-devel@lists.xenproject.org
Link: https://lkml.kernel.org/r/20190414160146.267376656@linutronix.de

x86/build/lto: Fix truncated .bss with -fdata-sections

2019-04-16T06:20:55+00:00

With CONFIG_LD_DEAD_CODE_DATA_ELIMINATION=y, we compile the kernel with
-fdata-sections, which also splits the .bss section.

The new section, with a new .bss.* name, which pattern gets missed by the
main x86 linker script which only expects the '.bss' name. This results
in the discarding of the second part and a too small, truncated .bss
section and an unhappy, non-working kernel.

Use the common BSS_MAIN macro in the linker script to properly capture
and merge all the generated BSS sections.

Signed-off-by: Sami Tolvanen 
Reviewed-by: Nick Desaulniers 
Reviewed-by: Kees Cook 
Cc: Borislav Petkov 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Nicholas Piggin 
Cc: Nick Desaulniers 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20190415164956.124067-1-samitolvanen@google.com
[ Extended the changelog. ]
Signed-off-by: Ingo Molnar