The changes to automatically test for working stack protector compiler
support in the Kconfig files removed the special STACKPROTECTOR_AUTO
option that picked the strongest stack protector that the compiler
supported.

That was all a nice cleanup - it makes no sense to have the AUTO case
now that the Kconfig phase can just determine the compiler support
directly.

HOWEVER.

It also meant that doing "make oldconfig" would now _disable_ the strong
stackprotector if you had AUTO enabled, because in a legacy config file,
the sane stack protector configuration would look like

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  # CONFIG_CC_STACKPROTECTOR_NONE is not set
  # CONFIG_CC_STACKPROTECTOR_REGULAR is not set
  # CONFIG_CC_STACKPROTECTOR_STRONG is not set
  CONFIG_CC_STACKPROTECTOR_AUTO=y

and when you ran this through "make oldconfig" with the Kbuild changes,
it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had
been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just
CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version
used to be disabled (because it was really enabled by AUTO), and would
disable it in the new config, resulting in:

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
  CONFIG_CC_STACKPROTECTOR=y
  # CONFIG_CC_STACKPROTECTOR_STRONG is not set
  CONFIG_CC_HAS_SANE_STACKPROTECTOR=y

That's dangerously subtle - people could suddenly find themselves with
the weaker stack protector setup without even realizing.

The solution here is to just rename not just the old RECULAR stack
protector option, but also the strong one.  This does that by just
removing the CC_ prefix entirely for the user choices, because it really
is not about the compiler support (the compiler support now instead
automatially impacts _visibility_ of the options to users).

This results in "make oldconfig" actually asking the user for their
choice, so that we don't have any silent subtle security model changes.
The end result would generally look like this:

  CONFIG_HAVE_CC_STACKPROTECTOR=y
  CONFIG_CC_HAS_STACKPROTECTOR_NONE=y
  CONFIG_STACKPROTECTOR=y
  CONFIG_STACKPROTECTOR_STRONG=y
  CONFIG_CC_HAS_SANE_STACKPROTECTOR=y

where the "CC_" versions really are about internal compiler
infrastructure, not the user selections.

Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The implementation is adopted from the ARM arch. GCC 7.3, 8 or newer is
required for building the xtensa kernel with SSP.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Remove duplicate definitions of EX() and similar TRY/CATCH and SRC/DST
macros from assembly sources and put single definition into asm/asmmacro.h

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Now that xtensa assembly sources are compiled with -mlongcalls let the
assembler and linker relax call instructions into l32r + callx where
needed. This change makes the code cleaner and potentially a bit faster.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

vmlinux.lds.S doesn't do anything special with literals, so instead of
keeping them separate put them into the corresponding text sections.
Drop explicit .literal sections from the vmlinux.lds.S, use standard
section macros. Mark literal pool locations in the assembly sources.
Unfortunately assembler doesn't put literals into .init sections and
external libgcc may still have .literal sections, so sed transformation
to the linker script is still needed.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Use tracehook_report_syscall_{entry,exit} instead of a local copy of it
in do_syscall_trace. Allow tracehook to cancel syscall by returning
invalid syscall number to the system_call function.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Pull uaccess.h prepwork from Al Viro:
 "Preparations to tree-wide switch to use of linux/uaccess.h (which,
  obviously, will allow to start unifying stuff for real). The last step
  there, ie

    PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
    sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
            `git grep -l "$PATT"|grep -v ^include/linux/uaccess.h`

  is not taken here - I would prefer to do it once just before or just
  after -rc1.  However, everything should be ready for it"

* 'work.uaccess2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  remove a stray reference to asm/uaccess.h in docs
  sparc64: separate extable_64.h, switch elf_64.h to it
  score: separate extable.h, switch module.h to it
  mips: separate extable.h, switch module.h to it
  x86: separate extable.h, switch sections.h to it
  remove stray include of asm/uaccess.h from cacheflush.h
  mn10300: remove a bogus processor.h->uaccess.h include
  xtensa: split uaccess.h into C and asm sides
  bonding: quit messing with IOCTL
  kill __kernel_ds_p off
  mn10300: finish verify_area() off
  frv: move HAVE_ARCH_UNMAPPED_AREA to pgtable.h
  exceptions: detritus removal

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

Make kernel load address explicit, independent of the selected MMU
configuration and configurable from Kconfig. Do not restrict it to the
first 512MB of the physical address space.

Cleanup kernel memory layout macros:

- rename VECBASE_RESET_VADDR to VECBASE_VADDR, XC_VADDR to VECTOR_VADDR;
- drop VIRTUAL_MEMORY_ADDRESS and LOAD_MEMORY_ADDRESS;
- introduce PHYS_OFFSET and use it in __va and __pa definitions;
- synchronize MMU/noMMU vectors, drop unused NMI vector;
- replace hardcoded vectors offset of 0x3000 with Kconfig symbol.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Use perf framework to manage hardware instruction and data breakpoints.
Add two new ptrace calls: PTRACE_GETHBPREGS and PTRACE_SETHBPREGS to
query and set instruction and data breakpoints.
Address bit 0 choose instruction (0) or data (1) break register, bits
31..1 are the register number.
Both calls transfer two 32-bit words: address (0) and control (1).
Instruction breakpoint contorl word is 0 to clear breakpoint, 1 to set.
Data breakpoint control word bit 31 is 'trigger on store', bit 30 is
'trigger on load, bits 29..0 are length. Length 0 is used to clear a
breakpoint. To set a breakpoint length must be a power of 2 in the range
1..64 and the address must be length-aligned.

Introduce new thread_info flag: TIF_DB_DISABLED. Set it if debug
exception is raised by the kernel code accessing watched userspace
address and disable corresponding data breakpoint. On exit to userspace
check that flag and, if set, restore all data breakpoints.

Handle debug exceptions raised with PS.EXCM set. This may happen when
window overflow/underflow handler or fast exception handler hits data
breakpoint, in which case save and disable all data breakpoints,
single-step faulting instruction and restore data breakpoints.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>