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  1. 01 Sep, 2019 1 commit
    • Max Filippov's avatar
      xtensa: add support for call0 ABI in userspace · 09f8a6db
      Max Filippov authored 
      

Provide a Kconfig choice to select whether only the default ABI, only
call0 ABI or both are supported. The default for XEA2 is windowed, but
it may change for XEA3. Call0 only runs userspace with PS.WOE disabled.
Supporting both windowed and call0 ABIs is tricky, as there's no
indication in the ELF binaries which ABI they use. So it is done by
probing: each process is started with PS.WOE disabled, but the handler
of an illegal instruction exception taken with PS.WOE retries faulting
instruction after enabling PS.WOE. It must happen before any signal is
delivered to the process, otherwise it may be delivered incorrectly.
Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
      09f8a6db
  3. 27 May, 2019 1 commit
  5. 04 Jan, 2019 1 commit
    • Linus Torvalds's avatar
      Remove 'type' argument from access_ok() function · 96d4f267
      Linus Torvalds authored 
      Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csk...
      96d4f267
  7. 17 Dec, 2018 1 commit
  9. 17 Dec, 2017 1 commit
  11. 01 May, 2017 1 commit
  13. 02 Mar, 2017 1 commit
  15. 24 Dec, 2016 1 commit
  17. 12 Apr, 2015 2 commits
  19. 13 Feb, 2015 1 commit
    • Andy Lutomirski's avatar
      all arches, signal: move restart_block to struct task_struct · f56141e3
      Andy Lutomirski authored 
      

If an attacker can cause a controlled kernel stack overflow, overwriting
the restart block is a very juicy exploit target.  This is because the
restart_block is held in the same memory allocation as the kernel stack.

Moving the restart block to struct task_struct prevents this exploit by
making the restart_block harder to locate.

Note that there are other fields in thread_info that are also easy
targets, at least on some architectures.

It's also a decent simplification, since the restart code is more or less
identical on all architectures.

[james.hogan@imgtec.com: metag: align thread_info::supervisor_stack]
Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: David Miller <davem@davemloft.net>
Acked-by: default avatarRichard Weinberger <richard@nod.at>
Cc: Richard H...
      f56141e3
  21. 06 Aug, 2014 1 commit
  23. 15 Oct, 2013 1 commit
  25. 24 Feb, 2013 1 commit
    • Chris Zankel's avatar
      xtensa: add support for TLS · c50842df
      Chris Zankel authored 
      

The Xtensa architecture provides a global register called THREADPTR
for the purpose of Thread Local Storage (TLS) support. This allows us
to use a fairly simple implementation, keeping the thread pointer in
the regset and simply saving and restoring it upon entering/exiting
the from user space.
Signed-off-by: default avatarChris Zankel <chris@zankel.net>
      c50842df
  27. 03 Feb, 2013 1 commit
  29. 19 Dec, 2012 1 commit
  31. 01 Oct, 2012 2 commits
  33. 04 Jun, 2012 1 commit
  35. 01 Jun, 2012 6 commits
  37. 24 May, 2012 1 commit
  39. 22 May, 2012 3 commits
  41. 23 Apr, 2012 1 commit
  43. 22 Mar, 2012 4 commits
  45. 14 Feb, 2008 3 commits
    • Chris Zankel's avatar
      [XTENSA] Add support for the sa_restorer function · 44c64e6b
      Chris Zankel authored 
      

Supporting the sa_restorer function allows for better security
since the sigreturn system call doesn't need to be placed on
the stack, so the stack doesn't need to be executable. This
requires support from the c-library as it has to provide the
restorer function.
Signed-off-by: default avatarChris Zankel <chris@zankel.net>
      44c64e6b
    • Chris Zankel's avatar
      [XTENSA] Add support for configurable registers and coprocessors · c658eac6
      Chris Zankel authored 
      

The Xtensa architecture allows to define custom instructions and
registers. Registers that are bound to a coprocessor are only
accessible if the corresponding enable bit is set, which allows
to implement a 'lazy' context switch mechanism. Other registers
needs to be saved and restore at the time of the context switch
or during interrupt handling.

This patch adds support for these additional states:

- save and restore registers that are used by the compiler upon
  interrupt entry and exit.
- context switch additional registers unbound to any coprocessor
- 'lazy' context switch of registers bound to a coprocessor
- ptrace interface to provide access to additional registers
- update configuration files in include/asm-xtensa/variant-fsf
Signed-off-by: default avatarChris Zankel <chris@zankel.net>
      c658eac6
    • Chris Zankel's avatar
      [XTENSA] Remove oldmask from sigcontext and fix register flush · 3befce8f
      Chris Zankel authored 
      

Remove oldmask from the sigcontext structure. Also update wmask
and windowstart when we flush the AR registers to stack.
Signed-off-by: default avatarChris Zankel <chris@zankel.net>
      3befce8f
  47. 01 Jun, 2007 1 commit
    • Chris Zankel's avatar
      [XTENSA] Remove non-rt signal handling · 29c4dfd9
      Chris Zankel authored 
      

The non-rt signal handling was never really used, so we don't break
anything. This patch also cleans up the signal stack-frame to make
it independent from the processor configuration. It also improves
the method used for controlling single-stepping. We now save and
restore the 'icountlevel' register that controls single stepping
and set or clear the saved state to enable or disable it.
Signed-off-by: default avatarChris Zankel <chris@zankel.net>
      29c4dfd9
  49. 08 May, 2007 1 commit
  51. 10 Dec, 2006 1 commit