linux-toradex.git/arch/x86/include/asm/compat.h, branch v4.9.66

x86/coredump: Always use user_regs_struct for compat_elf_gregset_t

2016-11-24T05:01:05+00:00

Commit:

  90954e7b9407 ("x86/coredump: Use pr_reg size, rather that TIF_IA32 flag")

changed the coredumping code to construct the elf coredump file according
to register set size - and that's good: if binary crashes with 32-bit code
selector, generate 32-bit ELF core, otherwise - 64-bit core.

That was made for restoring 32-bit applications on x86_64: we want
32-bit application after restore to generate 32-bit ELF dump on crash.

All was quite good and recently I started reworking 32-bit applications
dumping part of CRIU: now it has two parasites (32 and 64) for seizing
compat/native tasks, after rework it'll have one parasite, working in
64-bit mode, to which 32-bit prologue long-jumps during infection.

And while it has worked for my work machine, in VM with
!CONFIG_X86_X32_ABI during reworking I faced that segfault in 32-bit
binary, that has long-jumped to 64-bit mode results in dereference
of garbage:

 32-victim[19266]: segfault at f775ef65 ip 00000000f775ef65 sp 00000000f776aa50 error 14
 BUG: unable to handle kernel paging request at ffffffffffffffff
 IP: [] strlen+0x0/0x20
 [...]
 Call Trace:
  [] elf_core_dump+0x11a9/0x1480
  [] do_coredump+0xa6b/0xe60
  [] get_signal+0x1a8/0x5c0
  [] do_signal+0x23/0x660
  [] exit_to_usermode_loop+0x34/0x65
  [] prepare_exit_to_usermode+0x2f/0x40
  [] retint_user+0x8/0x10

That's because we have 64-bit registers set (with according total size)
and we're writing it to elf_thread_core_info which has smaller size
on !CONFIG_X86_X32_ABI. That lead to overwriting ELF notes part.

Tested on 32-, 64-bit ELF crashes and on 32-bit binaries that have
jumped with 64-bit code selector - all is readable with gdb.

Signed-off-by: Dmitry Safonov 
Cc: Andy Lutomirski 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Josh Poimboeuf 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: linux-mm@kvack.org
Fixes: 90954e7b9407 ("x86/coredump: Use pr_reg size, rather that TIF_IA32 flag")
Signed-off-by: Ingo Molnar

x86/coredump: Use pr_reg size, rather that TIF_IA32 flag

2016-09-14T19:28:10+00:00

Killed PR_REG_SIZE and PR_REG_PTR macro as we can get regset size
from regset view.
I wish I could also kill PRSTATUS_SIZE nicely.

Suggested-by: Oleg Nesterov 
Signed-off-by: Dmitry Safonov 
Cc: 0x7f454c46@gmail.com
Cc: linux-mm@kvack.org
Cc: luto@kernel.org
Cc: gorcunov@openvz.org
Cc: xemul@virtuozzo.com
Link: http://lkml.kernel.org/r/20160905133308.28234-5-dsafonov@virtuozzo.com
Signed-off-by: Thomas Gleixner

x86/signals: Add missing signal_compat code for x86 features

2016-06-14T10:19:24+00:00

The 32-bit siginfo is a different binary format than the 64-bit
one.  So, when running 32-bit binaries on 64-bit kernels, we have
to convert the kernel's 64-bit version to a 32-bit version that
userspace can grok.

We've added a few features to siginfo over the past few years and
neglected to add them to arch/x86/kernel/signal_compat.c:

   1. The si_addr_lsb used in SIGBUS's sent for machine checks
   2. The upper/lower bounds for MPX SIGSEGV faults
   3. The protection key for pkey faults

I caught this with some protection keys unit tests and realized
it affected a few more features.

This was tested only with my protection keys patch that looks
for a proper value in si_pkey.  I didn't actually test the machine
check or MPX code.

Signed-off-by: Dave Hansen 
Cc: Al Viro 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Dave Hansen 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: Tony Luck 
Cc: linux-edac@vger.kernel.org
Link: http://lkml.kernel.org/r/20160608172533.F8F05637@viggo.jf.intel.com
Signed-off-by: Ingo Molnar

x86/entry: Rename is_{ia32,x32}_task() to in_{ia32,x32}_syscall()

2016-04-19T08:44:52+00:00

The is_ia32_task()/is_x32_task() function names are a big misnomer: they
suggests that the compat-ness of a system call is a task property, which
is not true, the compatness of a system call purely depends on how it
was invoked through the system call layer.

A task may call 32-bit and 64-bit and x32 system calls without changing
any of its kernel visible state.

This specific minomer is also actively dangerous, as it might cause kernel
developers to use the wrong kind of security checks within system calls.

So rename it to in_{ia32,x32}_syscall().

Suggested-by: Andy Lutomirski 
Suggested-by: Ingo Molnar 
Signed-off-by: Dmitry Safonov 
[ Expanded the changelog. ]
Acked-by: Andy Lutomirski 
Cc: 0x7f454c46@gmail.com
Cc: Borislav Petkov 
Cc: Brian Gerst 
Cc: Denys Vlasenko 
Cc: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Peter Zijlstra 
Cc: Thomas Gleixner 
Cc: akpm@linux-foundation.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/1460987025-30360-1-git-send-email-dsafonov@virtuozzo.com
Signed-off-by: Ingo Molnar

x86/compat: remove is_compat_task()

2016-03-22T22:36:02+00:00

x86's is_compat_task always checked the current syscall type, not the
task type.  It has no non-arch users any more, so just remove it to
avoid confusion.

On x86, nothing should really be checking the task ABI.  There are
legitimate users for the syscall ABI and for the mm ABI.

Signed-off-by: Andy Lutomirski 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86/asm/entry/64: Save user RSP in pt_regs->sp on SYSCALL64 fastpath

2015-03-10T12:56:10+00:00

Prepare for the removal of 'usersp', by simplifying PER_CPU(old_rsp) usage:

  - use it only as temp storage

  - store the userspace stack pointer immediately in pt_regs->sp
    on syscall entry, instead of using it later, on syscall exit.

  - change C code to use pt_regs->sp only, instead of PER_CPU(old_rsp)
    and task->thread.usersp.

FIXUP/RESTORE_TOP_OF_STACK are simplified as well.

Signed-off-by: Denys Vlasenko 
Cc: Alexei Starovoitov 
Cc: Andy Lutomirski 
Cc: Borislav Petkov 
Cc: Frederic Weisbecker 
Cc: H. Peter Anvin 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Oleg Nesterov 
Cc: Steven Rostedt 
Cc: Will Drewry 
Link: http://lkml.kernel.org/r/1425926364-9526-4-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar

compat: move compat_siginfo_t definition to asm/compat.h

2012-10-05T18:05:16+00:00

This is a preparatory patch for the introduction of NT_SIGINFO elf note.

Make the location of compat_siginfo_t uniform across eight architectures
which have it.  Now it can be pulled in by including asm/compat.h or
linux/compat.h.

Most of the copies are verbatim.  compat_uid[32]_t had to be replaced by
__compat_uid[32]_t.  compat_uptr_t had to be moved up before
compat_siginfo_t in asm/compat.h on a several architectures (tile already
had it moved up).  compat_sigval_t had to be relocated from linux/compat.h
to asm/compat.h.

Signed-off-by: Denys Vlasenko 
Cc: Oleg Nesterov 
Cc: Amerigo Wang 
Cc: "Jonathan M. Foote" 
Cc: Roland McGrath 
Cc: Pedro Alves 
Cc: Fengguang Wu 
Cc: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: replace percpu_xxx funcs with this_cpu_xxx

2012-05-14T21:15:31+00:00

Since percpu_xxx() serial functions are duplicated with this_cpu_xxx().
Removing percpu_xxx() definition and replacing them by this_cpu_xxx()
in code. There is no function change in this patch, just preparation for
later percpu_xxx serial function removing.

On x86 machine the this_cpu_xxx() serial functions are same as
__this_cpu_xxx() without no unnecessary premmpt enable/disable.

Thanks for Stephen Rothwell, he found and fixed a i386 build error in
the patch.

Also thanks for Andrew Morton, he kept updating the patchset in Linus'
tree.

Signed-off-by: Alex Shi 
Acked-by: Christoph Lameter 
Acked-by: Tejun Heo 
Acked-by: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Signed-off-by: Stephen Rothwell 
Signed-off-by: Andrew Morton 
Signed-off-by: Tejun Heo

x86: Move is_ia32_task to asm/thread_info.h from asm/compat.h

2012-03-13T15:31:09+00:00

is_ia32_task() is useful even in !CONFIG_COMPAT cases - utrace will
use it for example. Hence move it to a more generic file: asm/thread_info.h

Also now is_ia32_task() returns true if CONFIG_X86_32 is defined.

Signed-off-by: Srikar Dronamraju 
Acked-by: H. Peter Anvin 
Cc: Linus Torvalds 
Cc: Ananth N Mavinakayanahalli 
Cc: Jim Keniston 
Cc: Linux-mm 
Cc: Oleg Nesterov 
Cc: Andi Kleen 
Cc: Christoph Hellwig 
Cc: Steven Rostedt 
Cc: Arnaldo Carvalho de Melo 
Cc: Masami Hiramatsu 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20120313140303.17134.1401.sendpatchset@srdronam.in.ibm.com
[ Performed minor cleanup ]
Signed-off-by: Ingo Molnar

x32: Provide separate is_ia32_task() and is_x32_task() predicates

2012-03-05T23:35:18+00:00

The is_compat_task() test is composed of two predicates already, so
make each of them available separately.

Signed-off-by: H. Peter Anvin 
Cc: H. J. Lu 
Link: http://lkml.kernel.org/r/1329696488-16970-1-git-send-email-hpa@zytor.com