linux.git/arch/um/kernel/trap.c, branch v5.6

um: add support for folded p4d page tables

2019-12-05T03:44:15+00:00

The UML port uses 4 and 5 level fixups to support higher level page
table directories in the generic VM code.

Implement primitives necessary for the 4th level folding, add walks of
p4d level where appropriate and drop usage of __ARCH_USE_5LEVEL_HACK.

Link: http://lkml.kernel.org/r/1572938135-31886-13-git-send-email-rppt@kernel.org
Signed-off-by: Mike Rapoport 
Cc: Anatoly Pugachev 
Cc: Anton Ivanov 
Cc: Arnd Bergmann 
Cc: "David S. Miller" 
Cc: Geert Uytterhoeven 
Cc: Greentime Hu 
Cc: Greg Ungerer 
Cc: Helge Deller 
Cc: "James E.J. Bottomley" 
Cc: Jeff Dike 
Cc: "Kirill A. Shutemov" 
Cc: Mark Salter 
Cc: Matt Turner 
Cc: Michal Simek 
Cc: Peter Rosin 
Cc: Richard Weinberger 
Cc: Rolf Eike Beer 
Cc: Russell King 
Cc: Russell King 
Cc: Sam Creasey 
Cc: Vincent Chen 
Cc: Vineet Gupta 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: Add SPDX headers to files in arch/um/kernel/

2019-09-15T19:37:17+00:00

Convert files to use SPDX header. All files are licensed under the
GPLv2.

Signed-off-by: Alex Dewar 
Signed-off-by: Richard Weinberger

signal: Remove the task parameter from force_sig_fault

2019-05-29T14:31:43+00:00

As synchronous exceptions really only make sense against the current
task (otherwise how are you synchronous) remove the task parameter
from from force_sig_fault to make it explicit that is what is going
on.

The two known exceptions that deliver a synchronous exception to a
stopped ptraced task have already been changed to
force_sig_fault_to_task.

The callers have been changed with the following emacs regular expression
(with obvious variations on the architectures that take more arguments)
to avoid typos:

force_sig_fault[(]\([^,]+\)[,]\([^,]+\)[,]\([^,]+\)[,]\W+current[)]
->
force_sig_fault(\1,\2,\3)

Signed-off-by: "Eric W. Biederman"

signal: Remove task parameter from force_sig

2019-05-27T14:36:28+00:00

All of the remaining callers pass current into force_sig so
remove the task parameter to make this obvious and to make
misuse more difficult in the future.

This also makes it clear force_sig passes current into force_sig_info.

Signed-off-by: "Eric W. Biederman"

signal: Remove task parameter from force_sigsegv

2019-05-27T14:36:28+00:00

The function force_sigsegv is always called on the current task
so passing in current is redundant and not passing in current
makes this fact obvious.

This also makes it clear force_sigsegv always calls force_sig
on the current task.

Signed-off-by: "Eric W. Biederman"

um: trap: fix spelling mistake, EACCESS -> EACCES

2018-10-29T21:34:15+00:00

Trivial fix to a spelling mistake of the error access name EACCESS,
rename to EACCES

Signed-off-by: Colin Ian King 
Signed-off-by: Richard Weinberger

mm: convert return type of handle_mm_fault() caller to vm_fault_t

2018-08-17T23:20:28+00:00

Use new return type vm_fault_t for fault handler.  For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno.  Once all instances are converted, vm_fault_t will become a
distinct type.

Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")

In this patch all the caller of handle_mm_fault() are changed to return
vm_fault_t type.

Link: http://lkml.kernel.org/r/20180617084810.GA6730@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder 
Cc: Matthew Wilcox 
Cc: Richard Henderson 
Cc: Tony Luck 
Cc: Matt Turner 
Cc: Vineet Gupta 
Cc: Russell King 
Cc: Catalin Marinas 
Cc: Will Deacon 
Cc: Richard Kuo 
Cc: Geert Uytterhoeven 
Cc: Michal Simek 
Cc: James Hogan 
Cc: Ley Foon Tan 
Cc: Jonas Bonn 
Cc: James E.J. Bottomley 
Cc: Benjamin Herrenschmidt 
Cc: Palmer Dabbelt 
Cc: Yoshinori Sato 
Cc: David S. Miller 
Cc: Richard Weinberger 
Cc: Guan Xuetao 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: "Levin, Alexander (Sasha Levin)" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

signal/um: More carefully relay signals in relay_signal.

2018-04-28T13:46:49+00:00

There is a bug in relay signal.  It assumes that when a signal is
relayed the signal never uses a signal independent si_code, such
as SI_USER, SI_KERNEL, SI_QUEUE, ... SI_SIGIO etc.  In practice
siginfo was assuming it was relaying a signal with the SIL_FAULT
layout.  As that is the common cases for the signals it supported
that is a reasonable assumption.

Further user mode linux must be very careful when relaying different
kinds of signals to prevent an information leak.  This means simply
increasing the kinds of signals that are handled in relay_signal
is non-trivial.

Therefore use siginfo_layout and force_sig_fault to simplify
the signal relaying in relay_signal.

By taking advantage of the fact that user mode linux only works
on x86 and x86_64 we can assume that si_trapno can be ignored,
and that si_errno is always zero.

For the signals SIGLL, SIGFPE, SIGSEGV, SIGBUS, and SIGTRAP the only
fault handler I know of that sets si_errno is SIGTRAP TRAP_HWBKPT on a
few oddball architectures.  Those architectures have been modified to
use force_sig_ptrace_errno_trap.

Similarly only a few architectures set __ARCH_SI_TRAPNO.

At the point uml supports those architectures again these additional
cases can be examined and supported if desired in relay_signal.

Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: Anton Ivanov 
Cc: Martin Pärtel 
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-um@lists.infradead.org
Fixes: d3c1cfcdb43e ("um: pass siginfo to guest process")
Signed-off-by: "Eric W. Biederman"

signal/um: Use force_sig_fault where appropriate

2018-04-25T15:44:11+00:00

Filling in struct siginfo before calling force_sig_info a tedious and
error prone process, where once in a great while the wrong fields
are filled out, and siginfo has been inconsistently cleared.

Simplify this process by using the helper force_sig_fault.  Which
takes as a parameters all of the information it needs, ensures
all of the fiddly bits of filling in struct siginfo are done properly
and then calls force_sig_info.

In short about a 5 line reduction in code for every time force_sig_info
is called, which makes the calling function clearer.

Cc: Jeff Dike 
Cc: Richard Weinberger 
Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-um@lists.infradead.org
Signed-off-by: "Eric W. Biederman"

signal: Ensure every siginfo we send has all bits initialized

2018-04-25T15:40:51+00:00

Call clear_siginfo to ensure every stack allocated siginfo is properly
initialized before being passed to the signal sending functions.

Note: It is not safe to depend on C initializers to initialize struct
siginfo on the stack because C is allowed to skip holes when
initializing a structure.

The initialization of struct siginfo in tracehook_report_syscall_exit
was moved from the helper user_single_step_siginfo into
tracehook_report_syscall_exit itself, to make it clear that the local
variable siginfo gets fully initialized.

In a few cases the scope of struct siginfo has been reduced to make it
clear that siginfo siginfo is not used on other paths in the function
in which it is declared.

Instances of using memset to initialize siginfo have been replaced
with calls clear_siginfo for clarity.

Signed-off-by: "Eric W. Biederman"