Pass signr, sicode, and address into unhandled_exception as explicit
parameters instead of members of struct siginfo. Then in unhandled
exception generate and send the siginfo using force_sig_fault.
This keeps the code simpler and less error prone.
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Pull siginfo cleanups from Eric Biederman:
"Long ago when 2.4 was just a testing release copy_siginfo_to_user was
made to copy individual fields to userspace, possibly for efficiency
and to ensure initialized values were not copied to userspace.
Unfortunately the design was complex, it's assumptions unstated, and
humans are fallible and so while it worked much of the time that
design failed to ensure unitialized memory is not copied to userspace.
This set of changes is part of a new design to clean up siginfo and
simplify things, and hopefully make the siginfo handling robust enough
that a simple inspection of the code can be made to ensure we don't
copy any unitializied fields to userspace.
The design is to unify struct siginfo and struct compat_siginfo into a
single definition that is shared between all architectures so that
anyone adding to the set of information shared with struct siginfo can
see the whole picture. Hopefully ensuring all future si_code
assignments are arch independent.
The design is to unify copy_siginfo_to_user32 and
copy_siginfo_from_user32 so that those function are complete and cope
with all of the different cases documented in signinfo_layout. I don't
think there was a single implementation of either of those functions
that was complete and correct before my changes unified them.
The design is to introduce a series of helpers including
force_siginfo_fault that take the values that are needed in struct
siginfo and build the siginfo structure for their callers. Ensuring
struct siginfo is built correctly.
The remaining work for 4.17 (unless someone thinks it is post -rc1
material) is to push usage of those helpers down into the
architectures so that architecture specific code will not need to deal
with the fiddly work of intializing struct siginfo, and then when
struct siginfo is guaranteed to be fully initialized change copy
siginfo_to_user into a simple wrapper around copy_to_user.
Further there is work in progress on the issues that have been
documented requires arch specific knowledge to sort out.
The changes below fix or at least document all of the issues that have
been found with siginfo generation. Then proceed to unify struct
siginfo the 32 bit helpers that copy siginfo to and from userspace,
and generally clean up anything that is not arch specific with regards
to siginfo generation.
It is a lot but with the unification you can of siginfo you can
already see the code reduction in the kernel"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (45 commits)
signal/memory-failure: Use force_sig_mceerr and send_sig_mceerr
mm/memory_failure: Remove unused trapno from memory_failure
signal/ptrace: Add force_sig_ptrace_errno_trap and use it where needed
signal/powerpc: Remove unnecessary signal_code parameter of do_send_trap
signal: Helpers for faults with specialized siginfo layouts
signal: Add send_sig_fault and force_sig_fault
signal: Replace memset(info,...) with clear_siginfo for clarity
signal: Don't use structure initializers for struct siginfo
signal/arm64: Better isolate the COMPAT_TASK portion of ptrace_hbptriggered
ptrace: Use copy_siginfo in setsiginfo and getsiginfo
signal: Unify and correct copy_siginfo_to_user32
signal: Remove the code to clear siginfo before calling copy_siginfo_from_user32
signal: Unify and correct copy_siginfo_from_user32
signal/blackfin: Remove pointless UID16_SIGINFO_COMPAT_NEEDED
signal/blackfin: Move the blackfin specific si_codes to asm-generic/siginfo.h
signal/tile: Move the tile specific si_codes to asm-generic/siginfo.h
signal/frv: Move the frv specific si_codes to asm-generic/siginfo.h
signal/ia64: Move the ia64 specific si_codes to asm-generic/siginfo.h
signal/powerpc: Remove redefinition of NSIGTRAP on powerpc
signal: Move addr_lsb into the _sigfault union for clarity
...
The siginfo structure has all manners of holes with the result that a
structure initializer is not guaranteed to initialize all of the bits.
As we have to copy the structure to userspace don't even try to use
a structure initializer. Instead use clear_siginfo followed by initializing
selected fields. This gives a guarantee that uninitialized kernel memory
is not copied to userspace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
ARC gcc prior to GNU 2018.03 release didn't have a target specific
__builtin_trap() implementation, generating default abort() call.
Implement the abort() call - emulating what newer gcc does for the same,
as suggested by Arnd.
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
gcc toggle -fisolate-erroneous-paths-dereference (default at -O2
onwards) isolates faulty code paths such as null pointer access, divide
by zero etc by emitting __builtin_trap()
Newer ARC gcc generates TRAP_S 5 instruction which needs to be handled
and treated like any other unexpected exception
- user mode : task terminated with a SEGV
- kernel mode: die() called after register and stack dump
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Currently we pass a string argument to show_kernel_fault_diag() which
describes the reason for the fault. This is not being used so just
add a pr_info() which outputs the fault information.
With this change we get from:
|
| Path: /bin/busybox
| CPU: 0 PID: 92 Comm: modprobe Not tainted 4.12.0-rc6 #30
| task: 9a254780 task.stack: 9a212000
|
| [ECR ]: 0x00200400 => Other Fatal Err
|
to:
|
| Unhandled Machine Check Exception
| Path: /bin/busybox
| CPU: 0 PID: 92 Comm: modprobe Not tainted 4.12.0-rc6 #37
| task: 9a240780 task.stack: 9a226000
|
|[ECR ]: 0x00200400 => Machine Check (Other Fatal Err)
|
Which can help debugging.
Cc: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
On ARC700 (and nSIM), user mode memory error triggers an L2 interrupt
which is handled gracefully by kernel (or it tries to despite this being
imprecise, and error could get charged to kernel itself). The offending
task is killed and kernel moves on.
NPS hardware however raises a Machine Check exception for same error
which is NOT recoverable by kernel.
This patch aligns kernel handling for nSIM case, to same as hardware by
overriding the default user space bus error handler.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Elad Kanfi <eladkan@mellanox.com>
[vgupta: rewrote changelog]
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
We are going to split <linux/sched/signal.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/signal.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With ECR now part of pt_regs
* No need to propagate from lowest asm handlers as arg
* No need to save it in tsk->thread.cause_code
* Avoid bit chopping to access the bit-fields
More code consolidation, cleanup
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
If CONFIG_ARC_MISALIGN_ACCESS is not enabled, or if the fixup fails,
call the same error handler: same signal/si_code to user (SIGBUS)
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
arch/arc/kernel/traps.c no longer compiles without explicitly including
asm/kprobes.h
Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Silences the following checkpatch warnings:
WARNING: Use #include <linux/ptrace.h> instead of <asm/ptrace.h>
WARNING: Use #include <linux/kprobes.h> instead of <asm/kprobes.h>
WARNING: Use #include <linux/kgdb.h> instead of <asm/kgdb.h>
WARNING: Use #include <linux/uaccess.h> instead of <asm/uaccess.h>
WARNING: Use #include <linux/cache.h> instead of <asm/cache.h>
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC700 doesn't natively support unaligned access, but can be emulated
-Unaligned Access Exception
-Disassembly at the Fault address to find the exact insn (long/short)
Also per Arnd's comment, we runtime control it using 2 sysctl knobs:
* SYSCTL_ARCH_UNALIGN_ALLOW: Runtime enable/disble
* SYSCTL_ARCH_UNALIGN_NO_WARN: Warn on each emulation attempt
Originally contributed by Tim Yao <tim.yao@amlogic.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Tim Yao <tim.yao@amlogic.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
