Inspired by the commit 42d038c4fb ("arm64: Add support for function
error injection"), this patch supports function error injection for
csky.
This patch mainly support two functions: one is regs_set_return_value()
which is used to overwrite the return value; the another function is
override_function_with_return() which is to override the probed
function returning and jump to its caller.
Test log:
cd /sys/kernel/debug/fail_function/
echo sys_clone > inject
echo 100 > probability
echo 1 > interval
ls /
[ 108.644163] FAULT_INJECTION: forcing a failure.
[ 108.644163] name fail_function, interval 1, probability 100, space 0, times 1
[ 108.647799] CPU: 0 PID: 104 Comm: sh Not tainted 5.8.0-rc5+ #46
[ 108.648384] Call Trace:
[ 108.649339] [<8005eed4>] walk_stackframe+0x0/0xf0
[ 108.649679] [<8005f16a>] show_stack+0x32/0x5c
[ 108.649927] [<8040f9d2>] dump_stack+0x6e/0x9c
[ 108.650271] [<80406f7e>] should_fail+0x15e/0x1ac
[ 108.650720] [<80118ba8>] fei_kprobe_handler+0x28/0x5c
[ 108.651519] [<80754110>] kprobe_breakpoint_handler+0x144/0x1cc
[ 108.652289] [<8005d6da>] trap_c+0x8e/0x110
[ 108.652816] [<8005ce8c>] csky_trap+0x5c/0x70
-sh: can't fork: Invalid argument
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
secure_computing() is called first in syscall_trace_enter() so that
a system call will be aborted quickly without doing succeeding syscall
tracing if seccomp rules want to deny that system call.
TODO:
- Update https://github.com/seccomp/libseccomp csky support
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Cc: Arnd Bergmann <arnd@arndb.de>
These are used nowhere in the tree (except for some architectures which
define them for their own use) and were already removed for other
architectures in:
commit 6474924e2b ("arch: remove unused macro/function thread_saved_pc()")
commit c17c02040b ("arch: remove unused *_segments() macros/functions")
Remove them from arch/csky as well.
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Signed-off-by: Guo Ren <guoren@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Most architectures define kmap_prot to be PAGE_KERNEL.
Let sparc and xtensa define there own and define PAGE_KERNEL as the
default if not overridden.
[akpm@linux-foundation.org: coding style fixes]
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-16-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Every single architecture (including !CONFIG_HIGHMEM) calls...
pagefault_enable();
preempt_enable();
... before returning from __kunmap_atomic(). Lift this code into the
kunmap_atomic() macro.
While we are at it rename __kunmap_atomic() to kunmap_atomic_high() to
be consistent.
[ira.weiny@intel.com: don't enable pagefault/preempt twice]
Link: http://lkml.kernel.org/r/20200518184843.3029640-1-ira.weiny@intel.com
[akpm@linux-foundation.org: coding style fixes]
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Link: http://lkml.kernel.org/r/20200507150004.1423069-8-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Every arch has the same code to ensure atomic operations and a check for
!HIGHMEM page.
Remove the duplicate code by defining a core kmap_atomic() which only
calls the arch specific kmap_atomic_high() when the page is high memory.
[akpm@linux-foundation.org: coding style fixes]
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-7-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All architectures do exactly the same thing for kunmap(); remove all the
duplicate definitions and lift the call to the core.
This also has the benefit of changing kmap_unmap() on a number of
architectures to be an inline call rather than an actual function.
[akpm@linux-foundation.org: fix CONFIG_HIGHMEM=n build on various architectures]
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian König <christian.koenig@amd.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200507150004.1423069-5-ira.weiny@intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There is no fixup or feature in the patch, we only cleanup with:
- Remove unnecessary reg used (r11, r12), just use r9 & r10 &
syscallid regs as temp useage.
- Add _TIF_SYSCALL_WORK and _TIF_WORK_MASK to gather macros.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
If raw_copy_from_user(to, from, N) returns K, callers expect
the first N - K bytes starting at to to have been replaced with
the contents of corresponding area starting at from and the last
K bytes of destination *left* *unmodified*.
What arch/sky/lib/usercopy.c is doing is broken - it can lead to e.g.
data corruption on write(2).
raw_copy_to_user() is inaccurate about return value, which is a bug,
but consequences are less drastic than for raw_copy_from_user().
And just what are those access_ok() doing in there? I mean, look into
linux/uaccess.h; that's where we do that check (as well as zero tail
on failure in the callers that need zeroing).
AFAICS, all of that shouldn't be hard to fix; something like a patch
below might make a useful starting point.
I would suggest moving these macros into usercopy.c (they are never
used anywhere else) and possibly expanding them there; if you leave
them alive, please at least rename __copy_user_zeroing(). Again,
it must not zero anything on failed read.
Said that, I'm not sure we won't be better off simply turning
usercopy.c into usercopy.S - all that is left there is a couple of
functions, each consisting only of inline asm.
Guo Ren reply:
Yes, raw_copy_from_user is wrong, it's no need zeroing code.
unsigned long _copy_from_user(void *to, const void __user *from,
unsigned long n)
{
unsigned long res = n;
might_fault();
if (likely(access_ok(from, n))) {
kasan_check_write(to, n);
res = raw_copy_from_user(to, from, n);
}
if (unlikely(res))
memset(to + (n - res), 0, res);
return res;
}
EXPORT_SYMBOL(_copy_from_user);
You are right and access_ok() should be removed.
but, how about:
do {
...
"2: stw %3, (%1, 0) \n" \
+ " subi %0, 4 \n" \
"9: stw %4, (%1, 4) \n" \
+ " subi %0, 4 \n" \
"10: stw %5, (%1, 8) \n" \
+ " subi %0, 4 \n" \
"11: stw %6, (%1, 12) \n" \
+ " subi %0, 4 \n" \
" addi %2, 16 \n" \
" addi %1, 16 \n" \
Don't expand __ex_table
AI Viro reply:
Hey, I've no idea about the instruction scheduling on csky -
if that doesn't slow the things down, all the better. It's just
that copy_to_user() and friends are on fairly hot codepaths,
and in quite a few situations they will dominate the speed of
e.g. read(2). So I tried to keep the fast path unchanged.
Up to the architecture maintainers, obviously. Which would be
you...
As for the fixups size increase (__ex_table size is unchanged)...
You have each of those macros expanded exactly once.
So the size is not a serious argument, IMO - useless complexity
would be, if it is, in fact, useless; the size... not really,
especially since those extra subi will at least offset it.
Again, up to you - asm optimizations of (essentially)
memcpy()-style loops are tricky and can depend upon the
fairly subtle details of architecture. So even on something
I know reasonably well I would resort to direct experiments
if I can't pass the buck to architecture maintainers.
It *is* worth optimizing - this is where read() from a file
that is already in page cache spends most of the time, etc.
Guo Ren reply:
Thx, after fixup some typo “sub %0, 4”, apply the patch.
TODO:
- user copy/from codes are still need optimizing.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
The gdbmacros.txt use sp in thread_struct, but csky use ksp. This
cause bttnobp fail to excute.
TODO:
- Still couldn't display the contents of stack.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
All processes' PSR could success from SETUP_MMU, so need set it
in INIT_THREAD again.
And use a3 instead of r7 in __switch_to for code convention.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
The implementation of show_stack will panic with wrong fp:
addr = *fp++;
because the fp isn't checked properly.
The current implementations of show_stack, wchan and stack_trace
haven't been designed properly, so just deprecate them.
This patch is a reference to riscv's way, all codes are modified from
arm's. The patch is passed with:
- cat /proc/<pid>/stack
- cat /proc/<pid>/wchan
- echo c > /proc/sysrq-trigger
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
This bug is from uprobe signal definition in thread_info.h. The
instruction (andi) of abiv1 immediate is smaller than abiv2, then
it will cause:
AS arch/csky/kernel/entry.o
arch/csky/kernel/entry.S: Assembler messages:
arch/csky/kernel/entry.S:224: Error: Operand 2 immediate is overflow.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com>
Pull csky updates from Guo Ren:
- Add kproobes/uprobes support
- Add lockdep, rseq, gcov support
- Fixup init_fpu
- Fixup ftrace_modify deadlock
- Fixup speculative execution on IO area
* tag 'csky-for-linus-5.7-rc1' of git://github.com/c-sky/csky-linux:
csky: Fixup cpu speculative execution to IO area
csky: Add uprobes support
csky: Add kprobes supported
csky: Enable LOCKDEP_SUPPORT
csky: Enable the gcov function
csky: Fixup get wrong psr value from phyical reg
csky/ftrace: Fixup ftrace_modify_code deadlock without CPU_HAS_ICACHE_INS
csky: Implement ftrace with regs
csky: Add support for restartable sequence
csky: Implement ptrace regs and stack API
csky: Fixup init_fpu compile warning with __init
