linux-toradex.git/arch/um/kernel/ptrace.c, branch v3.4.2

audit: inline audit_syscall_entry to reduce burden on archs

2012-01-17T21:16:56+00:00

Every arch calls:

if (unlikely(current->audit_context))
	audit_syscall_entry()

which requires knowledge about audit (the existance of audit_context) in
the arch code.  Just do it all in static inline in audit.h so that arch's
can remain blissfully ignorant.

Signed-off-by: Eric Paris

Audit: push audit success and retcode into arch ptrace.h

2012-01-17T21:16:56+00:00

The audit system previously expected arches calling to audit_syscall_exit to
supply as arguments if the syscall was a success and what the return code was.
Audit also provides a helper AUDITSC_RESULT which was supposed to simplify things
by converting from negative retcodes to an audit internal magic value stating
success or failure.  This helper was wrong and could indicate that a valid
pointer returned to userspace was a failed syscall.  The fix is to fix the
layering foolishness.  We now pass audit_syscall_exit a struct pt_reg and it
in turns calls back into arch code to collect the return value and to
determine if the syscall was a success or failure.  We also define a generic
is_syscall_success() macro which determines success/failure based on if the
value is < -MAX_ERRNO.  This works for arches like x86 which do not use a
separate mechanism to indicate syscall failure.

We make both the is_syscall_success() and regs_return_value() static inlines
instead of macros.  The reason is because the audit function must take a void*
for the regs.  (uml calls theirs struct uml_pt_regs instead of just struct
pt_regs so audit_syscall_exit can't take a struct pt_regs).  Since the audit
function takes a void* we need to use static inlines to cast it back to the
arch correct structure to dereference it.

The other major change is that on some arches, like ia64, MIPS and ppc, we
change regs_return_value() to give us the negative value on syscall failure.
THE only other user of this macro, kretprobe_example.c, won't notice and it
makes the value signed consistently for the audit functions across all archs.

In arch/sh/kernel/ptrace_64.c I see that we were using regs[9] in the old
audit code as the return value.  But the ptrace_64.h code defined the macro
regs_return_value() as regs[3].  I have no idea which one is correct, but this
patch now uses the regs_return_value() function, so it now uses regs[3].

For powerpc we previously used regs->result but now use the
regs_return_value() function which uses regs->gprs[3].  regs->gprs[3] is
always positive so the regs_return_value(), much like ia64 makes it negative
before calling the audit code when appropriate.

Signed-off-by: Eric Paris 
Acked-by: H. Peter Anvin  [for x86 portion]
Acked-by: Tony Luck  [for ia64]
Acked-by: Richard Weinberger  [for uml]
Acked-by: David S. Miller  [for sparc]
Acked-by: Ralf Baechle  [for mips]
Acked-by: Benjamin Herrenschmidt  [for ppc]

um: clean arch_ptrace() up a bit

2011-09-15T01:09:37+00:00

1) take subarch-specific stuff to subarch_ptrace()
2) PTRACE_{PEEK,POKE}{TEXT,DATA} is handled by ptrace_request() just fine...

Signed-off-by: Al Viro 
Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix ptrace build error

2010-11-12T15:55:30+00:00

Both commits 0a3d763f1a68 ("ptrace: cleanup arch_ptrace() on um") and
9b05a69e0534 ("ptrace: change signature of arch_ptrace()") broke the um
build.  This patch fixes the issues.

0a3d763f1a68 introduced the undeclared variable "datavp".  The patch seems
completely untested.  :-(

9b05a69e0534 changed arch_ptrace()'s signature but did not update
um/include/asm/ptrace-generic.h.

Signed-off-by: Richard Weinberger 
Cc: Namhyung Kim 
Cc: Jeff Dike 
Tested-by: Will Newton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: cleanup arch_ptrace() on um

2010-10-28T01:03:12+00:00

Remove unnecessary castings using void pointer and fix copy_to_user()
return value. Also add missing __user markup on the argument of
arch_ptrctl().

Signed-off-by: Namhyung Kim 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ptrace: change signature of arch_ptrace()

2010-10-28T01:03:10+00:00

Fix up the arguments to arch_ptrace() to take account of the fact that
@addr and @data are now unsigned long rather than long as of a preceding
patch in this series.

Signed-off-by: Namhyung Kim 
Cc: 
Acked-by: Roland McGrath 
Acked-by: David Howells 
Acked-by: Geert Uytterhoeven 
Acked-by: David S. Miller 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

arch/um/kernel/ptrace.c: remove dead PROC_MM

2010-08-10T03:45:04+00:00

PROC_MM doesn't exist in Kconfig.  Looking around it looks like a
left-over from 2.6.0 or even 2.4 times, last mentioned in a fedora patch
for 2.6.10.  I believe it's time to get rid of that last tiny parts here
that are still around.

Signed-off-by: Christoph Egger 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: use generic ptrace_resume code

2010-03-12T23:52:39+00:00

Use the generic ptrace_resume code for PTRACE_SYSCALL, PTRACE_CONT,
PTRACE_KILL and PTRACE_SINGLESTEP.  This implies defining
arch_has_single_step in  and implementing the
user_enable_single_step and user_disable_single_step functions, which also
causes the breakpoint information to be cleared on fork, which could be
considered a bug fix.

Also the TIF_SYSCALL_TRACE thread flag is now cleared on PTRACE_KILL which
it previously wasn't which is consistent with all architectures using the
modern ptrace code.

XXX: I'm not sure arch_has_single_step() is placed in the exactly correct
location, please verify in which of the ptrace headers it should really
be.

Signed-off-by: Christoph Hellwig 
Cc: Oleg Nesterov 
Cc: Roland McGrath 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

UML on UML fixed: it did not start

2009-03-12T23:20:23+00:00

It is currently impossible to run a user-mode linux machine inside another
user-mode linux (UML on UML).  It breaks after a few instructions.  When
it tries to check whether SYSEMU is installed (the inner) UML receives an
inconsistent result (from the outer UML).

This is the output of a broken attempt:
$ ./linux mem=256m ubd0=cow
Locating the bottom of the address space ... 0x0
Locating the top of the address space ... 0xc0000000
Core dump limits :
        soft - 0
        hard - NONE
Checking that ptrace can change system call numbers...OK
Checking ptrace new tags for syscall emulation...unsupported
Checking syscall emulation patch for ptrace...check_sysemu : expected SIGTRAP, got status = 256
$

The problem is the following:

PTRACE_SYSCALL/SINGLESTEP is currently managed inside arch_ptrace for ARCH=um.

PTRACE_SYSEMU/SUSEMU_SINGLESTEP is not captured in arch_ptrace's switch,
therefore it is erroneously passed back to ptrace_request (in
kernel/ptrace).

This simple patch simply forces ptrace to return an error on
PTRACE_SYSEMU/SUSEMU_SINGLESTEP as it is unsupported on ARCH=um, and fixes
the problem.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Renzo Davoli 
Reviewed-by: WANG Cong 
Cc: Jeff Dike 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

UML: make several more things static

2008-07-24T17:47:24+00:00

- Make some variables and functions static, since they don't need to be
  global.

- Remove an unused function - arch/um/kernel/time.c::sched_clock().

- Clean the style a bit as complained by checkpatch.pl.

Cc: Jeff Dike 
Signed-off-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds