linux-toradex.git/arch/microblaze/kernel/entry.S, branch v4.4.106 Linux kernel for Apalis and Colibri modules microblaze: Fix syscall error recovery for invalid syscall IDs 2015-03-04T14:12:27+00:00 Jamie Garside jamie.garside@york.ac.uk 2015-02-23T15:35:35+00:00 c2219eda547813c0c50dba90d9e989ae36cc3ab8 This patch fixes two bugs in the Microblaze syscall trap handler when an invalid syscall ID is used. First, the range check on line 351 only checks for syscall IDs greater than __NR_syscalls. A negative syscall ID (either passed to `syscall()` or as returned by `do_syscall_trace_enter()` on error) will still satisfy this test and cause the Linux kernel to access an invalid memory location and cause a kernel oops. This has been fixed by also checking for r12 < 0. Secondly, the current error recovery at line 378 returns using the wrong register (r15 instead of r14) and does not restore the previous stack state. This has been fixed by invoking `ret_from_trap` on error, setting r3 to `-ENOSYS`, similar to what would happen when calling a valid syscall. Signed-off-by: Jamie Garside <jamie.garside@york.ac.uk> Signed-off-by: Michal Simek <michal.simek@xilinx.com> 
This patch fixes two bugs in the Microblaze syscall trap handler when an invalid
syscall ID is used.

First, the range check on line 351 only checks for syscall IDs greater than
__NR_syscalls. A negative syscall ID (either passed to `syscall()` or as returned
by `do_syscall_trace_enter()` on error) will still satisfy this test and cause
the Linux kernel to access an invalid memory location and cause a kernel oops.
This has been fixed by also checking for r12 < 0.

Secondly, the current error recovery at line 378 returns using the wrong register
(r15 instead of r14) and does not restore the previous stack state. This has been
fixed by invoking `ret_from_trap` on error, setting r3 to `-ENOSYS`, similar to
what would happen when calling a valid syscall.

Signed-off-by: Jamie Garside <jamie.garside@york.ac.uk>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
microblaze: Coding style cleanup 2015-03-04T14:11:55+00:00 Michal Simek michal.simek@xilinx.com 2015-03-04T14:10:55+00:00 074fa7e76cfff4cd1a60753ee4596510f1b87183 No function change. Signed-off-by: Michal Simek <michal.simek@xilinx.com> 
No function change.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
microblaze: Move restart allowed out of block 2013-02-03T23:16:02+00:00 Michal Simek monstr@monstr.eu 2012-09-17T09:18:24+00:00 4de6ba68c9f52a361c89ea16c9c55eda2669253b Better not to break block which do work together. Signed-off-by: Michal Simek <monstr@monstr.eu> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
Better not to break block which do work together.

Signed-off-by: Michal Simek <monstr@monstr.eu>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
microblaze: fix handling of multiple pending signals 2013-02-03T23:16:02+00:00 Al Viro viro@zeniv.linux.org.uk 2012-04-29T08:43:50+00:00 e9f9252667e383c0ccfd3570b358ccb72cd51359 We need to keep building sigframes until no pending signals remain. Wrap do_notify_resume() calls into loops; do _not_ allow syscall restart logics to trigger after the first iteration. Incidentally, comments about pending signals that should (somehow) be in r18 are pure BS. Doesn't work that way and cannot work that way, sorry... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
We need to keep building sigframes until no pending signals remain.
Wrap do_notify_resume() calls into loops; do _not_ allow syscall
restart logics to trigger after the first iteration.

Incidentally, comments about pending signals that should (somehow)
be in r18 are pure BS.  Doesn't work that way and cannot work that
way, sorry...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
microblaze: fix the horror with restarts of sigreturn() 2013-02-03T23:16:02+00:00 Al Viro viro@zeniv.linux.org.uk 2012-04-29T08:11:34+00:00 14203e19cbc562a79f49117c45c80639a1e65bdd solution a-la arm one - pick a callee-saved register (r30), set it non-zero when entering a syscall, have sigreturn wrapper zero it out and pass the value in it to do_notify_resume() as "in_syscall" (actually, "restarts allowed") argument. Note that we don't give a damn about ret_from_fork() - return value is not restart-worthy anyway. Possible remaining bug: on !MMU we still have _debug_exception() restartable. If it hits with -ERESTART_... accidentally in r3, fun happens. MMU does _not_ have _debug_exception() restartable. If that's decided to be a bug (as I strongly suspect it to be), we'll just need to replace setting r30 to 1 with setting r30 to 0 in !MMU _debug_exception(). Up to microblaze maintainers... [folded a fix from Michal] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
solution a-la arm one - pick a callee-saved register (r30), set it
non-zero when entering a syscall, have sigreturn wrapper zero it out
and pass the value in it to do_notify_resume() as "in_syscall" (actually,
"restarts allowed") argument.

Note that we don't give a damn about ret_from_fork() - return value
is not restart-worthy anyway.

Possible remaining bug: on !MMU we still have _debug_exception()
restartable.  If it hits with -ERESTART_... accidentally in r3, fun happens.
MMU does _not_ have _debug_exception() restartable.  If that's decided to
be a bug (as I strongly suspect it to be), we'll just need to replace
setting r30 to 1 with setting r30 to 0 in !MMU _debug_exception().
Up to microblaze maintainers...

[folded a fix from Michal]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
microblaze: switch to generic fork/vfork/clone 2012-11-29T03:43:40+00:00 Al Viro viro@zeniv.linux.org.uk 2012-10-27T04:03:41+00:00 f3268edbe6fe0ce56e62c6d6b14640aeb04864b7 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Simek <michal.simek@xilinx.com> 
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
microblaze: switch to generic sys_execve() 2012-11-16T07:45:55+00:00 Al Viro viro@zeniv.linux.org.uk 2012-10-10T17:11:01+00:00 5f6c4ab6ee781c9aace7c8548ad9bd87f5678df7 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> 
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
microblaze: switch to generic kernel_execve() 2012-11-16T07:45:47+00:00 Al Viro viro@zeniv.linux.org.uk 2012-10-10T15:52:44+00:00 99c59f60fd751876c37fbea01e55606441ac6db4 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Simek <michal.simek@xilinx.com> 
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
microblaze: switch to generic kernel_thread() 2012-11-16T07:44:57+00:00 Al Viro viro@zeniv.linux.org.uk 2012-10-06T17:52:37+00:00 2319295dd8dbd076afa136bffb797ef726b605a0 Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Simek <michal.simek@xilinx.com> 
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
microblaze: Fix bug with schedule_tail 2012-11-15T10:56:27+00:00 Michal Simek monstr@monstr.eu 2012-10-09T07:32:32+00:00 fd11ff7380fe7c61f55e6caf33982edeab3fbc19 Signed-off-by: Michal Simek <monstr@monstr.eu> 
Signed-off-by: Michal Simek <monstr@monstr.eu>