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author | Al Viro <viro@zeniv.linux.org.uk> | 2012-04-29 04:11:34 -0400 |
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committer | Al Viro <viro@zeniv.linux.org.uk> | 2013-02-03 18:16:02 -0500 |
commit | 14203e19cbc562a79f49117c45c80639a1e65bdd (patch) | |
tree | 758937f82d73a963b9ed0f5979f303c1522195fa /arch/microblaze/kernel/entry-nommu.S | |
parent | c886a9fc1f69c0e53788a9c4a780b6b8825bd4ab (diff) | |
download | op-kernel-dev-14203e19cbc562a79f49117c45c80639a1e65bdd.zip op-kernel-dev-14203e19cbc562a79f49117c45c80639a1e65bdd.tar.gz |
microblaze: fix the horror with restarts of sigreturn()
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>
Diffstat (limited to 'arch/microblaze/kernel/entry-nommu.S')
-rw-r--r-- | arch/microblaze/kernel/entry-nommu.S | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/microblaze/kernel/entry-nommu.S b/arch/microblaze/kernel/entry-nommu.S index 29a05d6..96f97f8 100644 --- a/arch/microblaze/kernel/entry-nommu.S +++ b/arch/microblaze/kernel/entry-nommu.S @@ -280,6 +280,7 @@ ENTRY(_user_exception) /* Figure out which function to use for this system call. */ /* Note Microblaze barrel shift is optional, so don't rely on it */ add r12, r12, r12 /* convert num -> ptr */ + addik r30, r0, 1 /* restarts allowed */ add r12, r12, r12 lwi r12, r12, sys_call_table /* Get function pointer */ addik r15, r0, ret_to_user-8 /* set return address */ @@ -369,6 +370,7 @@ ENTRY(_debug_exception) bralid r15, send_sig add r7, r0, r0 /* 3rd param zero */ + addik r30, r0, 1 /* restarts allowed ??? */ /* Restore r3/r4 to work around how ret_to_user works */ lwi r3, r1, PT_R3 lwi r4, r1, PT_R4 @@ -492,7 +494,7 @@ work_pending: nop 1: andi r11, r19, _TIF_SIGPENDING | _TIF_NOTIFY_RESUME beqi r11, no_work_pending - addk r5, r1, r0 + addk r5, r30, r0 bralid r15, do_notify_resume addik r6, r0, 1 bri no_work_pending @@ -562,6 +564,7 @@ no_work_pending: nop sys_rt_sigreturn_wrapper: + addk r30, r0, r0 /* no restarts for this one */ brid sys_rt_sigreturn addk r5, r1, r0 |