Heikki Lindholm pointed out that there was a potential race with the
lazy CPU state (FP, VR, EVR) stuff if preempt is enabled. The race
is that in the process of restoring FP state on sigreturn, the task
gets preempted by a user task that wants to use the FPU. It will take
an FP unavailable exception, which will write the current FPU state
to the thread_struct, overwriting the values which sigreturn has
stored. Note that this can only happen on UP since we don't implement
lazy CPU state on SMP.
The fix is to flush the lazy CPU state before updating the
thread_struct. To do this we re-use the flush_lazy_cpu_state()
function from process.c.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Somehow this one slipped through the cracks; when we ended up in
do_signal() on a 32-bit kernel but without having the caller-saved
registers into the regs, we didn't set the TIF_SAVE_NVGPRS flag to
ensure they got saved later.
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This cleanup patch speeds up the null syscall path on ppc64 by about 3%,
and brings the ppc32 and ppc64 code slightly closer together.
The ppc64 code was checking current_thread_info()->flags twice in the
syscall exit path; once for TIF_SYSCALL_T_OR_A before disabling
interrupts, and then again for TIF_SIGPENDING|TIF_NEED_RESCHED etc after
disabling interrupts. Now we do the same as ppc32 -- check the flags
only once in the fast path, and re-enable interrupts if necessary in the
ptrace case.
The patch abolishes the 'syscall_noerror' member of struct thread_info
and replaces it with a TIF_NOERROR bit in the flags, which is handled in
the slow path. This shortens the syscall entry code, which no longer
needs to clear syscall_noerror.
The patch adds a TIF_SAVE_NVGPRS flag which causes the syscall exit slow
path to save the non-volatile GPRs into a signal frame. This removes the
need for the assembly wrappers around sys_sigsuspend(),
sys_rt_sigsuspend(), et al which existed solely to save those registers
in advance. It also means I don't have to add new wrappers for ppoll()
and pselect(), which is what I was supposed to be doing when I got
distracted into this...
Finally, it unifies the ppc64 and ppc32 methods of handling syscall exit
directly into a signal handler (as required by sigsuspend et al) by
introducing a TIF_RESTOREALL flag which causes _all_ the registers to be
reloaded from the pt_regs by taking the ret_from_exception path, instead
of the normal syscall exit path which stomps on the callee-saved GPRs.
It appears to pass an LTP test run on ppc64, and passes basic testing on
ppc32 too. Brief tests of ptrace functionality with strace and gdb also
appear OK. I wouldn't send it to Linus for 2.6.15 just yet though :)
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
As pointed out by Gary Byers, we were clearing the image of the FPSCR
(floating point status and control register) in the thread_struct before
copying it to the user stack when invoking a signal. Thus the task
would see its FPSCR getting cleared when it took a signal.
While fixing it I noticed that our swapcontext system call was also
clearing FPSCR. It shouldn't, so I fixed that too.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This patch moves the vdso's to arch/powerpc, adds support for the 32
bits vdso to the 32 bits kernel, rename systemcfg (finally !), and adds
some new (still untested) routines to both vdso's: clock_gettime() with
support for CLOCK_REALTIME and CLOCK_MONOTONIC, clock_getres() (same
clocks) and get_tbfreq() for glibc to retreive the timebase frequency.
Tom,Steve: The implementation of get_tbfreq() I've done for 32 bits
returns a long long (r3, r4) not a long. This is such that if we ever
add support for >4Ghz timebases on ppc32, the userland interface won't
have to change.
I have tested gettimeofday() using some glibc patches in both ppc32 and
ppc64 kernels using 32 bits userland (I haven't had a chance to test a
64 bits userland yet, but the implementation didn't change and was
tested earlier). I haven't tested yet the new functions.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Having already merged the ppc and ppc64 versions of signal.c, this
patch finishes the job by merging signal.h. The two versions were
almost identical already. Notable changes:
- We use BITS_PER_LONG to correctly size sigset_t
- Remove some uneeded #includes and struct forward
declarations. This does mean adding an include to signal_32.c which
relied on the indirect inclusion of sigcontext.h
- As the ppc64 version, the merged signal.h has prototypes for
do_signal() and do_signal32(). Thus remove extra prototypes from
ppc_ksyms.c which had them directly.
Built and booted on POWER5 LPAR (ARCH=ppc64 and ARCH=powerpc). Built
for 32-bit powermac (ARCH=ppc and ARCH=powerpc) and Walnut (ARCH=ppc).
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The ancient ppcdebug/PPCDBG mechanism is now only used in two places.
First, in the hash setup code, one of the bits allows the size of the
hash table to be reduced by a factor of 8 - which would be better
accomplished with a command line option for that purpose. The other
was a bunch of bus walking related messages in the iSeries code, which
would seem to be insufficient reason to keep the mechanism.
This patch removes the last traces of this mechanism.
Built and booted on iSeries and pSeries POWER5 LPAR (ARCH=powerpc).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
The recent merge of fpu.S broken the handling of fpscr for
ARCH=powerpc and CONFIG_PPC64=y. FP registers could be corrupted,
leading to strange random application crashes.
The confusion arises, because the thread_struct has (and requires) a
64-bit area to save the fpscr, because we use load/store double
instructions to get it in to/out of the FPU. However, only the low
32-bits are actually used, so we want to treat it as a 32-bit quantity
when manipulating its bits to avoid extra load/stores on 32-bit. This
patch replaces the current definition with a structure of two 32-bit
quantities (pad and val), to clarify things as much as is possible.
The 'val' field is used when manipulating bits, the structure itself
is used when obtaining the address for loading/unloading the value
from the FPU.
While we're at it, consolidate the 4 (!) almost identical versions of
cvt_fd() and cvt_df() (arch/ppc/kernel/misc.S,
arch/ppc64/kernel/misc.S, arch/powerpc/kernel/misc_32.S,
arch/powerpc/kernel/misc_64.S) into a single version in fpu.S. The
new version takes a pointer to thread_struct and applies the correct
offset itself, rather than a pointer to the fpscr field itself, again
to avoid confusion as to which is the correct field to use.
Finally, this patch makes ARCH=ppc64 also use the consolidated fpu.S
code, which it previously did not.
Built for G5 (ARCH=ppc64 and ARCH=powerpc), 32-bit powermac (ARCH=ppc
and ARCH=powerpc) and Walnut (ARCH=ppc, CONFIG_MATH_EMULATION=y).
Booted on G5 (ARCH=powerpc) and things which previously fell over no
longer do.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
An error in merging led to 32-bit processes getting the wrong link
register value on entry to RT signal handlers, and the wrong stack
chain as well. This fixes it.
Signed-off-by: Paul Mackerras <paulus@samba.org>
This allows us to get rid of one type of entry in systbl.S.
In passing we remove the duplicate compat_sys_getdents and
compat_sys_utimes for which there are generic versions.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Paul Mackerras
David Woodhouse
Benjamin Herrenschmidt
David Gibson
Stephen Rothwell