When building with -Wsometimes-uninitialized, Clang warns:
arch/powerpc/xmon/ppc-dis.c:157:7: warning: variable 'opcode' is used
uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
if (cpu_has_feature(CPU_FTRS_POWER9))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/powerpc/xmon/ppc-dis.c:167:7: note: uninitialized use occurs here
if (opcode == NULL)
^~~~~~
arch/powerpc/xmon/ppc-dis.c:157:3: note: remove the 'if' if its
condition is always true
if (cpu_has_feature(CPU_FTRS_POWER9))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
arch/powerpc/xmon/ppc-dis.c:132:38: note: initialize the variable
'opcode' to silence this warning
const struct powerpc_opcode *opcode;
^
= NULL
1 warning generated.
This warning seems to make no sense on the surface because opcode is set
to NULL right below this statement. However, there is a comma instead of
semicolon to end the dialect assignment, meaning that the opcode
assignment only happens in the if statement. Properly terminate that
line so that Clang no longer warns.
Fixes: 5b102782c7 ("powerpc/xmon: Enable disassembly files (compilation changes)")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When moving to CONFIG_THREAD_INFO_IN_TASK, the thread_info 'cpu' field
gets moved into task_struct and only defined when CONFIG_SMP is set.
This patch ensures that TI_CPU is only used when CONFIG_SMP is set and
that task_struct 'cpu' field is not used directly out of SMP code.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
kcov provides kernel coverage data that's useful for fuzzing tools like
syzkaller.
Wire up kcov support on powerpc. Disable kcov instrumentation on the same
files where we currently disable gcov and UBSan instrumentation, plus some
additional exclusions which appear necessary to boot on book3e machines.
Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Daniel Axtens <dja@axtens.net> # e6500
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
There is a plan to build the kernel with -Wimplicit-fallthrough and these
places in the code produced warnings, but because we build arch/powerpc
with -Werror, they became errors. Fix them up.
This patch produces no change in behaviour, but should be reviewed in
case these are actually bugs not intentional fallthoughs.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently xmon needs to get devtree_lock (through rtas_token()) during its
invocation (at crash time). If there is a crash while devtree_lock is being
held, then xmon tries to get the lock but spins forever and never get into
the interactive debugger, as in the following case:
int *ptr = NULL;
raw_spin_lock_irqsave(&devtree_lock, flags);
*ptr = 0xdeadbeef;
This patch avoids calling rtas_token(), thus trying to get the same lock,
at crash time. This new mechanism proposes getting the token at
initialization time (xmon_init()) and just consuming it at crash time.
This would allow xmon to be possible invoked independent of devtree_lock
being held or not.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Today we have:
config PPC_BOOK3S
def_bool y
depends on PPC_BOOK3S_32 || PPC_BOOK3S_64
config PPC_STD_MMU
def_bool y
depends on PPC_BOOK3S
PPC_STD_MMU is therefore redundant with PPC_BOOK3S. Lets remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Today we have:
config PPC_BOOK3S_32
bool "512x/52xx/6xx/7xx/74xx/82xx/83xx/86xx"
[depends on PPC32 within a choice]
config PPC_BOOK3S
def_bool y
depends on PPC_BOOK3S_32 || PPC_BOOK3S_64
config PPC_STD_MMU
def_bool y
depends on PPC_BOOK3S
config PPC_STD_MMU_32
def_bool y
depends on PPC_STD_MMU && PPC32
PPC_STD_MMU_32 is therefore redundant with PPC_BOOK3S_32.
In order to make the code clearer, lets use preferably PPC_BOOK3S_32.
This will allow to remove CONFIG_PPC_STD_MMU_32 in a later patch.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently sparse is complaining about three issues on the xmon code. Two
storage classes issues and a dereferencing a 'noderef' pointer. These are
the warnings:
arch/powerpc/xmon/xmon.c:2783:1: warning: symbol 'dump_log_buf' was not declared. Should it be static?
arch/powerpc/xmon/xmon.c:2989:6: warning: symbol 'format_pte' was not declared. Should it be static?
arch/powerpc/xmon/xmon.c:2983:30: warning: dereference of noderef expression
This patch fixes all of them, turning both functions static and
dereferencing a pointer calling rcu_dereference() instead of a
straightforward dereference.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
When building with clang (8 trunk, 7.0 release) the frame size limit is
hit:
arch/powerpc/xmon/xmon.c:452:12: warning: stack frame size of 2576
bytes in function 'xmon_core' [-Wframe-larger-than=]
Some investigation by Naveen indicates this is due to clang saving the
addresses to printf format strings on the stack.
While this issue is investigated, bump up the frame size limit for xmon
when building with clang.
Link: https://github.com/ClangBuiltLinux/linux/issues/252
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
scaled cputime is only meaningfull when the processor has
SPURR and/or PURR, which means only on PPC64.
Removing it on PPC32 significantly reduces the size of
vtime_account_system() and vtime_account_idle() on an 8xx:
Before:
00000000 l F .text 000000a8 vtime_delta
00000280 g F .text 0000010c vtime_account_system
0000038c g F .text 00000048 vtime_account_idle
After:
(vtime_delta gets inlined inside the two functions)
000001d8 g F .text 000000a0 vtime_account_system
00000278 g F .text 00000038 vtime_account_idle
In terms of performance, we also get approximatly 7% improvement on
task switch. The following small benchmark app is run with perf stat:
void *thread(void *arg)
{
int i;
for (i = 0; i < atoi((char*)arg); i++)
pthread_yield();
}
int main(int argc, char **argv)
{
pthread_t th1, th2;
pthread_create(&th1, NULL, thread, argv[1]);
pthread_create(&th2, NULL, thread, argv[1]);
pthread_join(th1, NULL);
pthread_join(th2, NULL);
return 0;
}
Before the patch:
Performance counter stats for 'chrt -f 98 ./sched 100000' (50 runs):
8228.476465 task-clock (msec) # 0.954 CPUs utilized ( +- 0.23% )
200004 context-switches # 0.024 M/sec ( +- 0.00% )
After the patch:
Performance counter stats for 'chrt -f 98 ./sched 100000' (50 runs):
7649.070444 task-clock (msec) # 0.955 CPUs utilized ( +- 0.27% )
200004 context-switches # 0.026 M/sec ( +- 0.00% )
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Back when I added -Werror in commit ba55bd7436 ("powerpc: Add
configurable -Werror for arch/powerpc") I did it by adding it to most
of the arch Makefiles.
At the time we excluded math-emu, because apparently it didn't build
cleanly. But that seems to have been fixed somewhere in the interim.
So move the -Werror addition to the top-level of the arch, this saves
us from repeating it in every Makefile and means we won't forget to
add it to any new sub-dirs.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add 32-entry bitmaps to track the allocation status of the first 32
SLB entries, and whether they are user or kernel entries. These are
used to allocate free SLB entries first, before resorting to the round
robin allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Get rid of platform specific _PAGE_XXXX in powerpc common code and
use helpers instead.
mm/dump_linuxpagetables.c will be handled separately
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The powerpc kernel uses setjmp which causes a warning when building
with clang:
In file included from arch/powerpc/xmon/xmon.c:51:
./arch/powerpc/include/asm/setjmp.h:15:13: error: declaration of
built-in function 'setjmp' requires inclusion of the header <setjmp.h>
[-Werror,-Wbuiltin-requires-header]
extern long setjmp(long *);
^
./arch/powerpc/include/asm/setjmp.h:16:13: error: declaration of
built-in function 'longjmp' requires inclusion of the header <setjmp.h>
[-Werror,-Wbuiltin-requires-header]
extern void longjmp(long *, long);
^
This *is* the header and we're not using the built-in setjump but
rather the one in arch/powerpc/kernel/misc.S. As the compiler warning
does not make sense, it for the files where setjmp is used.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
[mpe: Move subdir-ccflags in xmon/Makefile to not clobber -Werror]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This reverts commits:
5e46e29e6a ("powerpc/64s/hash: convert SLB miss handlers to C")
8fed04d0f6 ("powerpc/64s/hash: remove user SLB data from the paca")
655deecf67 ("powerpc/64s/hash: SLB allocation status bitmaps")
2e1626744e ("powerpc/64s/hash: provide arch_setup_exec hooks for hash slice setup")
89ca4e126a ("powerpc/64s/hash: Add a SLB preload cache")
This series had a few bugs, and the fixes are not all trivial. So
revert most of it for now.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Add 32-entry bitmaps to track the allocation status of the first 32
SLB entries, and whether they are user or kernel entries. These are
used to allocate free SLB entries first, before resorting to the round
robin allocator.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 introduces SLBIA IH=3, which invalidates all SLB entries and
associated lookaside information that have a class value of 1, which
Linux assigns to user addresses. This matches what switch_slb wants,
and allows a simple fast implementation that avoids the slb_cache
complexity.
As a side-effect, the POWER5 < DD2.1 SLB invalidation workaround is
also avoided on POWER9.
Process context switching rate is improved about 2.2% for a small
process that hits the slb cache which is the best case for the current
code.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Currently, in xmon, there is no obvious way to get an address for a
percpu symbol for a particular cpu. Having such an ability would be
good for debugging the system when percpu variables got involved.
Therefore, this patch introduces a new xmon command "lp" to lookup the
address for percpu symbols. Usage of "lp" is similar to "ls", except
that we could add a cpu number to choose the variable of which cpu we
want to lookup. If no cpu number is given, lookup for current cpu.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch moves ASM_CONST() and stringify_in_c() into
dedicated asm-const.h, then cleans all related inclusions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
[mpe: asm-compat.h should include asm-const.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge in some commits we're sharing with the KVM tree.
I manually propagated the change from commit d3d4ffaae4
("powerpc/powernv/ioda2: Reduce upper limit for DMA window size") into
pci-ioda-tce.c.
Conflicts:
arch/powerpc/include/asm/cputable.h
arch/powerpc/platforms/powernv/pci-ioda.c
arch/powerpc/platforms/powernv/pci.h
The recent change to add printf annotations to xmon inadvertently made
the disassembly output ugly, eg:
c00000002001e058 7ee00026 mfcr r23
c00000002001e05c fffffffffae101a0 std r23,416(r1)
c00000002001e060 fffffffff8230000 std r1,0(r3)
The problem being that negative 32-bit values are being displayed in
full 64-bits.
The printf conversion was actually correct, we are passing unsigned
long so it should use "lx". But powerpc instructions are only 4 bytes
and the code only reads 4 bytes, so inst should really just be
unsigned int, and that also fixes the printing to look the way we
want:
c00000002001e058 7ee00026 mfcr r23
c00000002001e05c fae101a0 std r23,416(r1)
c00000002001e060 f8230000 std r1,0(r3)
Fixes: e70d8f5526 ("powerpc/xmon: Add __printf annotation to xmon_printf()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
POWER9 DD1 was never a product. It is no longer supported by upstream
firmware, and it is not effectively supported in Linux due to lack of
testing.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au>
[mpe: Remove arch_make_huge_pte() entirely]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
get_monotonic_boottime() is deprecated, and may not be safe to call in
every context, as it has to read a hardware clocksource.
This changes xmon to print the time using ktime_get_coarse_boottime64()
instead, which avoids the old timespec type and the HW access.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
A CPU that gets stuck with interrupts hard disable can be difficult to
debug, as on some platforms we have no way to interrupt the CPU to
find out what it's doing.
A stop-gap is to have the CPU save it's stack pointer (r1) in its paca
when it hard disables interrupts. That way if we can't interrupt it,
we can at least trace the stack based on where it last disabled
interrupts.
In some cases that will be total junk, but the stack trace code should
handle that. In the simple case of a CPU that disable interrupts and
then gets stuck in a loop, the stack trace should be informative.
We could clear the saved stack pointer when we enable interrupts, but
that loses information which could be useful if we have nothing else
to go on.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
When the soft enabled flag was changed to a soft disable mask, xmon
and register dump code was not updated to reflect that, which is
confusing ('SOFTE: 1' previously meant interrupts were soft enabled,
currently it means the opposite, the general interrupt type has been
disabled).
Fix this by using the name irqmask, and printing it in hex.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
match_string() returns the index of an array for a matching string,
which can be used instead of open coded variant.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Yisheng Xie <xieyisheng1@huawei.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The set of paca fields we dump in xmon has gotten somewhat out of
date. Update to add some recently added fields.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
We've added some fields with longer names since we originally wrote
this, so the fields are no longer lined up. Adjust the widths to make
it all look nice again, eg:
0:mon> dp
paca for cpu 0x0 @ c000000001fa0000:
possible = yes
...
slb_shadow [0] = 0xc000000008000000 0x400ea1b217000500
slb_shadow [1] = 0xd000000008000001 0x400d43642f000510
...
rfi_flush_fallback_area = c0000000fff80000 (0xcc8)
...
accounting.starttime_user = 0x51582f07 (0xae8)
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This allows the compiler to verify the format strings vs the types of
the arguments.
Update the other prototype declarations in asm/xmon.h.
Silence warnings (triggered at W=1) by adding relevant __printf
attribute. Move #define at bottom of the file to prevent conflict with
gcc attribute.
Solves the original warning:
arch/powerpc/xmon/nonstdio.c:178:2: error: function might be
possible candidate for ‘gnu_printf’ format attribute
In turn this uncovered many formatting errors in xmon.c, all fixed in
this patch.
Signed-off-by: Mathieu Malaterre <malat@debian.org>
[mpe: Always use px not p, fixup the 44x specific code, tweak change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In dump_one_paca() the DUMP macro unconditionally prepends '#' to the
printf format specifier. In most cases we're using either 'x' or 'lx'
etc. and that is OK. But for 'p' and other formats using '#' is
actually undefined, and once we enable printf() checking for
xmon_printf() we will get warnings from the compiler.
So just have each usage specify the full format, that way we can omit
'#' when it's inappropriate.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Mathieu Malaterre <malat@debian.org>
When single-stepping kernel code from xmon without a debug hook
enabled the kernel crashes. This can happen when kernel starts with
xmon on crash disabled but xmon is entered using sysrq.
Call force_enable_xmon when single-stepping in xmon to install the
xmon debug hooks.
Fixes: e1368d0c9e ("powerpc/xmon: Setup debugger hooks when first break-point is set")
Signed-off-by: Michal Suchanek <msuchanek@suse.de>
Reviewed-by: Vaibhav Jain <vaibhav@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Bring in yet another series that touches KVM code, and might need to
be merged into the kvm-ppc branch to resolve conflicts.
This required some changes in pnv_power9_force_smt4_catch/release()
due to the paca array becomming an array of pointers.
Change the paca array into an array of pointers to pacas. Allocate
pacas individually.
This allows flexibility in where the PACAs are allocated. Future work
will allocate them node-local. Platforms that don't have address limits
on PACAs would be able to defer PACA allocations until later in boot
rather than allocate all possible ones up-front then freeing unused.
This is slightly more overhead (one additional indirection) for cross
CPU paca references, but those aren't too common.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The 'bd' command will now print an error and not set the breakpoint on
P9.
Signed-off-by: Michael Neuling <mikey@neuling.org>
[mpe: Unsplit quoted string]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Now that plpar_wrappers.h has an #ifdef PSERIES we can move the empty
version of plpar_set_ciabr() which xmon wants into there.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Back in 2013 we added some hypercall wrappers which misspelled
"plpar" (P-series Logical PARtition) as "plapr".
Visually they're hard to distinguish and it almost doesn't matter, but
it is confusing when grepping to miss some calls because of the typo.
They've also started spreading, so before they take over let's fix
them all to be "plpar".
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Presently when xmon is disabled by debugfs any existing
instruction/data-access breakpoints set are not disabled. This may
lead to kernel oops when those breakpoints are hit as the necessary
debugger hooks aren't installed.
Hence this patch introduces a new function named clear_all_bpt() which
is called when xmon is disabled via debugfs. The function will
unpatch/clear all the trap and ciabr/dab based breakpoints.
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Fix build break when CONFIG_DEBUG_FS=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Presently sysrq key for xmon('x') is registered during kernel init
irrespective of the value of kernel param 'xmon'. Thus xmon is enabled
even if 'xmon=off' is passed on the kernel command line. However this
doesn't enable the kernel debugger hooks needed for instruction or
data breakpoints. Thus when a break-point is hit with xmon=off a
kernel oops of the form below is reported:
Oops: Exception in kernel mode, sig: 5 [#1]
< snip >
Trace/breakpoint trap
To fix this the patch checks and enables debugger hooks when an
instruction or data break-point is set via xmon console.
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
[mpe: Just printf directly, no need for static const char[]]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
The fallback RFI flush is used when firmware does not provide a way
to flush the cache. It's a "displacement flush" that evicts useful
data by displacing it with an uninteresting buffer.
The flush has to take care to work with implementation specific cache
replacment policies, so the recipe has been in flux. The initial
slow but conservative approach is to touch all lines of a congruence
class, with dependencies between each load. It has since been
determined that a linear pattern of loads without dependencies is
sufficient, and is significantly faster.
Measuring the speed of a null syscall with RFI fallback flush enabled
gives the relative improvement:
P8 - 1.83x
P9 - 1.75x
The flush also becomes simpler and more adaptable to different cache
geometries.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
In commit 5b102782c7 ("powerpc/xmon: Enable disassembly files (compilation
changes)") usage of variable `op` has been removed. Completely remove opcode
computation since not used anymore.
Fix fatal warning:
arch/powerpc/xmon/ppc-dis.c: In function ‘lookup_powerpc’:
arch/powerpc/xmon/ppc-dis.c:96:17: error: variable ‘op’ set but not used [-Werror=unused-but-set-variable]
unsigned long op;
^~
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Merge our fixes branch from the 4.15 cycle.
Unusually the fixes branch saw some significant features merged,
notably the RFI flush patches, so we want the code in next to be
tested against that, to avoid any surprises when the two are merged.
There's also some other work on the panic handling that was reverted
in fixes and we now want to do properly in next, which would conflict.
And we also fix a few other minor merge conflicts.
Rename the paca->soft_enabled to paca->irq_soft_mask as it is no
longer used as a flag for interrupt state, but a mask.
Signed-off-by: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Remember when the biggest problem we had to worry about was hashed
pointers, those were the days.
These were missed in my earlier patch because they don't match "%p",
but the macro is hiding a "%p", so these all end up being hashed,
which is not what we want in xmon. Convert them to "%px".
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
