* Re: powerpc/traps: Avoid rate limit messages from show unhandled signals
From: Michael Ellerman @ 2018-08-21 10:35 UTC (permalink / raw)
To: Michael Ellerman, linuxppc-dev; +Cc: muriloo
In-Reply-To: <20180817065500.16899-1-mpe@ellerman.id.au>
On Fri, 2018-08-17 at 06:55:00 UTC, Michael Ellerman wrote:
> In the recent commit to add an explicit ratelimit state when showing
> unhandled signals, commit 35a52a10c3ac ("powerpc/traps: Use an
> explicit ratelimit state for show_signal_msg()"), I put the check of
> show_unhandled_signals and the ratelimit state before the call to
> unhandled_signal() so as to avoid unnecessarily calling the latter
> when show_unhandled_signals is false.
>
> However that causes us to check the ratelimit state on every call, so
> if we take a lot of *handled* signals that has the effect of making
> the ratelimit code print warnings that callbacks have been suppressed
> when they haven't.
>
> So rearrange the code so that we check show_unhandled_signals first,
> then call unhandled_signal() and finally check the ratelimit state.
>
> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
> Reviewed-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Applied to powerpc next.
https://git.kernel.org/powerpc/c/997dd26cb3c8b7c9b8765751cc1491
cheers
^ permalink raw reply
* Re: [v2] powerpc/powernv/pci: Work around races in PCI bridge enabling
From: Michael Ellerman @ 2018-08-21 10:35 UTC (permalink / raw)
To: Benjamin Herrenschmidt, linuxppc-dev; +Cc: Michael Ellerman
In-Reply-To: <3a742dd7a457874516daaf615ac0b883f87c2139.camel@kernel.crashing.org>
On Fri, 2018-08-17 at 07:30:39 UTC, Benjamin Herrenschmidt wrote:
> The generic code is race when multiple children of a PCI bridge try to
> enable it simultaneously.
>
> This leads to drivers trying to access a device through a not-yet-enabled
> bridge, and this EEH errors under various circumstances when using parallel
> driver probing.
>
> There is work going on to fix that properly in the PCI core but it will
> take some time.
>
> x86 gets away with it because (outside of hotplug), the BIOS enables all
> the bridges at boot time.
>
> This patch does the same thing on powernv by enabling all bridges that
> have child devices at boot time, thus avoiding subsequent races. It's suitable
> for backporting to stable and distros, while the proper PCI fix will probably
> be significantly more invasive.
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: stable@vger.kernel.org
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/db2173198b9513f7add8009f225afa
cheers
^ permalink raw reply
* Re: [v5] powerpc/topology: Get topology for shared processors at boot
From: Michael Ellerman @ 2018-08-21 10:35 UTC (permalink / raw)
To: Srikar Dronamraju, linuxppc-dev
Cc: Michal Suchanek, Srikar Dronamraju, Manjunatha H R,
Michael Bringmann
In-Reply-To: <1534517679-10792-1-git-send-email-srikar@linux.vnet.ibm.com>
On Fri, 2018-08-17 at 14:54:39 UTC, Srikar Dronamraju wrote:
> On a shared lpar, Phyp will not update the cpu associativity at boot
> time. Just after the boot system does recognize itself as a shared lpar and
> trigger a request for correct cpu associativity. But by then the scheduler
> would have already created/destroyed its sched domains.
>
> This causes
> - Broken load balance across Nodes causing islands of cores.
> - Performance degradation esp if the system is lightly loaded
> - dmesg to wrongly report all cpus to be in Node 0.
> - Messages in dmesg saying borken topology.
> - With commit 051f3ca02e46 ("sched/topology: Introduce NUMA identity
> node sched domain"), can cause rcu stalls at boot up.
>
> >From a scheduler maintainer's perspective, moving cpus from one node to
> another or creating more numa levels after boot is not appropriate
> without some notification to the user space.
> https://lore.kernel.org/lkml/20150406214558.GA38501@linux.vnet.ibm.com/T/#u
>
> The sched_domains_numa_masks table which is used to generate cpumasks is
> only created at boot time just before creating sched domains and never
> updated. Hence, its better to get the topology correct before the sched
> domains are created.
>
> For example on 64 core Power 8 shared lpar, dmesg reports
>
> [ 2.088360] Brought up 512 CPUs
> [ 2.088368] Node 0 CPUs: 0-511
> [ 2.088371] Node 1 CPUs:
> [ 2.088373] Node 2 CPUs:
> [ 2.088375] Node 3 CPUs:
> [ 2.088376] Node 4 CPUs:
> [ 2.088378] Node 5 CPUs:
> [ 2.088380] Node 6 CPUs:
> [ 2.088382] Node 7 CPUs:
> [ 2.088386] Node 8 CPUs:
> [ 2.088388] Node 9 CPUs:
> [ 2.088390] Node 10 CPUs:
> [ 2.088392] Node 11 CPUs:
> ...
> [ 3.916091] BUG: arch topology borken
> [ 3.916103] the DIE domain not a subset of the NUMA domain
> [ 3.916105] BUG: arch topology borken
> [ 3.916106] the DIE domain not a subset of the NUMA domain
> ...
>
> numactl/lscpu output will still be correct with cores spreading across
> all nodes.
>
> Socket(s): 64
> NUMA node(s): 12
> Model: 2.0 (pvr 004d 0200)
> Model name: POWER8 (architected), altivec supported
> Hypervisor vendor: pHyp
> Virtualization type: para
> L1d cache: 64K
> L1i cache: 32K
> NUMA node0 CPU(s): 0-7,32-39,64-71,96-103,176-183,272-279,368-375,464-471
> NUMA node1 CPU(s): 8-15,40-47,72-79,104-111,184-191,280-287,376-383,472-479
> NUMA node2 CPU(s): 16-23,48-55,80-87,112-119,192-199,288-295,384-391,480-487
> NUMA node3 CPU(s): 24-31,56-63,88-95,120-127,200-207,296-303,392-399,488-495
> NUMA node4 CPU(s): 208-215,304-311,400-407,496-503
> NUMA node5 CPU(s): 168-175,264-271,360-367,456-463
> NUMA node6 CPU(s): 128-135,224-231,320-327,416-423
> NUMA node7 CPU(s): 136-143,232-239,328-335,424-431
> NUMA node8 CPU(s): 216-223,312-319,408-415,504-511
> NUMA node9 CPU(s): 144-151,240-247,336-343,432-439
> NUMA node10 CPU(s): 152-159,248-255,344-351,440-447
> NUMA node11 CPU(s): 160-167,256-263,352-359,448-455
>
> Currently on this lpar, the scheduler detects 2 levels of Numa and
> created numa sched domains for all cpus, but it finds a single DIE
> domain consisting of all cpus. Hence it deletes all numa sched domains.
>
> To address this, detect the shared processor and update topology soon after
> cpus are setup so that correct topology is updated just before scheduler
> creates sched domain.
>
> With the fix, dmesg reports
>
> [ 0.491336] numa: Node 0 CPUs: 0-7 32-39 64-71 96-103 176-183 272-279 368-375 464-471
> [ 0.491351] numa: Node 1 CPUs: 8-15 40-47 72-79 104-111 184-191 280-287 376-383 472-479
> [ 0.491359] numa: Node 2 CPUs: 16-23 48-55 80-87 112-119 192-199 288-295 384-391 480-487
> [ 0.491366] numa: Node 3 CPUs: 24-31 56-63 88-95 120-127 200-207 296-303 392-399 488-495
> [ 0.491374] numa: Node 4 CPUs: 208-215 304-311 400-407 496-503
> [ 0.491379] numa: Node 5 CPUs: 168-175 264-271 360-367 456-463
> [ 0.491384] numa: Node 6 CPUs: 128-135 224-231 320-327 416-423
> [ 0.491389] numa: Node 7 CPUs: 136-143 232-239 328-335 424-431
> [ 0.491394] numa: Node 8 CPUs: 216-223 312-319 408-415 504-511
> [ 0.491399] numa: Node 9 CPUs: 144-151 240-247 336-343 432-439
> [ 0.491404] numa: Node 10 CPUs: 152-159 248-255 344-351 440-447
> [ 0.491409] numa: Node 11 CPUs: 160-167 256-263 352-359 448-455
>
> and lscpu would also report
>
> Socket(s): 64
> NUMA node(s): 12
> Model: 2.0 (pvr 004d 0200)
> Model name: POWER8 (architected), altivec supported
> Hypervisor vendor: pHyp
> Virtualization type: para
> L1d cache: 64K
> L1i cache: 32K
> NUMA node0 CPU(s): 0-7,32-39,64-71,96-103,176-183,272-279,368-375,464-471
> NUMA node1 CPU(s): 8-15,40-47,72-79,104-111,184-191,280-287,376-383,472-479
> NUMA node2 CPU(s): 16-23,48-55,80-87,112-119,192-199,288-295,384-391,480-487
> NUMA node3 CPU(s): 24-31,56-63,88-95,120-127,200-207,296-303,392-399,488-495
> NUMA node4 CPU(s): 208-215,304-311,400-407,496-503
> NUMA node5 CPU(s): 168-175,264-271,360-367,456-463
> NUMA node6 CPU(s): 128-135,224-231,320-327,416-423
> NUMA node7 CPU(s): 136-143,232-239,328-335,424-431
> NUMA node8 CPU(s): 216-223,312-319,408-415,504-511
> NUMA node9 CPU(s): 144-151,240-247,336-343,432-439
> NUMA node10 CPU(s): 152-159,248-255,344-351,440-447
> NUMA node11 CPU(s): 160-167,256-263,352-359,448-455
>
> Previous attempt to solve this problem
> https://patchwork.ozlabs.org/patch/530090/
>
> Reported-by: Manjunatha H R <manjuhr1@in.ibm.com>
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/2ea62630681027c455117aa471ea3a
cheers
^ permalink raw reply
* Re: powerpc/fadump: cleanup crash memory ranges support
From: Michael Ellerman @ 2018-08-21 10:35 UTC (permalink / raw)
To: Hari Bathini; +Cc: linuxppc-dev, Mahesh J Salgaonkar
In-Reply-To: <153453843169.1010.11894303551198228940.stgit@hbathini.in.ibm.com>
On Fri, 2018-08-17 at 20:40:56 UTC, Hari Bathini wrote:
> Commit 1bd6a1c4b80a ("powerpc/fadump: handle crash memory ranges array
> index overflow") changed crash memory ranges to a dynamic array that
> is reallocated on-demand with krealloc(). The relevant header for this
> call was not included. The kernel compiles though. But be cautious and
> add the header anyway.
>
> Also, memory allocation logic in fadump_add_crash_memory() takes care
> of memory allocation for crash memory ranges in all scenarios. Drop
> unnecessary memory allocation in fadump_setup_crash_memory_ranges().
>
> Fixes: 1bd6a1c4b80a ("powerpc/fadump: handle crash memory ranges array index overflow")
> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
> Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Applied to powerpc next, thanks.
https://git.kernel.org/powerpc/c/a58183138cb72059a0c278f8370a47
cheers
^ permalink raw reply
* [PATCH RFCv2 0/6] mm: online/offline_pages called w.o. mem_hotplug_lock
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Andrew Morton, Balbir Singh,
Benjamin Herrenschmidt, Boris Ostrovsky, Dan Williams,
Greg Kroah-Hartman, Haiyang Zhang, Heiko Carstens, John Allen,
Jonathan Corbet, Joonsoo Kim, Juergen Gross, Kate Stewart,
K. Y. Srinivasan, Len Brown, Martin Schwidefsky,
Mathieu Malaterre, Michael Ellerman, Michael Neuling,
Michal Hocko, Nathan Fontenot, Oscar Salvador, Paul Mackerras,
Pavel Tatashin, Philippe Ombredanne, Rafael J. Wysocki,
Rashmica Gupta, Stephen Hemminger, Thomas Gleixner,
Vlastimil Babka, YASUAKI ISHIMATSU
This is the same approach as in the first RFC, but this time without
exporting device_hotplug_lock (requested by Greg) and with some more
details and documentation regarding locking. Tested only on x86 so far.
--------------------------------------------------------------------------
Reading through the code and studying how mem_hotplug_lock is to be used,
I noticed that there are two places where we can end up calling
device_online()/device_offline() - online_pages()/offline_pages() without
the mem_hotplug_lock. And there are other places where we call
device_online()/device_offline() without the device_hotplug_lock.
While e.g.
echo "online" > /sys/devices/system/memory/memory9/state
is fine, e.g.
echo 1 > /sys/devices/system/memory/memory9/online
Will not take the mem_hotplug_lock. However the device_lock() and
device_hotplug_lock.
E.g. via memory_probe_store(), we can end up calling
add_memory()->online_pages() without the device_hotplug_lock. So we can
have concurrent callers in online_pages(). We e.g. touch in online_pages()
basically unprotected zone->present_pages then.
Looks like there is a longer history to that (see Patch #2 for details),
and fixing it to work the way it was intended is not really possible. We
would e.g. have to take the mem_hotplug_lock in device/base/core.c, which
sounds wrong.
Summary: We had a lock inversion on mem_hotplug_lock and device_lock().
More details can be found in patch 3 and patch 6.
I propose the general rules (documentation added in patch 6):
1. add_memory/add_memory_resource() must only be called with
device_hotplug_lock.
2. remove_memory() must only be called with device_hotplug_lock. This is
already documented and holds for all callers.
3. device_online()/device_offline() must only be called with
device_hotplug_lock. This is already documented and true for now in core
code. Other callers (related to memory hotplug) have to be fixed up.
4. mem_hotplug_lock is taken inside of add_memory/remove_memory/
online_pages/offline_pages.
To me, this looks way cleaner than what we have right now (and easier to
verify). And looking at the documentation of remove_memory, using
lock_device_hotplug also for add_memory() feels natural.
RFC -> RFCv2:
- Don't export device_hotplug_lock, provide proper remove_memory/add_memory
wrappers.
- Split up the patches a bit.
- Try to improve powernv memtrace locking
- Add some documentation for locking that matches my knowledge
David Hildenbrand (6):
mm/memory_hotplug: make remove_memory() take the device_hotplug_lock
mm/memory_hotplug: make add_memory() take the device_hotplug_lock
mm/memory_hotplug: fix online/offline_pages called w.o.
mem_hotplug_lock
powerpc/powernv: hold device_hotplug_lock when calling device_online()
powerpc/powernv: hold device_hotplug_lock in memtrace_offline_pages()
memory-hotplug.txt: Add some details about locking internals
Documentation/memory-hotplug.txt | 39 +++++++++++-
arch/powerpc/platforms/powernv/memtrace.c | 14 +++--
.../platforms/pseries/hotplug-memory.c | 8 +--
drivers/acpi/acpi_memhotplug.c | 4 +-
drivers/base/memory.c | 22 +++----
drivers/xen/balloon.c | 3 +
include/linux/memory_hotplug.h | 4 +-
mm/memory_hotplug.c | 59 +++++++++++++++----
8 files changed, 115 insertions(+), 38 deletions(-)
--
2.17.1
^ permalink raw reply
* [PATCH RFCv2 1/6] mm/memory_hotplug: make remove_memory() take the device_hotplug_lock
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Rafael J. Wysocki, Len Brown, Rashmica Gupta,
Michael Neuling, Balbir Singh, Nathan Fontenot, John Allen,
Andrew Morton, Michal Hocko, Dan Williams, Joonsoo Kim,
Vlastimil Babka, Pavel Tatashin, Greg Kroah-Hartman,
Oscar Salvador, YASUAKI ISHIMATSU, Mathieu Malaterre
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
remove_memory() is exported right now but requires the
device_hotplug_lock, which is not exported. So let's provide a variant
that takes the lock and only export that one.
The lock is already held in
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
So, let's use the locked variant.
The lock is not held (but taken in)
arch/powerpc/platforms/powernv/memtrace.c
So let's keep using the (now) locked variant.
Apart from that, there are not other users in the tree.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 2 --
arch/powerpc/platforms/pseries/hotplug-memory.c | 6 +++---
drivers/acpi/acpi_memhotplug.c | 2 +-
include/linux/memory_hotplug.h | 3 ++-
mm/memory_hotplug.c | 9 ++++++++-
5 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 51dc398ae3f7..8f1cd4f3bfd5 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -90,9 +90,7 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE,
change_memblock_state);
- lock_device_hotplug();
remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
- unlock_device_hotplug();
return true;
}
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index c1578f54c626..b3f54466e25f 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -334,7 +334,7 @@ static int pseries_remove_memblock(unsigned long base, unsigned int memblock_siz
nid = memory_add_physaddr_to_nid(base);
for (i = 0; i < sections_per_block; i++) {
- remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
+ __remove_memory(nid, base, MIN_MEMORY_BLOCK_SIZE);
base += MIN_MEMORY_BLOCK_SIZE;
}
@@ -423,7 +423,7 @@ static int dlpar_remove_lmb(struct drmem_lmb *lmb)
block_sz = pseries_memory_block_size();
nid = memory_add_physaddr_to_nid(lmb->base_addr);
- remove_memory(nid, lmb->base_addr, block_sz);
+ __remove_memory(nid, lmb->base_addr, block_sz);
/* Update memory regions for memory remove */
memblock_remove(lmb->base_addr, block_sz);
@@ -710,7 +710,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
rc = dlpar_online_lmb(lmb);
if (rc) {
- remove_memory(nid, lmb->base_addr, block_sz);
+ __remove_memory(nid, lmb->base_addr, block_sz);
dlpar_remove_device_tree_lmb(lmb);
} else {
lmb->flags |= DRCONF_MEM_ASSIGNED;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 6b0d3ef7309c..811148415993 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -282,7 +282,7 @@ static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
nid = memory_add_physaddr_to_nid(info->start_addr);
acpi_unbind_memory_blocks(info);
- remove_memory(nid, info->start_addr, info->length);
+ __remove_memory(nid, info->start_addr, info->length);
list_del(&info->list);
kfree(info);
}
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 34a28227068d..1f096852f479 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -301,6 +301,7 @@ extern bool is_mem_section_removable(unsigned long pfn, unsigned long nr_pages);
extern void try_offline_node(int nid);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern void remove_memory(int nid, u64 start, u64 size);
+extern void __remove_memory(int nid, u64 start, u64 size);
#else
static inline bool is_mem_section_removable(unsigned long pfn,
@@ -317,6 +318,7 @@ static inline int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
}
static inline void remove_memory(int nid, u64 start, u64 size) {}
+static inline void __remove_memory(int nid, u64 start, u64 size) {}
#endif /* CONFIG_MEMORY_HOTREMOVE */
extern void __ref free_area_init_core_hotplug(int nid);
@@ -330,7 +332,6 @@ extern void move_pfn_range_to_zone(struct zone *zone, unsigned long start_pfn,
unsigned long nr_pages, struct vmem_altmap *altmap);
extern int offline_pages(unsigned long start_pfn, unsigned long nr_pages);
extern bool is_memblock_offlined(struct memory_block *mem);
-extern void remove_memory(int nid, u64 start, u64 size);
extern int sparse_add_one_section(struct pglist_data *pgdat,
unsigned long start_pfn, struct vmem_altmap *altmap);
extern void sparse_remove_one_section(struct zone *zone, struct mem_section *ms,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 9eea6e809a4e..898e13d4d87d 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1872,7 +1872,7 @@ EXPORT_SYMBOL(try_offline_node);
* and online/offline operations before this call, as required by
* try_offline_node().
*/
-void __ref remove_memory(int nid, u64 start, u64 size)
+void __ref __remove_memory(int nid, u64 start, u64 size)
{
int ret;
@@ -1901,5 +1901,12 @@ void __ref remove_memory(int nid, u64 start, u64 size)
mem_hotplug_done();
}
+
+void __ref remove_memory(int nid, u64 start, u64 size)
+{
+ lock_device_hotplug();
+ __remove_memory(nid, start, size);
+ unlock_device_hotplug();
+}
EXPORT_SYMBOL_GPL(remove_memory);
#endif /* CONFIG_MEMORY_HOTREMOVE */
--
2.17.1
^ permalink raw reply related
* [PATCH RFCv2 2/6] mm/memory_hotplug: make add_memory() take the device_hotplug_lock
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Rafael J. Wysocki, Len Brown,
Greg Kroah-Hartman, Boris Ostrovsky, Juergen Gross,
Nathan Fontenot, John Allen, Andrew Morton, Michal Hocko,
Dan Williams, Joonsoo Kim, Vlastimil Babka, Oscar Salvador,
Mathieu Malaterre, Pavel Tatashin, YASUAKI ISHIMATSU
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
add_memory() currently does not take the device_hotplug_lock, however
is aleady called under the lock from
arch/powerpc/platforms/pseries/hotplug-memory.c
drivers/acpi/acpi_memhotplug.c
to synchronize against CPU hot-remove and similar.
In general, we should hold the device_hotplug_lock when adding memory
to synchronize against online/offline request (e.g. from user space) -
which already resulted in lock inversions due to device_lock() and
mem_hotplug_lock - see 30467e0b3be ("mm, hotplug: fix concurrent memory
hot-add deadlock"). add_memory()/add_memory_resource() will create memory
block devices, so this really feels like the right thing to do.
Holding the device_hotplug_lock makes sure that a memory block device
can really only be accessed (e.g. via .online/.state) from user space,
once the memory has been fully added to the system.
The lock is not held yet in
drivers/xen/balloon.c
arch/powerpc/platforms/powernv/memtrace.c
drivers/s390/char/sclp_cmd.c
drivers/hv/hv_balloon.c
So, let's either use the locked variants or take the lock.
Don't export add_memory_resource(), as it once was exported to be used
by XEN, which is never built as a module. If somebody requires it, we
also have to export a locked variant (as device_hotplug_lock is never
exported).
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com>
Cc: John Allen <jallen@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
.../platforms/pseries/hotplug-memory.c | 2 +-
drivers/acpi/acpi_memhotplug.c | 2 +-
drivers/base/memory.c | 9 ++++++--
drivers/xen/balloon.c | 3 +++
include/linux/memory_hotplug.h | 1 +
mm/memory_hotplug.c | 22 ++++++++++++++++---
6 files changed, 32 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index b3f54466e25f..2e6f41dc103a 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -702,7 +702,7 @@ static int dlpar_add_lmb(struct drmem_lmb *lmb)
nid = memory_add_physaddr_to_nid(lmb->base_addr);
/* Add the memory */
- rc = add_memory(nid, lmb->base_addr, block_sz);
+ rc = __add_memory(nid, lmb->base_addr, block_sz);
if (rc) {
dlpar_remove_device_tree_lmb(lmb);
return rc;
diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c
index 811148415993..8fe0960ea572 100644
--- a/drivers/acpi/acpi_memhotplug.c
+++ b/drivers/acpi/acpi_memhotplug.c
@@ -228,7 +228,7 @@ static int acpi_memory_enable_device(struct acpi_memory_device *mem_device)
if (node < 0)
node = memory_add_physaddr_to_nid(info->start_addr);
- result = add_memory(node, info->start_addr, info->length);
+ result = __add_memory(node, info->start_addr, info->length);
/*
* If the memory block has been used by the kernel, add_memory()
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index c8a1cb0b6136..5b0375be7f65 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -521,15 +521,20 @@ memory_probe_store(struct device *dev, struct device_attribute *attr,
if (phys_addr & ((pages_per_block << PAGE_SHIFT) - 1))
return -EINVAL;
+ ret = lock_device_hotplug_sysfs();
+ if (ret)
+ goto out;
+
nid = memory_add_physaddr_to_nid(phys_addr);
- ret = add_memory(nid, phys_addr,
- MIN_MEMORY_BLOCK_SIZE * sections_per_block);
+ ret = __add_memory(nid, phys_addr,
+ MIN_MEMORY_BLOCK_SIZE * sections_per_block);
if (ret)
goto out;
ret = count;
out:
+ unlock_device_hotplug();
return ret;
}
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index e12bb256036f..6bab019a82b1 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -395,7 +395,10 @@ static enum bp_state reserve_additional_memory(void)
* callers drop the mutex before trying again.
*/
mutex_unlock(&balloon_mutex);
+ /* add_memory_resource() requires the device_hotplug lock */
+ lock_device_hotplug();
rc = add_memory_resource(nid, resource, memhp_auto_online);
+ unlock_device_hotplug();
mutex_lock(&balloon_mutex);
if (rc) {
diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 1f096852f479..ffd9cd10fcf3 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -324,6 +324,7 @@ static inline void __remove_memory(int nid, u64 start, u64 size) {}
extern void __ref free_area_init_core_hotplug(int nid);
extern int walk_memory_range(unsigned long start_pfn, unsigned long end_pfn,
void *arg, int (*func)(struct memory_block *, void *));
+extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
extern int add_memory_resource(int nid, struct resource *resource, bool online);
extern int arch_add_memory(int nid, u64 start, u64 size,
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 898e13d4d87d..e2b5c751e3ea 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1111,7 +1111,12 @@ static int online_memory_block(struct memory_block *mem, void *arg)
return device_online(&mem->dev);
}
-/* we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG */
+/*
+ * NOTE: The caller must call lock_device_hotplug() to serialize hotplug
+ * and online/offline operations (triggered e.g. by sysfs).
+ *
+ * we are OK calling __meminit stuff here - we have CONFIG_MEMORY_HOTPLUG
+ */
int __ref add_memory_resource(int nid, struct resource *res, bool online)
{
u64 start, size;
@@ -1180,9 +1185,9 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
mem_hotplug_done();
return ret;
}
-EXPORT_SYMBOL_GPL(add_memory_resource);
-int __ref add_memory(int nid, u64 start, u64 size)
+/* requires device_hotplug_lock, see add_memory_resource() */
+int __ref __add_memory(int nid, u64 start, u64 size)
{
struct resource *res;
int ret;
@@ -1196,6 +1201,17 @@ int __ref add_memory(int nid, u64 start, u64 size)
release_memory_resource(res);
return ret;
}
+
+int add_memory(int nid, u64 start, u64 size)
+{
+ int rc;
+
+ lock_device_hotplug();
+ rc = __add_memory(nid, start, size);
+ unlock_device_hotplug();
+
+ return rc;
+}
EXPORT_SYMBOL_GPL(add_memory);
#ifdef CONFIG_MEMORY_HOTREMOVE
--
2.17.1
^ permalink raw reply related
* [PATCH RFCv2 3/6] mm/memory_hotplug: fix online/offline_pages called w.o. mem_hotplug_lock
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Rafael J. Wysocki, Len Brown,
Greg Kroah-Hartman, K. Y. Srinivasan, Haiyang Zhang,
Stephen Hemminger, Martin Schwidefsky, Heiko Carstens,
Boris Ostrovsky, Juergen Gross, Rashmica Gupta, Michael Neuling,
Balbir Singh, Kate Stewart, Thomas Gleixner, Philippe Ombredanne,
Andrew Morton, Michal Hocko, Pavel Tatashin, Vlastimil Babka,
Dan Williams, Oscar Salvador, YASUAKI ISHIMATSU,
Mathieu Malaterre
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
There seem to be some problems as result of 30467e0b3be ("mm, hotplug:
fix concurrent memory hot-add deadlock"), which tried to fix a possible
lock inversion reported and discussed in [1] due to the two locks
a) device_lock()
b) mem_hotplug_lock
While add_memory() first takes b), followed by a) during
bus_probe_device(), onlining of memory from user space first took b),
followed by a), exposing a possible deadlock.
In [1], and it was decided to not make use of device_hotplug_lock, but
rather to enforce a locking order.
The problems I spotted related to this:
1. Memory block device attributes: While .state first calls
mem_hotplug_begin() and the calls device_online() - which takes
device_lock() - .online does no longer call mem_hotplug_begin(), so
effectively calls online_pages() without mem_hotplug_lock.
2. device_online() should be called under device_hotplug_lock, however
onlining memory during add_memory() does not take care of that.
In addition, I think there is also something wrong about the locking in
3. arch/powerpc/platforms/powernv/memtrace.c calls offline_pages()
without locks. This was introduced after 30467e0b3be. And skimming over
the code, I assume it could need some more care in regards to locking
(e.g. device_online() called without device_hotplug_lock - but I'll
not touch that for now).
Now that we hold the device_hotplug_lock when
- adding memory (e.g. via add_memory()/add_memory_resource())
- removing memory (e.g. via remove_memory())
- device_online()/device_offline()
We can move mem_hotplug_lock usage back into
online_pages()/offline_pages().
Why is mem_hotplug_lock still needed? Essentially to make
get_online_mems()/put_online_mems() be very fast (relying on
device_hotplug_lock would be very slow), and to serialize against
addition of memory that does not create memory block devices (hmm).
[1] http://driverdev.linuxdriverproject.org/pipermail/ driverdev-devel/
2015-February/065324.html
This patch is partly based on a patch by Vitaly Kuznetsov.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Len Brown <lenb@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: YASUAKI ISHIMATSU <yasu.isimatu@gmail.com>
Cc: Mathieu Malaterre <malat@debian.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
drivers/base/memory.c | 13 +------------
mm/memory_hotplug.c | 28 ++++++++++++++++++++--------
2 files changed, 21 insertions(+), 20 deletions(-)
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 5b0375be7f65..04be13539eb8 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -228,7 +228,6 @@ static bool pages_correctly_probed(unsigned long start_pfn)
/*
* MEMORY_HOTPLUG depends on SPARSEMEM in mm/Kconfig, so it is
* OK to have direct references to sparsemem variables in here.
- * Must already be protected by mem_hotplug_begin().
*/
static int
memory_block_action(unsigned long phys_index, unsigned long action, int online_type)
@@ -294,7 +293,6 @@ static int memory_subsys_online(struct device *dev)
if (mem->online_type < 0)
mem->online_type = MMOP_ONLINE_KEEP;
- /* Already under protection of mem_hotplug_begin() */
ret = memory_block_change_state(mem, MEM_ONLINE, MEM_OFFLINE);
/* clear online_type */
@@ -341,19 +339,11 @@ store_mem_state(struct device *dev,
goto err;
}
- /*
- * Memory hotplug needs to hold mem_hotplug_begin() for probe to find
- * the correct memory block to online before doing device_online(dev),
- * which will take dev->mutex. Take the lock early to prevent an
- * inversion, memory_subsys_online() callbacks will be implemented by
- * assuming it's already protected.
- */
- mem_hotplug_begin();
-
switch (online_type) {
case MMOP_ONLINE_KERNEL:
case MMOP_ONLINE_MOVABLE:
case MMOP_ONLINE_KEEP:
+ /* mem->online_type is protected by device_hotplug_lock */
mem->online_type = online_type;
ret = device_online(&mem->dev);
break;
@@ -364,7 +354,6 @@ store_mem_state(struct device *dev,
ret = -EINVAL; /* should never happen */
}
- mem_hotplug_done();
err:
unlock_device_hotplug();
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index e2b5c751e3ea..a2c6c87d83f3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -881,7 +881,6 @@ static struct zone * __meminit move_pfn_range(int online_type, int nid,
return zone;
}
-/* Must be protected by mem_hotplug_begin() or a device_lock */
int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_type)
{
unsigned long flags;
@@ -893,6 +892,8 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
struct memory_notify arg;
struct memory_block *mem;
+ mem_hotplug_begin();
+
/*
* We can't use pfn_to_nid() because nid might be stored in struct page
* which is not yet initialized. Instead, we find nid from memory block.
@@ -957,6 +958,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
if (onlined_pages)
memory_notify(MEM_ONLINE, &arg);
+ mem_hotplug_done();
return 0;
failed_addition:
@@ -964,6 +966,7 @@ int __ref online_pages(unsigned long pfn, unsigned long nr_pages, int online_typ
(unsigned long long) pfn << PAGE_SHIFT,
(((unsigned long long) pfn + nr_pages) << PAGE_SHIFT) - 1);
memory_notify(MEM_CANCEL_ONLINE, &arg);
+ mem_hotplug_done();
return ret;
}
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
@@ -1168,20 +1171,20 @@ int __ref add_memory_resource(int nid, struct resource *res, bool online)
/* create new memmap entry */
firmware_map_add_hotplug(start, start + size, "System RAM");
+ /* device_online() will take the lock when calling online_pages() */
+ mem_hotplug_done();
+
/* online pages if requested */
if (online)
walk_memory_range(PFN_DOWN(start), PFN_UP(start + size - 1),
NULL, online_memory_block);
- goto out;
-
+ return ret;
error:
/* rollback pgdat allocation and others */
if (new_node)
rollback_node_hotadd(nid);
memblock_remove(start, size);
-
-out:
mem_hotplug_done();
return ret;
}
@@ -1621,10 +1624,16 @@ static int __ref __offline_pages(unsigned long start_pfn,
return -EINVAL;
if (!IS_ALIGNED(end_pfn, pageblock_nr_pages))
return -EINVAL;
+
+ mem_hotplug_begin();
+
/* This makes hotplug much easier...and readable.
we assume this for now. .*/
- if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start, &valid_end))
+ if (!test_pages_in_a_zone(start_pfn, end_pfn, &valid_start,
+ &valid_end)) {
+ mem_hotplug_done();
return -EINVAL;
+ }
zone = page_zone(pfn_to_page(valid_start));
node = zone_to_nid(zone);
@@ -1633,8 +1642,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
/* set above range as isolated */
ret = start_isolate_page_range(start_pfn, end_pfn,
MIGRATE_MOVABLE, true);
- if (ret)
+ if (ret) {
+ mem_hotplug_done();
return ret;
+ }
arg.start_pfn = start_pfn;
arg.nr_pages = nr_pages;
@@ -1705,6 +1716,7 @@ static int __ref __offline_pages(unsigned long start_pfn,
writeback_set_ratelimit();
memory_notify(MEM_OFFLINE, &arg);
+ mem_hotplug_done();
return 0;
failed_removal:
@@ -1714,10 +1726,10 @@ static int __ref __offline_pages(unsigned long start_pfn,
memory_notify(MEM_CANCEL_OFFLINE, &arg);
/* pushback to free area */
undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
+ mem_hotplug_done();
return ret;
}
-/* Must be protected by mem_hotplug_begin() or a device_lock */
int offline_pages(unsigned long start_pfn, unsigned long nr_pages)
{
return __offline_pages(start_pfn, start_pfn + nr_pages);
--
2.17.1
^ permalink raw reply related
* [PATCH RFCv2 4/6] powerpc/powernv: hold device_hotplug_lock when calling device_online()
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Rashmica Gupta, Balbir Singh, Michael Neuling
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
device_online() should be called with device_hotplug_lock() held.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 8f1cd4f3bfd5..ef7181d4fe68 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -229,9 +229,11 @@ static int memtrace_online(void)
* we need to online the memory ourselves.
*/
if (!memhp_auto_online) {
+ lock_device_hotplug();
walk_memory_range(PFN_DOWN(ent->start),
PFN_UP(ent->start + ent->size - 1),
NULL, online_mem_block);
+ unlock_device_hotplug();
}
/*
--
2.17.1
^ permalink raw reply related
* [PATCH RFCv2 5/6] powerpc/powernv: hold device_hotplug_lock in memtrace_offline_pages()
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, Rashmica Gupta, Balbir Singh, Michael Neuling
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
Let's perform all checking + offlining + removing under
device_hotplug_lock, so nobody can mess with these devices via
sysfs concurrently.
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Rashmica Gupta <rashmica.g@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michael Neuling <mikey@neuling.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
arch/powerpc/platforms/powernv/memtrace.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index ef7181d4fe68..473e59842ec5 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -74,9 +74,13 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
{
u64 end_pfn = start_pfn + nr_pages - 1;
+ lock_device_hotplug();
+
if (walk_memory_range(start_pfn, end_pfn, NULL,
- check_memblock_online))
+ check_memblock_online)) {
+ unlock_device_hotplug();
return false;
+ }
walk_memory_range(start_pfn, end_pfn, (void *)MEM_GOING_OFFLINE,
change_memblock_state);
@@ -84,14 +88,16 @@ static bool memtrace_offline_pages(u32 nid, u64 start_pfn, u64 nr_pages)
if (offline_pages(start_pfn, nr_pages)) {
walk_memory_range(start_pfn, end_pfn, (void *)MEM_ONLINE,
change_memblock_state);
+ unlock_device_hotplug();
return false;
}
walk_memory_range(start_pfn, end_pfn, (void *)MEM_OFFLINE,
change_memblock_state);
- remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
+ __remove_memory(nid, start_pfn << PAGE_SHIFT, nr_pages << PAGE_SHIFT);
+ unlock_device_hotplug();
return true;
}
--
2.17.1
^ permalink raw reply related
* [PATCH RFCv2 6/6] memory-hotplug.txt: Add some details about locking internals
From: David Hildenbrand @ 2018-08-21 10:44 UTC (permalink / raw)
To: linux-mm
Cc: linux-kernel, linux-doc, linuxppc-dev, linux-acpi, xen-devel,
devel, David Hildenbrand, Jonathan Corbet, Michal Hocko,
Andrew Morton
In-Reply-To: <20180821104418.12710-1-david@redhat.com>
Let's document the magic a bit, especially why device_hotplug_lock is
required when adding/removing memory and how it all play together with
requests to online/offline memory from user space.
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
Documentation/memory-hotplug.txt | 39 +++++++++++++++++++++++++++++++-
1 file changed, 38 insertions(+), 1 deletion(-)
diff --git a/Documentation/memory-hotplug.txt b/Documentation/memory-hotplug.txt
index 7f49ebf3ddb2..03aaad7d7373 100644
--- a/Documentation/memory-hotplug.txt
+++ b/Documentation/memory-hotplug.txt
@@ -3,7 +3,7 @@ Memory Hotplug
==============
:Created: Jul 28 2007
-:Updated: Add description of notifier of memory hotplug: Oct 11 2007
+:Updated: Add some details about locking internals: Aug 20 2018
This document is about memory hotplug including how-to-use and current status.
Because Memory Hotplug is still under development, contents of this text will
@@ -495,6 +495,43 @@ further processing of the notification queue.
NOTIFY_STOP stops further processing of the notification queue.
+
+Locking Internals
+=================
+
+When adding/removing memory that uses memory block devices (i.e. ordinary RAM),
+the device_hotplug_lock should be held to:
+
+- synchronize against online/offline requests (e.g. via sysfs). This way, memory
+ block devices can only be accessed (.online/.state attributes) by user
+ space once memory has been fully added. And when removing memory, we
+ know nobody is in critical sections.
+- synchronize against CPU hotplug and similar (e.g. relevant for ACPI and PPC)
+
+Especially, there is a possible lock inversion that is avoided using
+device_hotplug_lock when adding memory and user space tries to online that
+memory faster than expected:
+
+- device_online() will first take the device_lock(), followed by
+ mem_hotplug_lock
+- add_memory_resource() will first take the mem_hotplug_lock, followed by
+ the device_lock() (while creating the devices, during bus_add_device()).
+
+As the device is visible to user space before taking the device_lock(), this
+can result in a lock inversion.
+
+onlining/offlining of memory should be done via device_online()/
+device_offline() - to make sure it is properly synchronized to actions
+via sysfs. Holding device_hotplug_lock is advised (to e.g. protect online_type)
+
+When adding/removing/onlining/offlining memory or adding/removing
+heterogeneous/device memory, we should always hold the mem_hotplug_lock to
+serialise memory hotplug (e.g. access to global/zone variables).
+
+In addition, mem_hotplug_lock (in contrast to device_hotplug_lock) allows
+for a quite efficient get_online_mems/put_online_mems implementation.
+
+
Future Work
===========
--
2.17.1
^ permalink raw reply related
* Re: [PATCH 1/2] sched/topology: Set correct numa topology type
From: Srikar Dronamraju @ 2018-08-21 11:02 UTC (permalink / raw)
To: Peter Zijlstra, Ingo Molnar
Cc: LKML, Mel Gorman, Rik van Riel, Thomas Gleixner, Michael Ellerman,
Heiko Carstens, Suravee Suthikulpanit, Andre Wild, linuxppc-dev
In-Reply-To: <1533920419-17410-1-git-send-email-srikar@linux.vnet.ibm.com>
* Srikar Dronamraju <srikar@linux.vnet.ibm.com> [2018-08-10 22:30:18]:
> With commit 051f3ca02e46 ("sched/topology: Introduce NUMA identity node
> sched domain") scheduler introduces an new numa level. However this
> leads to numa topology on 2 node systems no more marked as NUMA_DIRECT.
> After this commit, it gets reported as NUMA_BACKPLANE. This is because
> sched_domains_numa_level is now 2 on 2 node systems.
>
> Fix this by allowing setting systems that have upto 2 numa levels as
> NUMA_DIRECT.
>
> While here remove a code that assumes level can be 0.
>
> Fixes: 051f3ca02e46 "Introduce NUMA identity node sched domain"
> Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> ---
Hey Peter,
Did you look at these two patches?
--
Thanks and Regards
Srikar Dronamraju
^ permalink raw reply
* Re: [PATCH] powerpc/64s/hash: convert SLB miss handlers to C
From: Nicholas Piggin @ 2018-08-21 11:51 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev, Aneesh Kumar K . V
In-Reply-To: <a8f6f7ca5ae67e0a7bce6ed8a37d50f6e282d256.camel@au1.ibm.com>
On Tue, 21 Aug 2018 16:12:44 +1000
Benjamin Herrenschmidt <benh@au1.ibm.com> wrote:
> On Tue, 2018-08-21 at 15:13 +1000, Nicholas Piggin wrote:
> > This patch moves SLB miss handlers completely to C, using the standard
> > exception handler macros to set up the stack and branch to C.
> >
> > This can be done because the segment containing the kernel stack is
> > always bolted, so accessing it with relocation on will not cause an
> > SLB exception.
> >
> > Arbitrary kernel memory may not be accessed when handling kernel space
> > SLB misses, so care should be taken there. However user SLB misses can
> > access any kernel memory, which can be used to move some fields out of
> > the paca (in later patches).
> >
> > User SLB misses could quite easily reconcile IRQs and set up a first
> > class kernel environment and exit via ret_from_except, however that
> > doesn't seem to be necessary at the moment, so we only do that if a
> > bad fault is encountered.
> >
> > [ Credit to Aneesh for bug fixes, error checks, and improvements to bad
> > address handling, etc ]
> >
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> >
> > Since RFC:
> > - Send patch 1 by itself to focus on the big change.
> > - Added MSR[RI] handling
> > - Fixed up a register loss bug exposed by irq tracing (Aneesh)
> > - Reject misses outside the defined kernel regions (Aneesh)
> > - Added several more sanity checks and error handlig (Aneesh), we may
> > look at consolidating these tests and tightenig up the code but for
> > a first pass we decided it's better to check carefully.
> > ---
> > arch/powerpc/include/asm/asm-prototypes.h | 2 +
> > arch/powerpc/kernel/exceptions-64s.S | 202 +++----------
> > arch/powerpc/mm/Makefile | 2 +-
> > arch/powerpc/mm/slb.c | 257 +++++++++--------
> > arch/powerpc/mm/slb_low.S | 335 ----------------------
> > 5 files changed, 185 insertions(+), 613 deletions(-)
> ^^^ ^^^
>
> Nice ! :-)
Okay with the subsequent improvements, the context switching benchmark
is about 30% faster. Radix is still faster, but hash now has 90% the
throughput rather than 70% with upstream. Although that's no longer
testing SLB miss performance because they are all eliminated.
I don't know of any other SLB miss intensive tests. I think these
numbers indicate it may be a reasonable approach wrt performance.
Though we should still look at HANA or something on a big memory
system.
Thanks,
Nick
^ permalink raw reply
* [PATCH v2] powerpc/64s/hash: convert SLB miss handlers to C
From: Nicholas Piggin @ 2018-08-21 11:54 UTC (permalink / raw)
To: linuxppc-dev; +Cc: Nicholas Piggin, Aneesh Kumar K . V
This patch moves SLB miss handlers completely to C, using the standard
exception handler macros to set up the stack and branch to C.
This can be done because the segment containing the kernel stack is
always bolted, so accessing it with relocation on will not cause an
SLB exception.
Arbitrary kernel memory may not be accessed when handling kernel space
SLB misses, so care should be taken there. However user SLB misses can
access any kernel memory, which can be used to move some fields out of
the paca (in later patches).
User SLB misses could quite easily reconcile IRQs and set up a first
class kernel environment and exit via ret_from_except, however that
doesn't seem to be necessary at the moment, so we only do that if a
bad fault is encountered.
[ Credit to Aneesh for bug fixes, error checks, and improvements to bad
address handling, etc. ]
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Since RFC:
- Added MSR[RI] handling
- Fixed up a register loss bug exposed by irq tracing (Aneesh)
- Reject misses outside the defined kernel regions (Aneesh)
- Added several more sanity checks and error handling (Aneesh), we may
look at consolidating these tests and tightenig up the code but for
a first pass we decided it's better to check carefully.
Since v1:
- Fixed SLB cache corruption (Aneesh)
- Fixed untidy SLBE allocation "leak" in get_vsid error case
- Now survives some stress testing on real hardware
---
arch/powerpc/include/asm/asm-prototypes.h | 2 +
arch/powerpc/kernel/exceptions-64s.S | 202 +++----------
arch/powerpc/mm/Makefile | 2 +-
arch/powerpc/mm/slb.c | 271 +++++++++--------
arch/powerpc/mm/slb_low.S | 335 ----------------------
5 files changed, 196 insertions(+), 616 deletions(-)
delete mode 100644 arch/powerpc/mm/slb_low.S
diff --git a/arch/powerpc/include/asm/asm-prototypes.h b/arch/powerpc/include/asm/asm-prototypes.h
index 1f4691ce4126..78ed3c3f879a 100644
--- a/arch/powerpc/include/asm/asm-prototypes.h
+++ b/arch/powerpc/include/asm/asm-prototypes.h
@@ -78,6 +78,8 @@ void kernel_bad_stack(struct pt_regs *regs);
void system_reset_exception(struct pt_regs *regs);
void machine_check_exception(struct pt_regs *regs);
void emulation_assist_interrupt(struct pt_regs *regs);
+long do_slb_fault(struct pt_regs *regs, unsigned long ea);
+void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err);
/* signals, syscalls and interrupts */
long sys_swapcontext(struct ucontext __user *old_ctx,
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index ea04dfb8c092..c3832243819b 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -566,28 +566,36 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
EXC_REAL_BEGIN(data_access_slb, 0x380, 0x80)
- SET_SCRATCH0(r13)
- EXCEPTION_PROLOG_0(PACA_EXSLB)
- EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x380)
- mr r12,r3 /* save r3 */
- mfspr r3,SPRN_DAR
- mfspr r11,SPRN_SRR1
- crset 4*cr6+eq
- BRANCH_TO_COMMON(r10, slb_miss_common)
+EXCEPTION_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, KVMTEST_PR, 0x380);
EXC_REAL_END(data_access_slb, 0x380, 0x80)
EXC_VIRT_BEGIN(data_access_slb, 0x4380, 0x80)
- SET_SCRATCH0(r13)
- EXCEPTION_PROLOG_0(PACA_EXSLB)
- EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x380)
- mr r12,r3 /* save r3 */
- mfspr r3,SPRN_DAR
- mfspr r11,SPRN_SRR1
- crset 4*cr6+eq
- BRANCH_TO_COMMON(r10, slb_miss_common)
+EXCEPTION_RELON_PROLOG(PACA_EXSLB, data_access_slb_common, EXC_STD, NOTEST, 0x380);
EXC_VIRT_END(data_access_slb, 0x4380, 0x80)
+
TRAMP_KVM_SKIP(PACA_EXSLB, 0x380)
+EXC_COMMON_BEGIN(data_access_slb_common)
+ mfspr r10,SPRN_DAR
+ std r10,PACA_EXSLB+EX_DAR(r13)
+ EXCEPTION_PROLOG_COMMON(0x380, PACA_EXSLB)
+ ld r4,PACA_EXSLB+EX_DAR(r13)
+ std r4,_DAR(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl do_slb_fault
+ cmpdi r3,0
+ bne- 1f
+ b fast_exception_return
+1: /* Error case */
+ std r3,RESULT(r1)
+ bl save_nvgprs
+ RECONCILE_IRQ_STATE(r10, r11)
+ ld r4,_DAR(r1)
+ ld r5,RESULT(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl do_bad_slb_fault
+ b ret_from_except
+
EXC_REAL(instruction_access, 0x400, 0x80)
EXC_VIRT(instruction_access, 0x4400, 0x80, 0x400)
@@ -610,160 +618,34 @@ ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_TYPE_RADIX)
EXC_REAL_BEGIN(instruction_access_slb, 0x480, 0x80)
- SET_SCRATCH0(r13)
- EXCEPTION_PROLOG_0(PACA_EXSLB)
- EXCEPTION_PROLOG_1(PACA_EXSLB, KVMTEST_PR, 0x480)
- mr r12,r3 /* save r3 */
- mfspr r3,SPRN_SRR0 /* SRR0 is faulting address */
- mfspr r11,SPRN_SRR1
- crclr 4*cr6+eq
- BRANCH_TO_COMMON(r10, slb_miss_common)
+EXCEPTION_PROLOG(PACA_EXSLB, instruction_access_slb_common, EXC_STD, KVMTEST_PR, 0x480);
EXC_REAL_END(instruction_access_slb, 0x480, 0x80)
EXC_VIRT_BEGIN(instruction_access_slb, 0x4480, 0x80)
- SET_SCRATCH0(r13)
- EXCEPTION_PROLOG_0(PACA_EXSLB)
- EXCEPTION_PROLOG_1(PACA_EXSLB, NOTEST, 0x480)
- mr r12,r3 /* save r3 */
- mfspr r3,SPRN_SRR0 /* SRR0 is faulting address */
- mfspr r11,SPRN_SRR1
- crclr 4*cr6+eq
- BRANCH_TO_COMMON(r10, slb_miss_common)
+EXCEPTION_RELON_PROLOG(PACA_EXSLB, instruction_access_slb_common, EXC_STD, NOTEST, 0x480);
EXC_VIRT_END(instruction_access_slb, 0x4480, 0x80)
-TRAMP_KVM(PACA_EXSLB, 0x480)
-
-
-/*
- * This handler is used by the 0x380 and 0x480 SLB miss interrupts, as well as
- * the virtual mode 0x4380 and 0x4480 interrupts if AIL is enabled.
- */
-EXC_COMMON_BEGIN(slb_miss_common)
- /*
- * r13 points to the PACA, r9 contains the saved CR,
- * r12 contains the saved r3,
- * r11 contain the saved SRR1, SRR0 is still ready for return
- * r3 has the faulting address
- * r9 - r13 are saved in paca->exslb.
- * cr6.eq is set for a D-SLB miss, clear for a I-SLB miss
- * We assume we aren't going to take any exceptions during this
- * procedure.
- */
- mflr r10
- stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */
- std r10,PACA_EXSLB+EX_LR(r13) /* save LR */
-
- andi. r9,r11,MSR_PR // Check for exception from userspace
- cmpdi cr4,r9,MSR_PR // And save the result in CR4 for later
-
- /*
- * Test MSR_RI before calling slb_allocate_realmode, because the
- * MSR in r11 gets clobbered. However we still want to allocate
- * SLB in case MSR_RI=0, to minimise the risk of getting stuck in
- * recursive SLB faults. So use cr5 for this, which is preserved.
- */
- andi. r11,r11,MSR_RI /* check for unrecoverable exception */
- cmpdi cr5,r11,MSR_RI
-
- crset 4*cr0+eq
-#ifdef CONFIG_PPC_BOOK3S_64
-BEGIN_MMU_FTR_SECTION
- bl slb_allocate
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
-#endif
-
- ld r10,PACA_EXSLB+EX_LR(r13)
- lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */
- mtlr r10
-
- /*
- * Large address, check whether we have to allocate new contexts.
- */
- beq- 8f
- bne- cr5,2f /* if unrecoverable exception, oops */
-
- /* All done -- return from exception. */
-
- bne cr4,1f /* returning to kernel */
-
- mtcrf 0x80,r9
- mtcrf 0x08,r9 /* MSR[PR] indication is in cr4 */
- mtcrf 0x04,r9 /* MSR[RI] indication is in cr5 */
- mtcrf 0x02,r9 /* I/D indication is in cr6 */
- mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */
-
- RESTORE_CTR(r9, PACA_EXSLB)
- RESTORE_PPR_PACA(PACA_EXSLB, r9)
- mr r3,r12
- ld r9,PACA_EXSLB+EX_R9(r13)
- ld r10,PACA_EXSLB+EX_R10(r13)
- ld r11,PACA_EXSLB+EX_R11(r13)
- ld r12,PACA_EXSLB+EX_R12(r13)
- ld r13,PACA_EXSLB+EX_R13(r13)
- RFI_TO_USER
- b . /* prevent speculative execution */
-1:
- mtcrf 0x80,r9
- mtcrf 0x08,r9 /* MSR[PR] indication is in cr4 */
- mtcrf 0x04,r9 /* MSR[RI] indication is in cr5 */
- mtcrf 0x02,r9 /* I/D indication is in cr6 */
- mtcrf 0x01,r9 /* slb_allocate uses cr0 and cr7 */
-
- RESTORE_CTR(r9, PACA_EXSLB)
- RESTORE_PPR_PACA(PACA_EXSLB, r9)
- mr r3,r12
- ld r9,PACA_EXSLB+EX_R9(r13)
- ld r10,PACA_EXSLB+EX_R10(r13)
- ld r11,PACA_EXSLB+EX_R11(r13)
- ld r12,PACA_EXSLB+EX_R12(r13)
- ld r13,PACA_EXSLB+EX_R13(r13)
- RFI_TO_KERNEL
- b . /* prevent speculative execution */
-
-
-2: std r3,PACA_EXSLB+EX_DAR(r13)
- mr r3,r12
- mfspr r11,SPRN_SRR0
- mfspr r12,SPRN_SRR1
- LOAD_HANDLER(r10,unrecov_slb)
- mtspr SPRN_SRR0,r10
- ld r10,PACAKMSR(r13)
- mtspr SPRN_SRR1,r10
- RFI_TO_KERNEL
- b .
-
-8: std r3,PACA_EXSLB+EX_DAR(r13)
- mr r3,r12
- mfspr r11,SPRN_SRR0
- mfspr r12,SPRN_SRR1
- LOAD_HANDLER(r10, large_addr_slb)
- mtspr SPRN_SRR0,r10
- ld r10,PACAKMSR(r13)
- mtspr SPRN_SRR1,r10
- RFI_TO_KERNEL
- b .
+TRAMP_KVM(PACA_EXSLB, 0x480)
-EXC_COMMON_BEGIN(unrecov_slb)
- EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB)
- RECONCILE_IRQ_STATE(r10, r11)
+EXC_COMMON_BEGIN(instruction_access_slb_common)
+ EXCEPTION_PROLOG_COMMON(0x480, PACA_EXSLB)
+ ld r4,_NIP(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl do_slb_fault
+ cmpdi r3,0
+ bne- 1f
+ b fast_exception_return
+1: /* Error case */
+ std r3,RESULT(r1)
bl save_nvgprs
-1: addi r3,r1,STACK_FRAME_OVERHEAD
- bl unrecoverable_exception
- b 1b
-
-EXC_COMMON_BEGIN(large_addr_slb)
- EXCEPTION_PROLOG_COMMON(0x380, PACA_EXSLB)
RECONCILE_IRQ_STATE(r10, r11)
- ld r3, PACA_EXSLB+EX_DAR(r13)
- std r3, _DAR(r1)
- beq cr6, 2f
- li r10, 0x481 /* fix trap number for I-SLB miss */
- std r10, _TRAP(r1)
-2: bl save_nvgprs
- addi r3, r1, STACK_FRAME_OVERHEAD
- bl slb_miss_large_addr
+ ld r4,_NIP(r1)
+ ld r5,RESULT(r1)
+ addi r3,r1,STACK_FRAME_OVERHEAD
+ bl do_bad_slb_fault
b ret_from_except
+
EXC_REAL_BEGIN(hardware_interrupt, 0x500, 0x100)
.globl hardware_interrupt_hv;
hardware_interrupt_hv:
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index cdf6a9960046..892d4e061d62 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -15,7 +15,7 @@ obj-$(CONFIG_PPC_MMU_NOHASH) += mmu_context_nohash.o tlb_nohash.o \
obj-$(CONFIG_PPC_BOOK3E) += tlb_low_$(BITS)e.o
hash64-$(CONFIG_PPC_NATIVE) := hash_native_64.o
obj-$(CONFIG_PPC_BOOK3E_64) += pgtable-book3e.o
-obj-$(CONFIG_PPC_BOOK3S_64) += pgtable-hash64.o hash_utils_64.o slb_low.o slb.o $(hash64-y) mmu_context_book3s64.o pgtable-book3s64.o
+obj-$(CONFIG_PPC_BOOK3S_64) += pgtable-hash64.o hash_utils_64.o slb.o $(hash64-y) mmu_context_book3s64.o pgtable-book3s64.o
obj-$(CONFIG_PPC_RADIX_MMU) += pgtable-radix.o tlb-radix.o
obj-$(CONFIG_PPC_STD_MMU_32) += ppc_mmu_32.o hash_low_32.o mmu_context_hash32.o
obj-$(CONFIG_PPC_STD_MMU) += tlb_hash$(BITS).o
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index ad9b898d56d9..ee0886252499 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -14,6 +14,7 @@
* 2 of the License, or (at your option) any later version.
*/
+#include <asm/asm-prototypes.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/mmu_context.h>
@@ -34,7 +35,7 @@ enum slb_index {
KSTACK_INDEX = 2, /* Kernel stack map */
};
-extern void slb_allocate(unsigned long ea);
+static long slb_allocate_user(struct mm_struct *mm, unsigned long ea);
#define slb_esid_mask(ssize) \
(((ssize) == MMU_SEGSIZE_256M)? ESID_MASK: ESID_MASK_1T)
@@ -45,13 +46,19 @@ static inline unsigned long mk_esid_data(unsigned long ea, int ssize,
return (ea & slb_esid_mask(ssize)) | SLB_ESID_V | index;
}
-static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
+static inline unsigned long __mk_vsid_data(unsigned long vsid, int ssize,
unsigned long flags)
{
- return (get_kernel_vsid(ea, ssize) << slb_vsid_shift(ssize)) | flags |
+ return (vsid << slb_vsid_shift(ssize)) | flags |
((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
}
+static inline unsigned long mk_vsid_data(unsigned long ea, int ssize,
+ unsigned long flags)
+{
+ return __mk_vsid_data(get_kernel_vsid(ea, ssize), ssize, flags);
+}
+
static inline void slb_shadow_update(unsigned long ea, int ssize,
unsigned long flags,
enum slb_index index)
@@ -274,49 +281,19 @@ void switch_slb(struct task_struct *tsk, struct mm_struct *mm)
is_kernel_addr(exec_base))
return;
- slb_allocate(pc);
+ slb_allocate_user(mm, pc);
if (!esids_match(pc, stack))
- slb_allocate(stack);
+ slb_allocate_user(mm, stack);
if (!esids_match(pc, exec_base) &&
!esids_match(stack, exec_base))
- slb_allocate(exec_base);
-}
-
-static inline void patch_slb_encoding(unsigned int *insn_addr,
- unsigned int immed)
-{
-
- /*
- * This function patches either an li or a cmpldi instruction with
- * a new immediate value. This relies on the fact that both li
- * (which is actually addi) and cmpldi both take a 16-bit immediate
- * value, and it is situated in the same location in the instruction,
- * ie. bits 16-31 (Big endian bit order) or the lower 16 bits.
- * The signedness of the immediate operand differs between the two
- * instructions however this code is only ever patching a small value,
- * much less than 1 << 15, so we can get away with it.
- * To patch the value we read the existing instruction, clear the
- * immediate value, and or in our new value, then write the instruction
- * back.
- */
- unsigned int insn = (*insn_addr & 0xffff0000) | immed;
- patch_instruction(insn_addr, insn);
+ slb_allocate_user(mm, exec_base);
}
-extern u32 slb_miss_kernel_load_linear[];
-extern u32 slb_miss_kernel_load_io[];
-extern u32 slb_compare_rr_to_size[];
-extern u32 slb_miss_kernel_load_vmemmap[];
-
void slb_set_size(u16 size)
{
- if (mmu_slb_size == size)
- return;
-
mmu_slb_size = size;
- patch_slb_encoding(slb_compare_rr_to_size, mmu_slb_size);
}
void slb_initialize(void)
@@ -338,19 +315,9 @@ void slb_initialize(void)
#endif
if (!slb_encoding_inited) {
slb_encoding_inited = 1;
- patch_slb_encoding(slb_miss_kernel_load_linear,
- SLB_VSID_KERNEL | linear_llp);
- patch_slb_encoding(slb_miss_kernel_load_io,
- SLB_VSID_KERNEL | io_llp);
- patch_slb_encoding(slb_compare_rr_to_size,
- mmu_slb_size);
-
pr_devel("SLB: linear LLP = %04lx\n", linear_llp);
pr_devel("SLB: io LLP = %04lx\n", io_llp);
-
#ifdef CONFIG_SPARSEMEM_VMEMMAP
- patch_slb_encoding(slb_miss_kernel_load_vmemmap,
- SLB_VSID_KERNEL | vmemmap_llp);
pr_devel("SLB: vmemmap LLP = %04lx\n", vmemmap_llp);
#endif
}
@@ -381,49 +348,10 @@ void slb_initialize(void)
asm volatile("isync":::"memory");
}
-static void insert_slb_entry(unsigned long vsid, unsigned long ea,
- int bpsize, int ssize)
+static void slb_cache_update(unsigned long esid_data)
{
- unsigned long flags, vsid_data, esid_data;
- enum slb_index index;
int slb_cache_index;
- /*
- * We are irq disabled, hence should be safe to access PACA.
- */
- VM_WARN_ON(!irqs_disabled());
-
- /*
- * We can't take a PMU exception in the following code, so hard
- * disable interrupts.
- */
- hard_irq_disable();
-
- index = get_paca()->stab_rr;
-
- /*
- * simple round-robin replacement of slb starting at SLB_NUM_BOLTED.
- */
- if (index < (mmu_slb_size - 1))
- index++;
- else
- index = SLB_NUM_BOLTED;
-
- get_paca()->stab_rr = index;
-
- flags = SLB_VSID_USER | mmu_psize_defs[bpsize].sllp;
- vsid_data = (vsid << slb_vsid_shift(ssize)) | flags |
- ((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT);
- esid_data = mk_esid_data(ea, ssize, index);
-
- /*
- * No need for an isync before or after this slbmte. The exception
- * we enter with and the rfid we exit with are context synchronizing.
- * Also we only handle user segments here.
- */
- asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data)
- : "memory");
-
/*
* Now update slb cache entries
*/
@@ -445,58 +373,161 @@ static void insert_slb_entry(unsigned long vsid, unsigned long ea,
}
}
-static void handle_multi_context_slb_miss(int context_id, unsigned long ea)
+static enum slb_index alloc_slb_index(void)
+{
+ enum slb_index index;
+
+ /* round-robin replacement of slb starting at SLB_NUM_BOLTED. */
+ index = get_paca()->stab_rr;
+ if (index < (mmu_slb_size - 1))
+ index++;
+ else
+ index = SLB_NUM_BOLTED;
+ get_paca()->stab_rr = index;
+
+ return index;
+}
+
+static long slb_insert_entry(unsigned long ea, unsigned long context,
+ unsigned long flags, int ssize, bool kernel)
{
- struct mm_struct *mm = current->mm;
unsigned long vsid;
- int bpsize;
+ unsigned long vsid_data, esid_data;
+ enum slb_index index;
+
+ vsid = get_vsid(context, ea, ssize);
+ if (!vsid)
+ return -EFAULT;
+
+ index = alloc_slb_index();
+
+ vsid_data = __mk_vsid_data(vsid, ssize, flags);
+ esid_data = mk_esid_data(ea, ssize, index);
/*
- * We are always above 1TB, hence use high user segment size.
+ * No need for an isync before or after this slbmte. The exception
+ * we enter with and the rfid we exit with are context synchronizing.
+ * Also we only handle user segments here.
*/
- vsid = get_vsid(context_id, ea, mmu_highuser_ssize);
- bpsize = get_slice_psize(mm, ea);
- insert_slb_entry(vsid, ea, bpsize, mmu_highuser_ssize);
+ asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data));
+
+ if (!kernel)
+ slb_cache_update(esid_data);
+
+ return 0;
}
-void slb_miss_large_addr(struct pt_regs *regs)
+static long slb_allocate_kernel(unsigned long ea, unsigned long id)
{
- enum ctx_state prev_state = exception_enter();
- unsigned long ea = regs->dar;
- int context;
+ unsigned long context;
+ unsigned long flags;
+ int ssize;
- if (REGION_ID(ea) != USER_REGION_ID)
- goto slb_bad_addr;
+ if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
+ return -EFAULT;
- /*
- * Are we beyound what the page table layout supports ?
- */
- if ((ea & ~REGION_MASK) >= H_PGTABLE_RANGE)
- goto slb_bad_addr;
+ if (id == KERNEL_REGION_ID) {
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp;
+#ifdef CONFIG_SPARSEMEM_VMEMMAP
+ } else if (id == VMEMMAP_REGION_ID) {
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmemmap_psize].sllp;
+#endif
+ } else if (id == VMALLOC_REGION_ID) {
+ if (ea < H_VMALLOC_END)
+ flags = get_paca()->vmalloc_sllp;
+ else
+ flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_io_psize].sllp;
+ } else {
+ return -EFAULT;
+ }
+
+ ssize = MMU_SEGSIZE_1T;
+ if (!mmu_has_feature(MMU_FTR_1T_SEGMENT))
+ ssize = MMU_SEGSIZE_256M;
+
+ context = id - KERNEL_REGION_CONTEXT_OFFSET;
- /* Lower address should have been handled by asm code */
- if (ea < (1UL << MAX_EA_BITS_PER_CONTEXT))
- goto slb_bad_addr;
+ return slb_insert_entry(ea, context, flags, ssize, true);
+}
+
+static long slb_allocate_user(struct mm_struct *mm, unsigned long ea)
+{
+ unsigned long context;
+ unsigned long flags;
+ int bpsize;
+ int ssize;
/*
* consider this as bad access if we take a SLB miss
* on an address above addr limit.
*/
- if (ea >= current->mm->context.slb_addr_limit)
- goto slb_bad_addr;
+ if (ea >= mm->context.slb_addr_limit)
+ return -EFAULT;
- context = get_ea_context(¤t->mm->context, ea);
+ context = get_ea_context(&mm->context, ea);
if (!context)
- goto slb_bad_addr;
+ return -EFAULT;
- handle_multi_context_slb_miss(context, ea);
- exception_exit(prev_state);
- return;
+ if (unlikely(ea >= H_PGTABLE_RANGE)) {
+ WARN_ON(1);
+ return -EFAULT;
+ }
-slb_bad_addr:
- if (user_mode(regs))
- _exception(SIGSEGV, regs, SEGV_BNDERR, ea);
- else
- bad_page_fault(regs, ea, SIGSEGV);
- exception_exit(prev_state);
+ ssize = user_segment_size(ea);
+
+ bpsize = get_slice_psize(mm, ea);
+ flags = SLB_VSID_USER | mmu_psize_defs[bpsize].sllp;
+
+ return slb_insert_entry(ea, context, flags, ssize, false);
+}
+
+long do_slb_fault(struct pt_regs *regs, unsigned long ea)
+{
+ unsigned long id = REGION_ID(ea);
+
+ /* IRQs are not reconciled here, so can't check irqs_disabled */
+ VM_WARN_ON(mfmsr() & MSR_EE);
+
+ if (unlikely(!(regs->msr & MSR_RI)))
+ return -EINVAL;
+
+ /*
+ * SLB kernel faults must be very careful not to touch anything
+ * that is not bolted. E.g., PACA and global variables are okay,
+ * mm->context stuff is not.
+ *
+ * SLB user faults can access all of kernel memory, but must be
+ * careful not to touch things like IRQ state because it is not
+ * "reconciled" here. The difficulty is that we must use
+ * fast_exception_return to return from kernel SLB faults without
+ * looking at possible non-bolted memory. We could test user vs
+ * kernel faults in the interrupt handler asm and do a full fault,
+ * reconcile, ret_from_except for user faults which would make them
+ * first class kernel code. But for performance it's probably nicer
+ * if they go via fast_exception_return too.
+ */
+ if (id >= KERNEL_REGION_ID) {
+ return slb_allocate_kernel(ea, id);
+ } else {
+ struct mm_struct *mm = current->mm;
+
+ if (unlikely(!mm))
+ return -EFAULT;
+
+ return slb_allocate_user(mm, ea);
+ }
+}
+
+void do_bad_slb_fault(struct pt_regs *regs, unsigned long ea, long err)
+{
+ if (err == -EFAULT) {
+ if (user_mode(regs))
+ _exception(SIGSEGV, regs, SEGV_BNDERR, ea);
+ else
+ bad_page_fault(regs, ea, SIGSEGV);
+ } else if (err == -EINVAL) {
+ unrecoverable_exception(regs);
+ } else {
+ BUG();
+ }
}
diff --git a/arch/powerpc/mm/slb_low.S b/arch/powerpc/mm/slb_low.S
deleted file mode 100644
index 4ac5057ad439..000000000000
--- a/arch/powerpc/mm/slb_low.S
+++ /dev/null
@@ -1,335 +0,0 @@
-/*
- * Low-level SLB routines
- *
- * Copyright (C) 2004 David Gibson <dwg@au.ibm.com>, IBM
- *
- * Based on earlier C version:
- * Dave Engebretsen and Mike Corrigan {engebret|mikejc}@us.ibm.com
- * Copyright (c) 2001 Dave Engebretsen
- * Copyright (C) 2002 Anton Blanchard <anton@au.ibm.com>, IBM
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; either version
- * 2 of the License, or (at your option) any later version.
- */
-
-#include <asm/processor.h>
-#include <asm/ppc_asm.h>
-#include <asm/asm-offsets.h>
-#include <asm/cputable.h>
-#include <asm/page.h>
-#include <asm/mmu.h>
-#include <asm/pgtable.h>
-#include <asm/firmware.h>
-#include <asm/feature-fixups.h>
-
-/*
- * This macro generates asm code to compute the VSID scramble
- * function. Used in slb_allocate() and do_stab_bolted. The function
- * computed is: (protovsid*VSID_MULTIPLIER) % VSID_MODULUS
- *
- * rt = register containing the proto-VSID and into which the
- * VSID will be stored
- * rx = scratch register (clobbered)
- * rf = flags
- *
- * - rt and rx must be different registers
- * - The answer will end up in the low VSID_BITS bits of rt. The higher
- * bits may contain other garbage, so you may need to mask the
- * result.
- */
-#define ASM_VSID_SCRAMBLE(rt, rx, rf, size) \
- lis rx,VSID_MULTIPLIER_##size@h; \
- ori rx,rx,VSID_MULTIPLIER_##size@l; \
- mulld rt,rt,rx; /* rt = rt * MULTIPLIER */ \
-/* \
- * powermac get slb fault before feature fixup, so make 65 bit part \
- * the default part of feature fixup \
- */ \
-BEGIN_MMU_FTR_SECTION \
- srdi rx,rt,VSID_BITS_65_##size; \
- clrldi rt,rt,(64-VSID_BITS_65_##size); \
- add rt,rt,rx; \
- addi rx,rt,1; \
- srdi rx,rx,VSID_BITS_65_##size; \
- add rt,rt,rx; \
- rldimi rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_65_##size)); \
-MMU_FTR_SECTION_ELSE \
- srdi rx,rt,VSID_BITS_##size; \
- clrldi rt,rt,(64-VSID_BITS_##size); \
- add rt,rt,rx; /* add high and low bits */ \
- addi rx,rt,1; \
- srdi rx,rx,VSID_BITS_##size; /* extract 2^VSID_BITS bit */ \
- add rt,rt,rx; \
- rldimi rf,rt,SLB_VSID_SHIFT_##size,(64 - (SLB_VSID_SHIFT_##size + VSID_BITS_##size)); \
-ALT_MMU_FTR_SECTION_END_IFCLR(MMU_FTR_68_BIT_VA)
-
-
-/* void slb_allocate(unsigned long ea);
- *
- * Create an SLB entry for the given EA (user or kernel).
- * r3 = faulting address, r13 = PACA
- * r9, r10, r11 are clobbered by this function
- * r3 is preserved.
- * No other registers are examined or changed.
- */
-_GLOBAL(slb_allocate)
- /*
- * Check if the address falls within the range of the first context, or
- * if we may need to handle multi context. For the first context we
- * allocate the slb entry via the fast path below. For large address we
- * branch out to C-code and see if additional contexts have been
- * allocated.
- * The test here is:
- * (ea & ~REGION_MASK) >= (1ull << MAX_EA_BITS_PER_CONTEXT)
- */
- rldicr. r9,r3,4,(63 - MAX_EA_BITS_PER_CONTEXT - 4)
- bne- 8f
-
- srdi r9,r3,60 /* get region */
- srdi r10,r3,SID_SHIFT /* get esid */
- cmpldi cr7,r9,0xc /* cmp PAGE_OFFSET for later use */
-
- /* r3 = address, r10 = esid, cr7 = <> PAGE_OFFSET */
- blt cr7,0f /* user or kernel? */
-
- /* Check if hitting the linear mapping or some other kernel space
- */
- bne cr7,1f
-
- /* Linear mapping encoding bits, the "li" instruction below will
- * be patched by the kernel at boot
- */
-.globl slb_miss_kernel_load_linear
-slb_miss_kernel_load_linear:
- li r11,0
- /*
- * context = (ea >> 60) - (0xc - 1)
- * r9 = region id.
- */
- subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET
-
-BEGIN_FTR_SECTION
- b .Lslb_finish_load
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
- b .Lslb_finish_load_1T
-
-1:
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
- cmpldi cr0,r9,0xf
- bne 1f
-/* Check virtual memmap region. To be patched at kernel boot */
-.globl slb_miss_kernel_load_vmemmap
-slb_miss_kernel_load_vmemmap:
- li r11,0
- b 6f
-1:
-#endif /* CONFIG_SPARSEMEM_VMEMMAP */
-
- /*
- * r10 contains the ESID, which is the original faulting EA shifted
- * right by 28 bits. We need to compare that with (H_VMALLOC_END >> 28)
- * which is 0xd00038000. That can't be used as an immediate, even if we
- * ignored the 0xd, so we have to load it into a register, and we only
- * have one register free. So we must load all of (H_VMALLOC_END >> 28)
- * into a register and compare ESID against that.
- */
- lis r11,(H_VMALLOC_END >> 32)@h // r11 = 0xffffffffd0000000
- ori r11,r11,(H_VMALLOC_END >> 32)@l // r11 = 0xffffffffd0003800
- // Rotate left 4, then mask with 0xffffffff0
- rldic r11,r11,4,28 // r11 = 0xd00038000
- cmpld r10,r11 // if r10 >= r11
- bge 5f // goto io_mapping
-
- /*
- * vmalloc mapping gets the encoding from the PACA as the mapping
- * can be demoted from 64K -> 4K dynamically on some machines.
- */
- lhz r11,PACAVMALLOCSLLP(r13)
- b 6f
-5:
- /* IO mapping */
-.globl slb_miss_kernel_load_io
-slb_miss_kernel_load_io:
- li r11,0
-6:
- /*
- * context = (ea >> 60) - (0xc - 1)
- * r9 = region id.
- */
- subi r9,r9,KERNEL_REGION_CONTEXT_OFFSET
-
-BEGIN_FTR_SECTION
- b .Lslb_finish_load
-END_MMU_FTR_SECTION_IFCLR(MMU_FTR_1T_SEGMENT)
- b .Lslb_finish_load_1T
-
-0: /*
- * For userspace addresses, make sure this is region 0.
- */
- cmpdi r9, 0
- bne- 8f
- /*
- * user space make sure we are within the allowed limit
- */
- ld r11,PACA_SLB_ADDR_LIMIT(r13)
- cmpld r3,r11
- bge- 8f
-
- /* when using slices, we extract the psize off the slice bitmaps
- * and then we need to get the sllp encoding off the mmu_psize_defs
- * array.
- *
- * XXX This is a bit inefficient especially for the normal case,
- * so we should try to implement a fast path for the standard page
- * size using the old sllp value so we avoid the array. We cannot
- * really do dynamic patching unfortunately as processes might flip
- * between 4k and 64k standard page size
- */
-#ifdef CONFIG_PPC_MM_SLICES
- /* r10 have esid */
- cmpldi r10,16
- /* below SLICE_LOW_TOP */
- blt 5f
- /*
- * Handle hpsizes,
- * r9 is get_paca()->context.high_slices_psize[index], r11 is mask_index
- */
- srdi r11,r10,(SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT + 1) /* index */
- addi r9,r11,PACAHIGHSLICEPSIZE
- lbzx r9,r13,r9 /* r9 is hpsizes[r11] */
- /* r11 = (r10 >> (SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT)) & 0x1 */
- rldicl r11,r10,(64 - (SLICE_HIGH_SHIFT - SLICE_LOW_SHIFT)),63
- b 6f
-
-5:
- /*
- * Handle lpsizes
- * r9 is get_paca()->context.low_slices_psize[index], r11 is mask_index
- */
- srdi r11,r10,1 /* index */
- addi r9,r11,PACALOWSLICESPSIZE
- lbzx r9,r13,r9 /* r9 is lpsizes[r11] */
- rldicl r11,r10,0,63 /* r11 = r10 & 0x1 */
-6:
- sldi r11,r11,2 /* index * 4 */
- /* Extract the psize and multiply to get an array offset */
- srd r9,r9,r11
- andi. r9,r9,0xf
- mulli r9,r9,MMUPSIZEDEFSIZE
-
- /* Now get to the array and obtain the sllp
- */
- ld r11,PACATOC(r13)
- ld r11,mmu_psize_defs@got(r11)
- add r11,r11,r9
- ld r11,MMUPSIZESLLP(r11)
- ori r11,r11,SLB_VSID_USER
-#else
- /* paca context sllp already contains the SLB_VSID_USER bits */
- lhz r11,PACACONTEXTSLLP(r13)
-#endif /* CONFIG_PPC_MM_SLICES */
-
- ld r9,PACACONTEXTID(r13)
-BEGIN_FTR_SECTION
- cmpldi r10,0x1000
- bge .Lslb_finish_load_1T
-END_MMU_FTR_SECTION_IFSET(MMU_FTR_1T_SEGMENT)
- b .Lslb_finish_load
-
-8: /* invalid EA - return an error indication */
- crset 4*cr0+eq /* indicate failure */
- blr
-
-/*
- * Finish loading of an SLB entry and return
- *
- * r3 = EA, r9 = context, r10 = ESID, r11 = flags, clobbers r9, cr7 = <> PAGE_OFFSET
- */
-.Lslb_finish_load:
- rldimi r10,r9,ESID_BITS,0
- ASM_VSID_SCRAMBLE(r10,r9,r11,256M)
- /* r3 = EA, r11 = VSID data */
- /*
- * Find a slot, round robin. Previously we tried to find a
- * free slot first but that took too long. Unfortunately we
- * dont have any LRU information to help us choose a slot.
- */
-
- mr r9,r3
-
- /* slb_finish_load_1T continues here. r9=EA with non-ESID bits clear */
-7: ld r10,PACASTABRR(r13)
- addi r10,r10,1
- /* This gets soft patched on boot. */
-.globl slb_compare_rr_to_size
-slb_compare_rr_to_size:
- cmpldi r10,0
-
- blt+ 4f
- li r10,SLB_NUM_BOLTED
-
-4:
- std r10,PACASTABRR(r13)
-
-3:
- rldimi r9,r10,0,36 /* r9 = EA[0:35] | entry */
- oris r10,r9,SLB_ESID_V@h /* r10 = r9 | SLB_ESID_V */
-
- /* r9 = ESID data, r11 = VSID data */
-
- /*
- * No need for an isync before or after this slbmte. The exception
- * we enter with and the rfid we exit with are context synchronizing.
- */
- slbmte r11,r10
-
- /* we're done for kernel addresses */
- crclr 4*cr0+eq /* set result to "success" */
- bgelr cr7
-
- /* Update the slb cache */
- lhz r9,PACASLBCACHEPTR(r13) /* offset = paca->slb_cache_ptr */
- cmpldi r9,SLB_CACHE_ENTRIES
- bge 1f
-
- /* still room in the slb cache */
- sldi r11,r9,2 /* r11 = offset * sizeof(u32) */
- srdi r10,r10,28 /* get the 36 bits of the ESID */
- add r11,r11,r13 /* r11 = (u32 *)paca + offset */
- stw r10,PACASLBCACHE(r11) /* paca->slb_cache[offset] = esid */
- addi r9,r9,1 /* offset++ */
- b 2f
-1: /* offset >= SLB_CACHE_ENTRIES */
- li r9,SLB_CACHE_ENTRIES+1
-2:
- sth r9,PACASLBCACHEPTR(r13) /* paca->slb_cache_ptr = offset */
- crclr 4*cr0+eq /* set result to "success" */
- blr
-
-/*
- * Finish loading of a 1T SLB entry (for the kernel linear mapping) and return.
- *
- * r3 = EA, r9 = context, r10 = ESID(256MB), r11 = flags, clobbers r9
- */
-.Lslb_finish_load_1T:
- srdi r10,r10,(SID_SHIFT_1T - SID_SHIFT) /* get 1T ESID */
- rldimi r10,r9,ESID_BITS_1T,0
- ASM_VSID_SCRAMBLE(r10,r9,r11,1T)
-
- li r10,MMU_SEGSIZE_1T
- rldimi r11,r10,SLB_VSID_SSIZE_SHIFT,0 /* insert segment size */
-
- /* r3 = EA, r11 = VSID data */
- clrrdi r9,r3,SID_SHIFT_1T /* clear out non-ESID bits */
- b 7b
-
-
-_ASM_NOKPROBE_SYMBOL(slb_allocate)
-_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_linear)
-_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_io)
-_ASM_NOKPROBE_SYMBOL(slb_compare_rr_to_size)
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-_ASM_NOKPROBE_SYMBOL(slb_miss_kernel_load_vmemmap)
-#endif
--
2.17.0
^ permalink raw reply related
* Re: [RFC 00/15] PCI: turn some __weak functions into callbacks
From: David Woodhouse @ 2018-08-21 11:30 UTC (permalink / raw)
To: Christoph Hellwig, Arnd Bergmann
Cc: linux-pci, Bjorn Helgaas, linux-kernel, Lorenzo Pieralisi,
Benjamin Herrenschmidt, linuxppc-dev, linux-acpi
In-Reply-To: <20180821061451.GB481@infradead.org>
[-- Attachment #1: Type: text/plain, Size: 490 bytes --]
On Mon, 2018-08-20 at 23:14 -0700, Christoph Hellwig wrote:
> On Fri, Aug 17, 2018 at 12:26:30PM +0200, Arnd Bergmann wrote:
> > Hi Bjorn and others,
> >
> > Triggered by Christoph's patches, I had another go at converting
> > all of the remaining pci host bridge implementations to be based
> > on pci_alloc_host_bridge and a separate registration function.
>
> I really like the idea behind this series.
Hm... are you turning direct calls into retpolined indirect calls?
[-- Attachment #2: smime.p7s --]
[-- Type: application/x-pkcs7-signature, Size: 5213 bytes --]
^ permalink raw reply
* [PATCH] powerpc/nohash: fix pte_access_permitted()
From: Christophe Leroy @ 2018-08-21 13:03 UTC (permalink / raw)
To: Benjamin Herrenschmidt, Paul Mackerras, Michael Ellerman,
aneesh.kumar
Cc: linux-kernel, linuxppc-dev, stable
Commit 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper
for other platforms") replaced generic pte_access_permitted() by an
arch specific one.
The generic one is defined as
(pte_present(pte) && (!(write) || pte_write(pte)))
The arch specific one is open coded checking that _PAGE_USER and
_PAGE_WRITE (_PAGE_RW) flags are set, but lacking to check that
_PAGE_RO and _PAGE_PRIVILEGED are unset, leading to a useless test
on targets like the 8xx which defines _PAGE_RW and _PAGE_USER as 0.
Commit 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted
for hugetlb access check") replaced some tests performed with
pte helpers by a call to pte_access_permitted(), leading to the same
issue.
This patch rewrites powerpc/nohash pte_access_permitted()
using pte helpers.
Fixes: 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper for other platforms")
Fixes: 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check")
Cc: stable@vger.kernel.org # v4.15+
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------
1 file changed, 3 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
index 2160be2e4339..b321c82b3624 100644
--- a/arch/powerpc/include/asm/nohash/pgtable.h
+++ b/arch/powerpc/include/asm/nohash/pgtable.h
@@ -51,17 +51,14 @@ static inline int pte_present(pte_t pte)
#define pte_access_permitted pte_access_permitted
static inline bool pte_access_permitted(pte_t pte, bool write)
{
- unsigned long pteval = pte_val(pte);
/*
* A read-only access is controlled by _PAGE_USER bit.
* We have _PAGE_READ set for WRITE and EXECUTE
*/
- unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_USER;
-
- if (write)
- need_pte_bits |= _PAGE_WRITE;
+ if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
+ return false;
- if ((pteval & need_pte_bits) != need_pte_bits)
+ if (write && !pte_write(pte))
return false;
return true;
--
2.13.3
^ permalink raw reply related
* Re: [RFC 00/15] PCI: turn some __weak functions into callbacks
From: Christoph Hellwig @ 2018-08-21 13:14 UTC (permalink / raw)
To: David Woodhouse
Cc: Christoph Hellwig, Arnd Bergmann, linux-pci, Bjorn Helgaas,
linux-kernel, Lorenzo Pieralisi, Benjamin Herrenschmidt,
linuxppc-dev, linux-acpi
In-Reply-To: <1534851050.14722.3.camel@infradead.org>
On Tue, Aug 21, 2018 at 12:30:50PM +0100, David Woodhouse wrote:
> On Mon, 2018-08-20 at 23:14 -0700, Christoph Hellwig wrote:
> > On Fri, Aug 17, 2018 at 12:26:30PM +0200, Arnd Bergmann wrote:
> > > Hi Bjorn and others,
> > >
> > > Triggered by Christoph's patches, I had another go at converting
> > > all of the remaining pci host bridge implementations to be based
> > > on pci_alloc_host_bridge and a separate registration function.
> >
> > I really like the idea behind this series.
>
> Hm... are you turning direct calls into retpolined indirect calls?
He does. But not anywhere near the fast path.
^ permalink raw reply
* [RFC PATCH 1/2] powerpc/mm/hash: Rename get_ea_context to get_user_context
From: Aneesh Kumar K.V @ 2018-08-21 13:32 UTC (permalink / raw)
To: npiggin, benh, paulus, mpe; +Cc: linuxppc-dev, Aneesh Kumar K.V
We will be adding get_kernel_context later. Update function name to indicate
this handle context allocation user space address.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
arch/powerpc/include/asm/book3s/64/mmu.h | 4 ++--
arch/powerpc/include/asm/mmu_context.h | 2 +-
arch/powerpc/mm/slb.c | 2 +-
3 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h
index 9c8c669a6b6a..6328857f259f 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu.h
@@ -208,7 +208,7 @@ extern void radix_init_pseries(void);
static inline void radix_init_pseries(void) { };
#endif
-static inline int get_ea_context(mm_context_t *ctx, unsigned long ea)
+static inline int get_user_context(mm_context_t *ctx, unsigned long ea)
{
int index = ea >> MAX_EA_BITS_PER_CONTEXT;
@@ -223,7 +223,7 @@ static inline int get_ea_context(mm_context_t *ctx, unsigned long ea)
static inline unsigned long get_user_vsid(mm_context_t *ctx,
unsigned long ea, int ssize)
{
- unsigned long context = get_ea_context(ctx, ea);
+ unsigned long context = get_user_context(ctx, ea);
return get_vsid(context, ea, ssize);
}
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index b2f89b621b15..dbbab7ba449b 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h
@@ -81,7 +81,7 @@ static inline bool need_extra_context(struct mm_struct *mm, unsigned long ea)
{
int context_id;
- context_id = get_ea_context(&mm->context, ea);
+ context_id = get_user_context(&mm->context, ea);
if (!context_id)
return true;
return false;
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index b0f4c038d658..f63a608922ca 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -464,7 +464,7 @@ static long slb_allocate_user(struct mm_struct *mm, unsigned long ea)
if (ea >= mm->context.slb_addr_limit)
return -EFAULT;
- context = get_ea_context(&mm->context, ea);
+ context = get_user_context(&mm->context, ea);
if (!context)
return -EFAULT;
--
2.17.1
^ permalink raw reply related
* [RFC PATCH 2/2] powerpc/mm: Increase the max addressable memory to 2PB
From: Aneesh Kumar K.V @ 2018-08-21 13:32 UTC (permalink / raw)
To: npiggin, benh, paulus, mpe; +Cc: linuxppc-dev, Aneesh Kumar K.V
In-Reply-To: <20180821133226.15908-1-aneesh.kumar@linux.ibm.com>
Currently we limit the max addressable memory to 128TB. This patch increase the
limit to 2PB. We can have devices like nvdimm which adds memory above 512TB
limit.
We still don't support regular system ram above 512TB. One of the challenge with
that is the percpu allocator, that allocates per node memory and use the max
distance between them as the percpu offsets. This means with large gap in
address space ( system ram above 1PB) we will run out of vmalloc space to map
the percpu allocation.
In order to support addressable memory above 512TB, kernel should be able to
linear map this range. To do that with hash translation we now add 4 context
to kernel linear map region. Our per context addressable range is 512TB. We
still keep VMALLOC and VMEMMAP region to old size. SLB miss handlers is updated
to validate these limit.
We also limit this update to SPARSEMEM_VMEMMAP and SPARSEMEM_EXTREME
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
Changes dependent on http://patchwork.ozlabs.org/patch/960211/
"powerpc/64s/hash: convert SLB miss handlers to C"
arch/powerpc/include/asm/book3s/64/mmu-hash.h | 49 ++++++++++++++++---
arch/powerpc/include/asm/mmu.h | 15 ++++++
arch/powerpc/include/asm/sparsemem.h | 11 -----
arch/powerpc/mm/slb.c | 20 ++++++--
4 files changed, 73 insertions(+), 22 deletions(-)
diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
index b3520b549cba..a184b71cead8 100644
--- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h
@@ -558,6 +558,26 @@ extern void slb_set_size(u16 size);
#define ESID_BITS_MASK ((1 << ESID_BITS) - 1)
#define ESID_BITS_1T_MASK ((1 << ESID_BITS_1T) - 1)
+/*
+ * Now certain config support MAX_PHYSMEM more than 512TB. Hence we will need
+ * to use more than one context for linear mapping the kernel.
+ * For vmalloc and memmap, we use just one context with 512TB. With 64 byte
+ * struct page size, we need ony 32 TB in memmap for 2PB (51 bits (MAX_PHYSMEM_BITS)).
+ */
+#if (MAX_PHYSMEM_BITS > MAX_EA_BITS_PER_CONTEXT)
+#define MAX_KERNEL_CTX_CNT (1UL << (MAX_PHYSMEM_BITS - MAX_EA_BITS_PER_CONTEXT))
+#else
+#define MAX_KERNEL_CTX_CNT 1
+#endif
+
+#define MAX_VMALLOC_CTX_CNT 1
+#define MAX_MEMMAP_CTX_CNT 1
+
+/*
+ * Would be nice to use KERNEL_REGION_ID here
+ */
+#define KERNEL_REGION_CONTEXT_OFFSET (0xc - 1)
+
/*
* 256MB segment
* The proto-VSID space has 2^(CONTEX_BITS + ESID_BITS) - 1 segments
@@ -568,12 +588,13 @@ extern void slb_set_size(u16 size);
* We also need to avoid the last segment of the last context, because that
* would give a protovsid of 0x1fffffffff. That will result in a VSID 0
* because of the modulo operation in vsid scramble.
+ *
+ * We add one extra context to MIN_USER_CONTEXT so that we can map kernel
+ * context easily. The +1 is to map the unused 0xe region mapping.
*/
#define MAX_USER_CONTEXT ((ASM_CONST(1) << CONTEXT_BITS) - 2)
-#define MIN_USER_CONTEXT (5)
-
-/* Would be nice to use KERNEL_REGION_ID here */
-#define KERNEL_REGION_CONTEXT_OFFSET (0xc - 1)
+#define MIN_USER_CONTEXT (MAX_KERNEL_CTX_CNT + MAX_VMALLOC_CTX_CNT + \
+ MAX_MEMMAP_CTX_CNT + 2)
/*
* For platforms that support on 65bit VA we limit the context bits
@@ -733,6 +754,23 @@ static inline unsigned long get_vsid(unsigned long context, unsigned long ea,
return vsid_scramble(protovsid, VSID_MULTIPLIER_1T, vsid_bits);
}
+static inline unsigned long get_kernel_context(unsigned long ea)
+{
+ unsigned long region_id = REGION_ID(ea);
+ unsigned long ctx = region_id - KERNEL_REGION_CONTEXT_OFFSET;
+ /*
+ * For linear mapping we do support multiple context
+ */
+ if (region_id == KERNEL_REGION_ID) {
+ /*
+ * We already verified ea to be not beyond the addr limit.
+ */
+ ctx += ((ea & ~REGION_MASK) >> MAX_EA_BITS_PER_CONTEXT);
+ }
+
+ return ctx;
+}
+
/*
* This is only valid for addresses >= PAGE_OFFSET
*/
@@ -755,8 +793,7 @@ static inline unsigned long get_kernel_vsid(unsigned long ea, int ssize)
* So we can compute the context from the region (top nibble) by
* subtracting 11, or 0xc - 1.
*/
- context = (ea >> 60) - KERNEL_REGION_CONTEXT_OFFSET;
-
+ context = get_kernel_context(ea);
return get_vsid(context, ea, ssize);
}
diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h
index 13ea441ac531..eb20eb3b8fb0 100644
--- a/arch/powerpc/include/asm/mmu.h
+++ b/arch/powerpc/include/asm/mmu.h
@@ -309,6 +309,21 @@ static inline u16 get_mm_addr_key(struct mm_struct *mm, unsigned long address)
*/
#define MMU_PAGE_COUNT 16
+/*
+ * If we store section details in page->flags we can't increase the MAX_PHYSMEM_BITS
+ * if we increase SECTIONS_WIDTH we will not store node details in page->flags and
+ * page_to_nid does a page->section->node lookup
+ * Hence only increase for VMEMMAP. Further depending on SPARSEMEM_EXTREME reduce
+ * memory requirements with large number of sections.
+ * 51 bits is the max physical real address on POWER9
+ */
+#if defined(CONFIG_SPARSEMEM_VMEMMAP) && defined(CONFIG_SPARSEMEM_EXTREME) && \
+ defined (CONFIG_PPC_64K_PAGES)
+#define MAX_PHYSMEM_BITS 51
+#else
+#define MAX_PHYSMEM_BITS 46
+#endif
+
#ifdef CONFIG_PPC_BOOK3S_64
#include <asm/book3s/64/mmu.h>
#else /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h
index 28f5dae25db6..68da49320592 100644
--- a/arch/powerpc/include/asm/sparsemem.h
+++ b/arch/powerpc/include/asm/sparsemem.h
@@ -9,17 +9,6 @@
* MAX_PHYSMEM_BITS 2^N: how much memory we can have in that space
*/
#define SECTION_SIZE_BITS 24
-/*
- * If we store section details in page->flags we can't increase the MAX_PHYSMEM_BITS
- * if we increase SECTIONS_WIDTH we will not store node details in page->flags and
- * page_to_nid does a page->section->node lookup
- * Hence only increase for VMEMMAP.
- */
-#ifdef CONFIG_SPARSEMEM_VMEMMAP
-#define MAX_PHYSMEM_BITS 47
-#else
-#define MAX_PHYSMEM_BITS 46
-#endif
#endif /* CONFIG_SPARSEMEM */
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c
index f63a608922ca..afad18763be3 100644
--- a/arch/powerpc/mm/slb.c
+++ b/arch/powerpc/mm/slb.c
@@ -423,16 +423,27 @@ static long slb_allocate_kernel(unsigned long ea, unsigned long id)
unsigned long flags;
int ssize;
- if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
- return -EFAULT;
-
if (id == KERNEL_REGION_ID) {
+
+ /* We only support upto MAX_PHYSMEM_BITS */
+ if ((ea & ~REGION_MASK) > (1UL << MAX_PHYSMEM_BITS))
+ return -EFAULT;
+
flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_linear_psize].sllp;
+
#ifdef CONFIG_SPARSEMEM_VMEMMAP
} else if (id == VMEMMAP_REGION_ID) {
+
+ if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
+ return -EFAULT;
+
flags = SLB_VSID_KERNEL | mmu_psize_defs[mmu_vmemmap_psize].sllp;
#endif
} else if (id == VMALLOC_REGION_ID) {
+
+ if ((ea & ~REGION_MASK) >= (1ULL << MAX_EA_BITS_PER_CONTEXT))
+ return -EFAULT;
+
if (ea < H_VMALLOC_END)
flags = get_paca()->vmalloc_sllp;
else
@@ -445,8 +456,7 @@ static long slb_allocate_kernel(unsigned long ea, unsigned long id)
if (!mmu_has_feature(MMU_FTR_1T_SEGMENT))
ssize = MMU_SEGSIZE_256M;
- context = id - KERNEL_REGION_CONTEXT_OFFSET;
-
+ context = get_kernel_context(ea);
return slb_insert_entry(ea, context, flags, ssize, true);
}
--
2.17.1
^ permalink raw reply related
* Re: [PATCH 1/2] sched/topology: Set correct numa topology type
From: Peter Zijlstra @ 2018-08-21 13:59 UTC (permalink / raw)
To: Srikar Dronamraju
Cc: Ingo Molnar, LKML, Mel Gorman, Rik van Riel, Thomas Gleixner,
Michael Ellerman, Heiko Carstens, Suravee Suthikulpanit,
Andre Wild, linuxppc-dev
In-Reply-To: <20180821110258.GA2080@linux.vnet.ibm.com>
On Tue, Aug 21, 2018 at 04:02:58AM -0700, Srikar Dronamraju wrote:
> * Srikar Dronamraju <srikar@linux.vnet.ibm.com> [2018-08-10 22:30:18]:
>
> > With commit 051f3ca02e46 ("sched/topology: Introduce NUMA identity node
> > sched domain") scheduler introduces an new numa level. However this
> > leads to numa topology on 2 node systems no more marked as NUMA_DIRECT.
> > After this commit, it gets reported as NUMA_BACKPLANE. This is because
> > sched_domains_numa_level is now 2 on 2 node systems.
> >
> > Fix this by allowing setting systems that have upto 2 numa levels as
> > NUMA_DIRECT.
> >
> > While here remove a code that assumes level can be 0.
> >
> > Fixes: 051f3ca02e46 "Introduce NUMA identity node sched domain"
> > Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
> > ---
>
> Hey Peter,
>
> Did you look at these two patches?
Nope, been on holidays and the inbox is an even bigger mess than normal.
I'll get to it, eventually :/
^ permalink raw reply
* Re: [PATCH] powerpc/nohash: fix pte_access_permitted()
From: Aneesh Kumar K.V @ 2018-08-21 14:25 UTC (permalink / raw)
To: Christophe Leroy, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, aneesh.kumar
Cc: linuxppc-dev, linux-kernel, stable
In-Reply-To: <8097a1d32403ea47d076803e9070869badfe24bc.1534856426.git.christophe.leroy@c-s.fr>
Christophe Leroy <christophe.leroy@c-s.fr> writes:
> Commit 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper
> for other platforms") replaced generic pte_access_permitted() by an
> arch specific one.
>
> The generic one is defined as
> (pte_present(pte) && (!(write) || pte_write(pte)))
>
> The arch specific one is open coded checking that _PAGE_USER and
> _PAGE_WRITE (_PAGE_RW) flags are set, but lacking to check that
> _PAGE_RO and _PAGE_PRIVILEGED are unset, leading to a useless test
> on targets like the 8xx which defines _PAGE_RW and _PAGE_USER as 0.
>
> Commit 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted
> for hugetlb access check") replaced some tests performed with
> pte helpers by a call to pte_access_permitted(), leading to the same
> issue.
>
> This patch rewrites powerpc/nohash pte_access_permitted()
> using pte helpers.
>
Thanks for fixing this. I should have used the helper instead of
opencoding it on nohash platforms. This is another reason why I was also
suggesting we should avoid consolidating pte accessors across platforms
and user accessors instead of opencoding.
https://lore.kernel.org/lkml/87lgcusc6z.fsf@linux.vnet.ibm.com/T/#u
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> Fixes: 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper for other platforms")
> Fixes: 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check")
> Cc: stable@vger.kernel.org # v4.15+
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
> index 2160be2e4339..b321c82b3624 100644
> --- a/arch/powerpc/include/asm/nohash/pgtable.h
> +++ b/arch/powerpc/include/asm/nohash/pgtable.h
> @@ -51,17 +51,14 @@ static inline int pte_present(pte_t pte)
> #define pte_access_permitted pte_access_permitted
> static inline bool pte_access_permitted(pte_t pte, bool write)
> {
> - unsigned long pteval = pte_val(pte);
> /*
> * A read-only access is controlled by _PAGE_USER bit.
> * We have _PAGE_READ set for WRITE and EXECUTE
> */
> - unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_USER;
> -
> - if (write)
> - need_pte_bits |= _PAGE_WRITE;
> + if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
> + return false;
>
> - if ((pteval & need_pte_bits) != need_pte_bits)
> + if (write && !pte_write(pte))
> return false;
>
> return true;
> --
> 2.13.3
^ permalink raw reply
* Re: [PATCH] powerpc/nohash: fix pte_access_permitted()
From: Christophe LEROY @ 2018-08-21 14:47 UTC (permalink / raw)
To: Aneesh Kumar K.V, Benjamin Herrenschmidt, Paul Mackerras,
Michael Ellerman, aneesh.kumar
Cc: linuxppc-dev, linux-kernel, stable
In-Reply-To: <87eferg5ki.fsf@linux.ibm.com>
Le 21/08/2018 à 16:25, Aneesh Kumar K.V a écrit :
> Christophe Leroy <christophe.leroy@c-s.fr> writes:
>
>> Commit 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper
>> for other platforms") replaced generic pte_access_permitted() by an
>> arch specific one.
>>
>> The generic one is defined as
>> (pte_present(pte) && (!(write) || pte_write(pte)))
>>
>> The arch specific one is open coded checking that _PAGE_USER and
>> _PAGE_WRITE (_PAGE_RW) flags are set, but lacking to check that
>> _PAGE_RO and _PAGE_PRIVILEGED are unset, leading to a useless test
>> on targets like the 8xx which defines _PAGE_RW and _PAGE_USER as 0.
>>
>> Commit 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted
>> for hugetlb access check") replaced some tests performed with
>> pte helpers by a call to pte_access_permitted(), leading to the same
>> issue.
>>
>> This patch rewrites powerpc/nohash pte_access_permitted()
>> using pte helpers.
>>
>
> Thanks for fixing this. I should have used the helper instead of
> opencoding it on nohash platforms. This is another reason why I was also
> suggesting we should avoid consolidating pte accessors across platforms
> and user accessors instead of opencoding.
I fully agree. I have opened a topic for that at
https://github.com/linuxppc/linux/issues/177
Christophe
>
> https://lore.kernel.org/lkml/87lgcusc6z.fsf@linux.vnet.ibm.com/T/#u
>
> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>
>> Fixes: 5769beaf180a8 ("powerpc/mm: Add proper pte access check helper for other platforms")
>> Fixes: 5fa5b16be5b31 ("powerpc/mm/hugetlb: Use pte_access_permitted for hugetlb access check")
>> Cc: stable@vger.kernel.org # v4.15+
>> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
>> ---
>> arch/powerpc/include/asm/nohash/pgtable.h | 9 +++------
>> 1 file changed, 3 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/nohash/pgtable.h b/arch/powerpc/include/asm/nohash/pgtable.h
>> index 2160be2e4339..b321c82b3624 100644
>> --- a/arch/powerpc/include/asm/nohash/pgtable.h
>> +++ b/arch/powerpc/include/asm/nohash/pgtable.h
>> @@ -51,17 +51,14 @@ static inline int pte_present(pte_t pte)
>> #define pte_access_permitted pte_access_permitted
>> static inline bool pte_access_permitted(pte_t pte, bool write)
>> {
>> - unsigned long pteval = pte_val(pte);
>> /*
>> * A read-only access is controlled by _PAGE_USER bit.
>> * We have _PAGE_READ set for WRITE and EXECUTE
>> */
>> - unsigned long need_pte_bits = _PAGE_PRESENT | _PAGE_USER;
>> -
>> - if (write)
>> - need_pte_bits |= _PAGE_WRITE;
>> + if (!pte_present(pte) || !pte_user(pte) || !pte_read(pte))
>> + return false;
>>
>> - if ((pteval & need_pte_bits) != need_pte_bits)
>> + if (write && !pte_write(pte))
>> return false;
>>
>> return true;
>> --
>> 2.13.3
^ permalink raw reply
* [PATCH 1/2] macintosh: therm_windtunnel: drop using attach_adapter
From: Wolfram Sang @ 2018-08-21 15:02 UTC (permalink / raw)
To: linux-i2c
Cc: linuxppc-dev, Benjamin Herrenschmidt, Michael Ellerman,
linux-kernel, Wolfram Sang
In-Reply-To: <20180821150240.19964-1-wsa@the-dreams.de>
As we now have deferred probing, we can use a custom mechanism and
finally get rid of the legacy interface from the i2c core.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/macintosh/therm_windtunnel.c | 25 +++++++++++++++++++++++--
1 file changed, 23 insertions(+), 2 deletions(-)
diff --git a/drivers/macintosh/therm_windtunnel.c b/drivers/macintosh/therm_windtunnel.c
index 68dcbcb4fc5b..8c744578122a 100644
--- a/drivers/macintosh/therm_windtunnel.c
+++ b/drivers/macintosh/therm_windtunnel.c
@@ -432,7 +432,6 @@ static struct i2c_driver g4fan_driver = {
.driver = {
.name = "therm_windtunnel",
},
- .attach_adapter = do_attach,
.probe = do_probe,
.remove = do_remove,
.id_table = therm_windtunnel_id,
@@ -445,7 +444,29 @@ static struct i2c_driver g4fan_driver = {
static int therm_of_probe(struct platform_device *dev)
{
- return i2c_add_driver( &g4fan_driver );
+ struct i2c_adapter *adap;
+ int ret, i = 0;
+
+ adap = i2c_get_adapter(0);
+ if (!adap)
+ return -EPROBE_DEFER;
+
+ ret = i2c_add_driver(&g4fan_driver);
+ if (ret) {
+ i2c_put_adapter(adap);
+ return ret;
+ }
+
+ /* We assume Macs have consecutive I2C bus numbers starting at 0 */
+ while (adap) {
+ do_attach(adap);
+ if (x.running)
+ return 0;
+ i2c_put_adapter(adap);
+ adap = i2c_get_adapter(++i);
+ }
+
+ return -ENODEV;
}
static int
--
2.11.0
^ permalink raw reply related
* [PATCH 2/2] i2c: remove deprecated attach_adapter callback
From: Wolfram Sang @ 2018-08-21 15:02 UTC (permalink / raw)
To: linux-i2c
Cc: linuxppc-dev, Benjamin Herrenschmidt, Michael Ellerman,
linux-kernel, Wolfram Sang
In-Reply-To: <20180821150240.19964-1-wsa@the-dreams.de>
There aren't any users left. Remove this callback from the 2.4 times.
Phew, finally, that took years to reach...
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
---
drivers/i2c/i2c-core-base.c | 11 +----------
include/linux/i2c.h | 6 ------
2 files changed, 1 insertion(+), 16 deletions(-)
diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 5a937109a289..f15737763608 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -62,7 +62,7 @@
/*
* core_lock protects i2c_adapter_idr, and guarantees that device detection,
- * deletion of detected devices, and attach_adapter calls are serialized
+ * deletion of detected devices are serialized
*/
static DEFINE_MUTEX(core_lock);
static DEFINE_IDR(i2c_adapter_idr);
@@ -1124,15 +1124,6 @@ static int i2c_do_add_adapter(struct i2c_driver *driver,
/* Detect supported devices on that bus, and instantiate them */
i2c_detect(adap, driver);
- /* Let legacy drivers scan this bus for matching devices */
- if (driver->attach_adapter) {
- dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
- driver->driver.name);
- dev_warn(&adap->dev,
- "Please use another way to instantiate your i2c_client\n");
- /* We ignore the return code; if it fails, too bad */
- driver->attach_adapter(adap);
- }
return 0;
}
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 36f357ecdf67..b79387fd57da 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -231,7 +231,6 @@ enum i2c_alert_protocol {
/**
* struct i2c_driver - represent an I2C device driver
* @class: What kind of i2c device we instantiate (for detect)
- * @attach_adapter: Callback for bus addition (deprecated)
* @probe: Callback for device binding - soon to be deprecated
* @probe_new: New callback for device binding
* @remove: Callback for device unbinding
@@ -268,11 +267,6 @@ enum i2c_alert_protocol {
struct i2c_driver {
unsigned int class;
- /* Notifies the driver that a new bus has appeared. You should avoid
- * using this, it will be removed in a near future.
- */
- int (*attach_adapter)(struct i2c_adapter *) __deprecated;
-
/* Standard driver model interfaces */
int (*probe)(struct i2c_client *, const struct i2c_device_id *);
int (*remove)(struct i2c_client *);
--
2.11.0
^ permalink raw reply related
* [PATCH 0/2] i2c: remove deprecated attach_adapter callback
From: Wolfram Sang @ 2018-08-21 15:02 UTC (permalink / raw)
To: linux-i2c
Cc: linuxppc-dev, Benjamin Herrenschmidt, Michael Ellerman,
linux-kernel, Wolfram Sang
So, I wanted to do this in the next cycle, but Linus seems to want it this
cycle already [1], so here it is:
Remove the attach_adapter callback from the 2.4 times by converting
the last user to a custom probing mechanism based on deferred probing. We used
this already in commit ac397c80de89 ("ALSA: ppc: keywest: drop using attach
adapter") successfully on HW, so we agreed to use it on the windtunnel driver
as well.
With the last user gone, we can then remove the callback \o/ I think this
allows for more cleanup in the core, but let's do this later and focus on the
removal for now.
Tested on a Renesas R-Car Salvator-XS board (M3N) by using and rebinding
various I2C busses. Build bot and checkpatch are happy, too.
I'd like to send a pull request to Linus this merge window, so looking forward
to super fast comments, acks, etc...
Thanks,
Wolfram
[1] http://patchwork.ozlabs.org/patch/959322/#1976742
Wolfram Sang (2):
macintosh: therm_windtunnel: drop using attach_adapter
i2c: remove deprecated attach_adapter callback
drivers/i2c/i2c-core-base.c | 11 +----------
drivers/macintosh/therm_windtunnel.c | 25 +++++++++++++++++++++++--
include/linux/i2c.h | 6 ------
3 files changed, 24 insertions(+), 18 deletions(-)
--
2.11.0
^ permalink raw reply
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