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Laurent Dufour 59545ebe33 powerpc/pseries: Call H_BLOCK_REMOVE when supported
Depending on the hardware and the hypervisor, the hcall H_BLOCK_REMOVE
may not be able to process all the page sizes for a segment base page
size, as reported by the TLB Invalidate Characteristics.

For each pair of base segment page size and actual page size, this
characteristic tells us the size of the block the hcall supports.

In the case, the hcall is not supporting a pair of base segment page
size, actual page size, it is returning H_PARAM which leads to a panic
like this:

  kernel BUG at /home/srikar/work/linux.git/arch/powerpc/platforms/pseries/lpar.c:466!
  Oops: Exception in kernel mode, sig: 5 [#1]
  BE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 28 PID: 583 Comm: modprobe Not tainted 5.2.0-master #5
  NIP: c0000000000be8dc LR: c0000000000be880 CTR: 0000000000000000
  REGS: c0000007e77fb130 TRAP: 0700  Not tainted (5.2.0-master)
  MSR: 8000000000029032 <SF,EE,ME,IR,DR,RI> CR: 42224824 XER: 20000000
  CFAR: c0000000000be8fc IRQMASK: 0
  GPR00: 0000000022224828 c0000007e77fb3c0 c000000001434d00 0000000000000005
  GPR04: 9000000004fa8c00 0000000000000000 0000000000000003 0000000000000001
  GPR08: c0000007e77fb450 0000000000000000 0000000000000001 ffffffffffffffff
  GPR12: c0000007e77fb450 c00000000edfcb80 0000cd7d3ea30000 c0000000016022b0
  GPR16: 00000000000000b0 0000cd7d3ea30000 0000000000000001 c080001f04f00105
  GPR20: 0000000000000003 0000000000000004 c000000fbeb05f58 c000000001602200
  GPR24: 0000000000000000 0000000000000004 8800000000000000 c000000000c5d148
  GPR28: c000000000000000 8000000000000000 a000000000000000 c0000007e77fb580
  NIP [c0000000000be8dc] .call_block_remove+0x12c/0x220
  LR [c0000000000be880] .call_block_remove+0xd0/0x220
  Call Trace:
    0xc000000fb8c00240 (unreliable)
    .pSeries_lpar_flush_hash_range+0x578/0x670
    .flush_hash_range+0x44/0x100
    .__flush_tlb_pending+0x3c/0xc0
    .zap_pte_range+0x7ec/0x830
    .unmap_page_range+0x3f4/0x540
    .unmap_vmas+0x94/0x120
    .exit_mmap+0xac/0x1f0
    .mmput+0x9c/0x1f0
    .do_exit+0x388/0xd60
    .do_group_exit+0x54/0x100
    .__se_sys_exit_group+0x14/0x20
    system_call+0x5c/0x70
  Instruction dump:
  39400001 38a00000 4800003c 60000000 60420000 7fa9e800 38e00000 419e0014
  7d29d278 7d290074 7929d182 69270001 <0b070000> 7d495378 394a0001 7fa93040

The call to H_BLOCK_REMOVE should only be made for the supported pair
of base segment page size, actual page size and using the correct
maximum block size.

Due to the required complexity in do_block_remove() and
call_block_remove(), and the fact that currently a block size of 8 is
returned by the hypervisor, we are only supporting 8 size block to the
H_BLOCK_REMOVE hcall.

In order to identify this limitation easily in the code, a local
define HBLKR_SUPPORTED_SIZE defining the currently supported block
size, and a dedicated checking helper is_supported_hlbkr() are
introduced.

For regular pages and hugetlb, the assumption is made that the page
size is equal to the base page size. For THP the page size is assumed
to be 16M.

Fixes: ba2dd8a26b ("powerpc/pseries/mm: call H_BLOCK_REMOVE")
Signed-off-by: Laurent Dufour <ldufour@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190920130523.20441-3-ldufour@linux.ibm.com
2019-09-24 19:58:47 +10:00
arch powerpc/pseries: Call H_BLOCK_REMOVE when supported 2019-09-24 19:58:47 +10:00
block dma-mapping updates for 5.4: 2019-09-19 13:27:23 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto padata, pcrypt: take CPU hotplug lock internally in padata_alloc_possible 2019-09-13 21:15:40 +10:00
Documentation powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
drivers powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
fs powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
include powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
init Kbuild updates for v5.4 2019-09-20 08:36:47 -07:00
ipc Merge branch 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-18 13:15:58 -07:00
kernel powerpc updates for 5.4 2019-09-20 11:48:06 -07:00
lib lz4: do not export static symbol 2019-09-20 09:06:26 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm dma-mapping updates for 5.4: 2019-09-19 13:27:23 -07:00
net Merge branch 'work.mount-base' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-09-18 13:15:58 -07:00
samples samples/bpf: fix xdpsock l2fwd tx for unaligned mode 2019-09-16 09:35:10 +02:00
scripts Tracing updates: 2019-09-20 11:19:48 -07:00
security keys: Fix missing null pointer check in request_key_auth_describe() 2019-09-05 14:19:25 -07:00
sound chrome platform changes for v5.4 2019-09-19 14:14:28 -07:00
tools powerpc/tm: Add tm-poison test 2019-09-21 08:36:53 +10:00
usr kbuild: remove clean-dirs syntax 2019-08-29 23:54:29 +09:00
virt * s390: ioctl hardening, selftests 2019-09-18 09:49:13 -07:00
.clang-format clang-format: Update with the latest for_each macro list 2019-08-31 10:00:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: ignore modules.order explicitly 2019-08-22 01:14:11 +09:00
.mailmap Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 2019-09-18 12:34:53 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS CREDITS: Update email address 2019-09-13 17:21:38 +03:00
Kbuild kbuild: do not descend to ./Kbuild when cleaning 2019-08-21 21:03:58 +09:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rkuo/linux-hexagon-kernel 2019-09-20 11:28:43 -07:00
Makefile Kbuild updates for v5.4 2019-09-20 08:36:47 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.