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Michael Ellerman b499fa070e powerpc/mm/radix: Fix overuse of small pages in splitting logic 
[ Upstream commit 3b5657ed5b ]

When we have CONFIG_STRICT_KERNEL_RWX enabled, we want to split the
linear mapping at the text/data boundary so we can map the kernel text
read only.

But the current logic uses small pages for the entire text section,
regardless of whether a larger page size would fit. eg. with the
boundary at 16M we could use 2M pages, but instead we use 64K pages up
to the 16M boundary:

  Mapped 0x0000000000000000-0x0000000001000000 with 64.0 KiB pages
  Mapped 0x0000000001000000-0x0000000040000000 with 2.00 MiB pages
  Mapped 0x0000000040000000-0x0000000100000000 with 1.00 GiB pages

This is because the test is checking if addr is < __init_begin
and addr + mapping_size is >= _stext. But that is true for all pages
between _stext and __init_begin.

Instead what we want to check is if we are crossing the text/data
boundary, which is at __init_begin. With that fixed we see:

  Mapped 0x0000000000000000-0x0000000000e00000 with 2.00 MiB pages
  Mapped 0x0000000000e00000-0x0000000001000000 with 64.0 KiB pages
  Mapped 0x0000000001000000-0x0000000040000000 with 2.00 MiB pages
  Mapped 0x0000000040000000-0x0000000100000000 with 1.00 GiB pages

ie. we're correctly using 2MB pages below __init_begin, but we still
drop down to 64K pages unnecessarily at the boundary.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-01 09:16:45 +01:00
arch powerpc/mm/radix: Fix overuse of small pages in splitting logic 2019-12-01 09:16:45 +01:00
block blok, bfq: do not plug I/O if all queues are weight-raised 2019-11-20 18:46:44 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: testmgr - fix sizeof() on COMP_BUF_SIZE 2019-12-01 09:16:13 +01:00
Documentation net: phy: mdio-bcm-unimac: Allow configuring MDIO clock divider 2019-11-20 18:47:14 +01:00
drivers scsi: hisi_sas: Fix NULL pointer dereference 2019-12-01 09:16:44 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs xfs: clear ail delwri queued bufs on unmount of shutdown fs 2019-12-01 09:16:34 +01:00
include cpuidle: menu: Fix wakeup statistics updates for polling state 2019-11-24 08:20:07 +01:00
init initramfs: don't free a non-existent initrd 2019-10-01 08:26:09 +02:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-08-06 19:06:52 +02:00
kernel swiotlb: do not panic on mapping failures 2019-12-01 09:16:42 +01:00
lib idr: Fix idr_get_next race with idr_remove 2019-11-24 08:19:11 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/ksm.c: don't WARN if page is still mapped in remove_stable_node() 2019-12-01 09:16:11 +01:00
net sunrpc: safely reallow resvport min/max inversion 2019-12-01 09:16:41 +01:00
samples mei: samples: fix a signedness bug in amt_host_if_call() 2019-11-24 08:19:50 +01:00
scripts scripts/setlocalversion: Improve -dirty check with git-status --no-optional-locks 2019-11-06 13:05:27 +01:00
security ima: fix freeing ongoing ahash_request 2019-10-11 18:21:11 +02:00
sound ALSA: i2c/cs8427: Fix int to char conversion 2019-12-01 09:16:36 +01:00
tools selftests/bpf: fix file resource leak in load_kallsyms 2019-12-01 09:16:40 +01:00
usr kbuild: clean compressed initramfs image 2019-10-07 18:57:16 +02:00
virt kvm: arm/arm64: Fix stage2_flush_memslot for 4 level page table 2019-11-24 08:19:31 +01:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS USB: rio500: Remove Rio 500 kernel driver 2019-10-17 13:44:47 -07:00
Makefile Linux 4.19.86 2019-11-24 08:21:09 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

README 

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.