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Steven Rostedt (VMware) b4c7e2bd2e ARM: 8780/1: ftrace: Only set kernel memory back to read-only after boot
Dynamic ftrace requires modifying the code segments that are usually
set to read-only. To do this, a per arch function is called both before
and after the ftrace modifications are performed. The "before" function
will set kernel code text to read-write to allow for ftrace to make the
modifications, and the "after" function will set the kernel code text
back to "read-only" to keep the kernel code text protected.

The issue happens when dynamic ftrace is tested at boot up. The test is
done before the kernel code text has been set to read-only. But the
"before" and "after" calls are still performed. The "after" call will
change the kernel code text to read-only prematurely, and other boot
code that expects this code to be read-write will fail.

The solution is to add a variable that is set when the kernel code text
is expected to be converted to read-only, and make the ftrace "before"
and "after" calls do nothing if that variable is not yet set. This is
similar to the x86 solution from commit 1623963097 ("ftrace, x86:
make kernel text writable only for conversions").

Link: http://lkml.kernel.org/r/20180620212906.24b7b66e@vmware.local.home

Reported-by: Stefan Agner <stefan@agner.ch>
Tested-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2018-07-11 22:57:57 +01:00
..
Kconfig Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2018-06-06 13:49:25 -07:00
Makefile Merge branches 'fixes', 'misc' and 'spectre' into for-linus 2018-06-05 10:03:27 +01:00
abort-ev4.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev4t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev5t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev5tj.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev6.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-ev7.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-lv4t.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-macro.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
abort-nommu.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
alignment.c signal: Ensure every siginfo we send has all bits initialized 2018-04-25 10:40:51 -05:00
cache-aurora-l2.h ARM: 7547/4: cache-l2x0: add support for Aurora L2 cache ctrl 2012-11-06 19:47:35 +00:00
cache-b15-rac.c ARM: B15: Update to support Brahma-B53 2018-04-16 15:16:48 -07:00
cache-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-feroceon-l2.c ARM: 8416/1: Feroceon: use of_iomap() to map register base 2015-08-18 14:00:30 +01:00
cache-l2x0-pmu.c perf: Fix sibling iteration 2018-03-16 20:44:12 +01:00
cache-l2x0.c ARM: 8659/1: l2c: allow CA9 optimizations to be disabled 2017-03-17 10:01:26 +00:00
cache-nop.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-tauros2.c ARM: l2c: tauros2: use descriptive definitions for register bits 2015-11-26 22:12:26 +00:00
cache-tauros3.h ARM: 7922/1: l2x0: add Marvell Tauros3 support 2013-12-29 12:32:47 +00:00
cache-uniphier.c ARM: 8652/1: cache-uniphier: clean up active way setup code 2017-02-28 11:06:17 +00:00
cache-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v4wb.S ARM: align .data section 2017-08-14 16:22:55 +01:00
cache-v4wt.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
cache-v7.S ARM: 8729/1: Hook B15 readahead cache functions based on processor 2017-12-17 22:15:36 +00:00
cache-v7m.S scripts/spelling.txt: add "swith" pattern and fix typo instances 2017-02-27 18:43:46 -08:00
cache-xsc3l2.c ARM: move CP15 definitions to separate header file 2012-03-28 18:30:01 +01:00
context.c ARM: 8465/1: mm: keep reserved ASIDs in sync with mm after multiple rollovers 2015-12-02 23:57:54 +00:00
copypage-fa.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-feroceon.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4mc.c mm: fix races between swapoff and flush dcache 2018-04-05 21:36:26 -07:00
copypage-v4wb.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v4wt.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-v6.c mm: fix races between swapoff and flush dcache 2018-04-05 21:36:26 -07:00
copypage-xsc3.c arm: remove the second argument of k[un]map_atomic() 2012-03-20 21:48:14 +08:00
copypage-xscale.c mm: fix races between swapoff and flush dcache 2018-04-05 21:36:26 -07:00
dma-mapping-nommu.c dma-debug: move initialization to common code 2018-05-08 13:02:42 +02:00
dma-mapping.c treewide: kzalloc() -> kcalloc() 2018-06-12 16:19:22 -07:00
dma.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
dump.c ARM: 8737/1: mm: dump: add checking for writable and executable 2018-01-21 15:32:20 +00:00
extable.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fault-armv.c mm: fix races between swapoff and flush dcache 2018-04-05 21:36:26 -07:00
fault.c Merge branch 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm 2018-06-06 13:49:25 -07:00
fault.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
flush.c mm: fix races between swapoff and flush dcache 2018-04-05 21:36:26 -07:00
fsr-2level.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
fsr-3level.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
highmem.c kmap_atomic_to_page() has no users, remove it 2015-11-09 15:11:24 -08:00
hugetlbpage.c mm/hugetlb: reduce arch dependent code about huge_pmd_unshare 2015-06-24 17:49:41 -07:00
idmap.c ARM: 8734/1: mm: idmap: Mark variables as ro_after_init 2017-12-17 22:16:20 +00:00
init.c ARM: 8780/1: ftrace: Only set kernel memory back to read-only after boot 2018-07-11 22:57:57 +01:00
iomap.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
ioremap.c ARM: Implement pci_remap_cfgspace() interface 2017-04-24 13:53:13 -05:00
l2c-common.c ARM: outer cache: add WARN_ON() to outer_disable() 2014-05-30 00:47:23 +01:00
l2c-l2x0-resume.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mm.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
mmap.c exec: pass stack rlimit into mm layout functions 2018-04-11 10:28:37 -07:00
mmu.c ARM: 8685/1: ensure memblock-limit is pmd-aligned 2017-06-29 23:10:12 +01:00
nommu.c ARM: 8757/1: NOMMU: Support PMSAv8 MPU 2018-05-19 11:53:46 +01:00
pabort-legacy.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pabort-v6.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pabort-v7.S License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pageattr.c arm: use set_memory.h header 2017-05-08 17:15:13 -07:00
pgd.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
physaddr.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
pmsa-v7.c ARM: 8754/1: NOMMU: Move PMSAv7 MPU under it's own namespace 2018-05-19 11:53:46 +01:00
pmsa-v8.c ARM: 8757/1: NOMMU: Support PMSAv8 MPU 2018-05-19 11:53:46 +01:00
proc-arm7tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm9tdmi.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm720.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm740.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm920.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm922.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm925.S ARM: 8349/1: arch/arm/mm/proc-arm925.S: remove dead #ifdef block 2015-05-03 23:22:27 +01:00
proc-arm926.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm940.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm946.S Merge branches 'misc', 'vdso' and 'fixes' into for-next 2015-04-14 22:28:25 +01:00
proc-arm1020.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1020e.S ARM: 8348/1: remove comments on CPU_ARM1020_CPU_IDLE 2015-05-03 23:22:09 +01:00
proc-arm1022.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-arm1026.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-fa526.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-feroceon.S ARM: 8350/1: proc-feroceon: Fix feroceon_proc_info macro 2015-05-03 23:23:09 +01:00
proc-macros.S ARM: bugs: add support for per-processor bug checking 2018-05-31 10:39:34 +01:00
proc-mohawk.S ARM: mohawk: allow building with MMU disabled 2015-12-01 21:44:25 +01:00
proc-sa110.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-sa1100.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-syms.c ARM: modules: don't export cpu_set_pte_ext when !MMU 2013-03-26 09:55:34 +00:00
proc-v6.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-v7-2level.S ARM: spectre-v2: harden branch predictor on context switches 2018-05-31 10:39:55 +01:00
proc-v7-3level.S ARM: 8690/1: lpae: build TTB control register value from scratch in v7_ttb_setup 2017-08-29 13:09:12 +01:00
proc-v7-bugs.c ARM: spectre-v2: warn about incorrect context switching functions 2018-05-31 11:09:03 +01:00
proc-v7.S Merge branches 'fixes', 'misc' and 'spectre' into for-linus 2018-06-05 10:03:27 +01:00
proc-v7m.S Merge branches 'fixes' and 'misc' into for-next 2017-04-26 10:59:49 +01:00
proc-xsc3.S ARM: 8314/1: replace PROCINFO embedded branch with relative offset 2015-03-28 15:46:14 +00:00
proc-xscale.S ARM: align .data section 2017-08-14 16:22:55 +01:00
ptdump_debugfs.c ARM: 8735/1: mm: dump: make page table dumping reusable 2018-01-21 15:32:17 +00:00
pv-fixup-asm.S ARM: re-implement physical address space switching 2015-06-01 23:46:33 +01:00
tcm.h ARM: 7694/1: ARM, TCM: initialize TCM in paging_init(), instead of setup_arch() 2013-04-17 16:53:24 +01:00
tlb-fa.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wb.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v4wbi.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v6.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00
tlb-v7.S ARM: convert all "mov.* pc, reg" to "bx reg" for ARMv6+ 2014-07-18 12:29:04 +01:00