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authorSteven Rostedt (Google) <rostedt@goodmis.org>2022-01-25 09:19:10 -0500
committerSteven Rostedt (Google) <rostedt@goodmis.org>2022-01-27 19:15:44 -0500
commit4ed308c445a1e3abac8f6c17928c1cb533867e38 (patch)
treedeb8e5474c0f738e4eb59a9be5cb54c2702a66e8 /scripts/Makefile
parente783362eb54cd99b2cac8b3a9aeac942e6f6ac07 (diff)
downloadlinux-4ed308c445a1e3abac8f6c17928c1cb533867e38.tar.gz
ftrace: Have architectures opt-in for mcount build time sorting
First S390 complained that the sorting of the mcount sections at build
time caused the kernel to crash on their architecture. Now PowerPC is
complaining about it too. And also ARM64 appears to be having issues.

It may be necessary to also update the relocation table for the values
in the mcount table. Not only do we have to sort the table, but also
update the relocations that may be applied to the items in the table.

If the system is not relocatable, then it is fine to sort, but if it is,
some architectures may have issues (although x86 does not as it shifts all
addresses the same).

Add a HAVE_BUILDTIME_MCOUNT_SORT that an architecture can set to say it is
safe to do the sorting at build time.

Also update the config to compile in build time sorting in the sorttable
code in scripts/ to depend on CONFIG_BUILDTIME_MCOUNT_SORT.

Link: https://lore.kernel.org/all/944D10DA-8200-4BA9-8D0A-3BED9AA99F82@linux.ibm.com/
Link: https://lkml.kernel.org/r/20220127153821.3bc1ac6e@gandalf.local.home

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Yinan Liu <yinan@linux.alibaba.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: Sachin Sant <sachinp@linux.ibm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com> [arm64]
Tested-by: Sachin Sant <sachinp@linux.ibm.com>
Fixes: 72b3942a173c ("scripts: ftrace - move the sort-processing in ftrace_init")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'scripts/Makefile')
-rw-r--r--scripts/Makefile2
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/Makefile b/scripts/Makefile
index ecd3acacd0ec..ce5aa9030b74 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -25,7 +25,7 @@ HOSTCFLAGS_sorttable.o += -I$(srctree)/tools/arch/x86/include
 HOSTCFLAGS_sorttable.o += -DUNWINDER_ORC_ENABLED
 endif
 
-ifdef CONFIG_DYNAMIC_FTRACE
+ifdef CONFIG_BUILDTIME_MCOUNT_SORT
 HOSTCFLAGS_sorttable.o += -DMCOUNT_SORT_ENABLED
 endif