Draft: create-diff-object: __patchable_function_entries section support #1415
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Fix the following:
In kpatch/kpatch line 358:
break
^-- SC2317 (info): Command appears to be unreachable. Check usage (or ignore if invoked indirectly).
In kpatch-build/kpatch-build line 1424:
"$TOOLSDIR"/create-diff-object $CDO_FLAGS "orig/$i" "patched/$i" "$KOBJFILE_NAME" \
^--------^ SC2086 (info): Double quote to prevent globbing and word splitting.
In kpatch-build/kpatch-build line 1494:
MAKEVARS[$idx]=${MAKEVARS[$idx]/${KPATCH_CC_PREFIX}/}
^--^ SC2004 (style): $/${} is unnecessary on arithmetic variables.
In kpatch-build/kpatch-build line 1510:
"$TOOLSDIR"/create-klp-module $extra_flags "$TEMPDIR/patch/tmp.ko" "$TEMPDIR/patch/$MODNAME.ko" 2>&1 | logger 1
^----------^ SC2086 (info): Double quote to prevent globbing and word splitting.
In test/integration/lib.sh line 119:
tdnf install -y linux-$flavor-debuginfo
^-----^ SC2086 (info): Double quote to prevent globbing and word splitting.
Signed-off-by: Joe Lawrence <[email protected]>
squash
The __mcount_loc section contains the addresses of patchable ftrace sites which is used by the ftrace infrastructure in the kernel to create a list of tracable functions and to know where to patch to enable tracing of them. On some kernel configurations, section is called __patchable_function_entries and is generated by the compiler. Either of __mcount_loc or __patchable_function_entries is recognised by the kernel but for these configurations, use __patchable_function_entries as it is what is expected. Note that x86_64 arch is special (of course). Unlike other arches (ppc64le and aarch64) a x86_64 kernel built with -fpatchable-function-entry will generate nops AND create rela__patchable_function_entries for functions even marked as notrace. For this arch, always create __mount_loc sections and rely on __fentry__ relocations to indicate ftrace call sites. Signed-off-by: Suraj Jitindar Singh <[email protected]> Signed-off-by: Pete Swain <[email protected]> Signed-off-by: Mihails Strasuns <[email protected]> Signed-off-by: Joe Lawrence <[email protected]>
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The __mcount_loc section contains the addresses of patchable ftrace sites which is used by the ftrace infrastructure in the kernel to create a list of tracable functions and to know where to patch to enable tracing of them. On some kernel configurations, section is called __patchable_function_entries and is generated by the compiler. Either of __mcount_loc or __patchable_function_entries is recognised by the kernel but for these configurations, use __patchable_function_entries as it is what is expected.
Note that x86_64 arch is special (of course). Unlike other arches (ppc64le and aarch64) a x86_64 kernel built with -fpatchable-function-entry will generate nops AND create rela__patchable_function_entries for functions even marked as notrace. For this arch, always create __mount_loc sections and rely on fentry relocations to indicate ftrace call sites.