[PATCH] tools/perf/tests: Update is_ignored_symbol function in vmlinux-kallsyms test

Athira Rajeev atrajeev at linux.vnet.ibm.com
Wed Sep 28 14:52:18 AEST 2022


The testcase “vmlinux-kallsyms.c” fails in powerpc.

	vmlinux symtab matches kallsyms: FAILED!

This test look at the symbols in the vmlinux DSO
and check if we find all of them in the kallsyms dso.
But from the powerpc logs , observed that the failure
happens for:
	ERR : 0xc0000000000fe9c8: .Lmfspr_table not on kallsyms
	ERR : 0xc0000000001009c8: .Lmtspr_table not on kallsyms

These are labels ( with .L) in the source code and
has to be ignored. Reference code with .Lmtspr_table:
arch/powerpc/xmon/spr_access.S

The testcases invokes is_ignored_symbol() function to
ignore hidden symbols in the dso like local symbols. This
function is adapted from is_ignored_symbol() kernel
function in code: scripts/kallsyms.c . The kernel
function got some updates which is not reflected in
the testcase function and the new updates also handles
ignoring "labels".

Below is the changes that went in the kernel function.

	 /* Symbol names that begin with the following are ignored.*/
	 static const char * const ignored_prefixes[] = {
	 		"$",			/* local symbols for ARM, MIPS, etc. */
	-		".LASANPC",		/* s390 kasan local symbols */
	+		".L",			/* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
	 		"__crc_",		/* modversions */
	 		"__efistub_",		/* arm64 EFI stub namespace */
	-		"__kvm_nvhe_",		/* arm64 non-VHE KVM namespace */
	+		"__kvm_nvhe_$",		/* arm64 local symbols in non-VHE KVM namespace */
	+		"__kvm_nvhe_.L",	/* arm64 local symbols in non-VHE KVM namespace */
	 		"__AArch64ADRPThunk_",	/* arm64 lld */
	 		"__ARMV5PILongThunk_",	/* arm lld */
	 		"__ARMV7PILongThunk_",

This change is part of below commits and will handle the
symbols with “.L”

commit d4c858643263 ("kallsyms: ignore all local labels prefixed
by '.L'")
commit 6ccf9cb557bd ("KVM: arm64: Symbolize the nVHE HYP addresses")

Update the testcase function to include the new
changes.

Reported-by: Disha Goel <disgoel at linux.vnet.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev at linux.vnet.ibm.com>
---
 tools/perf/tests/vmlinux-kallsyms.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/vmlinux-kallsyms.c b/tools/perf/tests/vmlinux-kallsyms.c
index 4fd8d703ff19..8ab035b55875 100644
--- a/tools/perf/tests/vmlinux-kallsyms.c
+++ b/tools/perf/tests/vmlinux-kallsyms.c
@@ -43,10 +43,11 @@ static bool is_ignored_symbol(const char *name, char type)
 	/* Symbol names that begin with the following are ignored.*/
 	static const char * const ignored_prefixes[] = {
 		"$",			/* local symbols for ARM, MIPS, etc. */
-		".LASANPC",		/* s390 kasan local symbols */
+		".L",			/* local labels, .LBB,.Ltmpxxx,.L__unnamed_xx,.LASANPC, etc. */
 		"__crc_",		/* modversions */
 		"__efistub_",		/* arm64 EFI stub namespace */
-		"__kvm_nvhe_",		/* arm64 non-VHE KVM namespace */
+		"__kvm_nvhe_$",		/* arm64 local symbols in non-VHE KVM namespace */
+		"__kvm_nvhe_.L",	/* arm64 local symbols in non-VHE KVM namespace */
 		"__AArch64ADRPThunk_",	/* arm64 lld */
 		"__ARMV5PILongThunk_",	/* arm lld */
 		"__ARMV7PILongThunk_",
-- 
2.31.1



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