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authorVictor Kamensky <kamensky@cisco.com>2020-02-11 11:24:34 -0800
committerPaul Burton <paulburton@kernel.org>2020-02-15 12:44:03 -0800
commit976c23af3ee5bd3447a7bfb6c356ceb4acf264a6 (patch)
tree8bbc4b3e442c7d736fb77d51844b8814c030f445 /arch/mips
parent07015d7a103c4420b69a287b8ef4d2535c0f4106 (diff)
mips: vdso: add build time check that no 'jalr t9' calls left
vdso shared object cannot have GOT based PIC 'jalr t9' calls because nobody set GOT table in vdso. Contributing into vdso .o files are compiled in PIC mode and as result for internal static functions calls compiler will generate 'jalr t9' instructions. Those are supposed to be converted into PC relative 'bal' calls by linker when relocation are processed. Mips global GOT entries do have dynamic relocations and they will be caught by cmd_vdso_check Makefile rule. Static PIC calls go through mips local GOT entries that do not have dynamic relocations. For those 'jalr t9' calls could be present but without dynamic relocations and they need to be converted to 'bal' calls by linker. Add additional build time check to make sure that no 'jalr t9' slip through because of some toolchain misconfiguration that prevents 'jalr t9' to 'bal' conversion. Signed-off-by: Victor Kamensky <kamensky@cisco.com> Signed-off-by: Paul Burton <paulburton@kernel.org> Cc: linux-mips@vger.kernel.org Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Vincenzo Frascino <vincenzo.frascino@arm.com> Cc: bruce.ashfield@gmail.com Cc: richard.purdie@linuxfoundation.org
Diffstat (limited to 'arch/mips')
-rw-r--r--arch/mips/vdso/Makefile8
1 files changed, 7 insertions, 1 deletions
diff --git a/arch/mips/vdso/Makefile b/arch/mips/vdso/Makefile
index b5e0bd82d47f..77374c1f0c77 100644
--- a/arch/mips/vdso/Makefile
+++ b/arch/mips/vdso/Makefile
@@ -97,12 +97,18 @@ GCOV_PROFILE := n
UBSAN_SANITIZE := n
KCOV_INSTRUMENT := n
+# Check that we don't have PIC 'jalr t9' calls left
+quiet_cmd_vdso_mips_check = VDSOCHK $@
+ cmd_vdso_mips_check = if $(OBJDUMP) --disassemble $@ | egrep -h "jalr.*t9" > /dev/null; \
+ then (echo >&2 "$@: PIC 'jalr t9' calls are not supported"; \
+ rm -f $@; /bin/false); fi
+
#
# Shared build commands.
#
quiet_cmd_vdsold_and_vdso_check = LD $@
- cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check)
+ cmd_vdsold_and_vdso_check = $(cmd_vdsold); $(cmd_vdso_check); $(cmd_vdso_mips_check)
quiet_cmd_vdsold = VDSO $@
cmd_vdsold = $(CC) $(c_flags) $(VDSO_LDFLAGS) \