powerpc: Enable kcov

kcov provides kernel coverage data that's useful for fuzzing tools like
syzkaller.

Wire up kcov support on powerpc. Disable kcov instrumentation on the same
files where we currently disable gcov and UBSan instrumentation, plus some
additional exclusions which appear necessary to boot on book3e machines.

Signed-off-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Daniel Axtens <dja@axtens.net> # e6500
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index ad8e22827de086288876c58d2f80dfa5bd8d6813..5b7945a7bd4171a060b37a8d4e21032a683a9428 100644 (file)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -130,6 +130,7 @@ config PPC
        select ARCH_HAS_ELF_RANDOMIZE
        select ARCH_HAS_FORTIFY_SOURCE
        select ARCH_HAS_GCOV_PROFILE_ALL
+       select ARCH_HAS_KCOV
        select ARCH_HAS_PHYS_TO_DMA
        select ARCH_HAS_PMEM_API                if PPC64
        select ARCH_HAS_PTE_SPECIAL

diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index 8809e287b80d2890a50242a6b461f7e69135ae42..cddadccf551d9ec018a68d37c9ab8db96a4548d7 100644 (file)
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -143,19 +143,29 @@ endif
 obj-$(CONFIG_EPAPR_PARAVIRT)   += epapr_paravirt.o epapr_hcalls.o
 obj-$(CONFIG_KVM_GUEST)                += kvm.o kvm_emul.o
 
-# Disable GCOV & sanitizers in odd or sensitive code
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_prom_init.o := n
+KCOV_INSTRUMENT_prom_init.o := n
 UBSAN_SANITIZE_prom_init.o := n
 GCOV_PROFILE_machine_kexec_64.o := n
+KCOV_INSTRUMENT_machine_kexec_64.o := n
 UBSAN_SANITIZE_machine_kexec_64.o := n
 GCOV_PROFILE_machine_kexec_32.o := n
+KCOV_INSTRUMENT_machine_kexec_32.o := n
 UBSAN_SANITIZE_machine_kexec_32.o := n
 GCOV_PROFILE_kprobes.o := n
+KCOV_INSTRUMENT_kprobes.o := n
 UBSAN_SANITIZE_kprobes.o := n
 GCOV_PROFILE_kprobes-ftrace.o := n
+KCOV_INSTRUMENT_kprobes-ftrace.o := n
 UBSAN_SANITIZE_kprobes-ftrace.o := n
 UBSAN_SANITIZE_vdso.o := n
 
+# Necessary for booting with kcov enabled on book3e machines
+KCOV_INSTRUMENT_cputable.o := n
+KCOV_INSTRUMENT_setup_64.o := n
+KCOV_INSTRUMENT_paca.o := n
+
 extra-$(CONFIG_PPC_FPU)                += fpu.o
 extra-$(CONFIG_ALTIVEC)                += vector.o
 extra-$(CONFIG_PPC64)          += entry_64.o

diff --git a/arch/powerpc/kernel/trace/Makefile b/arch/powerpc/kernel/trace/Makefile
index b1725ad3e13d4978f3b0317a2b762d49b4dd08a8..858503775c58338f799215caa1e8099ddc526ec5 100644 (file)
--- a/arch/powerpc/kernel/trace/Makefile
+++ b/arch/powerpc/kernel/trace/Makefile
@@ -23,6 +23,7 @@ obj-$(CONFIG_TRACING)                 += trace_clock.o
 obj-$(CONFIG_PPC64)                    += $(obj64-y)
 obj-$(CONFIG_PPC32)                    += $(obj32-y)
 
-# Disable GCOV & sanitizers in odd or sensitive code
+# Disable GCOV, KCOV & sanitizers in odd or sensitive code
 GCOV_PROFILE_ftrace.o := n
+KCOV_INSTRUMENT_ftrace.o := n
 UBSAN_SANITIZE_ftrace.o := n

diff --git a/arch/powerpc/kernel/vdso32/Makefile b/arch/powerpc/kernel/vdso32/Makefile
index 50112d4473bb9a9c3c6f1302f4a400d55f79db74..ce199f6e4256d2593d54d43e1652a1e6bb051d98 100644 (file)
--- a/arch/powerpc/kernel/vdso32/Makefile
+++ b/arch/powerpc/kernel/vdso32/Makefile
@@ -23,6 +23,7 @@ targets := $(obj-vdso32) vdso32.so vdso32.so.dbg
 obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 ccflags-y := -shared -fno-common -fno-builtin

diff --git a/arch/powerpc/kernel/vdso64/Makefile b/arch/powerpc/kernel/vdso64/Makefile
index 69cecb3462697a88107d8e966e2775fafe81628a..28e7d112aa2fc4a7ab268109df01a0b416d25a9b 100644 (file)
--- a/arch/powerpc/kernel/vdso64/Makefile
+++ b/arch/powerpc/kernel/vdso64/Makefile
@@ -9,6 +9,7 @@ targets := $(obj-vdso64) vdso64.so vdso64.so.dbg
 obj-vdso64 := $(addprefix $(obj)/, $(obj-vdso64))
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 ccflags-y := -shared -fno-common -fno-builtin

diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index ee1efa3b3382689285ff4e8cce09025d1a280bc0..d52ec118e09db842283a1bd9607f727711a92f35 100644 (file)
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -47,3 +47,8 @@ obj-$(CONFIG_PPC_COPRO_BASE)  += copro_fault.o
 obj-$(CONFIG_SPAPR_TCE_IOMMU)  += mmu_context_iommu.o
 obj-$(CONFIG_PPC_PTDUMP)       += ptdump/
 obj-$(CONFIG_PPC_MEM_KEYS)     += pkeys.o
+
+# Disable kcov instrumentation on sensitive code
+# This is necessary for booting with kcov enabled on book3e machines
+KCOV_INSTRUMENT_tlb_nohash.o := n
+KCOV_INSTRUMENT_fsl_booke_mmu.o := n

diff --git a/arch/powerpc/xmon/Makefile b/arch/powerpc/xmon/Makefile
index 878f9c1d36150c80a021413f23ac36577ef881c0..3050f9323254f0086ce911d93b045311864cbd13 100644 (file)
--- a/arch/powerpc/xmon/Makefile
+++ b/arch/powerpc/xmon/Makefile
@@ -5,6 +5,7 @@
 subdir-ccflags-y := $(call cc-disable-warning, builtin-requires-header)
 
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
 
 # Disable ftrace for the entire directory