[PATCH RESEND] riscv: Add kcov support

[Tobias Klauser]

Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to the riscv Kconfig.
Also disable instrumentation of some early boot code and vdso.

Tested on QEMU's riscv64 virt machine with syzkaller.

Acked-by: Dmitry Vyukov <dvyukov at google.com>
Signed-off-by: Tobias Klauser <tklauser at distanz.ch>
---
Resent due to infradead.org mailing list issues.

 arch/riscv/Kconfig              | 2 ++
 arch/riscv/boot/Makefile        | 2 ++
 arch/riscv/kernel/vdso/Makefile | 1 +
 arch/riscv/mm/Makefile          | 2 ++
 4 files changed, 7 insertions(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 089293e4ad46..a7d7f8184f15 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -19,6 +19,7 @@ config RISCV
 	select ARCH_HAS_DEBUG_WX
 	select ARCH_HAS_GCOV_PROFILE_ALL
 	select ARCH_HAS_GIGANTIC_PAGE
+	select ARCH_HAS_KCOV
 	select ARCH_HAS_MMIOWB
 	select ARCH_HAS_PTE_SPECIAL
 	select ARCH_HAS_SET_DIRECT_MAP
@@ -57,6 +58,7 @@ config RISCV
 	select HAVE_DMA_CONTIGUOUS if MMU
 	select HAVE_EBPF_JIT if MMU
 	select HAVE_FUTEX_CMPXCHG if FUTEX
+	select HAVE_GCC_PLUGINS
 	select HAVE_GENERIC_VDSO if MMU && 64BIT
 	select HAVE_PCI
 	select HAVE_PERF_EVENTS
diff --git a/arch/riscv/boot/Makefile b/arch/riscv/boot/Makefile
index 3530c59b3ea7..c59fca695f9d 100644
--- a/arch/riscv/boot/Makefile
+++ b/arch/riscv/boot/Makefile
@@ -14,6 +14,8 @@
 # Based on the ia64 and arm64 boot/Makefile.
 #
 
+KCOV_INSTRUMENT := n
+
 OBJCOPYFLAGS_Image :=-O binary -R .note -R .note.gnu.build-id -R .comment -S
 
 targets := Image loader
diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Makefile
index e4c7c2c8a02f..c8c9e40023c6 100644
--- a/arch/riscv/kernel/vdso/Makefile
+++ b/arch/riscv/kernel/vdso/Makefile
@@ -32,6 +32,7 @@ CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
 
 # Disable gcov profiling for VDSO code
 GCOV_PROFILE := n
+KCOV_INSTRUMENT := n
 
 # Force dependency
 $(obj)/vdso.o: $(obj)/vdso.so
diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
index 363ef01c30b1..c0185e556ca5 100644
--- a/arch/riscv/mm/Makefile
+++ b/arch/riscv/mm/Makefile
@@ -5,6 +5,8 @@ ifdef CONFIG_FTRACE
 CFLAGS_REMOVE_init.o = -pg
 endif
 
+KCOV_INSTRUMENT_init.o := n
+
 obj-y += init.o
 obj-y += extable.o
 obj-$(CONFIG_MMU) += fault.o pageattr.o
-- 
2.27.0