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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Fri, 26 Jun 2020 16:28:54 +0200
Message-ID: <CACT4Y+ZqbsyCQp8NJq9=TFvu92EMysQRyVe6yyarHhR2L2M4RQ@mail.gmail.com>
Subject: Re: [PATCH v2] riscv: Allow building with kcov coverage
To:     Tobias Klauser <tklauser@distanz.ch>
Cc:     Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        linux-riscv@lists.infradead.org,
        LKML <linux-kernel@vger.kernel.org>,
        =?UTF-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn.topel@gmail.com>
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On Fri, Jun 26, 2020 at 2:40 PM Tobias Klauser <tklauser@distanz.ch> wrote:
>
> Add ARCH_HAS_KCOV and HAVE_GCC_PLUGINS to the riscv Kconfig.
> Also disable instrumentation of some early boot code and vdso.
>
> Boot-tested on QEMU's riscv64 virt machine.
>
> Cc: Bj=C3=B6rn T=C3=B6pel <bjorn.topel@gmail.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Signed-off-by: Tobias Klauser <tklauser@distanz.ch>


Assuming it boots now :)

Acked-by: Dmitry Vyukov <dvyukov@google.com>

> ---
>  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 :=3D n
> +
>  OBJCOPYFLAGS_Image :=3D-O binary -R .note -R .note.gnu.build-id -R .comm=
ent -S
>
>  targets :=3D Image loader
> diff --git a/arch/riscv/kernel/vdso/Makefile b/arch/riscv/kernel/vdso/Mak=
efile
> index 29cf052f6541..4b0d3bcc44e5 100644
> --- a/arch/riscv/kernel/vdso/Makefile
> +++ b/arch/riscv/kernel/vdso/Makefile
> @@ -29,6 +29,7 @@ CPPFLAGS_vdso.lds +=3D -P -C -U$(ARCH)
>
>  # Disable gcov profiling for VDSO code
>  GCOV_PROFILE :=3D n
> +KCOV_INSTRUMENT :=3D n
>
>  # Force dependency
>  $(obj)/vdso.o: $(obj)/vdso.so
> diff --git a/arch/riscv/mm/Makefile b/arch/riscv/mm/Makefile
> index 363ef01c30b1..c0185e556ca5 100644
> --- a/arch/riscv/mm/Makefile
> +++ b/arch/riscv/mm/Makefile
> @@ -5,6 +5,8 @@ ifdef CONFIG_FTRACE
>  CFLAGS_REMOVE_init.o =3D -pg
>  endif
>
> +KCOV_INSTRUMENT_init.o :=3D n
> +
>  obj-y +=3D init.o
>  obj-y +=3D extable.o
>  obj-$(CONFIG_MMU) +=3D fault.o pageattr.o
> --
> 2.27.0
>