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Date:   Sun, 23 Apr 2023 09:56:52 +0100
From:   Conor Dooley <conor@kernel.org>
To:     ruanjinjie <ruanjinjie@huawei.com>, paul.walmsley@sifive.com,
        palmer@dabbelt.com, aou@eecs.berkeley.edu,
        linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
CC:     ruanjinjie@huawei.com
Subject: =?US-ASCII?Q?Re=3A_=5BPATCH_RESEND=5D_riscv=3A_fix_kprobe?= =?US-ASCII?Q?_=5F=5Fuser_string_arg_print_fault_issue?=
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On 23 April 2023 02:29:12 IST, ruanjinjie <ruanjinjie@huawei=2Ecom> wrote:
>On riscv qemu platform, when add kprobe event on do_sys_open() to show
>filename string arg, it just print fault as follow:
>
>echo 'p:myprobe do_sys_open dfd=3D$arg1 filename=3D+0($arg2):string flags=
=3D$arg3
>mode=3D$arg4' > kprobe_events
>
>bash-166     [000] =2E=2E=2E1=2E   360=2E195367: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D(fault) flags=3D0x8241 mode=3D0x1b6
>
>bash-166     [000] =2E=2E=2E1=2E   360=2E219369: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D(fault) flags=3D0x8241 mode=3D0x1b6
>
>bash-191     [000] =2E=2E=2E1=2E   360=2E378827: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D(fault) flags=3D0x98800 mode=3D0x0
>
>As riscv do not select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE,
>the +0($arg2) addr is processed as a kernel address though it is a
>userspace address, cause the above filename=3D(fault) print=2E So select
>ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE to avoid the issue, after that the
>kprobe trace is ok as below:
>
>bash-166     [000] =2E=2E=2E1=2E    96=2E767641: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D"/dev/null" flags=3D0x8241 mode=3D0x1=
b6
>
>bash-166     [000] =2E=2E=2E1=2E    96=2E793751: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D"/dev/null" flags=3D0x8241 mode=3D0x1=
b6
>
>bash-177     [000] =2E=2E=2E1=2E    96=2E962354: myprobe: (do_sys_open+0x=
0/0x84)
>dfd=3D0xffffffffffffff9c filename=3D"/sys/kernel/debug/tracing/events/kpr=
obes/"
>flags=3D0x98800 mode=3D0x0
>
>Signed-off-by: ruanjinjie <ruanjinjie@huawei=2Ecom>
>---
> arch/riscv/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
>
>diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
>index eb7f29a412f8=2E=2Ec51f0d3227af 100644
>--- a/arch/riscv/Kconfig
>+++ b/arch/riscv/Kconfig
>@@ -26,6 +26,7 @@ config RISCV
> 	select ARCH_HAS_KCOV
> 	select ARCH_HAS_MMIOWB
> 	select ARCH_HAS_PMEM_API
>+	select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE

Please add this in alphabetical order, thanks=2E

> 	select ARCH_HAS_PTE_SPECIAL
> 	select ARCH_HAS_SET_DIRECT_MAP if MMU
> 	select ARCH_HAS_SET_MEMORY if MMU