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Message-ID: <0ba77c9b-7986-14be-3306-355d58380a5e@yadro.com>
Date:   Tue, 10 Jan 2023 16:50:55 +0300
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Subject: Re: [PATCH -next V6 7/7] samples: ftrace: Add riscv support for
 SAMPLE_FTRACE_DIRECT[_MULTI]
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To:     <guoren@kernel.org>
CC:     <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
        <anup@brainfault.org>, <paul.walmsley@sifive.com>,
        <palmer@dabbelt.com>, <conor.dooley@microchip.com>,
        <heiko@sntech.de>, <rostedt@goodmis.org>, <mhiramat@kernel.org>,
        <jolsa@redhat.com>, <bp@suse.de>, <jpoimboe@kernel.org>,
        <suagrfillet@gmail.com>, <andy.chiu@sifive.com>
References: <20230107133549.4192639-1-guoren@kernel.org>
 <20230107133549.4192639-8-guoren@kernel.org>
From:   Evgenii Shatokhin <e.shatokhin@yadro.com>
In-Reply-To: <20230107133549.4192639-8-guoren@kernel.org>
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On 07.01.2023 16:35, guoren@kernel.org wrote:
> From: Song Shuai <suagrfillet@gmail.com>
> 
> select HAVE_SAMPLE_FTRACE_DIRECT and HAVE_SAMPLE_FTRACE_DIRECT_MULTI
> for ARCH_RV64I in arch/riscv/Kconfig. And add riscv asm code for
> the ftrace-direct*.c files in samples/ftrace/.

The samples fail to build for RV64GC system, because asm/nospec-branch.h 
is not available for RISC-V. As of 6.2-rc3, it seems, the header is only 
present on x86 and s390.

May be, place it under #ifdef, so that it is only used where available? 
nospec functionality is not yet implemented for RISC-V and is way out of 
scope of this patch series.

> 
> Signed-off-by: Song Shuai <suagrfillet@gmail.com>
> Tested-by: Guo Ren <guoren@kernel.org>
> Signed-off-by: Guo Ren <guoren@kernel.org>
> ---
>   samples/ftrace/ftrace-direct-modify.c       | 33 ++++++++++++++++++
>   samples/ftrace/ftrace-direct-multi-modify.c | 37 +++++++++++++++++++++
>   samples/ftrace/ftrace-direct-multi.c        | 22 ++++++++++++
>   samples/ftrace/ftrace-direct-too.c          | 26 +++++++++++++++
>   samples/ftrace/ftrace-direct.c              | 22 ++++++++++++
>   5 files changed, 140 insertions(+)
> 
> diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
> index de5a0f67f320..be7bf472c3c7 100644
> --- a/samples/ftrace/ftrace-direct-modify.c
> +++ b/samples/ftrace/ftrace-direct-modify.c
> @@ -23,6 +23,39 @@ extern void my_tramp2(void *);
> 
>   static unsigned long my_ip = (unsigned long)schedule;
> 
> +#ifdef CONFIG_RISCV
> +
> +asm (" .pushsection    .text, \"ax\", @progbits\n"
> +"      .type           my_tramp1, @function\n"
> +"      .globl          my_tramp1\n"
> +"   my_tramp1:\n"
> +"      addi sp,sp,-16\n"
> +"      sd   t0,0(sp)\n"
> +"      sd   ra,8(sp)\n"
> +"      call my_direct_func1\n"
> +"      ld   t0,0(sp)\n"
> +"      ld   ra,8(sp)\n"
> +"      addi sp,sp,16\n"
> +"      jr t0\n"
> +"      .size           my_tramp1, .-my_tramp1\n"
> +
> +"      .type           my_tramp2, @function\n"
> +"      .globl          my_tramp2\n"
> +"   my_tramp2:\n"
> +"      addi sp,sp,-16\n"
> +"      sd   t0,0(sp)\n"
> +"      sd   ra,8(sp)\n"
> +"      call my_direct_func2\n"
> +"      ld   t0,0(sp)\n"
> +"      ld   ra,8(sp)\n"
> +"      addi sp,sp,16\n"
> +"      jr t0\n"
> +"      .size           my_tramp2, .-my_tramp2\n"
> +"      .popsection\n"
> +);
> +
> +#endif /* CONFIG_RISCV */
> +
>   #ifdef CONFIG_X86_64
> 
>   #include <asm/ibt.h>
> diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
> index d52370cad0b6..10884bf418f7 100644
> --- a/samples/ftrace/ftrace-direct-multi-modify.c
> +++ b/samples/ftrace/ftrace-direct-multi-modify.c
> @@ -21,6 +21,43 @@ void my_direct_func2(unsigned long ip)
>   extern void my_tramp1(void *);
>   extern void my_tramp2(void *);
> 
> +#ifdef CONFIG_RISCV
> +
> +asm (" .pushsection    .text, \"ax\", @progbits\n"
> +"      .type           my_tramp1, @function\n"
> +"      .globl          my_tramp1\n"
> +"   my_tramp1:\n"
> +"       addi sp,sp,-24\n"
> +"       sd   a0,0(sp)\n"
> +"       sd   t0,8(sp)\n"
> +"       sd   ra,16(sp)\n"
> +"       call my_direct_func1\n"
> +"       ld   a0,0(sp)\n"
> +"       ld   t0,8(sp)\n"
> +"       ld   ra,16(sp)\n"
> +"       addi sp,sp,24\n"
> +"      jr t0\n"
> +"      .size           my_tramp1, .-my_tramp1\n"
> +
> +"      .type           my_tramp2, @function\n"
> +"      .globl          my_tramp2\n"
> +"   my_tramp2:\n"
> +"       addi sp,sp,-24\n"
> +"       sd   a0,0(sp)\n"
> +"       sd   t0,8(sp)\n"
> +"       sd   ra,16(sp)\n"
> +"       call my_direct_func2\n"
> +"       ld   a0,0(sp)\n"
> +"       ld   t0,8(sp)\n"
> +"       ld   ra,16(sp)\n"
> +"       addi sp,sp,24\n"
> +"      jr t0\n"
> +"      .size           my_tramp2, .-my_tramp2\n"
> +"      .popsection\n"
> +);
> +
> +#endif /* CONFIG_RISCV */
> +
>   #ifdef CONFIG_X86_64
> 
>   #include <asm/ibt.h>
> diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
> index ec1088922517..a35bf43bf6d7 100644
> --- a/samples/ftrace/ftrace-direct-multi.c
> +++ b/samples/ftrace/ftrace-direct-multi.c
> @@ -16,6 +16,28 @@ void my_direct_func(unsigned long ip)
> 
>   extern void my_tramp(void *);
> 
> +#ifdef CONFIG_RISCV
> +
> +asm ("       .pushsection    .text, \"ax\", @progbits\n"
> +"       .type           my_tramp, @function\n"
> +"       .globl          my_tramp\n"
> +"   my_tramp:\n"
> +"       addi sp,sp,-24\n"
> +"       sd   a0,0(sp)\n"
> +"       sd   t0,8(sp)\n"
> +"       sd   ra,16(sp)\n"
> +"       call my_direct_func\n"
> +"       ld   a0,0(sp)\n"
> +"       ld   t0,8(sp)\n"
> +"       ld   ra,16(sp)\n"
> +"       addi sp,sp,24\n"
> +"       jr t0\n"
> +"       .size           my_tramp, .-my_tramp\n"
> +"       .popsection\n"
> +);
> +
> +#endif /* CONFIG_RISCV */
> +
>   #ifdef CONFIG_X86_64
> 
>   #include <asm/ibt.h>
> diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
> index e13fb59a2b47..3b62e33c2e6d 100644
> --- a/samples/ftrace/ftrace-direct-too.c
> +++ b/samples/ftrace/ftrace-direct-too.c
> @@ -18,6 +18,32 @@ void my_direct_func(struct vm_area_struct *vma,
> 
>   extern void my_tramp(void *);
> 
> +#ifdef CONFIG_RISCV
> +
> +asm ("       .pushsection    .text, \"ax\", @progbits\n"
> +"       .type           my_tramp, @function\n"
> +"       .globl          my_tramp\n"
> +"   my_tramp:\n"
> +"       addi sp,sp,-40\n"
> +"       sd   a0,0(sp)\n"
> +"       sd   a1,8(sp)\n"
> +"       sd   a2,16(sp)\n"
> +"       sd   t0,24(sp)\n"
> +"       sd   ra,32(sp)\n"
> +"       call my_direct_func\n"
> +"       ld   a0,0(sp)\n"
> +"       ld   a1,8(sp)\n"
> +"       ld   a2,16(sp)\n"
> +"       ld   t0,24(sp)\n"
> +"       ld   ra,32(sp)\n"
> +"       addi sp,sp,40\n"
> +"       jr t0\n"
> +"       .size           my_tramp, .-my_tramp\n"
> +"       .popsection\n"
> +);
> +
> +#endif /* CONFIG_RISCV */
> +
>   #ifdef CONFIG_X86_64
> 
>   #include <asm/ibt.h>
> diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
> index 1f769d0db20f..2cfe5a7d2d70 100644
> --- a/samples/ftrace/ftrace-direct.c
> +++ b/samples/ftrace/ftrace-direct.c
> @@ -15,6 +15,28 @@ void my_direct_func(struct task_struct *p)
> 
>   extern void my_tramp(void *);
> 
> +#ifdef CONFIG_RISCV
> +
> +asm ("       .pushsection    .text, \"ax\", @progbits\n"
> +"       .type           my_tramp, @function\n"
> +"       .globl          my_tramp\n"
> +"   my_tramp:\n"
> +"       addi sp,sp,-24\n"
> +"       sd   a0,0(sp)\n"
> +"       sd   t0,8(sp)\n"
> +"       sd   ra,16(sp)\n"
> +"       call my_direct_func\n"
> +"       ld   a0,0(sp)\n"
> +"       ld   t0,8(sp)\n"
> +"       ld   ra,16(sp)\n"
> +"       addi sp,sp,24\n"
> +"       jr t0\n"
> +"       .size           my_tramp, .-my_tramp\n"
> +"       .popsection\n"
> +);
> +
> +#endif /* CONFIG_RISCV */
> +
>   #ifdef CONFIG_X86_64
> 
>   #include <asm/ibt.h>
> --
> 2.36.1
> 
> 

Regards,
Evgenii