From: Nathan Chancellor <nathan@kernel.org>
To: Andy Chiu <andy.chiu@sifive.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexandre Ghiti <alexghiti@rivosinc.com>,
Zong Li <zong.li@sifive.com>,
Steven Rostedt <rostedt@goodmis.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Nick Desaulniers <ndesaulniers@google.com>,
Bill Wendling <morbo@google.com>,
Justin Stitt <justinstitt@google.com>,
Puranjay Mohan <puranjay@kernel.org>,
Palmer Dabbelt <palmer@rivosinc.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org,
linux-trace-kernel@vger.kernel.org, llvm@lists.linux.dev,
Evgenii Shatokhin <e.shatokhin@yadro.com>
Subject: Re: [PATCH 3/8] riscv: ftrace: support fastcc in Clang for WITH_ARGS
Date: Thu, 13 Jun 2024 15:36:15 -0700 [thread overview]
Message-ID: <20240613223615.GA2739249@thelio-3990X> (raw)
In-Reply-To: <20240613-dev-andyc-dyn-ftrace-v4-v1-3-1a538e12c01e@sifive.com>
On Thu, Jun 13, 2024 at 03:11:08PM +0800, Andy Chiu wrote:
> Some caller-saved registers which are not defined as function arguments
> in the ABI can still be passed as arguments when the kernel is compiled
> with Clang. As a result, we must save and restore those registers to
> prevent ftrace from clobbering them.
>
> - [1]: https://reviews.llvm.org/D68559
> Reported-by: Evgenii Shatokhin <e.shatokhin@yadro.com>
> Closes: https://lore.kernel.org/linux-riscv/7e7c7914-445d-426d-89a0-59a9199c45b1@yadro.com/
> Signed-off-by: Andy Chiu <andy.chiu@sifive.com>
Acked-by: Nathan Chancellor <nathan@kernel.org>
> ---
> arch/riscv/include/asm/ftrace.h | 7 +++++++
> arch/riscv/kernel/asm-offsets.c | 7 +++++++
> arch/riscv/kernel/mcount-dyn.S | 16 ++++++++++++++--
> 3 files changed, 28 insertions(+), 2 deletions(-)
>
> diff --git a/arch/riscv/include/asm/ftrace.h b/arch/riscv/include/asm/ftrace.h
> index 9eb31a7ea0aa..5f81c53dbfd9 100644
> --- a/arch/riscv/include/asm/ftrace.h
> +++ b/arch/riscv/include/asm/ftrace.h
> @@ -144,6 +144,13 @@ struct ftrace_regs {
> unsigned long a5;
> unsigned long a6;
> unsigned long a7;
> +#ifdef CONFIG_CC_IS_CLANG
> + unsigned long t2;
> + unsigned long t3;
> + unsigned long t4;
> + unsigned long t5;
> + unsigned long t6;
> +#endif
> };
> };
> };
> diff --git a/arch/riscv/kernel/asm-offsets.c b/arch/riscv/kernel/asm-offsets.c
> index b09ca5f944f7..db5a26fcc9ae 100644
> --- a/arch/riscv/kernel/asm-offsets.c
> +++ b/arch/riscv/kernel/asm-offsets.c
> @@ -497,6 +497,13 @@ void asm_offsets(void)
> DEFINE(FREGS_SP, offsetof(struct ftrace_regs, sp));
> DEFINE(FREGS_S0, offsetof(struct ftrace_regs, s0));
> DEFINE(FREGS_T1, offsetof(struct ftrace_regs, t1));
> +#ifdef CONFIG_CC_IS_CLANG
> + DEFINE(FREGS_T2, offsetof(struct ftrace_regs, t2));
> + DEFINE(FREGS_T3, offsetof(struct ftrace_regs, t3));
> + DEFINE(FREGS_T4, offsetof(struct ftrace_regs, t4));
> + DEFINE(FREGS_T5, offsetof(struct ftrace_regs, t5));
> + DEFINE(FREGS_T6, offsetof(struct ftrace_regs, t6));
> +#endif
> DEFINE(FREGS_A0, offsetof(struct ftrace_regs, a0));
> DEFINE(FREGS_A1, offsetof(struct ftrace_regs, a1));
> DEFINE(FREGS_A2, offsetof(struct ftrace_regs, a2));
> diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S
> index 745dd4c4a69c..e988bd26b28b 100644
> --- a/arch/riscv/kernel/mcount-dyn.S
> +++ b/arch/riscv/kernel/mcount-dyn.S
> @@ -96,7 +96,13 @@
> REG_S x8, FREGS_S0(sp)
> #endif
> REG_S x6, FREGS_T1(sp)
> -
> +#ifdef CONFIG_CC_IS_CLANG
> + REG_S x7, FREGS_T2(sp)
> + REG_S x28, FREGS_T3(sp)
> + REG_S x29, FREGS_T4(sp)
> + REG_S x30, FREGS_T5(sp)
> + REG_S x31, FREGS_T6(sp)
> +#endif
> // save the arguments
> REG_S x10, FREGS_A0(sp)
> REG_S x11, FREGS_A1(sp)
> @@ -115,7 +121,13 @@
> REG_L x8, FREGS_S0(sp)
> #endif
> REG_L x6, FREGS_T1(sp)
> -
> +#ifdef CONFIG_CC_IS_CLANG
> + REG_L x7, FREGS_T2(sp)
> + REG_L x28, FREGS_T3(sp)
> + REG_L x29, FREGS_T4(sp)
> + REG_L x30, FREGS_T5(sp)
> + REG_L x31, FREGS_T6(sp)
> +#endif
> // restore the arguments
> REG_L x10, FREGS_A0(sp)
> REG_L x11, FREGS_A1(sp)
>
> --
> 2.43.0
>
next prev parent reply other threads:[~2024-06-13 22:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-06-13 7:11 [PATCH 0/8] riscv: ftrace: atmoic patching and preempt improvements Andy Chiu
2024-06-13 7:11 ` [PATCH 1/8] riscv: stacktrace: convert arch_stack_walk() to noinstr Andy Chiu
2024-06-18 9:55 ` Alexandre Ghiti
2024-06-25 15:45 ` Palmer Dabbelt
2024-06-13 7:11 ` [PATCH 2/8] tracing: do not trace kernel_text_address() Andy Chiu
2024-06-13 13:32 ` Steven Rostedt
2024-06-17 2:10 ` Andy Chiu
2024-06-13 7:11 ` [PATCH 3/8] riscv: ftrace: support fastcc in Clang for WITH_ARGS Andy Chiu
2024-06-13 22:36 ` Nathan Chancellor [this message]
2024-06-13 7:11 ` [PATCH 4/8] riscv: ftrace: align patchable functions to 4 Byte boundary Andy Chiu
2024-06-13 19:09 ` Nathan Chancellor
2024-06-17 2:38 ` Andy Chiu
2024-06-17 3:13 ` Andy Chiu
2024-06-17 16:52 ` Nathan Chancellor
2024-06-13 7:11 ` [PATCH 5/8] riscv: ftrace: prepare ftrace for atomic code patching Andy Chiu
2024-06-13 7:11 ` [PATCH 6/8] riscv: ftrace: do not use stop_machine to update code Andy Chiu
2024-06-13 7:11 ` [PATCH 7/8] riscv: vector: Support calling schedule() for preemptible Vector Andy Chiu
2024-06-13 7:11 ` [PATCH 8/8] riscv: ftrace: support PREEMPT Andy Chiu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20240613223615.GA2739249@thelio-3990X \
--to=nathan@kernel.org \
--cc=alexghiti@rivosinc.com \
--cc=andy.chiu@sifive.com \
--cc=aou@eecs.berkeley.edu \
--cc=e.shatokhin@yadro.com \
--cc=justinstitt@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=linux-trace-kernel@vger.kernel.org \
--cc=llvm@lists.linux.dev \
--cc=mark.rutland@arm.com \
--cc=mhiramat@kernel.org \
--cc=morbo@google.com \
--cc=ndesaulniers@google.com \
--cc=palmer@dabbelt.com \
--cc=palmer@rivosinc.com \
--cc=paul.walmsley@sifive.com \
--cc=puranjay@kernel.org \
--cc=rostedt@goodmis.org \
--cc=zong.li@sifive.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox