linux-kernel - Re: [PATCH 01/11] riscv: kprobes: Move branch_rs2

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <602a2de6-3b6f-4fc9-b50d-90539361c50b@ghiti.fr>
Date: Wed, 14 May 2025 09:24:55 +0200
From: Alexandre Ghiti <alex@...ti.fr>
To: Nam Cao <namcao@...utronix.de>, Paul Walmsley <paul.walmsley@...ive.com>,
 Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>,
 linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/11] riscv: kprobes: Move branch_rs2_idx to insn.h

Hi Nam,

On 11/05/2025 23:17, Nam Cao wrote:
> Similar to other instruction-processing macros/functions, branch_rs2_idx
> should be in insn.h.
>
> Move it into insn.h as RV_EXTRACT_RS2_REG. This new name matches the style
> in insn.h.
>
> Signed-off-by: Nam Cao <namcao@...utronix.de>
> ---
>   arch/riscv/include/asm/insn.h            | 5 +++++
>   arch/riscv/kernel/probes/simulate-insn.c | 5 +----
>   2 files changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/riscv/include/asm/insn.h b/arch/riscv/include/asm/insn.h
> index 09fde95a5e8f..debac13a3476 100644
> --- a/arch/riscv/include/asm/insn.h
> +++ b/arch/riscv/include/asm/insn.h
> @@ -64,6 +64,7 @@
>   #define RVG_RS2_OPOFF		20
>   #define RVG_RD_OPOFF		7
>   #define RVG_RS1_MASK		GENMASK(4, 0)
> +#define RVG_RS2_MASK		GENMASK(4, 0)
>   #define RVG_RD_MASK		GENMASK(4, 0)
>   
>   /* The bit field of immediate value in RVC J instruction */
> @@ -295,6 +296,10 @@ static __always_inline bool riscv_insn_is_c_jalr(u32 code)
>   	({typeof(x) x_ = (x); \
>   	(RV_X(x_, RVG_RS1_OPOFF, RVG_RS1_MASK)); })
>   
> +#define RV_EXTRACT_RS2_REG(x) \
> +	({typeof(x) x_ = (x); \
> +	(RV_X(x_, RVG_RS2_OPOFF, RVG_RS2_MASK)); })


RV_X() definition was inconsistent across multiple files, so I 
harmonized RV_X() it in this patch 
https://lore.kernel.org/linux-riscv/20250508125202.108613-3-alexghiti@rivosinc.com/

So here you use the "old" version, would you mind rebasing on top this 
patchset and use RV_X_mask() instead?

If you can't, let me know and I'll find some time, I'd like to merge 
those cleanups in 6.16.

Thanks,

Alex


> +
>   #define RV_EXTRACT_RD_REG(x) \
>   	({typeof(x) x_ = (x); \
>   	(RV_X(x_, RVG_RD_OPOFF, RVG_RD_MASK)); })
> diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/probes/simulate-insn.c
> index 6c166029079c..77be381bb8b4 100644
> --- a/arch/riscv/kernel/probes/simulate-insn.c
> +++ b/arch/riscv/kernel/probes/simulate-insn.c
> @@ -121,9 +121,6 @@ bool __kprobes simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *re
>   #define branch_rs1_idx(opcode) \
>   	(((opcode) >> 15) & 0x1f)
>   
> -#define branch_rs2_idx(opcode) \
> -	(((opcode) >> 20) & 0x1f)
> -
>   #define branch_funct3(opcode) \
>   	(((opcode) >> 12) & 0x7)
>   
> @@ -157,7 +154,7 @@ bool __kprobes simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *r
>   	unsigned long rs2_val;
>   
>   	if (!rv_insn_reg_get_val(regs, branch_rs1_idx(opcode), &rs1_val) ||
> -	    !rv_insn_reg_get_val(regs, branch_rs2_idx(opcode), &rs2_val))
> +	    !rv_insn_reg_get_val(regs, RV_EXTRACT_RS2_REG(opcode), &rs2_val))
>   		return false;
>   
>   	offset_tmp = branch_offset(opcode);