From: Charlie Jenkins <charlie@rivosinc.com>
To: Nam Cao <namcaov@gmail.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] riscv: kprobes: simulate c.j instruction
Date: Tue, 8 Aug 2023 18:05:35 -0700 [thread overview]
Message-ID: <ZNLmX1wXu3ZivilA@ghost> (raw)
In-Reply-To: <ZNLZxIRM5iIjmdcD@ghost>
On Tue, Aug 08, 2023 at 05:11:48PM -0700, Charlie Jenkins wrote:
> On Sun, Jul 30, 2023 at 10:27:07AM +0200, Nam Cao wrote:
> > kprobes currently rejects c.j instruction. Implement it.
> >
> > Signed-off-by: Nam Cao <namcaov@gmail.com>
> > ---
> > arch/riscv/kernel/probes/decode-insn.c | 3 ++-
> > arch/riscv/kernel/probes/simulate-insn.c | 24 ++++++++++++++++++++++++
> > arch/riscv/kernel/probes/simulate-insn.h | 1 +
> > 3 files changed, 27 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/riscv/kernel/probes/decode-insn.c b/arch/riscv/kernel/probes/decode-insn.c
> > index 64f6183b4717..39adb07a342d 100644
> > --- a/arch/riscv/kernel/probes/decode-insn.c
> > +++ b/arch/riscv/kernel/probes/decode-insn.c
> > @@ -29,13 +29,14 @@ riscv_probe_decode_insn(probe_opcode_t *addr, struct arch_probe_insn *api)
> > * TODO: the REJECTED ones below need to be implemented
> > */
> > #ifdef CONFIG_RISCV_ISA_C
> > - RISCV_INSN_REJECTED(c_j, insn);
> > RISCV_INSN_REJECTED(c_jr, insn);
> > RISCV_INSN_REJECTED(c_jal, insn);
> > RISCV_INSN_REJECTED(c_jalr, insn);
> > RISCV_INSN_REJECTED(c_beqz, insn);
> > RISCV_INSN_REJECTED(c_bnez, insn);
> > RISCV_INSN_REJECTED(c_ebreak, insn);
> > +
> > + RISCV_INSN_SET_SIMULATE(c_j, insn);
> > #endif
> >
> > RISCV_INSN_SET_SIMULATE(jal, insn);
> > diff --git a/arch/riscv/kernel/probes/simulate-insn.c b/arch/riscv/kernel/probes/simulate-insn.c
> > index 7441ac8a6843..3ba45c612cd8 100644
> > --- a/arch/riscv/kernel/probes/simulate-insn.c
> > +++ b/arch/riscv/kernel/probes/simulate-insn.c
> > @@ -188,3 +188,27 @@ bool __kprobes simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *r
> >
> > return true;
> > }
> > +
> > +bool __kprobes simulate_c_j(u32 opcode, unsigned long addr, struct pt_regs *regs)
> > +{
> > + /*
> > + * 15 13 12 2 1 0
> > + * | funct3 | offset[11|4|9:8|10|6|7|3:1|5] | opcode |
> > + * 3 11 2
> > + */
> > +
> > + s32 offset;
> > +
> > + offset = ((opcode >> 3) & 0x7) << 1;
> > + offset |= ((opcode >> 11) & 0x1) << 4;
> > + offset |= ((opcode >> 2) & 0x1) << 5;
> > + offset |= ((opcode >> 7) & 0x1) << 6;
> > + offset |= ((opcode >> 6) & 0x1) << 7;
> > + offset |= ((opcode >> 9) & 0x3) << 8;
> > + offset |= ((opcode >> 8) & 0x1) << 10;
> > + offset |= ((opcode >> 12) & 0x1) << 11;
> > +
> > + instruction_pointer_set(regs, addr + sign_extend32(offset, 11));
> Can you use riscv_insn_insert_jtype_imm() from insn.h since it is
> already created? It will also sign extend for you. Don't worry about
> creating a similar function for the branches, I am in the process of
> refactoring the insn.h file.
> > +
> > + return true;
> > +}
> > diff --git a/arch/riscv/kernel/probes/simulate-insn.h b/arch/riscv/kernel/probes/simulate-insn.h
> > index 61e35db31001..4bd6c266e7d3 100644
> > --- a/arch/riscv/kernel/probes/simulate-insn.h
> > +++ b/arch/riscv/kernel/probes/simulate-insn.h
> > @@ -24,5 +24,6 @@ bool simulate_auipc(u32 opcode, unsigned long addr, struct pt_regs *regs);
> > bool simulate_branch(u32 opcode, unsigned long addr, struct pt_regs *regs);
> > bool simulate_jal(u32 opcode, unsigned long addr, struct pt_regs *regs);
> > bool simulate_jalr(u32 opcode, unsigned long addr, struct pt_regs *regs);
> > +bool simulate_c_j(u32 opcode, unsigned long addr, struct pt_regs *regs);
> >
> > #endif /* _RISCV_KERNEL_PROBES_SIMULATE_INSN_H */
> > --
> > 2.34.1
> >
> >
> > _______________________________________________
> > linux-riscv mailing list
> > linux-riscv@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-riscv
> Thanks,
> Charlie
Oh sorry, I forgot this was compressed. You can ignore the last message.
The changes look good. You can add:
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2023-08-09 1:05 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-30 8:27 [PATCH 0/3] riscv: kprobes: simulate some instructions Nam Cao
2023-07-30 8:27 ` [PATCH 1/3] riscv: kprobes: simulate c.j instruction Nam Cao
2023-08-09 0:11 ` Charlie Jenkins
2023-08-09 1:05 ` Charlie Jenkins [this message]
2023-07-30 8:27 ` [PATCH 2/3] riscv: kprobes: simulate c.jr and c.jalr instructions Nam Cao
2023-08-09 1:06 ` Charlie Jenkins
2023-07-30 8:27 ` [PATCH 3/3] riscv: kprobes: simulate c.beqz and c.bnez Nam Cao
2023-08-09 1:14 ` Charlie Jenkins
2023-07-30 8:27 ` test code for kprobe Nam Cao
2023-08-14 12:28 ` Björn Töpel
2023-08-14 13:50 ` Nam Cao
2023-08-14 14:10 ` Björn Töpel
2023-08-30 13:20 ` [PATCH 0/3] riscv: kprobes: simulate some instructions patchwork-bot+linux-riscv
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=ZNLmX1wXu3ZivilA@ghost \
--to=charlie@rivosinc.com \
--cc=aou@eecs.berkeley.edu \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=namcaov@gmail.com \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@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;
as well as URLs for NNTP newsgroup(s).