From: "Clément Léger" <cleger@rivosinc.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>
Cc: "Clément Léger" <cleger@rivosinc.com>,
linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] riscv: blacklist assembly symbols for kprobe
Date: Wed, 4 Oct 2023 15:10:09 +0200 [thread overview]
Message-ID: <20231004131009.409193-1-cleger@rivosinc.com> (raw)
Adding kprobes on some assembly functions (mainly exception handling)
will result in crashes (either recursive trap or panic). To avoid such
errors, add ASM_NOKPROBE() macro which allow adding specific symbols
into the __kprobe_blacklist section and use to blacklist the following
symbols that showed to be problematic:
- handle_exception()
- ret_from_exception()
- handle_kernel_stack_overflow()
Signed-off-by: Clément Léger <cleger@rivosinc.com>
---
arch/riscv/include/asm/asm.h | 10 ++++++++++
arch/riscv/kernel/entry.S | 3 +++
2 files changed, 13 insertions(+)
diff --git a/arch/riscv/include/asm/asm.h b/arch/riscv/include/asm/asm.h
index 114bbadaef41..9194e334de15 100644
--- a/arch/riscv/include/asm/asm.h
+++ b/arch/riscv/include/asm/asm.h
@@ -142,6 +142,16 @@
REG_L x31, PT_T6(sp)
.endm
+/* Annotate a function as being unsuitable for kprobes. */
+#ifdef CONFIG_KPROBES
+#define ASM_NOKPROBE(name) \
+ .pushsection "_kprobe_blacklist", "aw"; \
+ RISCV_PTR name; \
+ .popsection
+#else
+#define ASM_NOKPROBE(name)
+#endif
+
#endif /* __ASSEMBLY__ */
#endif /* _ASM_RISCV_ASM_H */
diff --git a/arch/riscv/kernel/entry.S b/arch/riscv/kernel/entry.S
index 143a2bb3e697..f24bc4eeedde 100644
--- a/arch/riscv/kernel/entry.S
+++ b/arch/riscv/kernel/entry.S
@@ -101,6 +101,7 @@ _save_context:
1:
tail do_trap_unknown
SYM_CODE_END(handle_exception)
+ASM_NOKPROBE(handle_exception)
/*
* The ret_from_exception must be called with interrupt disabled. Here is the
@@ -167,6 +168,7 @@ SYM_CODE_START_NOALIGN(ret_from_exception)
sret
#endif
SYM_CODE_END(ret_from_exception)
+ASM_NOKPROBE(ret_from_exception)
#ifdef CONFIG_VMAP_STACK
SYM_CODE_START_LOCAL(handle_kernel_stack_overflow)
@@ -254,6 +256,7 @@ restore_caller_reg:
move a0, sp
tail handle_bad_stack
SYM_CODE_END(handle_kernel_stack_overflow)
+ASM_NOKPROBE(handle_kernel_stack_overflow)
#endif
SYM_CODE_START(ret_from_fork)
--
2.42.0
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next reply other threads:[~2023-10-04 13:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 13:10 Clément Léger [this message]
2023-10-09 17:43 ` [PATCH] riscv: blacklist assembly symbols for kprobe Charlie Jenkins
2024-01-25 21:30 ` 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=20231004131009.409193-1-cleger@rivosinc.com \
--to=cleger@rivosinc.com \
--cc=aou@eecs.berkeley.edu \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--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).