From: Naveen N Rao <naveen@kernel.org>
To: <linuxppc-dev@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Florent Revest <revest@chromium.org>,
Nicholas Piggin <npiggin@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
"Aneesh Kumar K.V" <aneesh.kumar@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [RFC PATCH 5/9] powerpc/kprobes: Use ftrace to determine if a probe is at function entry
Date: Fri, 8 Dec 2023 22:00:44 +0530 [thread overview]
Message-ID: <15f0b3a2e72326423cfb4ce4e89afff540042245.1702045299.git.naveen@kernel.org> (raw)
In-Reply-To: <cover.1702045299.git.naveen@kernel.org>
Rather than hard-coding the offset into a function to be used to
determine if a kprobe is at function entry, use ftrace_location() to
determine the ftrace location within the function and categorize all
instructions till that offset to be function entry.
For functions that cannot be traced, we fall back to using a fixed
offset of 8 (two instructions) to categorize a probe as being at
function entry for 64-bit elfv2.
Signed-off-by: Naveen N Rao <naveen@kernel.org>
---
arch/powerpc/kernel/kprobes.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c
index b20ee72e873a..42665dfab59e 100644
--- a/arch/powerpc/kernel/kprobes.c
+++ b/arch/powerpc/kernel/kprobes.c
@@ -105,24 +105,22 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset)
return addr;
}
-static bool arch_kprobe_on_func_entry(unsigned long offset)
+static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset)
{
-#ifdef CONFIG_PPC64_ELF_ABI_V2
-#ifdef CONFIG_KPROBES_ON_FTRACE
- return offset <= 16;
-#else
- return offset <= 8;
-#endif
-#else
+ unsigned long ip = ftrace_location(addr);
+
+ if (ip)
+ return offset <= (ip - addr);
+ if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2))
+ return offset <= 8;
return !offset;
-#endif
}
/* XXX try and fold the magic of kprobe_lookup_name() in this */
kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset,
bool *on_func_entry)
{
- *on_func_entry = arch_kprobe_on_func_entry(offset);
+ *on_func_entry = arch_kprobe_on_func_entry(addr, offset);
return (kprobe_opcode_t *)(addr + offset);
}
--
2.43.0
next prev parent reply other threads:[~2023-12-08 16:39 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-08 16:30 [RFC PATCH 0/9] powerpc: ftrace updates Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 1/9] powerpc/ftrace: Fix indentation in ftrace.h Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 2/9] powerpc/ftrace: Unify 32-bit and 64-bit ftrace entry code Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 3/9] powerpc/ftrace: Remove nops after the call to ftrace_stub Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 4/9] powerpc/Kconfig: Select FUNCTION_ALIGNMENT_4B Naveen N Rao
2023-12-08 16:30 ` Naveen N Rao [this message]
2023-12-11 5:39 ` [RFC PATCH 5/9] powerpc/kprobes: Use ftrace to determine if a probe is at function entry Masami Hiramatsu
2023-12-08 16:30 ` [RFC PATCH 6/9] powerpc/ftrace: Update and move function profile instructions out-of-line Naveen N Rao
2023-12-21 10:46 ` Christophe Leroy
2023-12-21 14:25 ` Steven Rostedt
2023-12-21 15:20 ` Christophe Leroy
2023-12-22 15:01 ` Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 7/9] powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPS Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 8/9] powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_DIRECT_CALLS Naveen N Rao
2023-12-08 16:30 ` [RFC PATCH 9/9] samples/ftrace: Add support for ftrace direct samples on powerpc Naveen N Rao
2023-12-21 10:38 ` (subset) [RFC PATCH 0/9] powerpc: ftrace updates Michael Ellerman
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