From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: kernel-team@android.com, akpm@linux-foundation.org,
Will Deacon <will@kernel.org>,
"K . Prasad" <prasad@linux.vnet.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Frederic Weisbecker <frederic@kernel.org>,
Christoph Hellwig <hch@lst.de>,
Quentin Perret <qperret@google.com>,
Alexei Starovoitov <ast@kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: [PATCH 2/3] samples/hw_breakpoint: Drop use of kallsyms_lookup_name()
Date: Fri, 21 Feb 2020 11:44:03 +0000 [thread overview]
Message-ID: <20200221114404.14641-3-will@kernel.org> (raw)
In-Reply-To: <20200221114404.14641-1-will@kernel.org>
The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad04 ("hw-breakpoints: Fix broken hw-breakpoint sample module").
In preparation for un-exporting this symbol, switch the test over to
using __symbol_get(), which can be used to place breakpoints on exported
symbols.
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Quentin Perret <qperret@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
samples/hw_breakpoint/data_breakpoint.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/samples/hw_breakpoint/data_breakpoint.c b/samples/hw_breakpoint/data_breakpoint.c
index 469b36f93696..418c46fe5ffc 100644
--- a/samples/hw_breakpoint/data_breakpoint.c
+++ b/samples/hw_breakpoint/data_breakpoint.c
@@ -23,7 +23,7 @@
struct perf_event * __percpu *sample_hbp;
-static char ksym_name[KSYM_NAME_LEN] = "pid_max";
+static char ksym_name[KSYM_NAME_LEN] = "jiffies";
module_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO);
MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any"
" write operations on the kernel symbol");
@@ -41,9 +41,13 @@ static int __init hw_break_module_init(void)
{
int ret;
struct perf_event_attr attr;
+ void *addr = __symbol_get(ksym_name);
+
+ if (!addr)
+ return -ENXIO;
hw_breakpoint_init(&attr);
- attr.bp_addr = kallsyms_lookup_name(ksym_name);
+ attr.bp_addr = (unsigned long)addr;
attr.bp_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = HW_BREAKPOINT_W;
@@ -66,6 +70,7 @@ static int __init hw_break_module_init(void)
static void __exit hw_break_module_exit(void)
{
unregister_wide_hw_breakpoint(sample_hbp);
+ symbol_put(ksym_name);
printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);
}
--
2.25.0.265.gbab2e86ba0-goog
next prev parent reply other threads:[~2020-02-21 11:44 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-21 11:44 [PATCH 0/3] Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol() Will Deacon
2020-02-21 11:44 ` [PATCH 1/3] samples/hw_breakpoint: Drop HW_BREAKPOINT_R when reporting writes Will Deacon
2020-02-21 14:12 ` Christoph Hellwig
2020-02-21 11:44 ` Will Deacon [this message]
2020-02-21 14:13 ` [PATCH 2/3] samples/hw_breakpoint: Drop use of kallsyms_lookup_name() Christoph Hellwig
2020-02-21 14:20 ` Will Deacon
2020-02-21 11:44 ` [PATCH 3/3] kallsyms: Unexport kallsyms_lookup_name() and kallsyms_on_each_symbol() Will Deacon
2020-02-21 11:53 ` Greg Kroah-Hartman
2020-02-21 14:14 ` Christoph Hellwig
2020-02-21 15:11 ` Alexei Starovoitov
2020-02-21 14:27 ` [PATCH 0/3] " Masami Hiramatsu
2020-02-21 14:48 ` Will Deacon
2020-02-21 23:44 ` Masami Hiramatsu
2020-02-21 15:41 ` David Laight
2020-02-21 16:25 ` Quentin Perret
2020-02-25 10:05 ` Miroslav Benes
2020-02-25 12:11 ` Petr Mladek
2020-02-25 15:00 ` Joe Lawrence
2020-02-25 18:01 ` Miroslav Benes
2020-02-26 14:16 ` Joe Lawrence
2020-03-02 19:28 ` Mathieu Desnoyers
2020-03-02 19:36 ` Greg Kroah-Hartman
2020-03-02 19:39 ` Greg Kroah-Hartman
2020-03-02 20:17 ` Mathieu Desnoyers
2020-03-03 6:57 ` Greg Kroah-Hartman
2020-03-03 16:58 ` Mathieu Desnoyers
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