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Commit 13a63354 authored by Will Deacon's avatar Will Deacon Committed by Quentin Perret
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FROMGIT: samples/hw_breakpoint: drop use of kallsyms_lookup_name() 

The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2 ("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.

Bug: 149978696
Change-Id: I589142af97a34484f9fa551b934148f445b33243
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org


Signed-off-by: default avatarWill Deacon <will@kernel.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
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: Quentin Perret <qperret@google.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
(cherry picked from commit e108898157d888c827a7176e02648cc3bd87025b
 https://github.com/hnaz/linux-mm.git

 master)
Signed-off-by: default avatarQuentin Perret <qperret@google.com>
parent b10b8187

samples/hw_breakpoint/data_breakpoint.c

+7 −2
Original line number Diff line number Diff line
@@ -36,7 +36,7 @@ 


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");
@@ -54,9 +54,13 @@ 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;
@@ -79,6 +83,7 @@ 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);

}