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samples/hw_breakpoint: drop use of kallsyms_lookup_name()

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The 'data_breakpoint' test code is the only modular user of
kallsyms_lookup_name(), which was exported as part of fixing the test in
f60d24d2ad ("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.

Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Quentin Perret <qperret@google.com>
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: Alexei Starovoitov <ast@kernel.org>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Joe Lawrence <joe.lawrence@redhat.com>
Link: http://lkml.kernel.org/r/20200221114404.14641-3-will@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Will Deacon 2020-04-06 20:11:39 -07:00 committed by Linus Torvalds
parent 4800314e19
commit d8a84d33a4
1 changed files with 7 additions and 2 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

9
samples/hw_breakpoint/data_breakpoint.c
View file

@ -23,7 +23,7 @@
struct perf_event * __percpu *sample_hbp; 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_param_string(ksym, ksym_name, KSYM_NAME_LEN, S_IRUGO);
MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any" MODULE_PARM_DESC(ksym, "Kernel symbol to monitor; this module will report any"
" write operations on the kernel symbol"); " write operations on the kernel symbol");
@ -41,9 +41,13 @@ static int __init hw_break_module_init(void)
{ {
int ret; int ret;
struct perf_event_attr attr; struct perf_event_attr attr;
void *addr = __symbol_get(ksym_name);
if (!addr)
return -ENXIO;
hw_breakpoint_init(&attr); 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_len = HW_BREAKPOINT_LEN_4;
attr.bp_type = HW_BREAKPOINT_W; 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) static void __exit hw_break_module_exit(void)
{ {
unregister_wide_hw_breakpoint(sample_hbp); unregister_wide_hw_breakpoint(sample_hbp);
symbol_put(ksym_name);
printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name); printk(KERN_INFO "HW Breakpoint for %s write uninstalled\n", ksym_name);
} }