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authorThomas Gleixner <tglx@linutronix.de>2020-03-11 01:47:39 +0300
committerThomas Gleixner <tglx@linutronix.de>2020-06-11 16:14:36 +0300
commit126f21f0e8d46e2c0e9daafb67546dbfb316d325 (patch)
tree409cadd1911f2e4e16b70e83d656222fa124ec12 /lib
parent0372007f5a79d61d3cb48a507717b9afb5d6addd (diff)
downloadlinux-126f21f0e8d46e2c0e9daafb67546dbfb316d325.tar.xz
lib/smp_processor_id: Move it into noinstr section
That code is already not traceable. Move it into the noinstr section so the objtool section validation does not trigger. Annotate the warning code as "safe". While it might be not under all circumstances, getting the information out is important enough. Should this ever trigger from the sensitive code which is shielded against instrumentation, e.g. low level entry, then the printk is the least of the worries. Addresses the objtool warnings: vmlinux.o: warning: objtool: context_tracking_recursion_enter()+0x7: call to __this_cpu_preempt_check() leaves .noinstr.text section vmlinux.o: warning: objtool: __context_tracking_exit()+0x17: call to __this_cpu_preempt_check() leaves .noinstr.text section vmlinux.o: warning: objtool: __context_tracking_enter()+0x2a: call to __this_cpu_preempt_check() leaves .noinstr.text section Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Link: https://lkml.kernel.org/r/20200505134340.902709267@linutronix.de
Diffstat (limited to 'lib')
-rw-r--r--lib/smp_processor_id.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/lib/smp_processor_id.c b/lib/smp_processor_id.c
index bd9571653288..525222e4f409 100644
--- a/lib/smp_processor_id.c
+++ b/lib/smp_processor_id.c
@@ -8,7 +8,7 @@
#include <linux/kprobes.h>
#include <linux/sched.h>
-notrace static nokprobe_inline
+noinstr static
unsigned int check_preemption_disabled(const char *what1, const char *what2)
{
int this_cpu = raw_smp_processor_id();
@@ -37,6 +37,7 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
*/
preempt_disable_notrace();
+ instrumentation_begin();
if (!printk_ratelimit())
goto out_enable;
@@ -45,6 +46,7 @@ unsigned int check_preemption_disabled(const char *what1, const char *what2)
printk("caller is %pS\n", __builtin_return_address(0));
dump_stack();
+ instrumentation_end();
out_enable:
preempt_enable_no_resched_notrace();
@@ -52,16 +54,14 @@ out:
return this_cpu;
}
-notrace unsigned int debug_smp_processor_id(void)
+noinstr unsigned int debug_smp_processor_id(void)
{
return check_preemption_disabled("smp_processor_id", "");
}
EXPORT_SYMBOL(debug_smp_processor_id);
-NOKPROBE_SYMBOL(debug_smp_processor_id);
-notrace void __this_cpu_preempt_check(const char *op)
+noinstr void __this_cpu_preempt_check(const char *op)
{
check_preemption_disabled("__this_cpu_", op);
}
EXPORT_SYMBOL(__this_cpu_preempt_check);
-NOKPROBE_SYMBOL(__this_cpu_preempt_check);