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Revision ca41b97ed9124fd62323a162de5852f6e28f94b8 authored by Peter Zijlstra on 31 January 2018, 09:18:28 UTC, committed by Ingo Molnar on 21 February 2018, 08:05:05 UTC 
objtool: Add module specific retpoline rules
 
David allowed retpolines in .init.text, except for modules, which will
trip up objtool retpoline validation, fix that.

Requested-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
1 parent b5bc223
Raw File
percpu_test.c 
#include <linux/module.h>

/* validate @native and @pcp counter values match @expected */
#define CHECK(native, pcp, expected)                                    \
	do {                                                            \
		WARN((native) != (expected),                            \
		     "raw %ld (0x%lx) != expected %lld (0x%llx)",	\
		     (native), (native),				\
		     (long long)(expected), (long long)(expected));	\
		WARN(__this_cpu_read(pcp) != (expected),                \
		     "pcp %ld (0x%lx) != expected %lld (0x%llx)",	\
		     __this_cpu_read(pcp), __this_cpu_read(pcp),	\
		     (long long)(expected), (long long)(expected));	\
	} while (0)

static DEFINE_PER_CPU(long, long_counter);
static DEFINE_PER_CPU(unsigned long, ulong_counter);

static int __init percpu_test_init(void)
{
	/*
	 * volatile prevents compiler from optimizing it uses, otherwise the
	 * +ul_one/-ul_one below would replace with inc/dec instructions.
	 */
	volatile unsigned int ui_one = 1;
	long l = 0;
	unsigned long ul = 0;

	pr_info("percpu test start\n");

	preempt_disable();

	l += -1;
	__this_cpu_add(long_counter, -1);
	CHECK(l, long_counter, -1);

	l += 1;
	__this_cpu_add(long_counter, 1);
	CHECK(l, long_counter, 0);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += 1UL;
	__this_cpu_add(ulong_counter, 1UL);
	CHECK(ul, ulong_counter, 1);

	ul += -1UL;
	__this_cpu_add(ulong_counter, -1UL);
	CHECK(ul, ulong_counter, 0);

	ul += -(unsigned long)1;
	__this_cpu_add(ulong_counter, -(unsigned long)1);
	CHECK(ul, ulong_counter, -1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= 1;
	__this_cpu_dec(ulong_counter);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, 0xffffffff);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);


	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	__this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l += ui_one;
	__this_cpu_add(long_counter, ui_one);
	CHECK(l, long_counter, 1);

	l += -ui_one;
	__this_cpu_add(long_counter, -ui_one);
	CHECK(l, long_counter, (long)0x100000000LL);

	l = 0;
	__this_cpu_write(long_counter, 0);

	l -= ui_one;
	this_cpu_sub(long_counter, ui_one);
	CHECK(l, long_counter, -1);
	CHECK(l, long_counter, ULONG_MAX);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul += ui_one;
	__this_cpu_add(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	ul = 0;
	__this_cpu_write(ulong_counter, 0);

	ul -= ui_one;
	__this_cpu_sub(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, -1);
	CHECK(ul, ulong_counter, ULONG_MAX);

	ul = 3;
	__this_cpu_write(ulong_counter, 3);

	ul = this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 2);

	ul = __this_cpu_sub_return(ulong_counter, ui_one);
	CHECK(ul, ulong_counter, 1);

	preempt_enable();

	pr_info("percpu test done\n");
	return -EAGAIN;  /* Fail will directly unload the module */
}

static void __exit percpu_test_exit(void)
{
}

module_init(percpu_test_init)
module_exit(percpu_test_exit)

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Greg Thelen");
MODULE_DESCRIPTION("percpu operations test");
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