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// SPDX-License-Identifier: GPL-2.0
/*
* Static call site in a patched function, laid out by hand as for
* jump_label.c. MODNAME selects whether the key belongs to vmlinux or a
* module.
*
* objtool's check pass would emit the site, and klp-write-tests.txt says to
* let it. Not here: it does not emit the ANNOTATE_DATA_SPECIAL describing
* the entry boundaries -- in the kernel that comes from the static_call
* macros -- and NO_ANNOTATE below has to be able to take it away. A fixture
* which varies the annotation has to write the entry that goes with it.
*
* NO_ANNOTATE drops the ANNOTATE_DATA_SPECIAL block from the patched build,
* leaving .static_call_sites with no annotation to describe its entry
* boundaries. The section carries no entsize either, so klp diff has to fall
* back on the annotations it can still see -- and when the patched object is
* the only one that lost them, the two sides disagree about how the section is
* divided up.
*
* NEW_CALL puts the call site behind PATCHED, so the patch introduces one
* where the original had none. The .static_call_sites entry is then new, with
* nothing in the original to correlate it against.
*/
#ifndef MODNAME
#define MODNAME "vmlinux"
#endif
static const char __modinfo[]
__attribute__((section(".modinfo"), used, aligned(1))) = "\0name=" MODNAME;
long __SCK__klp_test_call;
int target(int x)
{
#if defined(NEW_CALL) && !defined(PATCHED)
/* The original has no static call at all. */
return x + 1;
#else
__asm__ volatile(
"1: nop\n\t"
".pushsection .static_call_sites, \"aw\"\n\t"
".balign 8\n\t"
"912:\n\t"
#if !(defined(PATCHED) && defined(NO_ANNOTATE))
".pushsection .discard.annotate_data, \"M\", @progbits, 8\n\t"
".long 912b - ., 1\n\t"
".popsection\n\t"
#endif
".long 1b - ., %c0 - .\n\t"
".popsection\n\t"
:: "i" (&__SCK__klp_test_call));
#endif
#ifdef PATCHED
return x + 2;
#else
return x + 1;
#endif
}
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