x86/nmi: Fix section mismatch warnings on 32-bit

It was reported that compiling for 32-bit caused a bunch of section mismatch warnings: VDSOSYM arch/x86/vdso/vdso32-syms.lds LD arch/x86/vdso/built-in.o LD arch/x86/built-in.o WARNING: arch/x86/built-in.o(.data+0x5af0): Section mismatch in reference from the variable test_nmi_ipi_callback_na.10451 to the function .init.text:test_nmi_ipi_callback() [...] WARNING: arch/x86/built-in.o(.data+0x5b04): Section mismatch in reference from the variable nmi_unk_cb_na.10399 to the function .init.text:nmi_unk_cb() The variable nmi_unk_cb_na.10399 references the function __init nmi_unk_cb() [...] Both of these are attributed to the internal representation of the nmiaction struct created during register_nmi_handler. The reason for this is that those structs are not defined in the init section whereas the rest of the code in nmi_selftest.c is. To resolve this, I created a new #define, register_nmi_handler_initonly, that tags the struct as __initdata to resolve the mismatch. This #define should only be used in rare situations where the register/unregister is called during init of the kernel. Big thanks to Jan Beulich for decoding this for me as I didn't have a clue what was going on.

Don Zickus committed 14 years ago

Commit eeaaa961 parent d5d2d2e2 files · +16 −2Browse files

Unified · Split

2 files

arch/x86/include/asm/nmi.h +14 −0
arch/x86/kernel/nmi_selftest.c +2 −2

arch/x86/include/asm/nmi.h+14−0

@@ -54,6 +54,20 @@ struct nmiaction { · 53 unmodified lines
54	54	__register_nmi_handler((t), &fn##_na); \
55	55	})
56	56
	57	+/*
	58	+ * For special handlers that register/unregister in the
	59	+ * init section only. This should be considered rare.
	60	+ */
	61	+#define register_nmi_handler_initonly(t, fn, fg, n) \
	62	+({ \
	63	+ static struct nmiaction fn##_na __initdata = { \
	64	+ .handler = (fn), \
	65	+ .name = (n), \
	66	+ .flags = (fg), \
	67	+ }; \
	68	+ __register_nmi_handler((t), &fn##_na); \
	69	+})
	70	+
57	71	int __register_nmi_handler(unsigned int, struct nmiaction *);
58	72
59	73	void unregister_nmi_handler(unsigned int, const char *);

arch/x86/kernel/nmi_selftest.c+2−2

@@ -42,7 +42,7 @@ static int __init nmi_unk_cb(unsigned int val, struct pt_regs *regs) · 41 unmodified lines
42	42	static void __init init_nmi_testsuite(void)
43	43	{
44	44	/* trap all the unknown NMIs we may generate */
45		− register_nmi_handler(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk");
	45	+ register_nmi_handler_initonly(NMI_UNKNOWN, nmi_unk_cb, 0, "nmi_selftest_unk");
46	46	}
47	47
48	48	static void __init cleanup_nmi_testsuite(void)
@@ -64,7 +64,7 @@ static void __init test_nmi_ipi(struct cpumask *mask) · 15 unmodified lines
64	64	{
65	65	unsigned long timeout;
66	66
67		− if (register_nmi_handler(NMI_LOCAL, test_nmi_ipi_callback,
	67	+ if (register_nmi_handler_initonly(NMI_LOCAL, test_nmi_ipi_callback,
68	68	NMI_FLAG_FIRST, "nmi_selftest")) {
69	69	nmi_fail = FAILURE;
70	70	return;