kbuild: introduce __init_refok/__initdata_refok to supress section mismatch warnings (0e0d314e) · Commits · 戴 / test

include/asm-generic/vmlinux.lds.h

+4 −2

Original line number	Diff line number	Diff line
		@@ -11,7 +11,8 @@

		/* .data section */
		#define DATA_DATA \
		*(.data)
		*(.data) \
		*(.data.init.refok)

		#define RODATA \
		. = ALIGN(4096); \
		@@ -147,7 +148,8 @@
		* during second ld run in second ld pass when generating System.map */
		#define TEXT_TEXT \
		ALIGN_FUNCTION(); \
		*(.text)
		*(.text) \
		*(.text.init.refok)

		/* sched.text is aling to function alignment to secure we have same
		* address even at second ld pass when generating System.map */

+13 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,19 @@
		#define __exitdata __attribute__ ((__section__(".exit.data")))
		#define __exit_call __attribute_used__ __attribute__ ((__section__ (".exitcall.exit")))

		/* modpost check for section mismatches during the kernel build.
		* A section mismatch happens when there are references from a
		* code or data section to an init section (both code or data).
		* The init sections are (for most archs) discarded by the kernel
		* when early init has completed so all such references are potential bugs.
		* For exit sections the same issue exists.
		* The following markers are used for the cases where the reference to
		* the init/exit section (code or data) is valid and will teach modpost
		* not to issue a warning.
		* The markers follow same syntax rules as __init / __initdata. */
		#define __init_refok noinline __attribute__ ((__section__ (".text.init.refok")))
		#define __initdata_refok __attribute__ ((__section__ (".data.init.refok")))

		#ifdef MODULE
		#define __exit __attribute__ ((__section__(".exit.text")))
		#else

+11 −0

Original line number	Diff line number	Diff line
		@@ -583,6 +583,12 @@ static int strrcmp(const char s, const char sub)

		/**
		* Whitelist to allow certain references to pass with no warning.
		*
		* Pattern 0:
		* Do not warn if funtion/data are marked with __init_refok/__initdata_refok.
		* The pattern is identified by:
		* fromsec = .text.init.refok \| .data.init.refok
		*
		* Pattern 1:
		* If a module parameter is declared __initdata and permissions=0
		* then this is legal despite the warning generated.
		@@ -686,6 +692,11 @@ static int secref_whitelist(const char modname, const char tosec,
		NULL
		};

		/* Check for pattern 0 */
		if ((strcmp(fromsec, ".text.init.refok") == 0) \|\|
		(strcmp(fromsec, ".data.init.refok") == 0))
		return 1;

		/* Check for pattern 1 */
		if (strcmp(tosec, ".init.data") != 0)
		f1 = 0;