Merge branch 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (d09e356a) · Commits · 戴 / test

Pull read-only kernel memory updates from Ingo Molnar: "This tree adds two (security related) enhancements to the kernel's handling of read-only kernel memory: - extend read-only kernel memory to a new class of formerly writable kernel data: 'post-init read-only memory' via the __ro_after_init attribute, and mark the ARM and x86 vDSO as such read-only memory. This kind of attribute can be used for data that requires a once per bootup initialization sequence, but is otherwise never modified after that point. This feature was based on the work by PaX Team and Brad Spengler. (by Kees Cook, the ARM vDSO bits by David Brown.) - make CONFIG_DEBUG_RODATA always enabled on x86 and remove the Kconfig option. This simplifies the kernel and also signals that read-only memory is the default model and a first-class citizen. (Kees Cook)" * 'mm-readonly-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: ARM/vdso: Mark the vDSO code read-only after init x86/vdso: Mark the vDSO code read-only after init lkdtm: Verify that '__ro_after_init' works correctly arch: Introduce post-init read-only memory x86/mm: Always enable CONFIG_DEBUG_RODATA and remove the Kconfig option mm/init: Add 'rodata=off' boot cmdline parameter to disable read-only kernel mappings asm-generic: Consolidate mark_rodata_ro()

Documentation/kernel-parameters.txt

+4 −0

Original line number	Diff line number	Diff line
		@@ -3491,6 +3491,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.

		ro [KNL] Mount root device read-only on boot

		rodata= [KNL]
		on Mark read-only kernel memory as read-only (default).
		off Leave read-only kernel memory writable for debugging.

		root= [KNL] Root filesystem
		See name_to_dev_t comment in init/do_mounts.c.

arch/arm/include/asm/cacheflush.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -491,7 +491,6 @@ static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
		#endif

		#ifdef CONFIG_DEBUG_RODATA
		void mark_rodata_ro(void);
		void set_kernel_text_rw(void);
		void set_kernel_text_ro(void);
		#else

arch/arm/vdso/vdso.S

+1 −2

Original line number	Diff line number	Diff line
		@@ -23,9 +23,8 @@
		#include <linux/const.h>
		#include <asm/page.h>

		__PAGE_ALIGNED_DATA

		.globl vdso_start, vdso_end
		.section .data..ro_after_init
		.balign PAGE_SIZE
		vdso_start:
		.incbin "arch/arm/vdso/vdso.so"

arch/arm64/include/asm/cacheflush.h

+0 −4

Original line number	Diff line number	Diff line
		@@ -156,8 +156,4 @@ int set_memory_rw(unsigned long addr, int numpages);
		int set_memory_x(unsigned long addr, int numpages);
		int set_memory_nx(unsigned long addr, int numpages);

		#ifdef CONFIG_DEBUG_RODATA
		void mark_rodata_ro(void);
		#endif

		#endif

arch/parisc/include/asm/cache.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,9 @@

		#define __read_mostly __attribute__((__section__(".data..read_mostly")))

		/* Read-only memory is marked before mark_rodata_ro() is called. */
		#define __ro_after_init __read_mostly

		void parisc_cache_init(void); /* initializes cache-flushing */
		void disable_sr_hashing_asm(int); /* low level support for above */
		void disable_sr_hashing(void); /* turns off space register hashing */

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