x86/ftrace: Use vmalloc special flag (7fdfe1e4) · Commits · 戴 / test

Use new flag VM_FLUSH_RESET_PERMS for handling freeing of special permissioned memory in vmalloc and remove places where memory was set NX and RW before freeing which is no longer needed. Tested-by:

Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by:

Rick Edgecombe <rick.p.edgecombe@intel.com> Signed-off-by:

Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:

Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: <akpm@linux-foundation.org> Cc: <ard.biesheuvel@linaro.org> Cc: <deneen.t.dock@intel.com> Cc: <kernel-hardening@lists.openwall.com> Cc: <kristen@linux.intel.com> Cc: <linux_dti@icloud.com> Cc: <will.deacon@arm.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nadav Amit <nadav.amit@gmail.com> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20190426001143.4983-20-namit@vmware.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/ftrace.c

+6 −8

Original line number	Diff line number	Diff line
		@@ -678,12 +678,8 @@ static inline void *alloc_tramp(unsigned long size)
		{
		return module_alloc(size);
		}
		static inline void tramp_free(void *tramp, int size)
		static inline void tramp_free(void *tramp)
		{
		int npages = PAGE_ALIGN(size) >> PAGE_SHIFT;

		set_memory_nx((unsigned long)tramp, npages);
		set_memory_rw((unsigned long)tramp, npages);
		module_memfree(tramp);
		}
		#else
		@@ -692,7 +688,7 @@ static inline void *alloc_tramp(unsigned long size)
		{
		return NULL;
		}
		static inline void tramp_free(void *tramp, int size) { }
		static inline void tramp_free(void *tramp) { }
		#endif

		/* Defined as markers to the end of the ftrace default trampolines */
		@@ -808,6 +804,8 @@ create_trampoline(struct ftrace_ops ops, unsigned int tramp_size)
		/* ALLOC_TRAMP flags lets us know we created it */
		ops->flags \|= FTRACE_OPS_FL_ALLOC_TRAMP;

		set_vm_flush_reset_perms(trampoline);

		/*
		* Module allocation needs to be completed by making the page
		* executable. The page is still writable, which is a security hazard,
		@@ -816,7 +814,7 @@ create_trampoline(struct ftrace_ops ops, unsigned int tramp_size)
		set_memory_x((unsigned long)trampoline, npages);
		return (unsigned long)trampoline;
		fail:
		tramp_free(trampoline, *tramp_size);
		tramp_free(trampoline);
		return 0;
		}

		@@ -947,7 +945,7 @@ void arch_ftrace_trampoline_free(struct ftrace_ops *ops)
		if (!ops \|\| !(ops->flags & FTRACE_OPS_FL_ALLOC_TRAMP))
		return;

		tramp_free((void *)ops->trampoline, ops->trampoline_size);
		tramp_free((void *)ops->trampoline);
		ops->trampoline = 0;
		}

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