Merge branch 'topic/func-desc-lkdtm' into next

Merge a topic branch we are maintaining with some cross-architecture changes to function descriptor handling and their use in LKDTM. From Christophe's cover letter: Fix LKDTM for PPC64/IA64/PARISC PPC64/IA64/PARISC have function descriptors. LKDTM doesn't work on those three architectures because LKDTM messes up function descriptors with functions. This series does some cleanup in the three architectures and refactors function descriptors so that it can then easily use it in a generic way in LKDTM.

Michael Ellerman committed 4 years ago

Commit 4bc06c52 parents 8219d31 5e5a6c525 files · +155 −144Browse files

Showing the changes to kernel (1 of 25 files). Show all

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kernel/extable.c+23−1

@@ -3,6 +3,7 @@ · 2 unmodified lines
3	3	Copyright (C) 2001 Rusty Russell, 2002 Rusty Russell IBM.
4	4
5	5	*/
	6	+#include <linux/elf.h>
6	7	#include <linux/ftrace.h>
7	8	#include <linux/memory.h>
8	9	#include <linux/extable.h>
@@ -132,12 +133,33 @@ out: · 123 unmodified lines
132	133	}
133	134
134	135	/*
135		− * On some architectures (PPC64, IA64) function pointers
	136	+ * On some architectures (PPC64, IA64, PARISC) function pointers
136	137	* are actually only tokens to some data that then holds the
137	138	* real function address. As a result, to find if a function
138	139	* pointer is part of the kernel text, we need to do some
139	140	* special dereferencing first.
140	141	*/
	142	+#ifdef CONFIG_HAVE_FUNCTION_DESCRIPTORS
	143	+void dereference_function_descriptor(void ptr)
	144	+{
	145	+ func_desc_t *desc = ptr;
	146	+ void *p;
	147	+
	148	+ if (!get_kernel_nofault(p, (void *)&desc->addr))
	149	+ ptr = p;
	150	+ return ptr;
	151	+}
	152	+EXPORT_SYMBOL_GPL(dereference_function_descriptor);
	153	+
	154	+void dereference_kernel_function_descriptor(void ptr)
	155	+{
	156	+ if (ptr < (void )__start_opd \|\| ptr >= (void )__end_opd)
	157	+ return ptr;
	158	+
	159	+ return dereference_function_descriptor(ptr);
	160	+}
	161	+#endif
	162	+
141	163	int func_ptr_is_kernel_text(void *ptr)
142	164	{
143	165	unsigned long addr;