Commit dfec072e authored by Vegard Nossum's avatar Vegard Nossum
Browse files

kmemcheck: add the kmemcheck core 



General description: kmemcheck is a patch to the linux kernel that
detects use of uninitialized memory. It does this by trapping every
read and write to memory that was allocated dynamically (e.g. using
kmalloc()). If a memory address is read that has not previously been
written to, a message is printed to the kernel log.

Thanks to Andi Kleen for the set_memory_4k() solution.

Andrew Morton suggested documenting the shadow member of struct page.

Signed-off-by: default avatarVegard Nossum <vegardno@ifi.uio.no>
Signed-off-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>

[export kmemcheck_mark_initialized]
[build fix for setup_max_cpus]
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>

[rebased for mainline inclusion]
Signed-off-by: default avatarVegard Nossum <vegardno@ifi.uio.no>
parent e594c8de

arch/x86/Makefile

+5 −0
Original line number Diff line number Diff line
@@ -81,6 +81,11 @@ ifdef CONFIG_CC_STACKPROTECTOR 
        endif

endif



# Don't unroll struct assignments with kmemcheck enabled

ifeq ($(CONFIG_KMEMCHECK),y)

	KBUILD_CFLAGS += $(call cc-option,-fno-builtin-memcpy)

endif



# Stackpointer is addressed different for 32 bit and 64 bit x86

sp-$(CONFIG_X86_32) := esp

sp-$(CONFIG_X86_64) := rsp

arch/x86/include/asm/kmemcheck.h

0 → 100644
+42 −0
Original line number Diff line number Diff line 
#ifndef ASM_X86_KMEMCHECK_H

#define ASM_X86_KMEMCHECK_H



#include <linux/types.h>

#include <asm/ptrace.h>



#ifdef CONFIG_KMEMCHECK

bool kmemcheck_active(struct pt_regs *regs);



void kmemcheck_show(struct pt_regs *regs);

void kmemcheck_hide(struct pt_regs *regs);



bool kmemcheck_fault(struct pt_regs *regs,

	unsigned long address, unsigned long error_code);

bool kmemcheck_trap(struct pt_regs *regs);

#else

static inline bool kmemcheck_active(struct pt_regs *regs)

{

	return false;

}



static inline void kmemcheck_show(struct pt_regs *regs)

{

}



static inline void kmemcheck_hide(struct pt_regs *regs)

{

}



static inline bool kmemcheck_fault(struct pt_regs *regs,

	unsigned long address, unsigned long error_code)

{

	return false;

}



static inline bool kmemcheck_trap(struct pt_regs *regs)

{

	return false;

}

#endif /* CONFIG_KMEMCHECK */



#endif

arch/x86/include/asm/pgtable.h

+9 −0
Original line number Diff line number Diff line
@@ -317,6 +317,15 @@ static inline int pte_present(pte_t a) 
	return pte_flags(a) & (_PAGE_PRESENT | _PAGE_PROTNONE);

}



static inline int pte_hidden(pte_t x)

{

#ifdef CONFIG_KMEMCHECK

	return pte_flags(x) & _PAGE_HIDDEN;

#else

	return 0;

#endif

}



static inline int pmd_present(pmd_t pmd)

{

	return pmd_flags(pmd) & _PAGE_PRESENT;

arch/x86/include/asm/pgtable_types.h

+2 −2
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ 
#define _PAGE_BIT_GLOBAL	8	/* Global TLB entry PPro+ */

#define _PAGE_BIT_UNUSED1	9	/* available for programmer */

#define _PAGE_BIT_IOMAP		10	/* flag used to indicate IO mapping */

#define _PAGE_BIT_UNUSED3	11

#define _PAGE_BIT_HIDDEN	11	/* hidden by kmemcheck */

#define _PAGE_BIT_PAT_LARGE	12	/* On 2MB or 1GB pages */

#define _PAGE_BIT_SPECIAL	_PAGE_BIT_UNUSED1

#define _PAGE_BIT_CPA_TEST	_PAGE_BIT_UNUSED1
@@ -41,7 +41,7 @@ 
#define _PAGE_GLOBAL	(_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)

#define _PAGE_UNUSED1	(_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)

#define _PAGE_IOMAP	(_AT(pteval_t, 1) << _PAGE_BIT_IOMAP)

#define _PAGE_UNUSED3	(_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)

#define _PAGE_HIDDEN	(_AT(pteval_t, 1) << _PAGE_BIT_HIDDEN)

#define _PAGE_PAT	(_AT(pteval_t, 1) << _PAGE_BIT_PAT)

#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)

#define _PAGE_SPECIAL	(_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)

arch/x86/mm/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -10,6 +10,8 @@ obj-$(CONFIG_X86_PTDUMP) += dump_pagetables.o 


obj-$(CONFIG_HIGHMEM)		+= highmem_32.o



obj-$(CONFIG_KMEMCHECK)		+= kmemcheck/



obj-$(CONFIG_MMIOTRACE)		+= mmiotrace.o

mmiotrace-y			:= kmmio.o pf_in.o mmio-mod.o

obj-$(CONFIG_MMIOTRACE_TEST)	+= testmmiotrace.o

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