Commit 399145f9 authored by Anshuman Khandual's avatar Anshuman Khandual Committed by Linus Torvalds

mm/debug: add tests validating architecture page table helpers

This adds tests which will validate architecture page table helpers and
other accessors in their compliance with expected generic MM semantics.
This will help various architectures in validating changes to existing
page table helpers or addition of new ones.

This test covers basic page table entry transformations including but not
limited to old, young, dirty, clean, write, write protect etc at various
level along with populating intermediate entries with next page table page
and validating them.

Test page table pages are allocated from system memory with required size
and alignments.  The mapped pfns at page table levels are derived from a
real pfn representing a valid kernel text symbol.  This test gets called
via late_initcall().

This test gets built and run when CONFIG_DEBUG_VM_PGTABLE is selected.
Any architecture, which is willing to subscribe this test will need to
select ARCH_HAS_DEBUG_VM_PGTABLE.  For now this is limited to arc, arm64,
x86, s390 and powerpc platforms where the test is known to build and run
successfully Going forward, other architectures too can subscribe the test
after fixing any build or runtime problems with their page table helpers.

Folks interested in making sure that a given platform's page table helpers
conform to expected generic MM semantics should enable the above config
which will just trigger this test during boot.  Any non conformity here
will be reported as an warning which would need to be fixed.  This test
will help catch any changes to the agreed upon semantics expected from
generic MM and enable platforms to accommodate it thereafter.

[anshuman.khandual@arm.com: v17]
  Link: http://lkml.kernel.org/r/1587436495-22033-3-git-send-email-anshuman.khandual@arm.com
[anshuman.khandual@arm.com: v18]
  Link: http://lkml.kernel.org/r/1588564865-31160-3-git-send-email-anshuman.khandual@arm.comSuggested-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: default avatarQian Cai <cai@lca.pw>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Tested-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>	[s390]
Tested-by: Christophe Leroy <christophe.leroy@c-s.fr>	[ppc32]
Reviewed-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Link: http://lkml.kernel.org/r/1583919272-24178-1-git-send-email-anshuman.khandual@arm.comSigned-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 8898ad58
#
# Feature name: debug-vm-pgtable
# Kconfig: ARCH_HAS_DEBUG_VM_PGTABLE
# description: arch supports pgtable tests for semantics compliance
#
-----------------------
| arch |status|
-----------------------
| alpha: | TODO |
| arc: | ok |
| arm: | TODO |
| arm64: | ok |
| c6x: | TODO |
| csky: | TODO |
| h8300: | TODO |
| hexagon: | TODO |
| ia64: | TODO |
| m68k: | TODO |
| microblaze: | TODO |
| mips: | TODO |
| nds32: | TODO |
| nios2: | TODO |
| openrisc: | TODO |
| parisc: | TODO |
| powerpc: | ok |
| riscv: | TODO |
| s390: | ok |
| sh: | TODO |
| sparc: | TODO |
| um: | TODO |
| unicore32: | TODO |
| x86: | ok |
| xtensa: | TODO |
-----------------------
...@@ -6,6 +6,7 @@ ...@@ -6,6 +6,7 @@
config ARC config ARC
def_bool y def_bool y
select ARC_TIMERS select ARC_TIMERS
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_DMA_PREP_COHERENT
select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_PTE_SPECIAL
select ARCH_HAS_SETUP_DMA_OPS select ARCH_HAS_SETUP_DMA_OPS
......
...@@ -12,6 +12,7 @@ config ARM64 ...@@ -12,6 +12,7 @@ config ARM64
select ARCH_HAS_DEBUG_WX select ARCH_HAS_DEBUG_WX
select ARCH_BINFMT_ELF_STATE select ARCH_BINFMT_ELF_STATE
select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_DMA_PREP_COHERENT select ARCH_HAS_DMA_PREP_COHERENT
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
......
...@@ -116,6 +116,7 @@ config PPC ...@@ -116,6 +116,7 @@ config PPC
# #
select ARCH_32BIT_OFF_T if PPC32 select ARCH_32BIT_OFF_T if PPC32
select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_FORTIFY_SOURCE
......
...@@ -59,6 +59,7 @@ config KASAN_SHADOW_OFFSET ...@@ -59,6 +59,7 @@ config KASAN_SHADOW_OFFSET
config S390 config S390
def_bool y def_bool y
select ARCH_BINFMT_ELF_STATE select ARCH_BINFMT_ELF_STATE
select ARCH_HAS_DEBUG_VM_PGTABLE
select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_FORTIFY_SOURCE
......
...@@ -59,6 +59,7 @@ config X86 ...@@ -59,6 +59,7 @@ config X86
select ARCH_CLOCKSOURCE_INIT select ARCH_CLOCKSOURCE_INIT
select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI
select ARCH_HAS_DEBUG_VIRTUAL select ARCH_HAS_DEBUG_VIRTUAL
select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE
select ARCH_HAS_DEVMEM_IS_ALLOWED select ARCH_HAS_DEVMEM_IS_ALLOWED
select ARCH_HAS_EARLY_DEBUG if KGDB select ARCH_HAS_EARLY_DEBUG if KGDB
select ARCH_HAS_ELF_RANDOMIZE select ARCH_HAS_ELF_RANDOMIZE
......
...@@ -658,6 +658,12 @@ config SCHED_STACK_END_CHECK ...@@ -658,6 +658,12 @@ config SCHED_STACK_END_CHECK
data corruption or a sporadic crash at a later stage once the region data corruption or a sporadic crash at a later stage once the region
is examined. The runtime overhead introduced is minimal. is examined. The runtime overhead introduced is minimal.
config ARCH_HAS_DEBUG_VM_PGTABLE
bool
help
An architecture should select this when it can successfully
build and run DEBUG_VM_PGTABLE.
config DEBUG_VM config DEBUG_VM
bool "Debug VM" bool "Debug VM"
depends on DEBUG_KERNEL depends on DEBUG_KERNEL
...@@ -693,6 +699,22 @@ config DEBUG_VM_PGFLAGS ...@@ -693,6 +699,22 @@ config DEBUG_VM_PGFLAGS
If unsure, say N. If unsure, say N.
config DEBUG_VM_PGTABLE
bool "Debug arch page table for semantics compliance"
depends on MMU
depends on ARCH_HAS_DEBUG_VM_PGTABLE
default y if DEBUG_VM
help
This option provides a debug method which can be used to test
architecture page table helper functions on various platforms in
verifying if they comply with expected generic MM semantics. This
will help architecture code in making sure that any changes or
new additions of these helpers still conform to expected
semantics of the generic MM. Platforms will have to opt in for
this through ARCH_HAS_DEBUG_VM_PGTABLE.
If unsure, say N.
config ARCH_HAS_DEBUG_VIRTUAL config ARCH_HAS_DEBUG_VIRTUAL
bool bool
......
...@@ -88,6 +88,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o ...@@ -88,6 +88,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o
obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o
obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o
obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o
obj-$(CONFIG_DEBUG_VM_PGTABLE) += debug_vm_pgtable.o
obj-$(CONFIG_PAGE_OWNER) += page_owner.o obj-$(CONFIG_PAGE_OWNER) += page_owner.o
obj-$(CONFIG_CLEANCACHE) += cleancache.o obj-$(CONFIG_CLEANCACHE) += cleancache.o
obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o
......
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