On Wed, 2020-02-26 at 09:09 -0500, Qian Cai wrote: > On Mon, 2020-02-17 at 08:47 +0530, Anshuman Khandual wrote: > > 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 > > inside kernel_init() right after async_synchronize_full(). > > > > 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 ppc32 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. Meanwhile for > > better platform coverage, the test can also be enabled with CONFIG_EXPERT > > even without ARCH_HAS_DEBUG_VM_PGTABLE. > > > > 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. > > How useful is this that straightly crash the powerpc? And then generate warnings on arm64, [ 146.634626][ T1] debug_vm_pgtable: debug_vm_pgtable: Validating architecture page table helpers [ 146.643995][ T1] ------------[ cut here ]------------ [ 146.649350][ T1] virt_to_phys used for non-linear address: (____ptrval____) (start_kernel+0x0/0x580) [ 146.658840][ T1] WARNING: CPU: 165 PID: 1 at arch/arm64/mm/physaddr.c:15 __virt_to_phys+0x98/0xe0 [ 146.667976][ T1] Modules linked in: [ 146.671741][ T1] CPU: 165 PID: 1 Comm: swapper/0 Tainted: G L 5.6.0-rc3-next-20200226 #1 [ 146.681397][ T1] Hardware name: HPE Apollo 70 /C01_APACHE_MB , BIOS L50_5.13_1.11 06/18/2019 [ 146.691840][ T1] pstate: 60400009 (nZCv daif +PAN -UAO) [ 146.697334][ T1] pc : __virt_to_phys+0x98/0xe0 [ 146.702045][ T1] lr : __virt_to_phys+0x98/0xe0 [ 146.706753][ T1] sp : 18ff00082b7afe10 [ 146.710766][ T1] x29: 18ff00082b7afe30 x28: 0000000000000000 [ 146.716782][ T1] x27: 0000000000000000 x26: 0000000000000000 [ 146.722798][ T1] x25: 0000000000000000 x24: 0000000000000000 [ 146.728813][ T1] x23: 0000000000000000 x22: 0000000000000000 [ 146.734827][ T1] x21: 0000000000000000 x20: ffff9000135b4000 [ 146.740842][ T1] x19: ffff900011200858 x18: 0000000000000000 [ 146.746857][ T1] x17: 0000000000000000 x16: 0000000000000000 [ 146.752872][ T1] x15: 0000000000000000 x14: 3078302b6c656e72 [ 146.758887][ T1] x13: 656b5f7472617473 x12: ffff90001369ea90 [ 146.764901][ T1] x11: 00000000000000c9 x10: ffff800082b76c0e [ 146.770917][ T1] x9 : 9d6a2e2260401300 x8 : 9d6a2e2260401300 [ 146.776932][ T1] x7 : aaaaaaaaaaaaaaaa x6 : 0000000000000000 [ 146.782946][ T1] x5 : 0000000000000080 x4 : 0000000000000000 [ 146.788960][ T1] x3 : 0000000000000010 x2 : 0000000000000008 [ 146.794975][ T1] x1 : 0000000000000006 x0 : 0000000000000053 [ 146.800990][ T1] Call trace: [ 146.804140][ T1] __virt_to_phys+0x98/0xe0 [ 146.808512][ T1] debug_vm_pgtable+0x74/0x3fc [ 146.813140][ T1] kernel_init+0x1c/0x208 [ 146.817334][ T1] ret_from_fork+0x10/0x18 [ 146.821608][ T1] irq event stamp: 19843388 [ 146.825978][ T1] hardirqs last enabled at (19843387): [<ffff9000101d959c>] console_unlock+0x8d0/0x970 [ 146.835553][ T1] hardirqs last disabled at (19843388): [<ffff9000100ad0e0>] do_debug_exception+0x58/0x2cc [ 146.845387][ T1] softirqs last enabled at (19843384): [<ffff900010081b8c>] __do_softirq+0x864/0x900 [ 146.854796][ T1] softirqs last disabled at (19843377): [<ffff900010120b70>] irq_exit+0x1c8/0x238 [ 146.863845][ T1] ---[ end trace 31678d9e845dff89 ]--- > > [ 23.263425][ T1] debug_vm_pgtable: debug_vm_pgtable: Validating > architecture page table helpers > [ 23.263625][ T1] ------------[ cut here ]------------ > [ 23.263649][ T1] kernel BUG at arch/powerpc/mm/pgtable.c:274! > [ 23.263675][ T1] Oops: Exception in kernel mode, sig: 5 [#1] > [ 23.263698][ T1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=256 > DEBUG_PAGEALLOC NUMA PowerNV > [ 23.263731][ T1] Modules linked in: > [ 23.263752][ T1] CPU: 4 PID: 1 Comm: swapper/0 Not tainted 5.6.0-rc3-next- > 20200226 #1 > [ 23.263776][ T1] NIP: c00000000007308c LR: c00000000103dbd8 CTR: > 0000000000000000 > [ 23.263810][ T1] REGS: c00000003ddaf9c0 TRAP: 0700 Not tainted (5.6.0- > rc3-next-20200226) > [ 23.263846][ T1] MSR: 9000000000029033 <SF,HV,EE,ME,IR,DR,RI,LE> CR: > 22000228 XER: 00000000 > [ 23.263888][ T1] CFAR: c000000000073030 IRQMASK: 0 > [ 23.263888][ T1] GPR00: c00000000103dbd8 c00000003ddafc50 c000000001656f00 > c000001d7b4ca080 > [ 23.263888][ T1] GPR04: 0000000000000000 0000000000000009 c00000003ddafc04 > 0000000000000000 > [ 23.263888][ T1] GPR08: f0ffffffffffffff 0000000000000001 c0000000016279d0 > 00000000000a0000 > [ 23.263888][ T1] GPR12: 0000000000000000 c000001fffffae00 c000000000010e84 > 0000000000000000 > [ 23.263888][ T1] GPR16: 0000000000000000 8000000000000105 0000000000000100 > c000000001689a18 > [ 23.263888][ T1] GPR20: c00020032c660000 c00020032c620000 c000000001716030 > c00020032c600000 > [ 23.263888][ T1] GPR24: 000000000000000d c000000001716030 c000001d7b4ca080 > c000000001716040 > [ 23.263888][ T1] GPR28: c000000001716038 0000000000000000 0000000000000000 > 0000000000000000 > [ 23.264122][ T1] NIP [c00000000007308c] assert_pte_locked+0x11c/0x320 > [ 23.264154][ T1] LR [c00000000103dbd8] debug_vm_pgtable+0x770/0xb7c > [ 23.264186][ T1] Call Trace: > [ 23.264206][ T1] [c00000003ddafc50] [c000000000999760] > _raw_spin_unlock+0x30/0x70 (unreliable) > [ 23.264244][ T1] [c00000003ddafcd0] [c00000000103d924] > debug_vm_pgtable+0x4bc/0xb7c > [ 23.264279][ T1] [c00000003ddafdb0] [c000000000010eac] > kernel_init+0x30/0x194 > [ 23.264315][ T1] [c00000003ddafe20] [c00000000000b748] > ret_from_kernel_thread+0x5c/0x74 > [ 23.264349][ T1] Instruction dump: > [ 23.264368][ T1] 60000000 3be00001 7fbef436 eafa0040 7fffc030 3bffffff > 7fff07b4 7ffff038 > [ 23.264409][ T1] 7bff1f24 7d37f82a 7d290074 7929d182 <0b090000> ebdb0000 > e93c0000 7fde4a14 > [ 23.264460][ T1] ---[ end trace 72d2931022e9ab24 ]--- > [ 23.627311][ T1] > [ 24.627407][ T1] Kernel panic - not syncing: Fatal exception > [ 26.5 > > > > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx> > > Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx> > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > > Cc: Will Deacon <will@xxxxxxxxxx> > > Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> > > Cc: Paul Mackerras <paulus@xxxxxxxxx> > > Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> > > Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx> > > Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx> > > Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx> > > Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > > Cc: Borislav Petkov <bp@xxxxxxxxx> > > Cc: "H. Peter Anvin" <hpa@xxxxxxxxx> > > Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> > > Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx> > > Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx> > > Cc: linux-snps-arc@xxxxxxxxxxxxxxxxxxx > > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > > Cc: linuxppc-dev@xxxxxxxxxxxxxxxx > > Cc: linux-s390@xxxxxxxxxxxxxxx > > Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx > > Cc: x86@xxxxxxxxxx > > Cc: linux-arch@xxxxxxxxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx > > > > Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx> > > Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx> > > Tested-by: Gerald Schaefer <gerald.schaefer@xxxxxxxxxx> # s390 > > Tested-by: Christophe Leroy <christophe.leroy@xxxxxx> # ppc32 > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > > Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx> > > Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> > > --- > > This adds a test validation for architecture exported page table helpers. > > Patch adds basic transformation tests at various levels of the page table. > > > > This test was originally suggested by Catalin during arm64 THP migration > > RFC discussion earlier. Going forward it can include more specific tests > > with respect to various generic MM functions like THP, HugeTLB etc and > > platform specific tests. > > > > https://lore.kernel.org/linux-mm/20190628102003.GA56463@xxxxxxxxxxxxxxxxxxxx/ > > > > Needs to be applied on linux V5.6-rc2 > > > > Changes in V14: > > > > - Disabled DEBUG_VM_PGFLAGS for IA64 and ARM (32 Bit) per Andrew and Christophe > > - Updated DEBUG_VM_PGFLAGS documentation wrt EXPERT and disabled platforms > > - Updated RANDOM_[OR|NZ]VALUE open encodings with GENMASK() per Catalin > > - Updated s390 constraint bits from 12 to 4 (S390_MASK_BITS) per Gerald > > - Updated in-code documentation for RANDOM_ORVALUE per Gerald > > - Updated pxx_basic_tests() to use invert functions first per Catalin > > - Dropped ARCH_HAS_4LEVEL_HACK check from pud_basic_tests() > > - Replaced __ARCH_HAS_[4|5]LEVEL_HACK with __PAGETABLE_[PUD|P4D]_FOLDED per Catalin > > - Trimmed the CC list on the commit message per Catalin > > > > Changes in V13: (https://patchwork.kernel.org/project/linux-mm/list/?series=237125) > > > > - Subscribed s390 platform and updated debug-vm-pgtable/arch-support.txt per Gerald > > - Dropped keyword 'extern' from debug_vm_pgtable() declaration per Christophe > > - Moved debug_vm_pgtable() declarations to <linux/mmdebug.h> per Christophe > > - Moved debug_vm_pgtable() call site into kernel_init() per Christophe > > - Changed CONFIG_DEBUG_VM_PGTABLE rules per Christophe > > - Updated commit to include new supported platforms and changed config selection > > > > Changes in V12: (https://patchwork.kernel.org/project/linux-mm/list/?series=233905) > > > > - Replaced __mmdrop() with mmdrop() > > - Enable ARCH_HAS_DEBUG_VM_PGTABLE on X86 for non CONFIG_X86_PAE platforms as the > > test procedure interfere with pre-allocated PMDs attached to the PGD resulting > > in runtime failures with VM_BUG_ON() > > > > Changes in V11: (https://patchwork.kernel.org/project/linux-mm/list/?series=221135) > > > > - Rebased the patch on V5.4 > > > > Changes in V10: (https://patchwork.kernel.org/project/linux-mm/list/?series=205529) > > > > - Always enable DEBUG_VM_PGTABLE when DEBUG_VM is enabled per Ingo > > - Added tags from Ingo > > > > Changes in V9: (https://patchwork.kernel.org/project/linux-mm/list/?series=201429) > > > > - Changed feature support enumeration for powerpc platforms per Christophe > > - Changed config wrapper for basic_[pmd|pud]_tests() to enable ARC platform > > - Enabled the test on ARC platform > > > > Changes in V8: (https://patchwork.kernel.org/project/linux-mm/list/?series=194297) > > > > - Enabled ARCH_HAS_DEBUG_VM_PGTABLE on PPC32 platform per Christophe > > - Updated feature documentation as DEBUG_VM_PGTABLE is now enabled on PPC32 platform > > - Moved ARCH_HAS_DEBUG_VM_PGTABLE earlier to indent it with DEBUG_VM per Christophe > > - Added an information message in debug_vm_pgtable() per Christophe > > - Dropped random_vaddr boundary condition checks per Christophe and Qian > > - Replaced virt_addr_valid() check with pfn_valid() check in debug_vm_pgtable() > > - Slightly changed pr_fmt(fmt) information > > > > Changes in V7: (https://patchwork.kernel.org/project/linux-mm/list/?series=193051) > > > > - Memory allocation and free routines for mapped pages have been droped > > - Mapped pfns are derived from standard kernel text symbol per Matthew > > - Moved debug_vm_pgtaable() after page_alloc_init_late() per Michal and Qian > > - Updated the commit message per Michal > > - Updated W=1 GCC warning problem on x86 per Qian Cai > > - Addition of new alloc_contig_pages() helper has been submitted separately > > > > Changes in V6: (https://patchwork.kernel.org/project/linux-mm/list/?series=187589) > > > > - Moved alloc_gigantic_page_order() into mm/page_alloc.c per Michal > > - Moved alloc_gigantic_page_order() within CONFIG_CONTIG_ALLOC in the test > > - Folded Andrew's include/asm-generic/pgtable.h fix into the test patch 2/2 > > > > Changes in V5: (https://patchwork.kernel.org/project/linux-mm/list/?series=185991) > > > > - Redefined and moved X86 mm_p4d_folded() into a different header per Kirill/Ingo > > - Updated the config option comment per Ingo and dropped 'kernel module' reference > > - Updated the commit message and dropped 'kernel module' reference > > - Changed DEBUG_ARCH_PGTABLE_TEST into DEBUG_VM_PGTABLE per Ingo > > - Moved config option from mm/Kconfig.debug into lib/Kconfig.debug > > - Renamed core test function arch_pgtable_tests() as debug_vm_pgtable() > > - Renamed mm/arch_pgtable_test.c as mm/debug_vm_pgtable.c > > - debug_vm_pgtable() gets called from kernel_init_freeable() after init_mm_internals() > > - Added an entry in Documentation/features/debug/ per Ingo > > - Enabled the test on arm64 and x86 platforms for now > > > > Changes in V4: (https://patchwork.kernel.org/project/linux-mm/list/?series=183465) > > > > - Disable DEBUG_ARCH_PGTABLE_TEST for ARM and IA64 platforms > > > > Changes in V3: (https://lore.kernel.org/patchwork/project/lkml/list/?series=411216) > > > > - Changed test trigger from module format into late_initcall() > > - Marked all functions with __init to be freed after completion > > - Changed all __PGTABLE_PXX_FOLDED checks as mm_pxx_folded() > > - Folded in PPC32 fixes from Christophe > > > > Changes in V2: > > > > https://lore.kernel.org/linux-mm/1568268173-31302-1-git-send-email-anshuman.khandual@xxxxxxx/T/#t > > > > - Fixed small typo error in MODULE_DESCRIPTION() > > - Fixed m64k build problems for lvalue concerns in pmd_xxx_tests() > > - Fixed dynamic page table level folding problems on x86 as per Kirril > > - Fixed second pointers during pxx_populate_tests() per Kirill and Gerald > > - Allocate and free pte table with pte_alloc_one/pte_free per Kirill > > - Modified pxx_clear_tests() to accommodate s390 lower 12 bits situation > > - Changed RANDOM_NZVALUE value from 0xbe to 0xff > > - Changed allocation, usage, free sequence for saved_ptep > > - Renamed VMA_FLAGS as VMFLAGS > > - Implemented a new method for random vaddr generation > > - Implemented some other cleanups > > - Dropped extern reference to mm_alloc() > > - Created and exported new alloc_gigantic_page_order() > > - Dropped the custom allocator and used new alloc_gigantic_page_order() > > > > Changes in V1: > > > > https://lore.kernel.org/linux-mm/1567497706-8649-1-git-send-email-anshuman.khandual@xxxxxxx/ > > > > - Added fallback mechanism for PMD aligned memory allocation failure > > > > Changes in RFC V2: > > > > https://lore.kernel.org/linux-mm/1565335998-22553-1-git-send-email-anshuman.khandual@xxxxxxx/T/#u > > > > - Moved test module and it's config from lib/ to mm/ > > - Renamed config TEST_ARCH_PGTABLE as DEBUG_ARCH_PGTABLE_TEST > > - Renamed file from test_arch_pgtable.c to arch_pgtable_test.c > > - Added relevant MODULE_DESCRIPTION() and MODULE_AUTHOR() details > > - Dropped loadable module config option > > - Basic tests now use memory blocks with required size and alignment > > - PUD aligned memory block gets allocated with alloc_contig_range() > > - If PUD aligned memory could not be allocated it falls back on PMD aligned > > memory block from page allocator and pud_* tests are skipped > > - Clear and populate tests now operate on real in memory page table entries > > - Dummy mm_struct gets allocated with mm_alloc() > > - Dummy page table entries get allocated with [pud|pmd|pte]_alloc_[map]() > > - Simplified [p4d|pgd]_basic_tests(), now has random values in the entries > > > > Original RFC V1: > > > > https://lore.kernel.org/linux-mm/1564037723-26676-1-git-send-email-anshuman.khandual@xxxxxxx/ > > > > > > .../debug/debug-vm-pgtable/arch-support.txt | 35 ++ > > arch/arc/Kconfig | 1 + > > arch/arm64/Kconfig | 1 + > > arch/powerpc/Kconfig | 1 + > > arch/s390/Kconfig | 1 + > > arch/x86/Kconfig | 1 + > > arch/x86/include/asm/pgtable_64.h | 6 + > > include/linux/mmdebug.h | 5 + > > init/main.c | 2 + > > lib/Kconfig.debug | 26 ++ > > mm/Makefile | 1 + > > mm/debug_vm_pgtable.c | 389 ++++++++++++++++++ > > 12 files changed, 469 insertions(+) > > create mode 100644 Documentation/features/debug/debug-vm-pgtable/arch-support.txt > > create mode 100644 mm/debug_vm_pgtable.c > > > > diff --git a/Documentation/features/debug/debug-vm-pgtable/arch-support.txt b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt > > new file mode 100644 > > index 000000000000..64d0f9b15c49 > > --- /dev/null > > +++ b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt > > @@ -0,0 +1,35 @@ > > +# > > +# 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/32: | ok | > > + | powerpc/64: | TODO | > > + | riscv: | TODO | > > + | s390: | ok | > > + | sh: | TODO | > > + | sparc: | TODO | > > + | um: | TODO | > > + | unicore32: | TODO | > > + | x86: | ok | > > + | xtensa: | TODO | > > + ----------------------- > > diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig > > index ff2a393b635c..3e72e6cf0e42 100644 > > --- a/arch/arc/Kconfig > > +++ b/arch/arc/Kconfig > > @@ -6,6 +6,7 @@ > > config ARC > > def_bool y > > select ARC_TIMERS > > + select ARCH_HAS_DEBUG_VM_PGTABLE > > select ARCH_HAS_DMA_PREP_COHERENT > > select ARCH_HAS_PTE_SPECIAL > > select ARCH_HAS_SETUP_DMA_OPS > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > > index 0b30e884e088..aaf8ba415145 100644 > > --- a/arch/arm64/Kconfig > > +++ b/arch/arm64/Kconfig > > @@ -11,6 +11,7 @@ config ARM64 > > select ACPI_PPTT if ACPI > > select ARCH_CLOCKSOURCE_DATA > > select ARCH_HAS_DEBUG_VIRTUAL > > + select ARCH_HAS_DEBUG_VM_PGTABLE > > select ARCH_HAS_DEVMEM_IS_ALLOWED > > select ARCH_HAS_DMA_PREP_COHERENT > > select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI > > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig > > index 497b7d0b2d7e..8d5ae14c5d4c 100644 > > --- a/arch/powerpc/Kconfig > > +++ b/arch/powerpc/Kconfig > > @@ -116,6 +116,7 @@ config PPC > > # > > select ARCH_32BIT_OFF_T if PPC32 > > select ARCH_HAS_DEBUG_VIRTUAL > > + select ARCH_HAS_DEBUG_VM_PGTABLE if PPC32 > > select ARCH_HAS_DEVMEM_IS_ALLOWED > > select ARCH_HAS_ELF_RANDOMIZE > > select ARCH_HAS_FORTIFY_SOURCE > > diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig > > index 8abe77536d9d..af284dbb07e7 100644 > > --- a/arch/s390/Kconfig > > +++ b/arch/s390/Kconfig > > @@ -59,6 +59,7 @@ config KASAN_SHADOW_OFFSET > > config S390 > > def_bool y > > select ARCH_BINFMT_ELF_STATE > > + select ARCH_HAS_DEBUG_VM_PGTABLE > > select ARCH_HAS_DEVMEM_IS_ALLOWED > > select ARCH_HAS_ELF_RANDOMIZE > > select ARCH_HAS_FORTIFY_SOURCE > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > > index beea77046f9b..df8a19e52e82 100644 > > --- a/arch/x86/Kconfig > > +++ b/arch/x86/Kconfig > > @@ -61,6 +61,7 @@ config X86 > > select ARCH_CLOCKSOURCE_INIT > > select ARCH_HAS_ACPI_TABLE_UPGRADE if ACPI > > select ARCH_HAS_DEBUG_VIRTUAL > > + select ARCH_HAS_DEBUG_VM_PGTABLE if !X86_PAE > > select ARCH_HAS_DEVMEM_IS_ALLOWED > > select ARCH_HAS_ELF_RANDOMIZE > > select ARCH_HAS_FAST_MULTIPLIER > > diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h > > index 0b6c4042942a..fb0e76d254b3 100644 > > --- a/arch/x86/include/asm/pgtable_64.h > > +++ b/arch/x86/include/asm/pgtable_64.h > > @@ -53,6 +53,12 @@ static inline void sync_initial_page_table(void) { } > > > > struct mm_struct; > > > > +#define mm_p4d_folded mm_p4d_folded > > +static inline bool mm_p4d_folded(struct mm_struct *mm) > > +{ > > + return !pgtable_l5_enabled(); > > +} > > + > > void set_pte_vaddr_p4d(p4d_t *p4d_page, unsigned long vaddr, pte_t new_pte); > > void set_pte_vaddr_pud(pud_t *pud_page, unsigned long vaddr, pte_t new_pte); > > > > diff --git a/include/linux/mmdebug.h b/include/linux/mmdebug.h > > index 2ad72d2c8cc5..5339aa14b749 100644 > > --- a/include/linux/mmdebug.h > > +++ b/include/linux/mmdebug.h > > @@ -64,4 +64,9 @@ void dump_mm(const struct mm_struct *mm); > > #define VM_BUG_ON_PGFLAGS(cond, page) BUILD_BUG_ON_INVALID(cond) > > #endif > > > > +#ifdef CONFIG_DEBUG_VM_PGTABLE > > +void debug_vm_pgtable(void); > > +#else > > +static inline void debug_vm_pgtable(void) { } > > +#endif > > #endif > > diff --git a/init/main.c b/init/main.c > > index cc0ee4873419..adf37e8b1d69 100644 > > --- a/init/main.c > > +++ b/init/main.c > > @@ -94,6 +94,7 @@ > > #include <linux/rodata_test.h> > > #include <linux/jump_label.h> > > #include <linux/mem_encrypt.h> > > +#include <linux/mmdebug.h> > > > > #include <asm/io.h> > > #include <asm/bugs.h> > > @@ -1323,6 +1324,7 @@ static int __ref kernel_init(void *unused) > > kernel_init_freeable(); > > /* need to finish all async __init code before freeing the memory */ > > async_synchronize_full(); > > + debug_vm_pgtable(); > > ftrace_free_init_mem(); > > free_initmem(); > > mark_readonly(); > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > > index 69def4a9df00..1b5bd9f7c967 100644 > > --- a/lib/Kconfig.debug > > +++ b/lib/Kconfig.debug > > @@ -653,6 +653,12 @@ config SCHED_STACK_END_CHECK > > data corruption or a sporadic crash at a later stage once the region > > 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 > > bool "Debug VM" > > depends on DEBUG_KERNEL > > @@ -688,6 +694,26 @@ config DEBUG_VM_PGFLAGS > > > > If unsure, say N. > > > > +config DEBUG_VM_PGTABLE > > + bool "Debug arch page table for semantics compliance" > > + depends on MMU > > + depends on !IA64 && !ARM > > + depends on ARCH_HAS_DEBUG_VM_PGTABLE || EXPERT > > + default n if !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. Although it can also be > > + enabled through EXPERT without requiring code change. This test > > + is disabled on IA64 and ARM platforms where it fails to build. > > + > > + If unsure, say N. > > + > > config ARCH_HAS_DEBUG_VIRTUAL > > bool > > > > diff --git a/mm/Makefile b/mm/Makefile > > index 272e66039e70..b0692e6a4b58 100644 > > --- a/mm/Makefile > > +++ b/mm/Makefile > > @@ -87,6 +87,7 @@ obj-$(CONFIG_HWPOISON_INJECT) += hwpoison-inject.o > > obj-$(CONFIG_DEBUG_KMEMLEAK) += kmemleak.o > > obj-$(CONFIG_DEBUG_KMEMLEAK_TEST) += kmemleak-test.o > > obj-$(CONFIG_DEBUG_RODATA_TEST) += rodata_test.o > > +obj-$(CONFIG_DEBUG_VM_PGTABLE) += debug_vm_pgtable.o > > obj-$(CONFIG_PAGE_OWNER) += page_owner.o > > obj-$(CONFIG_CLEANCACHE) += cleancache.o > > obj-$(CONFIG_MEMORY_ISOLATION) += page_isolation.o > > diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c > > new file mode 100644 > > index 000000000000..70bf8ed8fd51 > > --- /dev/null > > +++ b/mm/debug_vm_pgtable.c > > @@ -0,0 +1,389 @@ > > +// SPDX-License-Identifier: GPL-2.0-only > > +/* > > + * This kernel test validates architecture page table helpers and > > + * accessors and helps in verifying their continued compliance with > > + * expected generic MM semantics. > > + * > > + * Copyright (C) 2019 ARM Ltd. > > + * > > + * Author: Anshuman Khandual <anshuman.khandual@xxxxxxx> > > + */ > > +#define pr_fmt(fmt) "debug_vm_pgtable: %s: " fmt, __func__ > > + > > +#include <linux/gfp.h> > > +#include <linux/highmem.h> > > +#include <linux/hugetlb.h> > > +#include <linux/kernel.h> > > +#include <linux/kconfig.h> > > +#include <linux/mm.h> > > +#include <linux/mman.h> > > +#include <linux/mm_types.h> > > +#include <linux/module.h> > > +#include <linux/pfn_t.h> > > +#include <linux/printk.h> > > +#include <linux/random.h> > > +#include <linux/spinlock.h> > > +#include <linux/swap.h> > > +#include <linux/swapops.h> > > +#include <linux/start_kernel.h> > > +#include <linux/sched/mm.h> > > +#include <asm/pgalloc.h> > > +#include <asm/pgtable.h> > > + > > +/* > > + * Basic operations > > + * > > + * mkold(entry) = An old and not a young entry > > + * mkyoung(entry) = A young and not an old entry > > + * mkdirty(entry) = A dirty and not a clean entry > > + * mkclean(entry) = A clean and not a dirty entry > > + * mkwrite(entry) = A write and not a write protected entry > > + * wrprotect(entry) = A write protected and not a write entry > > + * pxx_bad(entry) = A mapped and non-table entry > > + * pxx_same(entry1, entry2) = Both entries hold the exact same value > > + */ > > +#define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC) > > + > > +/* > > + * On s390 platform, the lower 4 bits are used to identify given page table > > + * entry type. But these bits might affect the ability to clear entries with > > + * pxx_clear() because of how dynamic page table folding works on s390. So > > + * while loading up the entries do not change the lower 4 bits. It does not > > + * have affect any other platform. > > + */ > > +#define S390_MASK_BITS 4 > > +#define RANDOM_ORVALUE GENMASK(BITS_PER_LONG - 1, S390_MASK_BITS) > > +#define RANDOM_NZVALUE GENMASK(7, 0) > > + > > +static void __init pte_basic_tests(unsigned long pfn, pgprot_t prot) > > +{ > > + pte_t pte = pfn_pte(pfn, prot); > > + > > + WARN_ON(!pte_same(pte, pte)); > > + WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte)))); > > + WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte)))); > > + WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte)))); > > + WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte)))); > > + WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte)))); > > + WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte)))); > > +} > > + > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > > +static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) > > +{ > > + pmd_t pmd = pfn_pmd(pfn, prot); > > + > > + WARN_ON(!pmd_same(pmd, pmd)); > > + WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd)))); > > + WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd)))); > > + WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd)))); > > + WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd)))); > > + WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd)))); > > + WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd)))); > > + /* > > + * A huge page does not point to next level page table > > + * entry. Hence this must qualify as pmd_bad(). > > + */ > > + WARN_ON(!pmd_bad(pmd_mkhuge(pmd))); > > +} > > + > > +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD > > +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) > > +{ > > + pud_t pud = pfn_pud(pfn, prot); > > + > > + WARN_ON(!pud_same(pud, pud)); > > + WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud)))); > > + WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud)))); > > + WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud)))); > > + WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud)))); > > + > > + if (mm_pmd_folded(mm)) > > + return; > > + > > + /* > > + * A huge page does not point to next level page table > > + * entry. Hence this must qualify as pud_bad(). > > + */ > > + WARN_ON(!pud_bad(pud_mkhuge(pud))); > > +} > > +#else > > +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } > > +#endif > > +#else > > +static void __init pmd_basic_tests(unsigned long pfn, pgprot_t prot) { } > > +static void __init pud_basic_tests(unsigned long pfn, pgprot_t prot) { } > > +#endif > > + > > +static void __init p4d_basic_tests(unsigned long pfn, pgprot_t prot) > > +{ > > + p4d_t p4d; > > + > > + memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t)); > > + WARN_ON(!p4d_same(p4d, p4d)); > > +} > > + > > +static void __init pgd_basic_tests(unsigned long pfn, pgprot_t prot) > > +{ > > + pgd_t pgd; > > + > > + memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t)); > > + WARN_ON(!pgd_same(pgd, pgd)); > > +} > > + > > +#ifndef __PAGETABLE_PUD_FOLDED > > +static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) > > +{ > > + pud_t pud = READ_ONCE(*pudp); > > + > > + if (mm_pmd_folded(mm)) > > + return; > > + > > + pud = __pud(pud_val(pud) | RANDOM_ORVALUE); > > + WRITE_ONCE(*pudp, pud); > > + pud_clear(pudp); > > + pud = READ_ONCE(*pudp); > > + WARN_ON(!pud_none(pud)); > > +} > > + > > +static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, > > + pmd_t *pmdp) > > +{ > > + pud_t pud; > > + > > + if (mm_pmd_folded(mm)) > > + return; > > + /* > > + * This entry points to next level page table page. > > + * Hence this must not qualify as pud_bad(). > > + */ > > + pmd_clear(pmdp); > > + pud_clear(pudp); > > + pud_populate(mm, pudp, pmdp); > > + pud = READ_ONCE(*pudp); > > + WARN_ON(pud_bad(pud)); > > +} > > +#else > > +static void __init pud_clear_tests(struct mm_struct *mm, pud_t *pudp) { } > > +static void __init pud_populate_tests(struct mm_struct *mm, pud_t *pudp, > > + pmd_t *pmdp) > > +{ > > +} > > +#endif > > + > > +#ifndef __PAGETABLE_P4D_FOLDED > > +static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) > > +{ > > + p4d_t p4d = READ_ONCE(*p4dp); > > + > > + if (mm_pud_folded(mm)) > > + return; > > + > > + p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE); > > + WRITE_ONCE(*p4dp, p4d); > > + p4d_clear(p4dp); > > + p4d = READ_ONCE(*p4dp); > > + WARN_ON(!p4d_none(p4d)); > > +} > > + > > +static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, > > + pud_t *pudp) > > +{ > > + p4d_t p4d; > > + > > + if (mm_pud_folded(mm)) > > + return; > > + > > + /* > > + * This entry points to next level page table page. > > + * Hence this must not qualify as p4d_bad(). > > + */ > > + pud_clear(pudp); > > + p4d_clear(p4dp); > > + p4d_populate(mm, p4dp, pudp); > > + p4d = READ_ONCE(*p4dp); > > + WARN_ON(p4d_bad(p4d)); > > +} > > + > > +static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) > > +{ > > + pgd_t pgd = READ_ONCE(*pgdp); > > + > > + if (mm_p4d_folded(mm)) > > + return; > > + > > + pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE); > > + WRITE_ONCE(*pgdp, pgd); > > + pgd_clear(pgdp); > > + pgd = READ_ONCE(*pgdp); > > + WARN_ON(!pgd_none(pgd)); > > +} > > + > > +static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > > + p4d_t *p4dp) > > +{ > > + pgd_t pgd; > > + > > + if (mm_p4d_folded(mm)) > > + return; > > + > > + /* > > + * This entry points to next level page table page. > > + * Hence this must not qualify as pgd_bad(). > > + */ > > + p4d_clear(p4dp); > > + pgd_clear(pgdp); > > + pgd_populate(mm, pgdp, p4dp); > > + pgd = READ_ONCE(*pgdp); > > + WARN_ON(pgd_bad(pgd)); > > +} > > +#else > > +static void __init p4d_clear_tests(struct mm_struct *mm, p4d_t *p4dp) { } > > +static void __init pgd_clear_tests(struct mm_struct *mm, pgd_t *pgdp) { } > > +static void __init p4d_populate_tests(struct mm_struct *mm, p4d_t *p4dp, > > + pud_t *pudp) > > +{ > > +} > > +static void __init pgd_populate_tests(struct mm_struct *mm, pgd_t *pgdp, > > + p4d_t *p4dp) > > +{ > > +} > > +#endif > > + > > +static void __init pte_clear_tests(struct mm_struct *mm, pte_t *ptep) > > +{ > > + pte_t pte = READ_ONCE(*ptep); > > + > > + pte = __pte(pte_val(pte) | RANDOM_ORVALUE); > > + WRITE_ONCE(*ptep, pte); > > + pte_clear(mm, 0, ptep); > > + pte = READ_ONCE(*ptep); > > + WARN_ON(!pte_none(pte)); > > +} > > + > > +static void __init pmd_clear_tests(struct mm_struct *mm, pmd_t *pmdp) > > +{ > > + pmd_t pmd = READ_ONCE(*pmdp); > > + > > + pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE); > > + WRITE_ONCE(*pmdp, pmd); > > + pmd_clear(pmdp); > > + pmd = READ_ONCE(*pmdp); > > + WARN_ON(!pmd_none(pmd)); > > +} > > + > > +static void __init pmd_populate_tests(struct mm_struct *mm, pmd_t *pmdp, > > + pgtable_t pgtable) > > +{ > > + pmd_t pmd; > > + > > + /* > > + * This entry points to next level page table page. > > + * Hence this must not qualify as pmd_bad(). > > + */ > > + pmd_clear(pmdp); > > + pmd_populate(mm, pmdp, pgtable); > > + pmd = READ_ONCE(*pmdp); > > + WARN_ON(pmd_bad(pmd)); > > +} > > + > > +static unsigned long __init get_random_vaddr(void) > > +{ > > + unsigned long random_vaddr, random_pages, total_user_pages; > > + > > + total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE; > > + > > + random_pages = get_random_long() % total_user_pages; > > + random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE; > > + > > + return random_vaddr; > > +} > > + > > +void __init debug_vm_pgtable(void) > > +{ > > + struct mm_struct *mm; > > + pgd_t *pgdp; > > + p4d_t *p4dp, *saved_p4dp; > > + pud_t *pudp, *saved_pudp; > > + pmd_t *pmdp, *saved_pmdp, pmd; > > + pte_t *ptep; > > + pgtable_t saved_ptep; > > + pgprot_t prot; > > + phys_addr_t paddr; > > + unsigned long vaddr, pte_aligned, pmd_aligned; > > + unsigned long pud_aligned, p4d_aligned, pgd_aligned; > > + > > + pr_info("Validating architecture page table helpers\n"); > > + prot = vm_get_page_prot(VMFLAGS); > > + vaddr = get_random_vaddr(); > > + mm = mm_alloc(); > > + if (!mm) { > > + pr_err("mm_struct allocation failed\n"); > > + return; > > + } > > + > > + /* > > + * PFN for mapping at PTE level is determined from a standard kernel > > + * text symbol. But pfns for higher page table levels are derived by > > + * masking lower bits of this real pfn. These derived pfns might not > > + * exist on the platform but that does not really matter as pfn_pxx() > > + * helpers will still create appropriate entries for the test. This > > + * helps avoid large memory block allocations to be used for mapping > > + * at higher page table levels. > > + */ > > + paddr = __pa(&start_kernel); > > + > > + pte_aligned = (paddr & PAGE_MASK) >> PAGE_SHIFT; > > + pmd_aligned = (paddr & PMD_MASK) >> PAGE_SHIFT; > > + pud_aligned = (paddr & PUD_MASK) >> PAGE_SHIFT; > > + p4d_aligned = (paddr & P4D_MASK) >> PAGE_SHIFT; > > + pgd_aligned = (paddr & PGDIR_MASK) >> PAGE_SHIFT; > > + WARN_ON(!pfn_valid(pte_aligned)); > > + > > + pgdp = pgd_offset(mm, vaddr); > > + p4dp = p4d_alloc(mm, pgdp, vaddr); > > + pudp = pud_alloc(mm, p4dp, vaddr); > > + pmdp = pmd_alloc(mm, pudp, vaddr); > > + ptep = pte_alloc_map(mm, pmdp, vaddr); > > + > > + /* > > + * Save all the page table page addresses as the page table > > + * entries will be used for testing with random or garbage > > + * values. These saved addresses will be used for freeing > > + * page table pages. > > + */ > > + pmd = READ_ONCE(*pmdp); > > + saved_p4dp = p4d_offset(pgdp, 0UL); > > + saved_pudp = pud_offset(p4dp, 0UL); > > + saved_pmdp = pmd_offset(pudp, 0UL); > > + saved_ptep = pmd_pgtable(pmd); > > + > > + pte_basic_tests(pte_aligned, prot); > > + pmd_basic_tests(pmd_aligned, prot); > > + pud_basic_tests(pud_aligned, prot); > > + p4d_basic_tests(p4d_aligned, prot); > > + pgd_basic_tests(pgd_aligned, prot); > > + > > + pte_clear_tests(mm, ptep); > > + pmd_clear_tests(mm, pmdp); > > + pud_clear_tests(mm, pudp); > > + p4d_clear_tests(mm, p4dp); > > + pgd_clear_tests(mm, pgdp); > > + > > + pte_unmap(ptep); > > + > > + pmd_populate_tests(mm, pmdp, saved_ptep); > > + pud_populate_tests(mm, pudp, saved_pmdp); > > + p4d_populate_tests(mm, p4dp, saved_pudp); > > + pgd_populate_tests(mm, pgdp, saved_p4dp); > > + > > + p4d_free(mm, saved_p4dp); > > + pud_free(mm, saved_pudp); > > + pmd_free(mm, saved_pmdp); > > + pte_free(mm, saved_ptep); > > + > > + mm_dec_nr_puds(mm); > > + mm_dec_nr_pmds(mm); > > + mm_dec_nr_ptes(mm); > > + mmdrop(mm); > > +}
