Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers
From: Gerald Schaefer <hidden>
Date: 2020-01-29 22:20:48
Also in:
linux-arm-kernel, linux-mips, linux-mm, linux-s390, linux-sh, lkml, sparclinux
On Tue, 28 Jan 2020 06:57:53 +0530 Anshuman Khandual [off-list ref] 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 right after page_alloc_init_late(). This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and arm64. Going forward, other architectures too can enable this after fixing build or runtime problems (if any) 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.
[...]
Tested-by: Christophe Leroy <redacted> #PPC32
Tested-by: Gerald Schaefer <redacted> # s390 Thanks again for this effort, and for keeping up the spirit against all odds and even after 12 iterations :-)
quoted hunk ↗ jump to hunk
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..f3f8111edbe3 --- /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: | TODO |
s390 is ok now, with my patches included in v5.5-rc1. So you can now add
--- a/Documentation/features/debug/debug-vm-pgtable/arch-support.txt
+++ b/Documentation/features/debug/debug-vm-pgtable/arch-support.txt@@ -25,7 +25,7 @@ | powerpc/32: | ok | | powerpc/64: | TODO | | riscv: | TODO | - | s390: | TODO | + | s390: | ok | | sh: | TODO | | sparc: | TODO | | um: | TODO | --- 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