[PATCH v15 23/23] selftests: vm: pkeys: Use the correct page size on powerpc

[Michael Ellerman]

Sandipan Das <sandipan at linux.ibm.com> writes:
> Both 4K and 64K pages are supported on powerpc. Parts of
> the selftest code perform alignment computations based on
> the PAGE_SIZE macro which is currently hardcoded to 64K
> for powerpc. This causes some test failures on kernels
> configured with 4K page size.
>
> This problem is solved by determining the correct page
> size during the build process rather than hardcoding it
> in the header file.

Doing it at build time is wrong, the test could be built on a 4K system
and then run on a 64K system, or vice versa.

You should just use getpagesize() at runtime.

cheers

> diff --git a/tools/testing/selftests/vm/Makefile b/tools/testing/selftests/vm/Makefile
> index 4e9c741be6af..ada3a67eaac6 100644
> --- a/tools/testing/selftests/vm/Makefile
> +++ b/tools/testing/selftests/vm/Makefile
> @@ -4,6 +4,10 @@ uname_M := $(shell uname -m 2>/dev/null || echo not)
>  ARCH ?= $(shell echo $(uname_M) | sed -e 's/aarch64.*/arm64/')
>  
>  CFLAGS = -Wall -I ../../../../usr/include $(EXTRA_CFLAGS)
> +ifneq (,$(filter $(ARCH), ppc64 ppc64le))
> +protection_keys: EXTRA_CFLAGS += -DPAGE_SIZE=$(shell getconf PAGESIZE)
> +endif
> +
>  LDLIBS = -lrt
>  TEST_GEN_FILES = compaction_test
>  TEST_GEN_FILES += gup_benchmark
> diff --git a/tools/testing/selftests/vm/pkey-powerpc.h b/tools/testing/selftests/vm/pkey-powerpc.h
> index 3cd8e03fd640..07fa9f529014 100644
> --- a/tools/testing/selftests/vm/pkey-powerpc.h
> +++ b/tools/testing/selftests/vm/pkey-powerpc.h
> @@ -36,7 +36,6 @@
>  					     pkey-31 and exec-only key */
>  #define PKEY_BITS_PER_PKEY	2
>  #define HPAGE_SIZE		(1UL << 24)
> -#define PAGE_SIZE		(1UL << 16)
>  #define pkey_reg_t		u64
>  #define PKEY_REG_FMT		"%016lx"
>  
> -- 
> 2.17.1