mm/rodata_test: verify test data is unchanged, rather than non-zero

Verify that the test variable holds the initialization value, rather than
any non-zero value.

Link: https://lkml.kernel.org/r/386

mm/rodata_test: verify test data is unchanged, rather than non-zero

Verify that the test variable holds the initialization value, rather than
any non-zero value.

Link: https://lkml.kernel.org/r/386ffda192eb4a26f68c526c496afd48a5cd87ce.1732016064.git.ptesarik@suse.com
Signed-off-by: Petr Tesarik <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Cc: Jinbum Park <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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mm/rodata_test: use READ_ONCE() to read const variable

Patch series "Fix mm/rodata_test", v2.

Make sure that the test actually reads the read-only memory location.
Verify that the variable contains

mm/rodata_test: use READ_ONCE() to read const variable

Patch series "Fix mm/rodata_test", v2.

Make sure that the test actually reads the read-only memory location.
Verify that the variable contains the expected value rather than any
non-zero value.


This patch (of 2):

The C compiler may optimize away the memory read of a const variable if
its value is known at compile time.

In particular, GCC14 with -O2 generates no code at all for test 1, and it
generates the following x86_64 instructions for test 3:

cmpl $195, 4(%rsp)
je .L14

That is, it replaces the read of rodata_test_data with an immediate value
and compares it to the value of the local variable "zero".

Use READ_ONCE() to undo any such compiler optimizations and enforce a
memory read.

Link: https://lkml.kernel.org/r/[email protected]
Link: https://lkml.kernel.org/r/2a66dee010151b25cb143efb39091ef7530aa00a.1732016064.git.ptesarik@suse.com
Fixes: 2959a5f726f6 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Petr Tesarik <[email protected]>
Reviewed-by: Kees Cook <[email protected]>
Cc: Jinbum Park <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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mm/rodata_test: use PAGE_ALIGNED() helper

Use PAGE_ALIGNED() helper instead of open-coding operation, no functional
changes here.

Link: https://lkml.kernel.org/r/20220906075312.166595-1-xiujianfeng

mm/rodata_test: use PAGE_ALIGNED() helper

Use PAGE_ALIGNED() helper instead of open-coding operation, no functional
changes here.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Xiu Jianfeng <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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mm/rodata_test.c: fix missing function declaration

The compilation with CONFIG_DEBUG_RODATA_TEST set produces the following
warning due to the missing include.

mm/rodata_test.c:15:6: warning: no p

mm/rodata_test.c: fix missing function declaration

The compilation with CONFIG_DEBUG_RODATA_TEST set produces the following
warning due to the missing include.

mm/rodata_test.c:15:6: warning: no previous prototype for 'rodata_test' [-Wmissing-prototypes]
15 | void rodata_test(void)
| ^~~~~~~~~~~

Fixes: 2959a5f726f6 ("mm: add arch-independent testcases for RODATA")
Signed-off-by: Leon Romanovsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Reviewed-by: Anshuman Khandual <[email protected]>
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>

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maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

Better describe what these functions do.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Chris

maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

Better describe what these functions do.

Suggested-by: Linus Torvalds <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 315 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Reviewed-by: Armijn Hemel <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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mm: fix RODATA_TEST failure "rodata_test: test data was not read only"

On powerpc, RODATA_TEST fails with message the following messages:

Freeing unused kernel memory: 528K
rodata_test: test da

mm: fix RODATA_TEST failure "rodata_test: test data was not read only"

On powerpc, RODATA_TEST fails with message the following messages:

Freeing unused kernel memory: 528K
rodata_test: test data was not read only

This is because GCC allocates it to .data section:

c0695034 g O .data 00000004 rodata_test_data

Since commit 056b9d8a7692 ("mm: remove rodata_test_data export, add
pr_fmt"), rodata_test_data is used only inside rodata_test.c By
declaring it static, it gets properly allocated into .rodata section
instead of .data:

c04df710 l O .rodata 00000004 rodata_test_data

Fixes: 056b9d8a7692 ("mm: remove rodata_test_data export, add pr_fmt")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Christophe Leroy <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Jinbum Park <[email protected]>
Cc: Segher Boessenkool <[email protected]>
Cc: David Laight <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: remove rodata_test_data export, add pr_fmt

Since commit 3ad38ceb2769 ("x86/mm: Remove CONFIG_DEBUG_NX_TEST"),
nothing is using the exported rodata_test_data variable, so drop the
export.

This a

mm: remove rodata_test_data export, add pr_fmt

Since commit 3ad38ceb2769 ("x86/mm: Remove CONFIG_DEBUG_NX_TEST"),
nothing is using the exported rodata_test_data variable, so drop the
export.

This additionally updates the pr_fmt to avoid redundant strings and
adjusts some whitespace.

Link: http://lkml.kernel.org/r/20170307005313.GA85809@beast
Signed-off-by: Kees Cook <[email protected]>
Cc: Jinbum Park <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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mm: add arch-independent testcases for RODATA

This patch makes arch-independent testcases for RODATA. Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using

mm: add arch-independent testcases for RODATA

This patch makes arch-independent testcases for RODATA. Both x86 and
x86_64 already have testcases for RODATA, But they are arch-specific
because using inline assembly directly.

And cacheflush.h is not a suitable location for rodata-test related
things. Since they were in cacheflush.h, If someone change the state of
CONFIG_DEBUG_RODATA_TEST, It cause overhead of kernel build.

To solve the above issues, write arch-independent testcases and move it
to shared location.

[[email protected]: fix config dependency]
Link: http://lkml.kernel.org/r/20170209131625.GA16954@pjb1027-Latitude-E5410
Link: http://lkml.kernel.org/r/20170129105436.GA9303@pjb1027-Latitude-E5410
Signed-off-by: Jinbum Park <[email protected]>
Acked-by: Kees Cook <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Arjan van de Ven <[email protected]>
Cc: Laura Abbott <[email protected]>
Cc: Russell King <[email protected]>
Cc: Valentin Rothberg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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