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Workaround for Linux PowerPC GPL-only cpu_has_feature()

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Linux since 4.7 makes interface 'cpu_has_feature' to use jump labels on
powerpc if CONFIG_JUMP_LABEL_FEATURE_CHECKS is enabled, in this case
however the inline function references GPL-only symbol
'cpu_feature_keys'.

ZFS currently uses 'cpu_has_feature' either directly or indirectly from
several places; while it is unknown how this issue didn't break ZFS on
64-bit little-endian powerpc, it is known to break ZFS with many Linux
versions on both 32-bit and 64-bit big-endian powerpc.

Until this issue is fixed in Linux, we have to workaround it by
overriding affected inline functions without depending on
'cpu_feature_keys'.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: WHR <msl0000023508@gmail.com>
Closes #14590
This commit is contained in:
Low-power 2023-03-11 01:35:00 +08:00 committed by GitHub
parent 7316fdd1c0
commit 589f59b52a
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5 changed files with 93 additions and 0 deletions
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29
config/kernel-cpu_has_feature.m4 Normal file
View File

@ -0,0 +1,29 @@
dnl #
dnl # cpu_has_feature() may referencing GPL-only cpu_feature_keys on powerpc
dnl #
dnl #
dnl # Checking if cpu_has_feature is exported GPL-only
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_CPU_HAS_FEATURE], [
ZFS_LINUX_TEST_SRC([cpu_has_feature], [
#include <linux/version.h>
#if LINUX_VERSION_CODE >= KERNEL_VERSION(4, 7, 0)
#include <asm/cpu_has_feature.h>
#else
#include <asm/cputable.h>
#endif
], [
return cpu_has_feature(CPU_FTR_ALTIVEC) ? 0 : 1;
], [], [ZFS_META_LICENSE])
])
AC_DEFUN([ZFS_AC_KERNEL_CPU_HAS_FEATURE], [
AC_MSG_CHECKING([whether cpu_has_feature() is GPL-only])
ZFS_LINUX_TEST_RESULT([cpu_has_feature_license], [
AC_MSG_RESULT(no)
], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_CPU_HAS_FEATURE_GPL_ONLY, 1,
[cpu_has_feature() is GPL-only])
])
])

26
config/kernel-flush_dcache_page.m4 Normal file
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@ -0,0 +1,26 @@
dnl #
dnl # Starting from Linux 5.13, flush_dcache_page() becomes an inline
dnl # function and may indirectly referencing GPL-only cpu_feature_keys on
dnl # powerpc
dnl #
dnl #
dnl # Checking if flush_dcache_page is exported GPL-only
dnl #
AC_DEFUN([ZFS_AC_KERNEL_SRC_FLUSH_DCACHE_PAGE], [
ZFS_LINUX_TEST_SRC([flush_dcache_page], [
#include <asm/cacheflush.h>
], [
flush_dcache_page(0);
], [], [ZFS_META_LICENSE])
])
AC_DEFUN([ZFS_AC_KERNEL_FLUSH_DCACHE_PAGE], [
AC_MSG_CHECKING([whether flush_dcache_page() is GPL-only])
ZFS_LINUX_TEST_RESULT([flush_dcache_page_license], [
AC_MSG_RESULT(no)
], [
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_FLUSH_DCACHE_PAGE_GPL_ONLY, 1,
[flush_dcache_page() is GPL-only])
])
])

12
config/kernel.m4
View File

@ -151,6 +151,12 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_SRC], [
ZFS_AC_KERNEL_SRC_IDMAP_MNT_API
ZFS_AC_KERNEL_SRC_IATTR_VFSID
ZFS_AC_KERNEL_SRC_FILEMAP
case "$host_cpu" in
powerpc*)
ZFS_AC_KERNEL_SRC_CPU_HAS_FEATURE
ZFS_AC_KERNEL_SRC_FLUSH_DCACHE_PAGE
;;
esac
AC_MSG_CHECKING([for available kernel interfaces])
ZFS_LINUX_TEST_COMPILE_ALL([kabi])
@ -275,6 +281,12 @@ AC_DEFUN([ZFS_AC_KERNEL_TEST_RESULT], [
ZFS_AC_KERNEL_IDMAP_MNT_API
ZFS_AC_KERNEL_IATTR_VFSID
ZFS_AC_KERNEL_FILEMAP
case "$host_cpu" in
powerpc*)
ZFS_AC_KERNEL_CPU_HAS_FEATURE
ZFS_AC_KERNEL_FLUSH_DCACHE_PAGE
;;
esac
])
dnl #

15
include/os/linux/kernel/linux/dcache_compat.h
View File

@ -39,6 +39,21 @@
#define d_alias d_u.d_alias
#endif
/*
* Starting from Linux 5.13, flush_dcache_page() becomes an inline function
* and under some configurations, may indirectly referencing GPL-only
* cpu_feature_keys on powerpc. Override this function when it is detected
* being GPL-only.
*/
#if defined __powerpc__ && defined HAVE_FLUSH_DCACHE_PAGE_GPL_ONLY
#include <linux/simd_powerpc.h>
#define flush_dcache_page(page) do { \
if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE) && \
test_bit(PG_dcache_clean, &(page)->flags)) \
clear_bit(PG_dcache_clean, &(page)->flags); \
} while (0)
#endif
/*
* 2.6.30 API change,
* The const keyword was added to the 'struct dentry_operations' in

11
include/os/linux/kernel/linux/simd_powerpc.h
View File

@ -118,6 +118,17 @@
#define kfpu_init() 0
#define kfpu_fini() ((void) 0)
/*
* Linux 4.7 makes cpu_has_feature to use jump labels on powerpc if
* CONFIG_JUMP_LABEL_FEATURE_CHECKS is enabled, in this case however it
* references GPL-only symbol cpu_feature_keys. Therefore we overrides this
* interface when it is detected being GPL-only.
*/
#if defined(CONFIG_JUMP_LABEL_FEATURE_CHECKS) && \
defined(HAVE_CPU_HAS_FEATURE_GPL_ONLY)
#define cpu_has_feature(feature) early_cpu_has_feature(feature)
#endif
/*
* Check if AltiVec instruction set is available
*/