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zfs/config/kernel-flush_dcache_page.m4

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Workaround for Linux PowerPC GPL-only cpu_has_feature() 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
2023-03-10 17:35:00 +00:00
dnl #
dnl # Starting from Linux 5.13, flush_dcache_page() becomes an inline
compact: workaround for GPL-only symbols on riscv from Linux 6.2 Since Linux 6.2, the implementation of flush_dcache_page on riscv references GPL-only symbol `PageHuge`, breaking the build of zfs. This patch uses existing mechanism to override flush_dcache_page, removing the call to `PageHuge`. According to comments in kernel, it is only used to do some check against HugeTLB pages, which only exist in userspace. ZFS uses flush_dcache_page only on kernel pages, thus this patch will not introduce any behaviour change. See also: torvalds/linux@d33deda, openzfs/zfs@589f59b Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Shengqi Chen <harry-chen@outlook.com> Closes #14974 Closes #15627
2023-12-06 20:37:50 +00:00
dnl # function and may indirectly referencing GPL-only symbols:
dnl # on powerpc: cpu_feature_keys
dnl # on riscv: PageHuge (added from 6.2)
Workaround for Linux PowerPC GPL-only cpu_has_feature() 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
2023-03-10 17:35:00 +00:00
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])
])
])