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powerpc: add link stack flush mitigation status in debugfs.
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The link stack flush status is not visible in debugfs. It can be enabled
even when count cache flush is disabled. Add separate file for its
status.

Signed-off-by: Michal Suchanek <msuchanek@suse.de>
[mpe: Update for change to link_stack_flush_type]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191127220959.6208-1-msuchanek@suse.de
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Michal Suchanek authored and Michael Ellerman committed Jan 31, 2022
1 parent 279d1a7 commit b2a6f60
Showing 1 changed file with 15 additions and 0 deletions.
15 changes: 15 additions & 0 deletions arch/powerpc/kernel/security.c
Original file line number Diff line number Diff line change
@@ -747,14 +747,29 @@ static int count_cache_flush_get(void *data, u64 *val)
return 0;
}

static int link_stack_flush_get(void *data, u64 *val)
{
if (link_stack_flush_type == BRANCH_CACHE_FLUSH_NONE)
*val = 0;
else
*val = 1;

return 0;
}

DEFINE_DEBUGFS_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
count_cache_flush_set, "%llu\n");
DEFINE_DEBUGFS_ATTRIBUTE(fops_link_stack_flush, link_stack_flush_get,
count_cache_flush_set, "%llu\n");

static __init int count_cache_flush_debugfs_init(void)
{
debugfs_create_file_unsafe("count_cache_flush", 0600,
arch_debugfs_dir, NULL,
&fops_count_cache_flush);
debugfs_create_file_unsafe("link_stack_flush", 0600,
arch_debugfs_dir, NULL,
&fops_link_stack_flush);
return 0;
}
device_initcall(count_cache_flush_debugfs_init);

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