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x86/pkeys/selftests: Add a test for pkey 0

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Protection key 0 is the default key for all memory and will
not normally come back from pkey_alloc().  But, you might
still want pass it to mprotect_pkey().

This check ensures that you can use pkey 0.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180509171356.9E40B254@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Dave Hansen 2018-05-09 10:13:56 -07:00 committed by Ingo Molnar
parent acb25d761d
commit 3488a600d9
1 changed files with 30 additions and 0 deletions
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30
tools/testing/selftests/x86/protection_keys.c
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@ -1184,6 +1184,35 @@ void test_pkey_alloc_exhaust(int *ptr, u16 pkey)
}
}
/*
* pkey 0 is special. It is allocated by default, so you do not
* have to call pkey_alloc() to use it first. Make sure that it
* is usable.
*/
void test_mprotect_with_pkey_0(int *ptr, u16 pkey)
{
long size;
int prot;
assert(pkey_last_malloc_record);
size = pkey_last_malloc_record->size;
/*
* This is a bit of a hack. But mprotect() requires
* huge-page-aligned sizes when operating on hugetlbfs.
* So, make sure that we use something that's a multiple
* of a huge page when we can.
*/
if (size >= HPAGE_SIZE)
size = HPAGE_SIZE;
prot = pkey_last_malloc_record->prot;
/* Use pkey 0 */
mprotect_pkey(ptr, size, prot, 0);
/* Make sure that we can set it back to the original pkey. */
mprotect_pkey(ptr, size, prot, pkey);
}
void test_ptrace_of_child(int *ptr, u16 pkey)
{
__attribute__((__unused__)) int peek_result;
@ -1378,6 +1407,7 @@ void (*pkey_tests[])(int *ptr, u16 pkey) = {
test_kernel_gup_write_to_write_disabled_region,
test_executing_on_unreadable_memory,
test_implicit_mprotect_exec_only_memory,
test_mprotect_with_pkey_0,
test_ptrace_of_child,
test_pkey_syscalls_on_non_allocated_pkey,
test_pkey_syscalls_bad_args,