4.4-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski luto@kernel.org
[ Upstream commit fec8f5ae1715a01c72ad52cb2ecd8aacaf142302 ]
We weren't testing the .limit and .limit_in_pages fields very well. Add more tests.
This addition seems to trigger the "bits 16:19 are undefined" issue that was fixed in an earlier patch. I think that, at least on my CPU, the high nibble of the limit ends in LAR bits 16:19.
Signed-off-by: Andy Lutomirski luto@kernel.org Cc: Borislav Petkov bpetkov@suse.de Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Thomas Gleixner tglx@linutronix.de Link: http://lkml.kernel.org/r/5601c15ea9b3113d288953fd2838b18bedf6bc67.1509794321... Signed-off-by: Ingo Molnar mingo@kernel.org Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- tools/testing/selftests/x86/ldt_gdt.c | 17 ++++++++++++++++- 1 file changed, 16 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/x86/ldt_gdt.c +++ b/tools/testing/selftests/x86/ldt_gdt.c @@ -351,9 +351,24 @@ static void do_simple_tests(void) install_invalid(&desc, false);
desc.seg_not_present = 0; - desc.read_exec_only = 0; desc.seg_32bit = 1; + desc.read_exec_only = 0; + desc.limit = 0xfffff; + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB); + + desc.limit_in_pages = 1; + + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB | AR_G); + desc.read_exec_only = 1; + install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P | AR_DB | AR_G); + desc.contents = 1; + desc.read_exec_only = 0; + install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); + desc.read_exec_only = 1; + install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); + + desc.limit = 0; install_invalid(&desc, true); }