Commit-ID:  fec8f5ae1715a01c72ad52cb2ecd8aacaf142302
Gitweb:     https://git.kernel.org/tip/fec8f5ae1715a01c72ad52cb2ecd8aacaf142302
Author:     Andy Lutomirski <[email protected]>
AuthorDate: Sat, 4 Nov 2017 04:19:52 -0700
Committer:  Ingo Molnar <[email protected]>
CommitDate: Tue, 7 Nov 2017 11:13:43 +0100

selftests/x86/ldt_get: Add a few additional tests for limits

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 <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Link: 
http://lkml.kernel.org/r/5601c15ea9b3113d288953fd2838b18bedf6bc67.1509794321.git.l...@kernel.org
Signed-off-by: Ingo Molnar <[email protected]>
---
 tools/testing/selftests/x86/ldt_gdt.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/x86/ldt_gdt.c 
b/tools/testing/selftests/x86/ldt_gdt.c
index 3bb42ff..66e5ce5 100644
--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -404,9 +404,24 @@ 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);
 }
 

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