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From: Andy Lutomirski <luto@kernel.org>
To: X86 ML <x86@kernel.org>
Cc: Borislav Petkov <bpetkov@suse.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Andy Lutomirski <luto@kernel.org>
Subject: [PATCH 5/5] selftests/x86/ldt_get: Add a few additional tests for limits
Date: Sat,  4 Nov 2017 04:19:52 -0700
Message-ID: <5601c15ea9b3113d288953fd2838b18bedf6bc67.1509794321.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1509794321.git.luto@kernel.org>
In-Reply-To: <cover.1509794321.git.luto@kernel.org>

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>
---
 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 05d0d6f49c2c..8e290c9b2c3f 100644
--- a/tools/testing/selftests/x86/ldt_gdt.c
+++ b/tools/testing/selftests/x86/ldt_gdt.c
@@ -403,9 +403,24 @@ 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);
 }
 
-- 
2.13.6

  parent reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-04 11:19 [PATCH 0/5] Minor selftests improvements Andy Lutomirski
2017-11-04 11:19 ` [PATCH 1/5] selftests/x86/protection_keys: Fix syscall NR redefinition warnings Andy Lutomirski
2017-11-07 10:16   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2017-11-04 11:19 ` [PATCH 2/5] selftests/x86/ldt_gdt: Robustify against set_thread_area() and LAR oddities Andy Lutomirski
2017-11-07 10:17   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2017-11-04 11:19 ` [PATCH 3/5] selftests/x86/ldt_gdt: Add infrastructure to test set_thread_area() Andy Lutomirski
2017-11-07 10:17   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2017-11-04 11:19 ` [PATCH 4/5] selftests/x86/ldt_gdt: Run most existing LDT test cases against the GDT as well Andy Lutomirski
2017-11-07 10:17   ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2017-11-04 11:19 ` Andy Lutomirski [this message]
2017-11-07 10:18   ` [tip:x86/asm] selftests/x86/ldt_get: Add a few additional tests for limits tip-bot for Andy Lutomirski
2017-11-07 10:13 ` [PATCH 0/5] Minor selftests improvements Ingo Molnar

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