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| Started by | Andy Lutomirski <luto@kernel.org> |
|---|---|
| First post | 2016-01-12 02:30 +0100 |
| Last post | 2016-01-12 11:30 +0100 |
| Articles | 2 — 2 participants |
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[PATCH v2] selftests/x86: Disable ldt_gdt_64 for now Andy Lutomirski <luto@kernel.org> - 2016-01-12 02:30 +0100
[tip:x86/urgent] selftests/x86: Disable the ldt_gdt_64 test for now tip-bot for Andy Lutomirski <tipbot@zytor.com> - 2016-01-12 11:30 +0100
| From | Andy Lutomirski <luto@kernel.org> |
|---|---|
| Date | 2016-01-12 02:30 +0100 |
| Subject | [PATCH v2] selftests/x86: Disable ldt_gdt_64 for now |
| Message-ID | <qPVWy-2fD-17@gated-at.bofh.it> |
ldt_gdt.c relies on cross-cpu invalidation of SS to do one of its tests. On 32-bit builds, this works fine, but on 64-bit builds, it only works if the kernel has proper SS sigcontext handling for 64-bit user programs. Since the SS fixes are currently reverted, restrict the test case to 32 bits for now. In principle, I could change the test to use a different segment register, but it would be messy: CS can't point to the LDT for 64-bit code, and the other registers don't result in immediate faults because they aren't reloaded on kernel -> user transitions. When we fix sigcontext (in 4.6?), we can revert this. Signed-off-by: Andy Lutomirski <luto@kernel.org> --- Changes from v1: based on tip:x86/asm tools/testing/selftests/x86/Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index eabcff411984..398bb0e6e38c 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -4,9 +4,10 @@ include ../lib.mk .PHONY: all all_32 all_64 warn_32bit_failure clean -TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt ptrace_syscall +TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn test_syscall_vdso unwind_vdso \ - test_FCMOV test_FCOMI test_FISTTP + test_FCMOV test_FCOMI test_FISTTP \ + ldt_gdt TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32) -- 2.5.0
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| From | tip-bot for Andy Lutomirski <tipbot@zytor.com> |
|---|---|
| Date | 2016-01-12 11:30 +0100 |
| Subject | [tip:x86/urgent] selftests/x86: Disable the ldt_gdt_64 test for now |
| Message-ID | <qQ4n8-81P-9@gated-at.bofh.it> |
| In reply to | #1306894 |
Commit-ID: 0f672809f91abd0aee01624ccad9199a62e3da7a Gitweb: http://git.kernel.org/tip/0f672809f91abd0aee01624ccad9199a62e3da7a Author: Andy Lutomirski <luto@kernel.org> AuthorDate: Mon, 11 Jan 2016 17:23:32 -0800 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Tue, 12 Jan 2016 11:09:26 +0100 selftests/x86: Disable the ldt_gdt_64 test for now ldt_gdt.c relies on cross-cpu invalidation of SS to do one of its tests. On 32-bit builds, this works fine, but on 64-bit builds, it only works if the kernel has proper SS sigcontext handling for 64-bit user programs. Since the SS fixes are currently reverted, restrict the test case to 32 bits for now. In principle, I could change the test to use a different segment register, but it would be messy: CS can't point to the LDT for 64-bit code, and the other registers don't result in immediate faults because they aren't reloaded on kernel -> user transitions. When we fix sigcontext (in 4.6?), we can revert this. Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shuah Khan <shuahkh@osg.samsung.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/231591d9122d282402d8f53175134f8db5b3bc73.1452561752.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> --- tools/testing/selftests/x86/Makefile | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile index eabcff4..398bb0e 100644 --- a/tools/testing/selftests/x86/Makefile +++ b/tools/testing/selftests/x86/Makefile @@ -4,9 +4,10 @@ include ../lib.mk .PHONY: all all_32 all_64 warn_32bit_failure clean -TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs ldt_gdt syscall_nt ptrace_syscall +TARGETS_C_BOTHBITS := single_step_syscall sysret_ss_attrs syscall_nt ptrace_syscall TARGETS_C_32BIT_ONLY := entry_from_vm86 syscall_arg_fault sigreturn test_syscall_vdso unwind_vdso \ - test_FCMOV test_FCOMI test_FISTTP + test_FCMOV test_FCOMI test_FISTTP \ + ldt_gdt TARGETS_C_32BIT_ALL := $(TARGETS_C_BOTHBITS) $(TARGETS_C_32BIT_ONLY) BINARIES_32 := $(TARGETS_C_32BIT_ALL:%=%_32)
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