x86/asm/entry/32, selftests: Add 'test_syscall_vdso' test

This new test checks that all x86 registers are preserved across
32-bit syscalls. It tests syscalls through VDSO (if available)
and through INT 0x80, normally and under ptrace.

If kernel is a 64-bit one, high registers (r8..r15) are poisoned
before the syscall is called and are checked afterwards.

They must be either preserved, or cleared to zero (but r11 is
special); r12..15 must be preserved for INT 0x80.

EFLAGS is checked for changes too, but change there is not
considered to be a bug (paravirt kernels do not preserve
arithmetic flags).

Run-tested on 64-bit kernel:

	$ ./test_syscall_vdso_32
	[RUN]	Executing 6-argument 32-bit syscall via VDSO
	[OK]	Arguments are preserved across syscall
	[NOTE]	R11 has changed:0000000000200ed7 - assuming clobbered by
	SYSRET insn [OK]	R8..R15 did not leak kernel data
	[RUN]	Executing 6-argument 32-bit syscall via INT 80
	[OK]	Arguments are preserved across syscall
	[OK]	R8..R15 did not leak kernel data
	[RUN]	Running tests under ptrace
	[RUN]	Executing 6-argument 32-bit syscall via VDSO
	[OK]	Arguments are preserved across syscall
	[OK]	R8..R15 did not leak kernel data
	[RUN]	Executing 6-argument 32-bit syscall via INT 80
	[OK]	Arguments are preserved across syscall
	[OK]	R8..R15 did not leak kernel data

On 32-bit paravirt kernel:

	$ ./test_syscall_vdso_32
	[NOTE]	Not a 64-bit kernel, won't test R8..R15 leaks
	[RUN]	Executing 6-argument 32-bit syscall via VDSO
	[WARN]	Flags before=0000000000200ed7 id 0 00 o d i s z 0 a 0 p 1 c
	[WARN]	Flags  after=0000000000200246 id 0 00 i z 0 0 p 1
	[WARN]	Flags change=0000000000000c91 0 00 o d s 0 a 0 0 c
	[OK]	Arguments are preserved across syscall
	[RUN]	Executing 6-argument 32-bit syscall via INT 80
	[OK]	Arguments are preserved across syscall
	[RUN]	Running tests under ptrace
	[RUN]	Executing 6-argument 32-bit syscall via VDSO
	[OK]	Arguments are preserved across syscall
	[RUN]	Executing 6-argument 32-bit syscall via INT 80
	[OK]	Arguments are preserved across syscall

Signed-off-by: Denys Vlasenko <[email protected]>
Acked-by: Andy Lutomirski <[email protected]>
Cc: Alexei Starovoitov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Shuah Khan <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Drewry <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

0 files changed, 0 insertions, 0 deletions