x86/entry/64/compat: Fix SYSENTER's NT flag before user memory access (dd27f998) · Commits · 戴 / test

Clearing NT is part of the prologue, whereas loading up arg6 makes more sense to think about as part of syscall processing. Reorder them. 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: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/19eb235828b2d2a52c53459e09f2974e15e65a35.1444091584.git.luto@kernel.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/entry/entry_64_compat.S

+9 −9

Original line number	Diff line number	Diff line
		@@ -88,15 +88,6 @@ ENTRY(entry_SYSENTER_compat)
		cld
		sub $(108), %rsp / pt_regs->r8-11, bp, bx, r12-15 not saved */

		/*
		* no need to do an access_ok check here because rbp has been
		* 32-bit zero extended
		*/
		ASM_STAC
		1: movl (%rbp), %ebp
		_ASM_EXTABLE(1b, ia32_badarg)
		ASM_CLAC

		/*
		* Sysenter doesn't filter flags, so we need to clear NT
		* ourselves. To save a few cycles, we can check whether
		@@ -106,6 +97,15 @@ ENTRY(entry_SYSENTER_compat)
		jnz sysenter_fix_flags
		sysenter_flags_fixed:

		/*
		* No need to do an access_ok() check here because RBP has been
		* 32-bit zero extended:
		*/
		ASM_STAC
		1: movl (%rbp), %ebp
		_ASM_EXTABLE(1b, ia32_badarg)
		ASM_CLAC

		orl $TS_COMPAT, ASM_THREAD_INFO(TI_status, %rsp, SIZEOF_PTREGS)
		testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS)
		jnz sysenter_tracesys

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