From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@redhat.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Rik van Riel <riel@redhat.com>,
daniel.gruss@iaik.tugraz.at, hughd@google.com,
keescook@google.com, linux-mm@kvack.org,
michael.schwarz@iaik.tugraz.at, moritz.lipp@iaik.tugraz.at,
richard.fellner@student.tugraz.at
Subject: [PATCH 4/5] x86/mm/kaiser: Remove superfluous SWITCH_TO_KERNEL
Date: Mon, 27 Nov 2017 23:31:14 +0100 [thread overview]
Message-ID: <20171127223405.329572992@infradead.org> (raw)
In-Reply-To: <20171127223110.479550152@infradead.org>
[-- Attachment #1: peterz-kaiser-fixup-syscall-switch.patch --]
[-- Type: text/plain, Size: 1044 bytes --]
We never use this code-path with KAISER enabled.
Fixes: ("Prepare the x86/entry assembly code for entry/exit CR3 switching")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
arch/x86/entry/entry_64.S | 8 --------
1 file changed, 8 deletions(-)
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -201,14 +201,6 @@ ENTRY(entry_SYSCALL_64)
swapgs
movq %rsp, PER_CPU_VAR(rsp_scratch)
-
- /*
- * The kernel CR3 is needed to map the process stack, but we
- * need a scratch register to be able to load CR3. %rsp is
- * clobberable right now, so use it as a scratch register.
- * %rsp will look crazy here for a couple instructions.
- */
- SWITCH_TO_KERNEL_CR3 scratch_reg=%rsp
movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp
/* Construct struct pt_regs on stack */
--
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next prev parent reply other threads:[~2017-11-27 22:35 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-27 22:31 [PATCH 0/5] KAISER fixlets Peter Zijlstra
2017-11-27 22:31 ` [PATCH 1/5] x86/mm/kaiser: Alternative ESPFIX Peter Zijlstra
2017-11-27 22:39 ` Peter Zijlstra
2017-11-27 22:41 ` Dave Hansen
2017-11-27 22:31 ` [PATCH 2/5] x86/mm/kaiser: Add a banner Peter Zijlstra
2017-11-28 3:36 ` Andy Lutomirski
2017-11-28 5:03 ` Josh Poimboeuf
2017-11-28 5:23 ` Andy Lutomirski
2017-11-28 12:54 ` Borislav Petkov
2017-11-27 22:31 ` [PATCH 3/5] x86/mm/kaiser: Revert ("Map the entry stack variables") Peter Zijlstra
2017-11-27 22:31 ` Peter Zijlstra [this message]
2017-11-27 22:47 ` [PATCH 4/5] x86/mm/kaiser: Remove superfluous SWITCH_TO_KERNEL Dave Hansen
2017-11-27 22:53 ` Peter Zijlstra
2017-11-27 22:31 ` [PATCH 5/5] x86/mm/kaiser: Disable the SYSCALL-64 trampoline along with KAISER Peter Zijlstra
2017-11-27 22:53 ` Dave Hansen
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