From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Al Viro <viro@zeniv.linux.org.uk>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Joerg Roedel <jroedel@suse.de>,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Reinette Chatre <reinette.chatre@intel.com>,
Andrew Morton <akpm@linux-foundation.org>,
Gabriel Krisman Bertazi <krisman@collabora.com>,
Kees Cook <keescook@chromium.org>,
Frederic Weisbecker <frederic@kernel.org>,
Jens Axboe <axboe@kernel.dk>,
Arvind Sankar <nivedita@alum.mit.edu>,
Brian Gerst <brgerst@gmail.com>, Ard Biesheuvel <ardb@kernel.org>,
Andi Kleen <ak@linux.intel.com>, Mike Rapoport <rppt@kernel.org>,
Mike Hommey <mh@glandium.org>,
Mark Gross <mgross@linux.intel.com>,
Fenghua Yu <fenghua.yu@intel.com>,
Tony Luck <tony.luck@intel.com>,
Anthony Steinhauser <asteinhauser@google.com>,
Jay Lang <jaytlang@mit.edu>,
"Chang S. Bae" <chang.seok.bae@intel.com>
Subject: [PATCH V2 2/6] x86_32: use percpu instead of offset-calculation to get thread.sp0 when SWITCH_TO_KERNEL_STACK
Date: Tue, 26 Jan 2021 01:34:30 +0800 [thread overview]
Message-ID: <20210125173444.22696-3-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20210125173444.22696-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <laijs@linux.alibaba.com>
TSS_entry2task_stack is used to refer to tss.sp1 which is stored the value
of thread.sp0.
At the code where TSS_entry2task_stack is used in SWITCH_TO_KERNEL_STACK,
the CR3 is already kernel CR3 and kernel segments is loaded.
So we can directly use the percpu to get tss.sp1(thread.sp0) instead of
the complex offset-calculation.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/entry_32.S | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S
index df8c017e6161..3b4d1a63d1f0 100644
--- a/arch/x86/entry/entry_32.S
+++ b/arch/x86/entry/entry_32.S
@@ -465,16 +465,11 @@
cmpl $SIZEOF_entry_stack, %ecx
jae .Lend_\@
- /* Load stack pointer into %esi and %edi */
+ /* Load stack pointer into %esi */
movl %esp, %esi
- movl %esi, %edi
-
- /* Move %edi to the top of the entry stack */
- andl $(MASK_entry_stack), %edi
- addl $(SIZEOF_entry_stack), %edi
/* Load top of task-stack into %edi */
- movl TSS_entry2task_stack(%edi), %edi
+ movl PER_CPU_VAR(cpu_tss_rw + TSS_sp1), %edi
/* Special case - entry from kernel mode via entry stack */
#ifdef CONFIG_VM86
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2021-01-25 16:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-23 8:48 [PATCH] x86_64: move cpu_current_top_of_stack out of TSS Lai Jiangshan
2021-01-25 2:24 ` Andy Lutomirski
2021-01-25 17:34 ` [PATCH V2 0/6] x86: don't abuse tss.sp1 Lai Jiangshan
2021-01-25 17:34 ` [PATCH V2 1/6] x86_64: move cpu_current_top_of_stack out of TSS Lai Jiangshan
2021-03-28 20:46 ` [tip: x86/cleanups] x86/process/64: Move " tip-bot2 for Lai Jiangshan
2021-01-25 17:34 ` Lai Jiangshan [this message]
2021-01-25 17:34 ` [PATCH V2 3/6] x86_32/sysenter: switch to the task stack without emptying the entry stack Lai Jiangshan
2021-01-26 6:04 ` Brian Gerst
2021-01-25 17:34 ` [PATCH V2 4/6] x86_32/sysenter: restore %fs before switching stack Lai Jiangshan
2021-01-25 17:34 ` [PATCH V2 5/6] x86_32/sysenter: use percpu to get thread.sp0 when sysenter Lai Jiangshan
2021-01-25 17:34 ` [PATCH V2 6/6] x86_32: use cpu_current_thread_sp0 instead of cpu_tss_rw.x86_tss.sp1 Lai Jiangshan
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