On Wed, Feb 10, 2021 at 09:39:11PM +0800, Lai Jiangshan wrote:
> From: Lai Jiangshan <la...@linux.alibaba.com>
>
> In x86_64, tss.sp1 is reused as cpu_current_top_of_stack. We'd better
> directly use percpu since CR3 and gs_base is correct when it is used.
Be more direct if not using percpu is incorrect in some way.
>
> In x86_32, tss.sp1 is resued as thread.sp0 in three places in entry
s/resued/reused
> code. We have the correct CR3 and %fs at two of the places. The last
> one is sysenter. This patchset makes %fs available earlier so that
> we can also use percpu in sysenter. And add a percpu cpu_current_thread_sp0
> for thread.sp0 instead of tss.sp1
>
> [V3]:
> https://lore.kernel.org/lkml/20210127163231.12709-1-jiangshan...@gmail.com/
> [V2]:
> https://lore.kernel.org/lkml/20210125173444.22696-1-jiangshan...@gmail.com/
> [V1]:
> https://lore.kernel.org/lkml/20210123084900.3118-1-jiangshan...@gmail.com/
>
> Changed from V3:
> Update subjects as Borislav's imperative request. ^_^
> Update changelog as Borislav suggested.
> Change EXPORT_PER_CPU_SYMBOL to EXPORT_PER_CPU_SYMBOL_GPL.
>
> Changed from V2:
> Add missing "%ss:" reported by Brian Gerst.
>
> Changed from V1:
> Requested from Andy to also fix sp1 for x86_32.
> Update comments in the x86_64 patch as Andy sugguested.
>
> Lai Jiangshan (6):
> x86/entry/64: Move cpu_current_top_of_stack out of TSS
> x86/entry/32: Use percpu instead of offset-calculation to get
> thread.sp0 in SWITCH_TO_KERNEL_STACK
> x86/entry/32: Switch to the task stack without emptying the entry
> stack
> x86/entry/32: Restore %fs before switching stack
> x86/entry/32: Use percpu to get thread.sp0 in SYSENTER
> x86/entry/32: Introduce cpu_current_thread_sp0 to replace
> cpu_tss_rw.x86_tss.sp1
>
> arch/x86/entry/entry_32.S | 38 +++++++++++++++++-------------
> arch/x86/include/asm/processor.h | 12 ++--------
> arch/x86/include/asm/switch_to.h | 8 +------
> arch/x86/include/asm/thread_info.h | 6 -----
> arch/x86/kernel/asm-offsets.c | 1 -
> arch/x86/kernel/asm-offsets_32.c | 10 --------
> arch/x86/kernel/cpu/common.c | 12 +++++++++-
> arch/x86/kernel/process.c | 7 ------
> arch/x86/mm/pti.c | 7 +++---
> 9 files changed, 39 insertions(+), 62 deletions(-)
>
> --
> 2.19.1.6.gb485710b
>
