Messages in this thread | | | From | Lai Jiangshan <> | Subject | [PATCH V3 0/6] x86: don't abuse tss.sp1 | Date | Thu, 28 Jan 2021 00:32:16 +0800 |
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From: Lai Jiangshan <laijs@linux.alibaba.com>
In x86_64, tss.sp1 is reused as cpu_current_top_of_stack. But we can directly use percpu since CR3 and gs_base is correct when it is used.
In x86_32, tss.sp1 is resued as thread.sp0 in three places in entry 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
[V2]: https://lore.kernel.org/lkml/20210125173444.22696-1-jiangshanlai@gmail.com/ [V1]: https://lore.kernel.org/lkml/20210123084900.3118-1-jiangshanlai@gmail.com/
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_64: move cpu_current_top_of_stack out of TSS x86_32: use percpu instead of offset-calculation to get thread.sp0 when SWITCH_TO_KERNEL_STACK x86_32/sysenter: switch to the task stack without emptying the entry stack x86_32/sysenter: restore %fs before switching stack x86_32/sysenter: use percpu to get thread.sp0 when sysenter x86_32: use cpu_current_thread_sp0 instead of 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 | 9 ++----- 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, 40 insertions(+), 62 deletions(-)
-- 2.19.1.6.gb485710b
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