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.
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 [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
