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Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linu…
…x/kernel/git/tip/tip
Pull x86 PTI preparatory patches from Thomas Gleixner:
"Todays Advent calendar window contains twentyfour easy to digest
patches. The original plan was to have twenty three matching the date,
but a late fixup made that moot.
- Move the cpu_entry_area mapping out of the fixmap into a separate
address space. That's necessary because the fixmap becomes too big
with NRCPUS=8192 and this caused already subtle and hard to
diagnose failures.
The top most patch is fresh from today and cures a brain slip of
that tall grumpy german greybeard, who ignored the intricacies of
32bit wraparounds.
- Limit the number of CPUs on 32bit to 64. That's insane big already,
but at least it's small enough to prevent address space issues with
the cpu_entry_area map, which have been observed and debugged with
the fixmap code
- A few TLB flush fixes in various places plus documentation which of
the TLB functions should be used for what.
- Rename the SYSENTER stack to CPU_ENTRY_AREA stack as it is used for
more than sysenter now and keeping the name makes backtraces
confusing.
- Prevent LDT inheritance on exec() by moving it to arch_dup_mmap(),
which is only invoked on fork().
- Make vysycall more robust.
- A few fixes and cleanups of the debug_pagetables code. Check
PAGE_PRESENT instead of checking the PTE for 0 and a cleanup of the
C89 initialization of the address hint array which already was out
of sync with the index enums.
- Move the ESPFIX init to a different place to prepare for PTI.
- Several code moves with no functional change to make PTI
integration simpler and header files less convoluted.
- Documentation fixes and clarifications"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/cpu_entry_area: Prevent wraparound in setup_cpu_entry_area_ptes() on 32bit
init: Invoke init_espfix_bsp() from mm_init()
x86/cpu_entry_area: Move it out of the fixmap
x86/cpu_entry_area: Move it to a separate unit
x86/mm: Create asm/invpcid.h
x86/mm: Put MMU to hardware ASID translation in one place
x86/mm: Remove hard-coded ASID limit checks
x86/mm: Move the CR3 construction functions to tlbflush.h
x86/mm: Add comments to clarify which TLB-flush functions are supposed to flush what
x86/mm: Remove superfluous barriers
x86/mm: Use __flush_tlb_one() for kernel memory
x86/microcode: Dont abuse the TLB-flush interface
x86/uv: Use the right TLB-flush API
x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack
x86/doc: Remove obvious weirdnesses from the x86 MM layout documentation
x86/mm/64: Improve the memory map documentation
x86/ldt: Prevent LDT inheritance on exec
x86/ldt: Rework locking
arch, mm: Allow arch_dup_mmap() to fail
x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,68 @@ | ||
| // SPDX-License-Identifier: GPL-2.0 | ||
|
|
||
| #ifndef _ASM_X86_CPU_ENTRY_AREA_H | ||
| #define _ASM_X86_CPU_ENTRY_AREA_H | ||
|
|
||
| #include <linux/percpu-defs.h> | ||
| #include <asm/processor.h> | ||
|
|
||
| /* | ||
| * cpu_entry_area is a percpu region that contains things needed by the CPU | ||
| * and early entry/exit code. Real types aren't used for all fields here | ||
| * to avoid circular header dependencies. | ||
| * | ||
| * Every field is a virtual alias of some other allocated backing store. | ||
| * There is no direct allocation of a struct cpu_entry_area. | ||
| */ | ||
| struct cpu_entry_area { | ||
| char gdt[PAGE_SIZE]; | ||
|
|
||
| /* | ||
| * The GDT is just below entry_stack and thus serves (on x86_64) as | ||
| * a a read-only guard page. | ||
| */ | ||
| struct entry_stack_page entry_stack_page; | ||
|
|
||
| /* | ||
| * On x86_64, the TSS is mapped RO. On x86_32, it's mapped RW because | ||
| * we need task switches to work, and task switches write to the TSS. | ||
| */ | ||
| struct tss_struct tss; | ||
|
|
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| char entry_trampoline[PAGE_SIZE]; | ||
|
|
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| #ifdef CONFIG_X86_64 | ||
| /* | ||
| * Exception stacks used for IST entries. | ||
| * | ||
| * In the future, this should have a separate slot for each stack | ||
| * with guard pages between them. | ||
| */ | ||
| char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]; | ||
| #endif | ||
| }; | ||
|
|
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| #define CPU_ENTRY_AREA_SIZE (sizeof(struct cpu_entry_area)) | ||
| #define CPU_ENTRY_AREA_TOT_SIZE (CPU_ENTRY_AREA_SIZE * NR_CPUS) | ||
|
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| DECLARE_PER_CPU(struct cpu_entry_area *, cpu_entry_area); | ||
|
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| extern void setup_cpu_entry_areas(void); | ||
| extern void cea_set_pte(void *cea_vaddr, phys_addr_t pa, pgprot_t flags); | ||
|
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| #define CPU_ENTRY_AREA_RO_IDT CPU_ENTRY_AREA_BASE | ||
| #define CPU_ENTRY_AREA_PER_CPU (CPU_ENTRY_AREA_RO_IDT + PAGE_SIZE) | ||
|
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| #define CPU_ENTRY_AREA_RO_IDT_VADDR ((void *)CPU_ENTRY_AREA_RO_IDT) | ||
|
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| #define CPU_ENTRY_AREA_MAP_SIZE \ | ||
| (CPU_ENTRY_AREA_PER_CPU + CPU_ENTRY_AREA_TOT_SIZE - CPU_ENTRY_AREA_BASE) | ||
|
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| extern struct cpu_entry_area *get_cpu_entry_area(int cpu); | ||
|
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| static inline struct entry_stack *cpu_entry_stack(int cpu) | ||
| { | ||
| return &get_cpu_entry_area(cpu)->entry_stack_page.stack; | ||
| } | ||
|
|
||
| #endif |
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