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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2024-11-19 14:48:31 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2024-11-19 14:48:31 -0800 |
| commit | a5c93bfec0beca4435d1995bc3ff2ac003fe7552 (patch) | |
| tree | 3b3a47c33db8cd9fc628042303de5643d180a867 | |
| parent | 89c45f3823d05fae1896ee2d1adb6926ab6be3c2 (diff) | |
| parent | 7e33001b8b9a78062679e0fdf5b0842a49063135 (diff) | |
| download | lwn-a5c93bfec0beca4435d1995bc3ff2ac003fe7552.tar.gz lwn-a5c93bfec0beca4435d1995bc3ff2ac003fe7552.zip | |
Merge tag 'x86-mm-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 mm updates from Ingo Molnar:
- Put cpumask_test_cpu() check in switch_mm_irqs_off() under
CONFIG_DEBUG_VM, to micro-optimize the context-switching code (Rik
van Riel)
- Add missing details in virtual memory layout (Kirill A. Shutemov)
* tag 'x86-mm-2024-11-18' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/tlb: Put cpumask_test_cpu() check in switch_mm_irqs_off() under CONFIG_DEBUG_VM
x86/mm/doc: Add missing details in virtual memory layout
| -rw-r--r-- | Documentation/arch/x86/x86_64/mm.rst | 35 | ||||
| -rw-r--r-- | arch/x86/mm/tlb.c | 2 |
2 files changed, 30 insertions, 7 deletions
diff --git a/Documentation/arch/x86/x86_64/mm.rst b/Documentation/arch/x86/x86_64/mm.rst index 35e5e18c83d0..f2db178b353f 100644 --- a/Documentation/arch/x86/x86_64/mm.rst +++ b/Documentation/arch/x86/x86_64/mm.rst @@ -29,15 +29,27 @@ Complete virtual memory map with 4-level page tables Start addr | Offset | End addr | Size | VM area description ======================================================================================================================== | | | | - 0000000000000000 | 0 | 00007fffffffffff | 128 TB | user-space virtual memory, different per mm + 0000000000000000 | 0 | 00007fffffffefff | ~128 TB | user-space virtual memory, different per mm + 00007ffffffff000 | ~128 TB | 00007fffffffffff | 4 kB | ... guard hole __________________|____________|__________________|_________|___________________________________________________________ | | | | - 0000800000000000 | +128 TB | ffff7fffffffffff | ~16M TB | ... huge, almost 64 bits wide hole of non-canonical - | | | | virtual memory addresses up to the -128 TB + 0000800000000000 | +128 TB | 7fffffffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical + | | | | virtual memory addresses up to the -8 EB | | | | starting offset of kernel mappings. + | | | | + | | | | LAM relaxes canonicallity check allowing to create aliases + | | | | for userspace memory here. __________________|____________|__________________|_________|___________________________________________________________ | | Kernel-space virtual memory, shared between all processes: + __________________|____________|__________________|_________|___________________________________________________________ + | | | | + 8000000000000000 | -8 EB | ffff7fffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical + | | | | virtual memory addresses up to the -128 TB + | | | | starting offset of kernel mappings. + | | | | + | | | | LAM_SUP relaxes canonicallity check allowing to create + | | | | aliases for kernel memory here. ____________________________________________________________|___________________________________________________________ | | | | ffff800000000000 | -128 TB | ffff87ffffffffff | 8 TB | ... guard hole, also reserved for hypervisor @@ -88,16 +100,27 @@ Complete virtual memory map with 5-level page tables Start addr | Offset | End addr | Size | VM area description ======================================================================================================================== | | | | - 0000000000000000 | 0 | 00ffffffffffffff | 64 PB | user-space virtual memory, different per mm + 0000000000000000 | 0 | 00fffffffffff000 | ~64 PB | user-space virtual memory, different per mm + 00fffffffffff000 | ~64 PB | 00ffffffffffffff | 4 kB | ... guard hole __________________|____________|__________________|_________|___________________________________________________________ | | | | - 0100000000000000 | +64 PB | feffffffffffffff | ~16K PB | ... huge, still almost 64 bits wide hole of non-canonical - | | | | virtual memory addresses up to the -64 PB + 0100000000000000 | +64 PB | 7fffffffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical + | | | | virtual memory addresses up to the -8EB TB | | | | starting offset of kernel mappings. + | | | | + | | | | LAM relaxes canonicallity check allowing to create aliases + | | | | for userspace memory here. __________________|____________|__________________|_________|___________________________________________________________ | | Kernel-space virtual memory, shared between all processes: ____________________________________________________________|___________________________________________________________ + 8000000000000000 | -8 EB | feffffffffffffff | ~8 EB | ... huge, almost 63 bits wide hole of non-canonical + | | | | virtual memory addresses up to the -64 PB + | | | | starting offset of kernel mappings. + | | | | + | | | | LAM_SUP relaxes canonicallity check allowing to create + | | | | aliases for kernel memory here. + ____________________________________________________________|___________________________________________________________ | | | | ff00000000000000 | -64 PB | ff0fffffffffffff | 4 PB | ... guard hole, also reserved for hypervisor ff10000000000000 | -60 PB | ff10ffffffffffff | 0.25 PB | LDT remap for PTI diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 86593d1b787d..b0d5a644fc84 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -568,7 +568,7 @@ void switch_mm_irqs_off(struct mm_struct *unused, struct mm_struct *next, * mm_cpumask. The TLB shootdown code can figure out from * cpu_tlbstate_shared.is_lazy whether or not to send an IPI. */ - if (WARN_ON_ONCE(prev != &init_mm && + if (IS_ENABLED(CONFIG_DEBUG_VM) && WARN_ON_ONCE(prev != &init_mm && !cpumask_test_cpu(cpu, mm_cpumask(next)))) cpumask_set_cpu(cpu, mm_cpumask(next)); |