diff options
Diffstat (limited to 'arch/x86/include/asm/tlb.h')
| -rw-r--r-- | arch/x86/include/asm/tlb.h | 147 |
1 files changed, 136 insertions, 11 deletions
diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h index 4d3c9d00d6b6..866ea78ba156 100644 --- a/arch/x86/include/asm/tlb.h +++ b/arch/x86/include/asm/tlb.h @@ -6,6 +6,9 @@ static inline void tlb_flush(struct mmu_gather *tlb); #include <asm-generic/tlb.h> +#include <linux/kernel.h> +#include <vdso/bits.h> +#include <vdso/page.h> static inline void tlb_flush(struct mmu_gather *tlb) { @@ -20,22 +23,144 @@ static inline void tlb_flush(struct mmu_gather *tlb) flush_tlb_mm_range(tlb->mm, start, end, stride_shift, tlb->freed_tables); } +static inline void invlpg(unsigned long addr) +{ + asm volatile("invlpg (%0)" ::"r" (addr) : "memory"); +} + +enum addr_stride { + PTE_STRIDE = 0, + PMD_STRIDE = 1 +}; + /* - * While x86 architecture in general requires an IPI to perform TLB - * shootdown, enablement code for several hypervisors overrides - * .flush_tlb_others hook in pv_mmu_ops and implements it by issuing - * a hypercall. To keep software pagetable walkers safe in this case we - * switch to RCU based table free (MMU_GATHER_RCU_TABLE_FREE). See the comment - * below 'ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE' in include/asm-generic/tlb.h - * for more details. + * INVLPGB can be targeted by virtual address, PCID, ASID, or any combination + * of the three. For example: + * - FLAG_VA | FLAG_INCLUDE_GLOBAL: invalidate all TLB entries at the address + * - FLAG_PCID: invalidate all TLB entries matching the PCID + * + * The first is used to invalidate (kernel) mappings at a particular + * address across all processes. + * + * The latter invalidates all TLB entries matching a PCID. */ -static inline void __tlb_remove_table(void *table) +#define INVLPGB_FLAG_VA BIT(0) +#define INVLPGB_FLAG_PCID BIT(1) +#define INVLPGB_FLAG_ASID BIT(2) +#define INVLPGB_FLAG_INCLUDE_GLOBAL BIT(3) +#define INVLPGB_FLAG_FINAL_ONLY BIT(4) +#define INVLPGB_FLAG_INCLUDE_NESTED BIT(5) + +/* The implied mode when all bits are clear: */ +#define INVLPGB_MODE_ALL_NONGLOBALS 0UL + +#ifdef CONFIG_BROADCAST_TLB_FLUSH +/* + * INVLPGB does broadcast TLB invalidation across all the CPUs in the system. + * + * The INVLPGB instruction is weakly ordered, and a batch of invalidations can + * be done in a parallel fashion. + * + * The instruction takes the number of extra pages to invalidate, beyond the + * first page, while __invlpgb gets the more human readable number of pages to + * invalidate. + * + * The bits in rax[0:2] determine respectively which components of the address + * (VA, PCID, ASID) get compared when flushing. If neither bits are set, *any* + * address in the specified range matches. + * + * Since it is desired to only flush TLB entries for the ASID that is executing + * the instruction (a host/hypervisor or a guest), the ASID valid bit should + * always be set. On a host/hypervisor, the hardware will use the ASID value + * specified in EDX[15:0] (which should be 0). On a guest, the hardware will + * use the actual ASID value of the guest. + * + * TLBSYNC is used to ensure that pending INVLPGB invalidations initiated from + * this CPU have completed. + */ +static inline void __invlpgb(unsigned long asid, unsigned long pcid, + unsigned long addr, u16 nr_pages, + enum addr_stride stride, u8 flags) { - free_page_and_swap_cache(table); + u64 rax = addr | flags | INVLPGB_FLAG_ASID; + u32 ecx = (stride << 31) | (nr_pages - 1); + u32 edx = (pcid << 16) | asid; + + /* The low bits in rax are for flags. Verify addr is clean. */ + VM_WARN_ON_ONCE(addr & ~PAGE_MASK); + + /* INVLPGB; supported in binutils >= 2.36. */ + asm volatile(".byte 0x0f, 0x01, 0xfe" :: "a" (rax), "c" (ecx), "d" (edx)); } -static inline void invlpg(unsigned long addr) +static inline void __invlpgb_all(unsigned long asid, unsigned long pcid, u8 flags) { - asm volatile("invlpg (%0)" ::"r" (addr) : "memory"); + __invlpgb(asid, pcid, 0, 1, 0, flags); +} + +static inline void __tlbsync(void) +{ + /* + * TLBSYNC waits for INVLPGB instructions originating on the same CPU + * to have completed. Print a warning if the task has been migrated, + * and might not be waiting on all the INVLPGBs issued during this TLB + * invalidation sequence. + */ + cant_migrate(); + + /* TLBSYNC: supported in binutils >= 0.36. */ + asm volatile(".byte 0x0f, 0x01, 0xff" ::: "memory"); +} +#else +/* Some compilers (I'm looking at you clang!) simply can't do DCE */ +static inline void __invlpgb(unsigned long asid, unsigned long pcid, + unsigned long addr, u16 nr_pages, + enum addr_stride s, u8 flags) { } +static inline void __invlpgb_all(unsigned long asid, unsigned long pcid, u8 flags) { } +static inline void __tlbsync(void) { } +#endif + +static inline void invlpgb_flush_user_nr_nosync(unsigned long pcid, + unsigned long addr, + u16 nr, bool stride) +{ + enum addr_stride str = stride ? PMD_STRIDE : PTE_STRIDE; + u8 flags = INVLPGB_FLAG_PCID | INVLPGB_FLAG_VA; + + __invlpgb(0, pcid, addr, nr, str, flags); +} + +/* Flush all mappings for a given PCID, not including globals. */ +static inline void invlpgb_flush_single_pcid_nosync(unsigned long pcid) +{ + __invlpgb_all(0, pcid, INVLPGB_FLAG_PCID); +} + +/* Flush all mappings, including globals, for all PCIDs. */ +static inline void invlpgb_flush_all(void) +{ + /* + * TLBSYNC at the end needs to make sure all flushes done on the + * current CPU have been executed system-wide. Therefore, make + * sure nothing gets migrated in-between but disable preemption + * as it is cheaper. + */ + guard(preempt)(); + __invlpgb_all(0, 0, INVLPGB_FLAG_INCLUDE_GLOBAL); + __tlbsync(); +} + +/* Flush addr, including globals, for all PCIDs. */ +static inline void invlpgb_flush_addr_nosync(unsigned long addr, u16 nr) +{ + __invlpgb(0, 0, addr, nr, PTE_STRIDE, INVLPGB_FLAG_INCLUDE_GLOBAL); +} + +/* Flush all mappings for all PCIDs except globals. */ +static inline void invlpgb_flush_all_nonglobals(void) +{ + guard(preempt)(); + __invlpgb_all(0, 0, INVLPGB_MODE_ALL_NONGLOBALS); + __tlbsync(); } #endif /* _ASM_X86_TLB_H */ |