Just like regular pages, page directories need to observe the following order: 1) unhook 2) TLB invalidate 3) free to ensure it is safe against concurrent accesses. MIPS has (thanks to Paul Burton for setting me straight): - HAVE_FAST_GUP, which means we need to consider software walkers (many MIPS also have software TLB-fill, which is a similar software walker). - non-page, page directories, which requires a custom table free. - Mostly IPI-based TLB invalidate, but it wouldn't be MIPS if it didn't also have broadcast TLB invalidate (I6500, GINVT). This means that in generic MIPS needs HAVE_RCU_TABLE_FREE. Cc: Paul Burton <paul.burton@xxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> --- arch/mips/Kconfig | 1 + arch/mips/include/asm/pgalloc.h | 13 ++++++------- arch/mips/mm/pgtable.c | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 41 insertions(+), 7 deletions(-) --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -57,6 +57,7 @@ config MIPS select HAVE_DYNAMIC_FTRACE select HAVE_EXIT_THREAD select HAVE_FAST_GUP + select MMU_GATHER_RCU_TABLE_FREE select HAVE_FTRACE_MCOUNT_RECORD select HAVE_FUNCTION_GRAPH_TRACER select HAVE_FUNCTION_TRACER --- a/arch/mips/include/asm/pgalloc.h +++ b/arch/mips/include/asm/pgalloc.h @@ -41,6 +41,9 @@ static inline void pud_populate(struct m } #endif +extern void __tlb_remove_table(void *table); +extern void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int idx); + /* * Initialize a new pgd / pmd table with invalid pointers. */ @@ -52,11 +55,7 @@ static inline void pgd_free(struct mm_st free_pages((unsigned long)pgd, PGD_ORDER); } -#define __pte_free_tlb(tlb,pte,address) \ -do { \ - pgtable_pte_page_dtor(pte); \ - tlb_remove_page((tlb), pte); \ -} while (0) +#define __pte_free_tlb(tlb,pte,address) pgtable_free_tlb((tlb), (pte), 0) #ifndef __PAGETABLE_PMD_FOLDED @@ -75,7 +74,7 @@ static inline void pmd_free(struct mm_st free_pages((unsigned long)pmd, PMD_ORDER); } -#define __pmd_free_tlb(tlb, x, addr) pmd_free((tlb)->mm, x) +#define __pmd_free_tlb(tlb, x, addr) pgtable_free_tlb((tlb), (x), 1) #endif @@ -101,7 +100,7 @@ static inline void p4d_populate(struct m set_p4d(p4d, __p4d((unsigned long)pud)); } -#define __pud_free_tlb(tlb, x, addr) pud_free((tlb)->mm, x) +#define __pud_free_tlb(tlb, x, addr) pgtable_free_tlb((tlb), (x), 2) #endif /* __PAGETABLE_PUD_FOLDED */ --- a/arch/mips/mm/pgtable.c +++ b/arch/mips/mm/pgtable.c @@ -7,6 +7,7 @@ #include <linux/mm.h> #include <linux/string.h> #include <asm/pgalloc.h> +#include <asm-generic/tlb.h> pgd_t *pgd_alloc(struct mm_struct *mm) { @@ -23,3 +24,36 @@ pgd_t *pgd_alloc(struct mm_struct *mm) return ret; } EXPORT_SYMBOL_GPL(pgd_alloc); + +#define TLB_IDX_MASK 0x3 + +void pgtable_free_tlb(struct mmu_gather *tlb, void *table, int idx) +{ + unsigned long pgf = (unsigned long)table; + BUG_ON(idx > TLB_IDX_MASK); + BUG_ON(pgf & TLB_IDX_MASK); + pgf |= idx; + tlb_remove_table(tlb, (void *)pgf); +} + +void __tlb_remove_table(void *table) +{ + void *dir = (void *)((unsigned long)table & ~TLB_IDX_MASK); + int idx = (unsigned long)table & TLB_IDX_MASK; + + switch (idx) { +#ifndef __PAGETABLE_PUD_FOLDED + case 2: /* PUD */ + pud_free(NULL, dir); + break; +#endif +#ifndef __PAGETABLE_PMD_FOLDED + case 1: /* PMD */ + pmd_free(NULL, dir); + break; +#endif + case 0: /* PTE */ + pte_free(NULL, dir); + break; + } +}