Author: jhibbits Date: Sat Apr 11 00:17:55 2020 New Revision: 359793 URL: https://svnweb.freebsd.org/changeset/base/359793
Log: powerpc/booke: Use power-of-two mappings in 64-bit pmap_mapdev Summary: This reduces the precious TLB1 entry consumption (64 possible in existing 64-bit cores), by adjusting the size and alignment of a device mapping to a power of 2, to encompass the full mapping and its surroundings. One caveat with this: If a mapping really is smaller than a power of 2, it's possible to get a machine check or hang if the 'missing' physical space is accessed. In practice this should not be an issue for users, as devices overwhelmingly have physical spaces on power-of-two sizes and alignments, and any design that includes devices which don't follow this can be addressed by undefining the POW2_MAPPINGS guard. Reviewed by: bdragon Differential Revision: https://reviews.freebsd.org/D24248 Modified: head/sys/powerpc/booke/pmap.c Modified: head/sys/powerpc/booke/pmap.c ============================================================================== --- head/sys/powerpc/booke/pmap.c Sat Apr 11 00:16:50 2020 (r359792) +++ head/sys/powerpc/booke/pmap.c Sat Apr 11 00:17:55 2020 (r359793) @@ -128,6 +128,10 @@ __FBSDID("$FreeBSD$"); #include "mmu_if.h" #define SPARSE_MAPDEV + +/* Use power-of-two mappings in mmu_booke_mapdev(), to save entries. */ +#define POW2_MAPPINGS + #ifdef DEBUG #define debugf(fmt, args...) printf(fmt, ##args) #else @@ -2211,6 +2215,8 @@ tlb1_find_pa(vm_paddr_t pa, tlb_entry_t *e) for (i = 0; i < TLB1_ENTRIES; i++) { tlb1_read_entry(e, i); if ((e->mas1 & MAS1_VALID) == 0) + continue; + if (e->phys == pa) return (i); } return (-1); @@ -2224,7 +2230,7 @@ mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_siz #ifndef __powerpc64__ uintptr_t tmpva; #endif - uintptr_t va; + uintptr_t va, retva; vm_size_t sz; int i; int wimge; @@ -2245,7 +2251,7 @@ mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_siz if (tmppa >= e.phys && tmppa < e.phys + e.size) { va = e.virt + (pa - e.phys); tmppa = e.phys + e.size; - sz -= MIN(sz, e.size); + sz -= MIN(sz, e.size - (pa - e.phys)); while (sz > 0 && (i = tlb1_find_pa(tmppa, &e)) != -1) { if (wimge != (e.mas2 & (MAS2_WIMGE_MASK & ~_TLB_ENTRY_SHARED))) break; @@ -2264,6 +2270,25 @@ mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_siz KASSERT(pa < VM_MAPDEV_PA_MAX, ("Unsupported physical address! %lx", pa)); va = VM_MAPDEV_BASE + pa; + retva = va; +#ifdef POW2_MAPPINGS + /* + * Align the mapping to a power of 2 size, taking into account that we + * may need to increase the size multiple times to satisfy the size and + * alignment requirements. + * + * This works in the general case because it's very rare (near never?) + * to have different access properties (WIMG) within a single + * power-of-two region. If a design does call for that, POW2_MAPPINGS + * can be undefined, and exact mappings will be used instead. + */ + sz = size; + size = roundup2(size, 1 << ilog2(size)); + while (rounddown2(va, size) + size < va + sz) + size <<= 1; + va = rounddown2(va, size); + pa = rounddown2(pa, size); +#endif #else /* * The device mapping area is between VM_MAXUSER_ADDRESS and @@ -2288,14 +2313,15 @@ mmu_booke_mapdev_attr(mmu_t mmu, vm_paddr_t pa, vm_siz sz = sz ? min(roundup(sz + 3, 4), flsl(size) - 1) : flsl(size) - 1; va = roundup(tlb1_map_base, 1 << sz) | (((1 << sz) - 1) & pa); } while (!atomic_cmpset_int(&tlb1_map_base, tmpva, va + size)); +#endif va = atomic_fetchadd_int(&tlb1_map_base, size); + retva = va; #endif -#endif if (tlb1_mapin_region(va, pa, size, tlb_calc_wimg(pa, ma)) != size) return (NULL); - return ((void *)va); + return ((void *)retva); } /* @@ -2584,6 +2610,24 @@ tlb1_find_free(void) } static void +tlb1_purge_va_range(vm_offset_t va, vm_size_t size) +{ + tlb_entry_t e; + int i; + + for (i = 0; i < TLB1_ENTRIES; i++) { + tlb1_read_entry(&e, i); + if ((e.mas1 & MAS1_VALID) == 0) + continue; + if ((e.mas2 & MAS2_EPN_MASK) >= va && + (e.mas2 & MAS2_EPN_MASK) < va + size) { + mtspr(SPR_MAS1, e.mas1 & ~MAS1_VALID); + __asm __volatile("isync; tlbwe; isync; msync"); + } + } +} + +static void tlb1_write_entry_int(void *arg) { struct tlbwrite_args *args = arg; @@ -2591,6 +2635,7 @@ tlb1_write_entry_int(void *arg) idx = args->idx; if (idx == -1) { + tlb1_purge_va_range(args->e->virt, args->e->size); idx = tlb1_find_free(); if (idx == -1) panic("No free TLB1 entries!\n"); _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
