From c647673ce4d72a8789703c62a7f3cbc732cb1ea8 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 8 May 2020 08:43:54 -0700 Subject: target/arm: Update contiguous first-fault and no-fault loads With sve_cont_ldst_pages, the differences between first-fault and no-fault are minimal, so unify the routines. With cpu_probe_watchpoint, we are able to make progress through pages with TLB_WATCHPOINT set when the watchpoint does not actually fire. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson Message-id: 20200508154359.7494-15-richard.henderson@linaro.org Signed-off-by: Peter Maydell --- target/arm/sve_helper.c | 338 ++++++++++++++++++++++-------------------------- 1 file changed, 158 insertions(+), 180 deletions(-) (limited to 'target') diff --git a/target/arm/sve_helper.c b/target/arm/sve_helper.c index 9365e32..f496934 100644 --- a/target/arm/sve_helper.c +++ b/target/arm/sve_helper.c @@ -4102,18 +4102,6 @@ static intptr_t find_next_active(uint64_t *vg, intptr_t reg_off, } /* - * Return the maximum offset <= @mem_max which is still within the page - * referenced by @base + @mem_off. - */ -static intptr_t max_for_page(target_ulong base, intptr_t mem_off, - intptr_t mem_max) -{ - target_ulong addr = base + mem_off; - intptr_t split = -(intptr_t)(addr | TARGET_PAGE_MASK); - return MIN(split, mem_max - mem_off) + mem_off; -} - -/* * Resolve the guest virtual address to info->host and info->flags. * If @nofault, return false if the page is invalid, otherwise * exit via page fault exception. @@ -4436,19 +4424,6 @@ static void sve_cont_ldst_watchpoints(SVEContLdSt *info, CPUARMState *env, } /* - * The result of tlb_vaddr_to_host for user-only is just g2h(x), - * which is always non-null. Elide the useless test. - */ -static inline bool test_host_page(void *host) -{ -#ifdef CONFIG_USER_ONLY - return true; -#else - return likely(host != NULL); -#endif -} - -/* * Common helper for all contiguous 1,2,3,4-register predicated stores. */ static inline QEMU_ALWAYS_INLINE @@ -4705,167 +4680,167 @@ static void record_fault(CPUARMState *env, uintptr_t i, uintptr_t oprsz) } /* - * Common helper for all contiguous first-fault loads. + * Common helper for all contiguous no-fault and first-fault loads. */ -static void sve_ldff1_r(CPUARMState *env, void *vg, const target_ulong addr, - uint32_t desc, const uintptr_t retaddr, - const int esz, const int msz, - sve_ldst1_host_fn *host_fn, - sve_ldst1_tlb_fn *tlb_fn) +static inline QEMU_ALWAYS_INLINE +void sve_ldnfff1_r(CPUARMState *env, void *vg, const target_ulong addr, + uint32_t desc, const uintptr_t retaddr, + const int esz, const int msz, const SVEContFault fault, + sve_ldst1_host_fn *host_fn, + sve_ldst1_tlb_fn *tlb_fn) { - const TCGMemOpIdx oi = extract32(desc, SIMD_DATA_SHIFT, MEMOPIDX_SHIFT); - const int mmu_idx = get_mmuidx(oi); const unsigned rd = extract32(desc, SIMD_DATA_SHIFT + MEMOPIDX_SHIFT, 5); void *vd = &env->vfp.zregs[rd]; - const int diffsz = esz - msz; const intptr_t reg_max = simd_oprsz(desc); - const intptr_t mem_max = reg_max >> diffsz; - intptr_t split, reg_off, mem_off, i; + intptr_t reg_off, mem_off, reg_last; + SVEContLdSt info; + int flags; void *host; - /* Skip to the first active element. */ - reg_off = find_next_active(vg, 0, reg_max, esz); - if (unlikely(reg_off == reg_max)) { + /* Find the active elements. */ + if (!sve_cont_ldst_elements(&info, addr, vg, reg_max, esz, 1 << msz)) { /* The entire predicate was false; no load occurs. */ memset(vd, 0, reg_max); return; } - mem_off = reg_off >> diffsz; + reg_off = info.reg_off_first[0]; - /* - * If the (remaining) load is entirely within a single page, then: - * For softmmu, and the tlb hits, then no faults will occur; - * For user-only, either the first load will fault or none will. - * We can thus perform the load directly to the destination and - * Vd will be unmodified on any exception path. - */ - split = max_for_page(addr, mem_off, mem_max); - if (likely(split == mem_max)) { - host = tlb_vaddr_to_host(env, addr + mem_off, MMU_DATA_LOAD, mmu_idx); - if (test_host_page(host)) { - i = reg_off; - host -= mem_off; - do { - host_fn(vd, i, host + (i >> diffsz)); - i = find_next_active(vg, i + (1 << esz), reg_max, esz); - } while (i < reg_max); - /* After any fault, zero any leading inactive elements. */ + /* Probe the page(s). */ + if (!sve_cont_ldst_pages(&info, fault, env, addr, MMU_DATA_LOAD, retaddr)) { + /* Fault on first element. */ + tcg_debug_assert(fault == FAULT_NO); + memset(vd, 0, reg_max); + goto do_fault; + } + + mem_off = info.mem_off_first[0]; + flags = info.page[0].flags; + + if (fault == FAULT_FIRST) { + /* + * Special handling of the first active element, + * if it crosses a page boundary or is MMIO. + */ + bool is_split = mem_off == info.mem_off_split; + /* TODO: MTE check. */ + if (unlikely(flags != 0) || unlikely(is_split)) { + /* + * Use the slow path for cross-page handling. + * Might trap for MMIO or watchpoints. + */ + tlb_fn(env, vd, reg_off, addr + mem_off, retaddr); + + /* After any fault, zero the other elements. */ swap_memzero(vd, reg_off); - return; + reg_off += 1 << esz; + mem_off += 1 << msz; + swap_memzero(vd + reg_off, reg_max - reg_off); + + if (is_split) { + goto second_page; + } + } else { + memset(vd, 0, reg_max); + } + } else { + memset(vd, 0, reg_max); + if (unlikely(mem_off == info.mem_off_split)) { + /* The first active element crosses a page boundary. */ + flags |= info.page[1].flags; + if (unlikely(flags & TLB_MMIO)) { + /* Some page is MMIO, see below. */ + goto do_fault; + } + if (unlikely(flags & TLB_WATCHPOINT) && + (cpu_watchpoint_address_matches + (env_cpu(env), addr + mem_off, 1 << msz) + & BP_MEM_READ)) { + /* Watchpoint hit, see below. */ + goto do_fault; + } + /* TODO: MTE check. */ + /* + * Use the slow path for cross-page handling. + * This is RAM, without a watchpoint, and will not trap. + */ + tlb_fn(env, vd, reg_off, addr + mem_off, retaddr); + goto second_page; } } /* - * Perform one normal read, which will fault or not. - * But it is likely to bring the page into the tlb. + * From this point on, all memory operations are MemSingleNF. + * + * Per the MemSingleNF pseudocode, a no-fault load from Device memory + * must not actually hit the bus -- it returns (UNKNOWN, FAULT) instead. + * + * Unfortuately we do not have access to the memory attributes from the + * PTE to tell Device memory from Normal memory. So we make a mostly + * correct check, and indicate (UNKNOWN, FAULT) for any MMIO. + * This gives the right answer for the common cases of "Normal memory, + * backed by host RAM" and "Device memory, backed by MMIO". + * The architecture allows us to suppress an NF load and return + * (UNKNOWN, FAULT) for any reason, so our behaviour for the corner + * case of "Normal memory, backed by MMIO" is permitted. The case we + * get wrong is "Device memory, backed by host RAM", for which we + * should return (UNKNOWN, FAULT) for but do not. + * + * Similarly, CPU_BP breakpoints would raise exceptions, and so + * return (UNKNOWN, FAULT). For simplicity, we consider gdb and + * architectural breakpoints the same. */ - tlb_fn(env, vd, reg_off, addr + mem_off, retaddr); - - /* After any fault, zero any leading predicated false elts. */ - swap_memzero(vd, reg_off); - mem_off += 1 << msz; - reg_off += 1 << esz; - - /* Try again to read the balance of the page. */ - split = max_for_page(addr, mem_off - 1, mem_max); - if (split >= (1 << msz)) { - host = tlb_vaddr_to_host(env, addr + mem_off, MMU_DATA_LOAD, mmu_idx); - if (host) { - host -= mem_off; - do { - host_fn(vd, reg_off, host + mem_off); - reg_off += 1 << esz; - reg_off = find_next_active(vg, reg_off, reg_max, esz); - mem_off = reg_off >> diffsz; - } while (split - mem_off >= (1 << msz)); - } + if (unlikely(flags & TLB_MMIO)) { + goto do_fault; } - record_fault(env, reg_off, reg_max); -} - -/* - * Common helper for all contiguous no-fault loads. - */ -static void sve_ldnf1_r(CPUARMState *env, void *vg, const target_ulong addr, - uint32_t desc, const int esz, const int msz, - sve_ldst1_host_fn *host_fn) -{ - const unsigned rd = extract32(desc, SIMD_DATA_SHIFT + MEMOPIDX_SHIFT, 5); - void *vd = &env->vfp.zregs[rd]; - const int diffsz = esz - msz; - const intptr_t reg_max = simd_oprsz(desc); - const intptr_t mem_max = reg_max >> diffsz; - const int mmu_idx = cpu_mmu_index(env, false); - intptr_t split, reg_off, mem_off; - void *host; + reg_last = info.reg_off_last[0]; + host = info.page[0].host; -#ifdef CONFIG_USER_ONLY - host = tlb_vaddr_to_host(env, addr, MMU_DATA_LOAD, mmu_idx); - if (likely(page_check_range(addr, mem_max, PAGE_READ) == 0)) { - /* The entire operation is valid and will not fault. */ - reg_off = 0; + do { + uint64_t pg = *(uint64_t *)(vg + (reg_off >> 3)); do { - mem_off = reg_off >> diffsz; - host_fn(vd, reg_off, host + mem_off); + if ((pg >> (reg_off & 63)) & 1) { + if (unlikely(flags & TLB_WATCHPOINT) && + (cpu_watchpoint_address_matches + (env_cpu(env), addr + mem_off, 1 << msz) + & BP_MEM_READ)) { + goto do_fault; + } + /* TODO: MTE check. */ + host_fn(vd, reg_off, host + mem_off); + } reg_off += 1 << esz; - reg_off = find_next_active(vg, reg_off, reg_max, esz); - } while (reg_off < reg_max); - return; - } -#endif + mem_off += 1 << msz; + } while (reg_off <= reg_last && (reg_off & 63)); + } while (reg_off <= reg_last); - /* There will be no fault, so we may modify in advance. */ - memset(vd, 0, reg_max); + /* + * MemSingleNF is allowed to fail for any reason. We have special + * code above to handle the first element crossing a page boundary. + * As an implementation choice, decline to handle a cross-page element + * in any other position. + */ + reg_off = info.reg_off_split; + if (reg_off >= 0) { + goto do_fault; + } - /* Skip to the first active element. */ - reg_off = find_next_active(vg, 0, reg_max, esz); - if (unlikely(reg_off == reg_max)) { - /* The entire predicate was false; no load occurs. */ + second_page: + reg_off = info.reg_off_first[1]; + if (likely(reg_off < 0)) { + /* No active elements on the second page. All done. */ return; } - mem_off = reg_off >> diffsz; -#ifdef CONFIG_USER_ONLY - if (page_check_range(addr + mem_off, 1 << msz, PAGE_READ) == 0) { - /* At least one load is valid; take the rest of the page. */ - split = max_for_page(addr, mem_off + (1 << msz) - 1, mem_max); - do { - host_fn(vd, reg_off, host + mem_off); - reg_off += 1 << esz; - reg_off = find_next_active(vg, reg_off, reg_max, esz); - mem_off = reg_off >> diffsz; - } while (split - mem_off >= (1 << msz)); - } -#else /* - * If the address is not in the TLB, we have no way to bring the - * entry into the TLB without also risking a fault. Note that - * the corollary is that we never load from an address not in RAM. - * - * This last is out of spec, in a weird corner case. - * Per the MemNF/MemSingleNF pseudocode, a NF load from Device memory - * must not actually hit the bus -- it returns UNKNOWN data instead. - * But if you map non-RAM with Normal memory attributes and do a NF - * load then it should access the bus. (Nobody ought actually do this - * in the real world, obviously.) - * - * Then there are the annoying special cases with watchpoints... - * TODO: Add a form of non-faulting loads using cc->tlb_fill(probe=true). + * MemSingleNF is allowed to fail for any reason. As an implementation + * choice, decline to handle elements on the second page. This should + * be low frequency as the guest walks through memory -- the next + * iteration of the guest's loop should be aligned on the page boundary, + * and then all following iterations will stay aligned. */ - host = tlb_vaddr_to_host(env, addr + mem_off, MMU_DATA_LOAD, mmu_idx); - split = max_for_page(addr, mem_off, mem_max); - if (host && split >= (1 << msz)) { - host -= mem_off; - do { - host_fn(vd, reg_off, host + mem_off); - reg_off += 1 << esz; - reg_off = find_next_active(vg, reg_off, reg_max, esz); - mem_off = reg_off >> diffsz; - } while (split - mem_off >= (1 << msz)); - } -#endif + do_fault: record_fault(env, reg_off, reg_max); } @@ -4873,58 +4848,61 @@ static void sve_ldnf1_r(CPUARMState *env, void *vg, const target_ulong addr, void HELPER(sve_ldff1##PART##_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldff1_r(env, vg, addr, desc, GETPC(), ESZ, 0, \ - sve_ld1##PART##_host, sve_ld1##PART##_tlb); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MO_8, FAULT_FIRST, \ + sve_ld1##PART##_host, sve_ld1##PART##_tlb); \ } \ void HELPER(sve_ldnf1##PART##_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldnf1_r(env, vg, addr, desc, ESZ, 0, sve_ld1##PART##_host); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MO_8, FAULT_NO, \ + sve_ld1##PART##_host, sve_ld1##PART##_tlb); \ } #define DO_LDFF1_LDNF1_2(PART, ESZ, MSZ) \ void HELPER(sve_ldff1##PART##_le_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, \ - sve_ld1##PART##_le_host, sve_ld1##PART##_le_tlb); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, FAULT_FIRST, \ + sve_ld1##PART##_le_host, sve_ld1##PART##_le_tlb); \ } \ void HELPER(sve_ldnf1##PART##_le_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldnf1_r(env, vg, addr, desc, ESZ, MSZ, sve_ld1##PART##_le_host); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, FAULT_NO, \ + sve_ld1##PART##_le_host, sve_ld1##PART##_le_tlb); \ } \ void HELPER(sve_ldff1##PART##_be_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, \ - sve_ld1##PART##_be_host, sve_ld1##PART##_be_tlb); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, FAULT_FIRST, \ + sve_ld1##PART##_be_host, sve_ld1##PART##_be_tlb); \ } \ void HELPER(sve_ldnf1##PART##_be_r)(CPUARMState *env, void *vg, \ target_ulong addr, uint32_t desc) \ { \ - sve_ldnf1_r(env, vg, addr, desc, ESZ, MSZ, sve_ld1##PART##_be_host); \ + sve_ldnfff1_r(env, vg, addr, desc, GETPC(), ESZ, MSZ, FAULT_NO, \ + sve_ld1##PART##_be_host, sve_ld1##PART##_be_tlb); \ } -DO_LDFF1_LDNF1_1(bb, 0) -DO_LDFF1_LDNF1_1(bhu, 1) -DO_LDFF1_LDNF1_1(bhs, 1) -DO_LDFF1_LDNF1_1(bsu, 2) -DO_LDFF1_LDNF1_1(bss, 2) -DO_LDFF1_LDNF1_1(bdu, 3) -DO_LDFF1_LDNF1_1(bds, 3) +DO_LDFF1_LDNF1_1(bb, MO_8) +DO_LDFF1_LDNF1_1(bhu, MO_16) +DO_LDFF1_LDNF1_1(bhs, MO_16) +DO_LDFF1_LDNF1_1(bsu, MO_32) +DO_LDFF1_LDNF1_1(bss, MO_32) +DO_LDFF1_LDNF1_1(bdu, MO_64) +DO_LDFF1_LDNF1_1(bds, MO_64) -DO_LDFF1_LDNF1_2(hh, 1, 1) -DO_LDFF1_LDNF1_2(hsu, 2, 1) -DO_LDFF1_LDNF1_2(hss, 2, 1) -DO_LDFF1_LDNF1_2(hdu, 3, 1) -DO_LDFF1_LDNF1_2(hds, 3, 1) +DO_LDFF1_LDNF1_2(hh, MO_16, MO_16) +DO_LDFF1_LDNF1_2(hsu, MO_32, MO_16) +DO_LDFF1_LDNF1_2(hss, MO_32, MO_16) +DO_LDFF1_LDNF1_2(hdu, MO_64, MO_16) +DO_LDFF1_LDNF1_2(hds, MO_64, MO_16) -DO_LDFF1_LDNF1_2(ss, 2, 2) -DO_LDFF1_LDNF1_2(sdu, 3, 2) -DO_LDFF1_LDNF1_2(sds, 3, 2) +DO_LDFF1_LDNF1_2(ss, MO_32, MO_32) +DO_LDFF1_LDNF1_2(sdu, MO_64, MO_32) +DO_LDFF1_LDNF1_2(sds, MO_64, MO_32) -DO_LDFF1_LDNF1_2(dd, 3, 3) +DO_LDFF1_LDNF1_2(dd, MO_64, MO_64) #undef DO_LDFF1_LDNF1_1 #undef DO_LDFF1_LDNF1_2 -- cgit v1.1