David Gibson <da...@gibson.dropbear.id.au> writes: > On Thu, Jul 22, 2021 at 12:37:46PM +0530, Aneesh Kumar K.V wrote: >> David Gibson <da...@gibson.dropbear.id.au> writes: >> >> > On Mon, Jun 28, 2021 at 08:41:15PM +0530, Aneesh Kumar K.V wrote:
.... > >> > >> >> + nid = of_read_number(&aa.arrays[index], 1); >> >> + >> >> + if (nid == 0xffff || nid >= nr_node_ids) >> >> + nid = default_nid; >> >> + if (nid > 0 && affinity_form == FORM1_AFFINITY) { >> >> + int i; >> >> + const __be32 *associativity; >> >> + >> >> + index = lmb->aa_index * aa.array_sz; >> >> + associativity = &aa.arrays[index]; >> >> + /* >> >> + * lookup array associativity entries have different >> >> format >> >> + * There is no length of the array as the first element. >> > >> > The difference it very small, and this is not a hot path. Couldn't >> > you reduce a chunk of code by prepending aa.array_sz, then re-using >> > __initialize_form1_numa_distance. Or even making >> > __initialize_form1_numa_distance() take the length as a parameter. >> >> The changes are small but confusing w.r.t how we look at the >> associativity-lookup-arrays. The way we interpret associativity array >> and associativity lookup array using primary_domain_index is different. >> Hence the '-1' in the node lookup here. > > They're really not, though. It's exactly the same interpretation of > the associativity array itself - it's just that one of them has the > array prepended with a (redundant) length. So you can make > __initialize_form1_numa_distance() work on the "bare" associativity > array, with a given length. Here you call it with aa.array_sz as the > length, and in the other place you call it with prop[0] as the length. > >> >> index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; >> nid = of_read_number(&aa.arrays[index], 1); >> >> >> > >> >> + */ >> >> + for (i = 0; i < max_associativity_domain_index; i++) { >> >> + const __be32 *entry; >> >> + >> >> + entry = >> >> &associativity[be32_to_cpu(distance_ref_points[i]) - 1]; >> > >> > Does anywhere verify that distance_ref_points[i] <= aa.array_size for >> > every i? >> >> We do check for >> >> if (primary_domain_index <= aa.array_sz && > > Right, but that doesn't check the other distance_ref_points entries. > Not that there's any reason to have extra entries with Form2, but we > still don't want stray array accesses. This is how the change looks. I am not convinced this makes it simpler. I will add that as the last patch and we can drop that if we find that not helpful? modified arch/powerpc/mm/numa.c @@ -171,20 +171,31 @@ static void unmap_cpu_from_node(unsigned long cpu) } #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */ -/* - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA - * info is found. - */ -static int associativity_to_nid(const __be32 *associativity) +static int __associativity_to_nid(const __be32 *associativity, + bool lookup_array_assoc, + int max_array_index) { int nid = NUMA_NO_NODE; + int index; if (!numa_enabled) goto out; + /* + * ibm,associativity-lookup-array doesn't have element + * count at the start of the associativity. Hence + * decrement the primary_domain_index when used with + * lookup-array associativity. + */ + if (lookup_array_assoc) + index = primary_domain_index - 1; + else { + index = primary_domain_index; + max_array_index = of_read_number(associativity, 1); + } + if (index > max_array_index) + goto out; - if (of_read_number(associativity, 1) >= primary_domain_index) - nid = of_read_number(&associativity[primary_domain_index], 1); - + nid = of_read_number(&associativity[index], 1); /* POWER4 LPAR uses 0xffff as invalid node */ if (nid == 0xffff || nid >= nr_node_ids) nid = NUMA_NO_NODE; @@ -192,6 +203,15 @@ static int associativity_to_nid(const __be32 *associativity) return nid; } +/* + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA + * info is found. + */ +static inline int associativity_to_nid(const __be32 *associativity) +{ + return __associativity_to_nid(associativity, false, 0); +} + static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc) { int dist; @@ -295,19 +315,38 @@ int of_node_to_nid(struct device_node *device) } EXPORT_SYMBOL(of_node_to_nid); -static void __initialize_form1_numa_distance(const __be32 *associativity) +static void __initialize_form1_numa_distance(const __be32 *associativity, + bool lookup_array_assoc, + int max_array_index) { int i, nid; + int index_offset = 0; if (affinity_form != FORM1_AFFINITY) return; + /* + * ibm,associativity-lookup-array doesn't have element + * count at the start of the associativity. Hence + * decrement the distance_ref_points index when used with + * lookup-array associativity. + */ + if (lookup_array_assoc) + index_offset = 1; + else + max_array_index = of_read_number(associativity, 1); - nid = associativity_to_nid(associativity); + nid = __associativity_to_nid(associativity, lookup_array_assoc, max_array_index); if (nid != NUMA_NO_NODE) { for (i = 0; i < distance_ref_points_depth; i++) { const __be32 *entry; + int index = be32_to_cpu(distance_ref_points[i]) - index_offset; - entry = &associativity[be32_to_cpu(distance_ref_points[i])]; + /* + * broken hierarchy, return with broken distance table + */ + if (index > max_array_index) + return; + entry = &associativity[index]; distance_lookup_table[nid][i] = of_read_number(entry, 1); } } @@ -321,7 +360,7 @@ static void initialize_form1_numa_distance(struct device_node *node) if (!associativity) return; - __initialize_form1_numa_distance(associativity); + __initialize_form1_numa_distance(associativity, false, 0); } /* @@ -586,27 +625,14 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb) if (primary_domain_index <= aa.array_sz && !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) { - index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; - nid = of_read_number(&aa.arrays[index], 1); + const __be32 *associativity; - if (nid == 0xffff || nid >= nr_node_ids) - nid = default_nid; + index = lmb->aa_index * aa.array_sz; + associativity = &aa.arrays[index]; + nid = __associativity_to_nid(associativity, true, aa.array_sz - 1); if (nid > 0 && affinity_form == FORM1_AFFINITY) { - int i; - const __be32 *associativity; - - index = lmb->aa_index * aa.array_sz; - associativity = &aa.arrays[index]; - /* - * lookup array associativity entries have different format - * There is no length of the array as the first element. - */ - for (i = 0; i < distance_ref_points_depth; i++) { - const __be32 *entry; - - entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1]; - distance_lookup_table[nid][i] = of_read_number(entry, 1); - } + __initialize_form1_numa_distance(associativity, + true, aa.array_sz - 1); } } return nid; @@ -632,9 +658,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb) if (primary_domain_index <= aa.array_sz && !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) { - index = lmb->aa_index * aa.array_sz + primary_domain_index - 1; - nid = of_read_number(&aa.arrays[index], 1); + const __be32 *associativity; + index = lmb->aa_index * aa.array_sz; + associativity = &aa.arrays[index]; + nid = __associativity_to_nid(associativity, true, aa.array_sz - 1); if (nid == 0xffff || nid >= nr_node_ids) nid = default_nid; } @@ -939,7 +967,7 @@ static int __init parse_numa_properties(void) if (__vphn_get_associativity(i, vphn_assoc) == 0) { nid = associativity_to_nid(vphn_assoc); - __initialize_form1_numa_distance(vphn_assoc); + __initialize_form1_numa_distance(vphn_assoc, false, 0); } else { /* @@ -953,7 +981,7 @@ static int __init parse_numa_properties(void) associativity = of_get_associativity(cpu); if (associativity) { nid = associativity_to_nid(associativity); - __initialize_form1_numa_distance(associativity); + __initialize_form1_numa_distance(associativity, false, 0); } of_node_put(cpu); } @@ -993,7 +1021,7 @@ static int __init parse_numa_properties(void) associativity = of_get_associativity(memory); if (associativity) { nid = associativity_to_nid(associativity); - __initialize_form1_numa_distance(associativity); + __initialize_form1_numa_distance(associativity, false, 0); } else nid = default_nid;