[PATCH v03 1/5] powerpc/drmem: Export 'dynamic-memory' loader
Michael Bringmann
mwb at linux.vnet.ibm.com
Wed Oct 3 23:22:46 AEST 2018
On 10/02/2018 03:56 PM, Tyrel Datwyler wrote:
> On 10/01/2018 05:59 AM, Michael Bringmann wrote:
>> powerpc/drmem: Export many of the functions of DRMEM to parse
>> "ibm,dynamic-memory" and "ibm,dynamic-memory-v2" during hotplug
>> operations and for Post Migration events.
>>
>> Also modify the DRMEM initialization code to allow it to,
>>
>> * Be called after system initialization
>> * Provide a separate user copy of the LMB array that is produces
>> * Free the user copy upon request
>>
>> In addition, a couple of changes were made to make the creation
>> of additional copies of the LMB array more useful including,
>>
>> * Add new iterator to work through a pair of drmem_info arrays.
>> * Modify DRMEM code to replace usages of dt_root_addr_cells, and
>> dt_mem_next_cell, as these are only available at first boot.
>>
>> Signed-off-by: Michael Bringmann <mwb at linux.vnet.ibm.com>
>> ---
>> arch/powerpc/include/asm/drmem.h | 15 ++++++++
>> arch/powerpc/mm/drmem.c | 75 ++++++++++++++++++++++++++++----------
>> 2 files changed, 70 insertions(+), 20 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/drmem.h b/arch/powerpc/include/asm/drmem.h
>> index ce242b9..b0e70fd 100644
>> --- a/arch/powerpc/include/asm/drmem.h
>> +++ b/arch/powerpc/include/asm/drmem.h
>> @@ -35,6 +35,18 @@ struct drmem_lmb_info {
>> &drmem_info->lmbs[0], \
>> &drmem_info->lmbs[drmem_info->n_lmbs - 1])
>>
>> +#define for_each_dinfo_lmb(dinfo, lmb) \
>> + for_each_drmem_lmb_in_range((lmb), \
>> + &dinfo->lmbs[0], \
>> + &dinfo->lmbs[dinfo->n_lmbs - 1])
>> +
>> +#define for_each_pair_dinfo_lmb(dinfo1, lmb1, dinfo2, lmb2) \
>> + for ((lmb1) = (&dinfo1->lmbs[0]), \
>> + (lmb2) = (&dinfo2->lmbs[0]); \
>> + ((lmb1) <= (&dinfo1->lmbs[dinfo1->n_lmbs - 1])) && \
>> + ((lmb2) <= (&dinfo2->lmbs[dinfo2->n_lmbs - 1])); \
>> + (lmb1)++, (lmb2)++)
>> +
>> /*
>> * The of_drconf_cell_v1 struct defines the layout of the LMB data
>> * specified in the ibm,dynamic-memory device tree property.
>> @@ -94,6 +106,9 @@ void __init walk_drmem_lmbs(struct device_node *dn,
>> void (*func)(struct drmem_lmb *, const __be32 **));
>> int drmem_update_dt(void);
>>
>> +struct drmem_lmb_info *drmem_lmbs_init(struct property *prop);
>> +void drmem_lmbs_free(struct drmem_lmb_info *dinfo);
>> +
>> #ifdef CONFIG_PPC_PSERIES
>> void __init walk_drmem_lmbs_early(unsigned long node,
>> void (*func)(struct drmem_lmb *, const __be32 **));
>> diff --git a/arch/powerpc/mm/drmem.c b/arch/powerpc/mm/drmem.c
>> index 3f18036..13d2abb 100644
>> --- a/arch/powerpc/mm/drmem.c
>> +++ b/arch/powerpc/mm/drmem.c
>> @@ -20,6 +20,7 @@
>>
>> static struct drmem_lmb_info __drmem_info;
>> struct drmem_lmb_info *drmem_info = &__drmem_info;
>> +static int n_root_addr_cells;
>
> What is the point of this new global? I see two places were it gets initialized if it is null, and both those initializers simply set it to "dt_root_addr_cells". I also checked the rest of the patches in the series and none of those even reference this variable.
The point of these changes is to introduce code that can be used after
an LPAR migration. The variable dt_root_addr_cells was observed to be
zero (0) after migration on powerpc. As it is defined as,
./drivers/of/fdt.c:int __initdata dt_root_addr_cells;
its definition may be replaced by other code/variables after initial boot.
We needed the value to persist, and it was cheaper to cache it.
>
>>
>> u64 drmem_lmb_memory_max(void)
>> {
>> @@ -193,12 +194,13 @@ int drmem_update_dt(void)
>> return rc;
>> }
>>
>> -static void __init read_drconf_v1_cell(struct drmem_lmb *lmb,
>> +static void read_drconf_v1_cell(struct drmem_lmb *lmb,
>> const __be32 **prop)
>> {
>> const __be32 *p = *prop;
>>
>> - lmb->base_addr = dt_mem_next_cell(dt_root_addr_cells, &p);
>> + lmb->base_addr = of_read_number(p, n_root_addr_cells);
>> + p += n_root_addr_cells;
>
> Unnecessary code churn do to the introduction of "n_root_addr_cells".'
See note above.
>
>> lmb->drc_index = of_read_number(p++, 1);
>>
>> p++; /* skip reserved field */
>> @@ -209,7 +211,7 @@ static void __init read_drconf_v1_cell(struct drmem_lmb *lmb,
>> *prop = p;
>> }
>>
>> -static void __init __walk_drmem_v1_lmbs(const __be32 *prop, const __be32 *usm,
>> +static void __walk_drmem_v1_lmbs(const __be32 *prop, const __be32 *usm,
>> void (*func)(struct drmem_lmb *, const __be32 **))
>> {
>> struct drmem_lmb lmb;
>> @@ -225,13 +227,14 @@ static void __init __walk_drmem_v1_lmbs(const __be32 *prop, const __be32 *usm,
>> }
>> }
>>
>> -static void __init read_drconf_v2_cell(struct of_drconf_cell_v2 *dr_cell,
>> +static void read_drconf_v2_cell(struct of_drconf_cell_v2 *dr_cell,
>> const __be32 **prop)
>> {
>> const __be32 *p = *prop;
>>
>> dr_cell->seq_lmbs = of_read_number(p++, 1);
>> - dr_cell->base_addr = dt_mem_next_cell(dt_root_addr_cells, &p);
>> + dr_cell->base_addr = of_read_number(p, n_root_addr_cells);
>> + p += n_root_addr_cells;
>
> Same comment as above.
See note above.
>
>> dr_cell->drc_index = of_read_number(p++, 1);
>> dr_cell->aa_index = of_read_number(p++, 1);
>> dr_cell->flags = of_read_number(p++, 1);
>> @@ -239,7 +242,7 @@ static void __init read_drconf_v2_cell(struct of_drconf_cell_v2 *dr_cell,
>> *prop = p;
>> }
>>
>> -static void __init __walk_drmem_v2_lmbs(const __be32 *prop, const __be32 *usm,
>> +static void __walk_drmem_v2_lmbs(const __be32 *prop, const __be32 *usm,
>> void (*func)(struct drmem_lmb *, const __be32 **))
>> {
>> struct of_drconf_cell_v2 dr_cell;
>> @@ -275,6 +278,9 @@ void __init walk_drmem_lmbs_early(unsigned long node,
>> const __be32 *prop, *usm;
>> int len;
>>
>> + if (n_root_addr_cells == 0)
>> + n_root_addr_cells = dt_root_addr_cells;
>> +
>
> As I mentioned initially whats the point? Why not just use "dt_root_addr_cells"?
See note above.
>
>> prop = of_get_flat_dt_prop(node, "ibm,lmb-size", &len);
>> if (!prop || len < dt_root_size_cells * sizeof(__be32))
>> return;
>> @@ -353,24 +359,26 @@ void __init walk_drmem_lmbs(struct device_node *dn,
>> }
>> }
>>
>> -static void __init init_drmem_v1_lmbs(const __be32 *prop)
>> +static void init_drmem_v1_lmbs(const __be32 *prop,
>> + struct drmem_lmb_info *dinfo)
>> {
>> struct drmem_lmb *lmb;
>>
>> - drmem_info->n_lmbs = of_read_number(prop++, 1);
>> - if (drmem_info->n_lmbs == 0)
>> + dinfo->n_lmbs = of_read_number(prop++, 1);
>> + if (dinfo->n_lmbs == 0)
>> return;
>>
>> - drmem_info->lmbs = kcalloc(drmem_info->n_lmbs, sizeof(*lmb),
>> + dinfo->lmbs = kcalloc(dinfo->n_lmbs, sizeof(*lmb),
>> GFP_KERNEL);
>> - if (!drmem_info->lmbs)
>> + if (!dinfo->lmbs)
>> return;
>>
>> - for_each_drmem_lmb(lmb)
>> + for_each_dinfo_lmb(dinfo, lmb)
>> read_drconf_v1_cell(lmb, &prop);
>> }
>>
>> -static void __init init_drmem_v2_lmbs(const __be32 *prop)
>> +static void init_drmem_v2_lmbs(const __be32 *prop,
>> + struct drmem_lmb_info *dinfo)
>> {
>> struct drmem_lmb *lmb;
>> struct of_drconf_cell_v2 dr_cell;
>> @@ -386,12 +394,12 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop)
>> p = prop;
>> for (i = 0; i < lmb_sets; i++) {
>> read_drconf_v2_cell(&dr_cell, &p);
>> - drmem_info->n_lmbs += dr_cell.seq_lmbs;
>> + dinfo->n_lmbs += dr_cell.seq_lmbs;
>> }
>>
>> - drmem_info->lmbs = kcalloc(drmem_info->n_lmbs, sizeof(*lmb),
>> + dinfo->lmbs = kcalloc(dinfo->n_lmbs, sizeof(*lmb),
>> GFP_KERNEL);
>> - if (!drmem_info->lmbs)
>> + if (!dinfo->lmbs)
>> return;
>>
>> /* second pass, read in the LMB information */
>> @@ -402,10 +410,10 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop)
>> read_drconf_v2_cell(&dr_cell, &p);
>>
>> for (j = 0; j < dr_cell.seq_lmbs; j++) {
>> - lmb = &drmem_info->lmbs[lmb_index++];
>> + lmb = &dinfo->lmbs[lmb_index++];
>>
>> lmb->base_addr = dr_cell.base_addr;
>> - dr_cell.base_addr += drmem_info->lmb_size;
>> + dr_cell.base_addr += dinfo->lmb_size;
>>
>> lmb->drc_index = dr_cell.drc_index;
>> dr_cell.drc_index++;
>> @@ -416,11 +424,38 @@ static void __init init_drmem_v2_lmbs(const __be32 *prop)
>> }
>> }
>>
>> +void drmem_lmbs_free(struct drmem_lmb_info *dinfo)
>> +{
>> + if (dinfo) {
>> + kfree(dinfo->lmbs);
>> + kfree(dinfo);
>> + }
>> +}
>> +
>> +struct drmem_lmb_info *drmem_lmbs_init(struct property *prop)
>> +{
>> + struct drmem_lmb_info *dinfo;
>> +
>> + dinfo = kzalloc(sizeof(*dinfo), GFP_KERNEL);
>> + if (!dinfo)
>> + return NULL;
>> +
>> + if (!strcmp("ibm,dynamic-memory", prop->name))
>> + init_drmem_v1_lmbs(prop->value, dinfo);
>> + else if (!strcmp("ibm,dynamic-memory-v2", prop->name))
>> + init_drmem_v2_lmbs(prop->value, dinfo);
>> +
>> + return dinfo;
>> +}
>> +
>> static int __init drmem_init(void)
>> {
>> struct device_node *dn;
>> const __be32 *prop;
>>
>> + if (n_root_addr_cells == 0)
>> + n_root_addr_cells = dt_root_addr_cells;
>> +
>
> See previous comment.
See note above.
>
> -Tyrel
Michael
>
>> dn = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
>> if (!dn) {
>> pr_info("No dynamic reconfiguration memory found\n");
>> @@ -434,11 +469,11 @@ static int __init drmem_init(void)
>>
>> prop = of_get_property(dn, "ibm,dynamic-memory", NULL);
>> if (prop) {
>> - init_drmem_v1_lmbs(prop);
>> + init_drmem_v1_lmbs(prop, drmem_info);
>> } else {
>> prop = of_get_property(dn, "ibm,dynamic-memory-v2", NULL);
>> if (prop)
>> - init_drmem_v2_lmbs(prop);
>> + init_drmem_v2_lmbs(prop, drmem_info);
>> }
>>
>> of_node_put(dn);
>>
>
>
--
Michael W. Bringmann
Linux Technology Center
IBM Corporation
Tie-Line 363-5196
External: (512) 286-5196
Cell: (512) 466-0650
mwb at linux.vnet.ibm.com
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