[tip: x86/cache] x86/resctrl: Use schema type to determine the schema format string

From: tip-bot2 for James Morse
Date: Wed Mar 12 2025 - 13:25:34 EST


The following commit has been merged into the x86/cache branch of tip:

Commit-ID: bb9343c8f2906ac7087a7f9560b37636c220551d
Gitweb: https://git.kernel.org/tip/bb9343c8f2906ac7087a7f9560b37636c220551d
Author: James Morse <james.morse@xxxxxxx>
AuthorDate: Tue, 11 Mar 2025 18:36:50
Committer: Borislav Petkov (AMD) <bp@xxxxxxxxx>
CommitterDate: Wed, 12 Mar 2025 12:22:33 +01:00

x86/resctrl: Use schema type to determine the schema format string

Resctrl's architecture code gets to specify a format string that is
used when printing schema entries. This is expected to be one of two
values that the filesystem code supports.

Setting this format string allows the architecture code to change
the ABI resctrl presents to user-space.

Instead, use the schema format enum to choose which format string to
use.

Signed-off-by: James Morse <james.morse@xxxxxxx>
Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx>
Reviewed-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Reviewed-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
Reviewed-by: Tony Luck <tony.luck@xxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghuay@xxxxxxxxxx>
Reviewed-by: Babu Moger <babu.moger@xxxxxxx>
Tested-by: Carl Worth <carl@xxxxxxxxxxxxxxxxxxxxxx> # arm64
Tested-by: Shaopeng Tan <tan.shaopeng@xxxxxxxxxxxxxx>
Tested-by: Peter Newman <peternewman@xxxxxxxxxx>
Tested-by: Amit Singh Tomar <amitsinght@xxxxxxxxxxx> # arm64
Tested-by: Shanker Donthineni <sdonthineni@xxxxxxxxxx> # arm64
Tested-by: Babu Moger <babu.moger@xxxxxxx>
Link: https://lore.kernel.org/r/20250311183715.16445-6-james.morse@xxxxxxx
---
arch/x86/kernel/cpu/resctrl/core.c | 4 ----
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 2 +-
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 14 ++++++++++++++
include/linux/resctrl.h | 4 ++--
4 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
index e9fe129..542503a 100644
--- a/arch/x86/kernel/cpu/resctrl/core.c
+++ b/arch/x86/kernel/cpu/resctrl/core.c
@@ -73,7 +73,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
.ctrl_domains = ctrl_domain_init(RDT_RESOURCE_L3),
.mon_domains = mon_domain_init(RDT_RESOURCE_L3),
.schema_fmt = RESCTRL_SCHEMA_BITMAP,
- .format_str = "%d=%0*x",
},
.msr_base = MSR_IA32_L3_CBM_BASE,
.msr_update = cat_wrmsr,
@@ -86,7 +85,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
.ctrl_scope = RESCTRL_L2_CACHE,
.ctrl_domains = ctrl_domain_init(RDT_RESOURCE_L2),
.schema_fmt = RESCTRL_SCHEMA_BITMAP,
- .format_str = "%d=%0*x",
},
.msr_base = MSR_IA32_L2_CBM_BASE,
.msr_update = cat_wrmsr,
@@ -99,7 +97,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
.ctrl_scope = RESCTRL_L3_CACHE,
.ctrl_domains = ctrl_domain_init(RDT_RESOURCE_MBA),
.schema_fmt = RESCTRL_SCHEMA_RANGE,
- .format_str = "%d=%*u",
},
},
[RDT_RESOURCE_SMBA] =
@@ -110,7 +107,6 @@ struct rdt_hw_resource rdt_resources_all[RDT_NUM_RESOURCES] = {
.ctrl_scope = RESCTRL_L3_CACHE,
.ctrl_domains = ctrl_domain_init(RDT_RESOURCE_SMBA),
.schema_fmt = RESCTRL_SCHEMA_RANGE,
- .format_str = "%d=%*u",
},
},
};
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index f4334f4..c763cb4 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -487,7 +487,7 @@ static void show_doms(struct seq_file *s, struct resctrl_schema *schema, int clo
ctrl_val = resctrl_arch_get_config(r, dom, closid,
schema->conf_type);

- seq_printf(s, r->format_str, dom->hdr.id, max_data_width,
+ seq_printf(s, schema->fmt_str, dom->hdr.id, max_data_width,
ctrl_val);
sep = true;
}
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 3391ac8..e7862d0 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2611,6 +2611,20 @@ static int schemata_list_add(struct rdt_resource *r, enum resctrl_conf_type type
if (cl > max_name_width)
max_name_width = cl;

+ switch (r->schema_fmt) {
+ case RESCTRL_SCHEMA_BITMAP:
+ s->fmt_str = "%d=%0*x";
+ break;
+ case RESCTRL_SCHEMA_RANGE:
+ s->fmt_str = "%d=%0*u";
+ break;
+ }
+
+ if (WARN_ON_ONCE(!s->fmt_str)) {
+ kfree(s);
+ return -EINVAL;
+ }
+
INIT_LIST_HEAD(&s->list);
list_add(&s->list, &resctrl_schema_all);

diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index 3e1a413..736b9a9 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -216,7 +216,6 @@ enum resctrl_schema_fmt {
* @name: Name to use in "schemata" file.
* @data_width: Character width of data when displaying
* @default_ctrl: Specifies default cache cbm or memory B/W percent.
- * @format_str: Per resource format string to show domain value
* @schema_fmt: Which format string and parser is used for this schema.
* @evt_list: List of monitoring events
* @cdp_capable: Is the CDP feature available on this resource
@@ -235,7 +234,6 @@ struct rdt_resource {
char *name;
int data_width;
u32 default_ctrl;
- const char *format_str;
enum resctrl_schema_fmt schema_fmt;
struct list_head evt_list;
bool cdp_capable;
@@ -253,6 +251,7 @@ struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l);
* user-space
* @list: Member of resctrl_schema_all.
* @name: The name to use in the "schemata" file.
+ * @fmt_str: Format string to show domain value.
* @conf_type: Whether this schema is specific to code/data.
* @res: The resource structure exported by the architecture to describe
* the hardware that is configured by this schema.
@@ -263,6 +262,7 @@ struct rdt_resource *resctrl_arch_get_resource(enum resctrl_res_level l);
struct resctrl_schema {
struct list_head list;
char name[8];
+ const char *fmt_str;
enum resctrl_conf_type conf_type;
struct rdt_resource *res;
u32 num_closid;