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Subject[RFC v2 12/26] mm/asi: Function to copy page-table entries for percpu buffer
Date
Provide functions to copy page-table entries from the kernel page-table
to an ASI page-table for a percpu buffer. A percpu buffer have a different
VA range for each cpu and all them have to be copied.

Signed-off-by: Alexandre Chartre <alexandre.chartre@oracle.com>
---
arch/x86/include/asm/asi.h | 6 ++++++
arch/x86/mm/asi_pagetable.c | 38 ++++++++++++++++++++++++++++++++++++++
2 files changed, 44 insertions(+), 0 deletions(-)

diff --git a/arch/x86/include/asm/asi.h b/arch/x86/include/asm/asi.h
index 919129f..912b6a7 100644
--- a/arch/x86/include/asm/asi.h
+++ b/arch/x86/include/asm/asi.h
@@ -105,6 +105,12 @@ static inline int asi_map_module(struct asi *asi, char *module_name)
return asi_map(asi, module->core_layout.base, module->core_layout.size);
}

+#define ASI_MAP_CPUVAR(asi, cpuvar) \
+ asi_map_percpu(asi, &cpuvar, sizeof(cpuvar))
+
+extern int asi_map_percpu(struct asi *asi, void *percpu_ptr, size_t size);
+extern void asi_unmap_percpu(struct asi *asi, void *percpu_ptr);
+
/*
* Function to exit the current isolation. This is used to abort isolation
* when a task using isolation is scheduled out.
diff --git a/arch/x86/mm/asi_pagetable.c b/arch/x86/mm/asi_pagetable.c
index 7aee236..a4fe867 100644
--- a/arch/x86/mm/asi_pagetable.c
+++ b/arch/x86/mm/asi_pagetable.c
@@ -804,3 +804,41 @@ void asi_unmap(struct asi *asi, void *ptr)
spin_unlock_irqrestore(&asi->lock, flags);
}
EXPORT_SYMBOL(asi_unmap);
+
+void asi_unmap_percpu(struct asi *asi, void *percpu_ptr)
+{
+ void *ptr;
+ int cpu;
+
+ pr_debug("ASI %p: UNMAP PERCPU %px\n", asi, percpu_ptr);
+ for_each_possible_cpu(cpu) {
+ ptr = per_cpu_ptr(percpu_ptr, cpu);
+ pr_debug("ASI %p: UNMAP PERCPU%d %px\n", asi, cpu, ptr);
+ asi_unmap(asi, ptr);
+ }
+}
+EXPORT_SYMBOL(asi_unmap_percpu);
+
+int asi_map_percpu(struct asi *asi, void *percpu_ptr, size_t size)
+{
+ int cpu, err;
+ void *ptr;
+
+ pr_debug("ASI %p: MAP PERCPU %px\n", asi, percpu_ptr);
+ for_each_possible_cpu(cpu) {
+ ptr = per_cpu_ptr(percpu_ptr, cpu);
+ pr_debug("ASI %p: MAP PERCPU%d %px\n", asi, cpu, ptr);
+ err = asi_map(asi, ptr, size);
+ if (err) {
+ /*
+ * Need to unmap any percpu mapping which has
+ * succeeded before the failure.
+ */
+ asi_unmap_percpu(asi, percpu_ptr);
+ return err;
+ }
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(asi_map_percpu);
--
1.7.1
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