[RFC PATCH v2 5/7] pmpool: Update device tree on kexec
Stanislav Kinsburskii
skinsburskii at linux.microsoft.com
Mon Sep 25 14:28:16 PDT 2023
From: Stanislav Kinsburskii <stanislav.kinsburskii at gmail.com>
Introduce a pmpool kexec fdt notifier that enables pmpool to pass its
metadata, including the bitmap address, to the new kernel during kexec.
Signed-off-by: Stanislav Kinsburskii <skinsburskii at linux.microsoft.com>
---
mm/Kconfig | 1 +
mm/pmpool.c | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 64 insertions(+), 1 deletion(-)
diff --git a/mm/Kconfig b/mm/Kconfig
index e7c10094fb10..1eefdd4c82ba 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -925,6 +925,7 @@ config CMA_AREAS
config PMPOOL
bool "Persistent memory pool support"
select CMA
+ select LIBFDT
help
This option adds support for CMA-based persistent memory pool
feature, which provides pages allocation and freeing from a set of
diff --git a/mm/pmpool.c b/mm/pmpool.c
index 12a8cac75558..f2173db782d6 100644
--- a/mm/pmpool.c
+++ b/mm/pmpool.c
@@ -6,6 +6,7 @@
#include <linux/cma.h>
#include <linux/io.h>
#include <linux/kexec.h>
+#include <linux/libfdt.h>
#include <linux/memblock.h>
#include <linux/mm.h>
#include <linux/pmpool.h>
@@ -58,6 +59,59 @@ static int __init default_pmpool_fixup_cma(void)
}
postcore_initcall(default_pmpool_fixup_cma);
+static int pmpool_fdt_update(struct notifier_block *nb, unsigned long val,
+ void *data)
+{
+ void *fdt = data;
+ int node, status;
+
+ if (!fdt)
+ goto err;
+
+ node = fdt_subnode_offset(fdt, 0, "chosen");
+ if (node < 0) {
+ node = fdt_add_subnode(fdt, 0, "chosen");
+ if (node < 0)
+ goto err;
+ }
+
+ node = fdt_add_subnode(fdt, node, "default_pmpool");
+ if (node == -FDT_ERR_EXISTS)
+ return 0;
+ if (node < 0)
+ goto err;
+
+ status = fdt_setprop(fdt, node, "compatible",
+ "pmpool", sizeof("pmpool"));
+ if (status)
+ goto err;
+
+ status = fdt_setprop_u64(fdt, node, "bitmap",
+ virt_to_phys(default_pmpool->cma->bitmap));
+ if (status)
+ goto err;
+
+ status = fdt_setprop_u64(fdt, node, "size",
+ default_pmpool->cma->count << PAGE_SHIFT);
+ if (status)
+ goto err;
+
+ status = fdt_setprop_u64(fdt, node, "base",
+ default_pmpool->cma->base_pfn << PAGE_SHIFT);
+ if (status)
+ goto err;
+
+ return NOTIFY_DONE;
+
+err:
+ pr_err("failed to update fdt\n");
+ return NOTIFY_DONE;
+}
+
+static struct notifier_block pmpool_kexec_fdt_nb = {
+ .notifier_call = pmpool_fdt_update,
+};
+
static int __init parse_pmpool_opt(char *str)
{
static struct pmpool pmpool;
@@ -80,10 +134,16 @@ static int __init parse_pmpool_opt(char *str)
return 0;
}
+ err = register_kexec_fdt_notifier(&pmpool_kexec_fdt_nb);
+ if (err) {
+ pr_err("failed to register kexec fdt notifier: %d\n", err);
+ goto free_memblock;
+ }
+
err = cma_init_reserved_mem(base, size, 0, "pmpool", &pmpool.cma);
if (err) {
pr_err("failed to initialize CMA: %d\n", err);
- goto free_memblock;
+ goto notifier_unregister;
}
pr_info("default memory pool is created: %#llx-%#llx\n",
@@ -93,6 +153,8 @@ static int __init parse_pmpool_opt(char *str)
return 0;
+notifier_unregister:
+ unregister_kexec_fdt_notifier(&pmpool_kexec_fdt_nb);
free_memblock:
memblock_phys_free(base, size);
return 0;
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