[RFC PATCH 1/3] of: reserved_mem: Change the order that reserved_mem regions are stored
Oreoluwa Babatunde
quic_obabatun at quicinc.com
Thu Oct 19 11:48:23 PDT 2023
The dynamic allocation of the reserved_mem array needs to be done after
paging_init() is called because memory allocated using memblock_alloc()
is not writeable before that.
Nodes that already have their starting address specified in the DT
(i.e. nodes that are defined using the "reg" property) can wait until
after paging_init() to be stored in the array.
But nodes that are dynamically placed need to be reserved and saved in
the array before paging_init() so that page table entries are not
created for these regions.
Hence, change the code to:
1. Before paging_init(), allocate and store information for the
dynamically placed reserved memory regions.
2. After paging_init(), store the rest of the reserved memory regions
which are defined with the "reg" property.
Signed-off-by: Oreoluwa Babatunde <quic_obabatun at quicinc.com>
---
arch/arm64/kernel/setup.c | 4 +++
drivers/of/fdt.c | 56 ++++++++++++++++++++++++++-------
drivers/of/of_private.h | 1 -
drivers/of/of_reserved_mem.c | 54 ++++++++++++++-----------------
include/linux/of_fdt.h | 1 +
include/linux/of_reserved_mem.h | 9 ++++++
6 files changed, 83 insertions(+), 42 deletions(-)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index 417a8a86b2db..6002d3ad0b19 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -27,6 +27,8 @@
#include <linux/proc_fs.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+
#include <linux/efi.h>
#include <linux/psci.h>
#include <linux/sched/task.h>
@@ -346,6 +348,8 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
paging_init();
+ fdt_init_reserved_mem();
+
acpi_table_upgrade();
/* Parse the ACPI tables for possible boot-time configuration */
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index bf502ba8da95..d51a1176a7b9 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -504,7 +504,6 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
phys_addr_t base, size;
int len;
const __be32 *prop;
- int first = 1;
bool nomap;
prop = of_get_flat_dt_prop(node, "reg", &len);
@@ -532,10 +531,6 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,
uname, &base, (unsigned long)(size / SZ_1M));
len -= t_len;
- if (first) {
- fdt_reserved_mem_save_node(node, uname, base, size);
- first = 0;
- }
}
return 0;
}
@@ -564,9 +559,44 @@ static int __init __reserved_mem_check_root(unsigned long node)
}
/*
- * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ * Save the reserved_mem reg nodes in the reserved_mem array
*/
-static int __init fdt_scan_reserved_mem(void)
+static void save_reserved_mem_reg_nodes(unsigned long node, const char *uname)
+
+{
+ int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+ phys_addr_t base, size;
+ int len;
+ const __be32 *prop;
+
+ prop = of_get_flat_dt_prop(node, "reg", &len);
+ if (!prop)
+ return;
+
+ if (len && len % t_len != 0) {
+ pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
+ uname);
+ return;
+ }
+ base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+ size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+ if (size)
+ fdt_reserved_mem_save_node(node, uname, base, size);
+}
+
+/*
+ * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory.
+ * @save_only: Option to determine what kind of fdt scan the caller is
+ * requesting.
+ *
+ * The fdt is scanned twice here during device bootup. The first scan
+ * is used to save the dynamically allocated reserved memory regions to
+ * the reserved_mem array. The second scan is used to save the 'reg'
+ * defined regions to the array. @save_only indicates which of the scans
+ * the caller is requesting.
+ */
+int __init fdt_scan_reserved_mem(bool save_only)
{
int node, child;
const void *fdt = initial_boot_params;
@@ -589,9 +619,14 @@ static int __init fdt_scan_reserved_mem(void)
uname = fdt_get_name(fdt, child, NULL);
+ if (save_only) {
+ save_reserved_mem_reg_nodes(child, uname);
+ continue;
+ }
+
err = __reserved_mem_reserve_reg(child, uname);
if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
- fdt_reserved_mem_save_node(child, uname, 0, 0);
+ __reserved_mem_alloc_size(child, uname);
}
return 0;
}
@@ -631,11 +666,12 @@ void __init early_init_fdt_scan_reserved_mem(void)
{
int n;
u64 base, size;
+ bool save_only = false;
if (!initial_boot_params)
return;
- fdt_scan_reserved_mem();
+ fdt_scan_reserved_mem(save_only);
fdt_reserve_elfcorehdr();
/* Process header /memreserve/ fields */
@@ -645,8 +681,6 @@ void __init early_init_fdt_scan_reserved_mem(void)
break;
memblock_reserve(base, size);
}
-
- fdt_init_reserved_mem();
}
/**
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index f38397c7b582..e52b27b8392d 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -175,7 +175,6 @@ static inline struct device_node *__of_get_dma_parent(const struct device_node *
}
#endif
-void fdt_init_reserved_mem(void);
void fdt_reserved_mem_save_node(unsigned long node, const char *uname,
phys_addr_t base, phys_addr_t size);
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 7ec94cfcbddb..13e694f5e316 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -132,8 +132,7 @@ static int __init __reserved_mem_alloc_in_range(phys_addr_t size,
* __reserved_mem_alloc_size() - allocate reserved memory described by
* 'size', 'alignment' and 'alloc-ranges' properties.
*/
-static int __init __reserved_mem_alloc_size(unsigned long node,
- const char *uname, phys_addr_t *res_base, phys_addr_t *res_size)
+int __init __reserved_mem_alloc_size(unsigned long node, const char *uname)
{
int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
phys_addr_t start = 0, end = 0;
@@ -212,10 +211,7 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
uname, (unsigned long)(size / SZ_1M));
return -ENOMEM;
}
-
- *res_base = base;
- *res_size = size;
-
+ fdt_reserved_mem_save_node(node, uname, base, size);
return 0;
}
@@ -309,6 +305,9 @@ static void __init __rmem_check_for_overlap(void)
void __init fdt_init_reserved_mem(void)
{
int i;
+ bool save_only = true;
+
+ fdt_scan_reserved_mem(save_only);
/* check for overlapping reserved regions */
__rmem_check_for_overlap();
@@ -328,30 +327,25 @@ void __init fdt_init_reserved_mem(void)
if (prop)
rmem->phandle = of_read_number(prop, len/4);
- if (rmem->size == 0)
- err = __reserved_mem_alloc_size(node, rmem->name,
- &rmem->base, &rmem->size);
- if (err == 0) {
- err = __reserved_mem_init_node(rmem);
- if (err != 0 && err != -ENOENT) {
- pr_info("node %s compatible matching fail\n",
- rmem->name);
- if (nomap)
- memblock_clear_nomap(rmem->base, rmem->size);
- else
- memblock_phys_free(rmem->base,
- rmem->size);
- } else {
- phys_addr_t end = rmem->base + rmem->size - 1;
- bool reusable =
- (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
-
- pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
- &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
- nomap ? "nomap" : "map",
- reusable ? "reusable" : "non-reusable",
- rmem->name ? rmem->name : "unknown");
- }
+ err = __reserved_mem_init_node(rmem);
+ if (err != 0 && err != -ENOENT) {
+ pr_info("node %s compatible matching fail\n",
+ rmem->name);
+ if (nomap)
+ memblock_clear_nomap(rmem->base, rmem->size);
+ else
+ memblock_phys_free(rmem->base,
+ rmem->size);
+ } else {
+ phys_addr_t end = rmem->base + rmem->size - 1;
+ bool reusable =
+ (of_get_flat_dt_prop(node, "reusable", NULL)) != NULL;
+
+ pr_info("%pa..%pa (%lu KiB) %s %s %s\n",
+ &rmem->base, &end, (unsigned long)(rmem->size / SZ_1K),
+ nomap ? "nomap" : "map",
+ reusable ? "reusable" : "non-reusable",
+ rmem->name ? rmem->name : "unknown");
}
}
}
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index d69ad5bb1eb1..a9a9f70dabea 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -77,6 +77,7 @@ extern void early_init_dt_scan_nodes(void);
extern const char *of_flat_dt_get_machine_name(void);
extern const void *of_flat_dt_match_machine(const void *default_match,
const void * (*get_next_compat)(const char * const**));
+extern int fdt_scan_reserved_mem(bool save_only);
/* Other Prototypes */
extern void unflatten_device_tree(void);
diff --git a/include/linux/of_reserved_mem.h b/include/linux/of_reserved_mem.h
index 4de2a24cadc9..e310336cef37 100644
--- a/include/linux/of_reserved_mem.h
+++ b/include/linux/of_reserved_mem.h
@@ -38,6 +38,8 @@ int of_reserved_mem_device_init_by_name(struct device *dev,
struct device_node *np,
const char *name);
void of_reserved_mem_device_release(struct device *dev);
+void fdt_init_reserved_mem(void);
+int __reserved_mem_alloc_size(unsigned long node, const char *uname);
struct reserved_mem *of_reserved_mem_lookup(struct device_node *np);
#else
@@ -60,6 +62,13 @@ static inline int of_reserved_mem_device_init_by_name(struct device *dev,
static inline void of_reserved_mem_device_release(struct device *pdev) { }
+static inline int __reserved_mem_alloc_size(unsigned long node, const char *uname)
+{
+ return -ENOSYS;
+}
+
+static inline void fdt_init_reserved_mem(void) { }
+
static inline struct reserved_mem *of_reserved_mem_lookup(struct device_node *np)
{
return NULL;
--
2.17.1
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