After all the reserved memory regions have been added to the
reserved_mem array, a region specific initialization function is called
on each of reserved memory regions in a loop to initialize them.
With recent changes made to allow the reserved_mem array be dynamically
allocated, the cma reserved memory regions are not initialized until
after the page tables are setup. This causes the warning seen in the
dump stack below:
WARNING: CPU: 0 PID: 1 at mm/memory.c:2789 __apply_to_page_range+0x360/0x380
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.10.0-rc1-00007-ga46cccb0ee2d #1
Hardware name: Generic DT based system
Call trace:
unwind_backtrace from show_stack+0x18/0x1c
show_stack from dump_stack_lvl+0x54/0x68
dump_stack_lvl from __warn+0x74/0x114
__warn from warn_slowpath_fmt+0x13c/0x1c0
warn_slowpath_fmt from __apply_to_page_range+0x360/0x380
__apply_to_page_range from apply_to_page_range+0x24/0x2c
apply_to_page_range from __alloc_from_contiguous+0xc4/0x158
__alloc_from_contiguous from cma_allocator_alloc+0x3c/0x44
cma_allocator_alloc from arch_dma_alloc+0x128/0x2b4
arch_dma_alloc from dma_alloc_attrs+0x90/0x150
dma_alloc_attrs from drm_gem_dma_create+0xa4/0x13c
drm_gem_dma_create from drm_gem_dma_create_with_handle+0x24/0xac
drm_gem_dma_create_with_handle from drm_gem_dma_dumb_create+0x44/0x50
drm_gem_dma_dumb_create from drm_client_framebuffer_create+0x9c/0x164
drm_client_framebuffer_create from drm_fbdev_dma_helper_fb_probe+0x84/0x23c
drm_fbdev_dma_helper_fb_probe from __drm_fb_helper_initial_config_and_unlock+0x2e4/0x4f8
__drm_fb_helper_initial_config_and_unlock from drm_fbdev_dma_client_hotplug+0x74/0xb8
drm_fbdev_dma_client_hotplug from drm_client_register+0x5c/0x98
drm_client_register from aspeed_gfx_probe+0x278/0x3c0
aspeed_gfx_probe from platform_probe+0x60/0xb8
platform_probe from really_probe+0xd4/0x3b4
really_probe from __driver_probe_device+0x90/0x1dc
__driver_probe_device from driver_probe_device+0x38/0xd0
driver_probe_device from __driver_attach+0x118/0x1dc
__driver_attach from bus_for_each_dev+0x84/0xd4
bus_for_each_dev from bus_add_driver+0xec/0x1f0
bus_add_driver from driver_register+0x84/0x11c
driver_register from do_one_initcall+0x84/0x1c8
do_one_initcall from kernel_init_freeable+0x1a4/0x230
kernel_init_freeable from kernel_init+0x1c/0x138
kernel_init from ret_from_fork+0x14/0x28
Exception stack(0x9f015fb0 to 0x9f015ff8)
5fa0: 00000000 00000000 00000000 00000000
5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
---[ end trace 0000000000000000 ]---
aspeed_gfx 1e6e6000.display: [drm] fb0: aspeed-gfx-drmd frame buffer device
Hence, restructure the code to initialize the regions as soon as each
of them are added to the reserved_mem array.
Fixes: a46cccb0ee2d ("of: reserved_mem: Restruture how the reserved memory regions are processed")
Signed-off-by: Oreoluwa Babatunde <quic_obabatun@xxxxxxxxxxx>
---
v2:
- Fix kernel-doc for of_init_reserved_mem_node() in response to the
below warning from v1:
https://lore.kernel.org/all/202406181626.126X1Nbz-lkp@xxxxxxxxx/
v1:
https://lore.kernel.org/all/20240617193357.3929092-1-quic_obabatun@xxxxxxxxxxx/
drivers/of/fdt.c | 2 +-
drivers/of/of_private.h | 2 +-
drivers/of/of_reserved_mem.c | 83 +++++++++++++++++++++---------------
3 files changed, 50 insertions(+), 37 deletions(-)
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 9cde2abd2fc0..ea2dff0478c7 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -1239,7 +1239,7 @@ void __init unflatten_device_tree(void)
unittest_unflatten_overlay_base();
/* initialize the reserved memory regions */
- of_init_reserved_mem();
+ of_scan_reserved_mem_reg_nodes();
}
/**
diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
index 01b33c4b1e9f..7412aed903df 100644
--- a/drivers/of/of_private.h
+++ b/drivers/of/of_private.h
@@ -181,7 +181,7 @@ static inline struct device_node *__of_get_dma_parent(const struct device_node *
#endif
int fdt_scan_reserved_mem(void);
-void of_init_reserved_mem(void);
+void of_scan_reserved_mem_reg_nodes(void);
bool of_fdt_device_is_available(const void *blob, unsigned long node);
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index eb54490a0a11..b31001728866 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -97,6 +97,8 @@ static void __init alloc_reserved_mem_array(void)
reserved_mem = new_array;
}
+static void __init of_init_reserved_mem_node(struct reserved_mem *rmem);
+
/*
* of_reserved_mem_save_node() - save fdt node for second pass initialization
*/
@@ -115,6 +117,12 @@ static void __init of_reserved_mem_save_node(struct device_node *node, const cha
rmem->base = base;
rmem->size = size;
+ /*
+ * Run the region specific initialization function for the rmem
+ * node.
+ */
+ of_init_reserved_mem_node(rmem);
+
reserved_mem_count++;
return;
}
@@ -201,6 +209,8 @@ static int __init __fdt_reserved_mem_check_root(unsigned long node)
return 0;
}
+static void __init __rmem_check_for_overlap(void);
+
/**
* of_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
* reserved memory regions.
@@ -211,7 +221,7 @@ static int __init __fdt_reserved_mem_check_root(unsigned long node)
* size are all stored in the reserved_mem array by calling the
* of_reserved_mem_save_node() function.
*/
-static void __init of_scan_reserved_mem_reg_nodes(void)
+void __init of_scan_reserved_mem_reg_nodes(void)
{
struct device_node *node, *child;
phys_addr_t base, size;
@@ -222,6 +232,13 @@ static void __init of_scan_reserved_mem_reg_nodes(void)
return;
}
+ /*
+ * Before moving forward, allocate the exact size needed for the
+ * reserved_mem array and copy all previously saved contents
+ * into the new array if successful.
+ */
+ alloc_reserved_mem_array();
+
for_each_child_of_node(node, child) {
int ret = 0;
const char *uname;
@@ -246,6 +263,8 @@ static void __init of_scan_reserved_mem_reg_nodes(void)
if (size)
of_reserved_mem_save_node(child, uname, base, size);
}
+ /* check for overlapping reserved regions */
+ __rmem_check_for_overlap();
}
static int __init __reserved_mem_alloc_size(unsigned long node, const char *uname);
@@ -526,44 +545,38 @@ static void __init __rmem_check_for_overlap(void)
}
/**
- * of_init_reserved_mem() - allocate and init all saved reserved memory regions
+ * of_init_reserved_mem_node() - Initialize a saved reserved memory region.
+ * @rmem: reserved_mem object of the memory region to be initialized.
+ *
+ * This function is used to call the region specific initialization
+ * function on the rmem object passed as an argument. The rmem object
+ * will contain the base address, size, node name, and device_node of
+ * the reserved memory region to be initialized.
*/
-void __init of_init_reserved_mem(void)
+static void __init of_init_reserved_mem_node(struct reserved_mem *rmem)
{
- int i;
-
- alloc_reserved_mem_array();
-
- of_scan_reserved_mem_reg_nodes();
+ int err;
+ bool nomap;
+ struct device_node *node = rmem->dev_node;
- /* check for overlapping reserved regions */
- __rmem_check_for_overlap();
+ nomap = of_property_present(node, "no-map");
- for (i = 0; i < reserved_mem_count; i++) {
- struct reserved_mem *rmem = &reserved_mem[i];
- struct device_node *node = rmem->dev_node;
- int err = 0;
- bool nomap;
-
- nomap = of_property_present(node, "no-map");
-
- 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_property_present(node, "reusable");
-
- 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_property_present(node, "reusable");
+
+ 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");
}
}
--
2.34.1
