CC linux-renesas-soc
On Tue, Oct 29, 2024 at 1:41 PM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> On Wed, Oct 9, 2024 at 12:08 AM Oreoluwa Babatunde
> <quic_obabatun@xxxxxxxxxxx> wrote:
> > Reserved memory regions defined in the devicetree can be broken up into
> > two groups:
> > i) Statically-placed reserved memory regions
> > i.e. regions defined with a static start address and size using the
> > "reg" property.
> > ii) Dynamically-placed reserved memory regions.
> > i.e. regions defined by specifying an address range where they can be
> > placed in memory using the "alloc_ranges" and "size" properties.
> >
> > These regions are processed and set aside at boot time.
> > This is done in two stages as seen below:
> >
> > Stage 1:
> > At this stage, fdt_scan_reserved_mem() scans through the child nodes of
> > the reserved_memory node using the flattened devicetree and does the
> > following:
> >
> > 1) If the node represents a statically-placed reserved memory region,
> > i.e. if it is defined using the "reg" property:
> > - Call memblock_reserve() or memblock_mark_nomap() as needed.
> > - Add the information for that region into the reserved_mem array
> > using fdt_reserved_mem_save_node().
> > i.e. fdt_reserved_mem_save_node(node, name, base, size).
> >
> > 2) If the node represents a dynamically-placed reserved memory region,
> > i.e. if it is defined using "alloc-ranges" and "size" properties:
> > - Add the information for that region to the reserved_mem array with
> > the starting address and size set to 0.
> > i.e. fdt_reserved_mem_save_node(node, name, 0, 0).
> > Note: This region is saved to the array with a starting address of 0
> > because a starting address is not yet allocated for it.
> >
> > Stage 2:
> > After iterating through all the reserved memory nodes and storing their
> > relevant information in the reserved_mem array,fdt_init_reserved_mem() is
> > called and does the following:
> >
> > 1) For statically-placed reserved memory regions:
> > - Call the region specific init function using
> > __reserved_mem_init_node().
> > 2) For dynamically-placed reserved memory regions:
> > - Call __reserved_mem_alloc_size() which is used to allocate memory
> > for each of these regions, and mark them as nomap if they have the
> > nomap property specified in the DT.
> > - Call the region specific init function.
> >
> > The current size of the resvered_mem array is 64 as is defined by
> > MAX_RESERVED_REGIONS. This means that there is a limitation of 64 for
> > how many reserved memory regions can be specified on a system.
> > As systems continue to grow more and more complex, the number of
> > reserved memory regions needed are also growing and are starting to hit
> > this 64 count limit, hence the need to make the reserved_mem array
> > dynamically sized (i.e. dynamically allocating memory for the
> > reserved_mem array using membock_alloc_*).
> >
> > On architectures such as arm64, memory allocated using memblock is
> > writable only after the page tables have been setup. This means that if
> > the reserved_mem array is going to be dynamically allocated, it needs to
> > happen after the page tables have been setup, not before.
> >
> > Since the reserved memory regions are currently being processed and
> > added to the array before the page tables are setup, there is a need to
> > change the order in which some of the processing is done to allow for
> > the reserved_mem array to be dynamically sized.
> >
> > It is possible to process the statically-placed reserved memory regions
> > without needing to store them in the reserved_mem array until after the
> > page tables have been setup because all the information stored in the
> > array is readily available in the devicetree and can be referenced at
> > any time.
> > Dynamically-placed reserved memory regions on the other hand get
> > assigned a start address only at runtime, and hence need a place to be
> > stored once they are allocated since there is no other referrence to the
> > start address for these regions.
> >
> > Hence this patch changes the processing order of the reserved memory
> > regions in the following ways:
> >
> > Step 1:
> > fdt_scan_reserved_mem() scans through the child nodes of
> > the reserved_memory node using the flattened devicetree and does the
> > following:
> >
> > 1) If the node represents a statically-placed reserved memory region,
> > i.e. if it is defined using the "reg" property:
> > - Call memblock_reserve() or memblock_mark_nomap() as needed.
> >
> > 2) If the node represents a dynamically-placed reserved memory region,
> > i.e. if it is defined using "alloc-ranges" and "size" properties:
> > - Call __reserved_mem_alloc_size() which will:
> > i) Allocate memory for the reserved region and call
> > memblock_mark_nomap() as needed.
> > ii) Call the region specific initialization function using
> > fdt_init_reserved_mem_node().
> > iii) Save the region information in the reserved_mem array using
> > fdt_reserved_mem_save_node().
> >
> > Step 2:
> > 1) This stage of the reserved memory processing is now only used to add
> > the statically-placed reserved memory regions into the reserved_mem
> > array using fdt_scan_reserved_mem_reg_nodes(), as well as call their
> > region specific initialization functions.
> >
> > 2) This step has also been moved to be after the page tables are
> > setup. Moving this will allow us to replace the reserved_mem
> > array with a dynamically sized array before storing the rest of
> > these regions.
> >
> > Signed-off-by: Oreoluwa Babatunde <quic_obabatun@xxxxxxxxxxx>
>
> Thanks for your patch, which is now commit 8a6e02d0c00e7b62
> ("of: reserved_mem: Restructure how the reserved memory regions
> are processed") in dt-rh/for-next.
>
> I have bisected a boot issue on RZ/Five to this commit.
> With "earlycon keep_bootcon" (else there is no output):
>
> Oops - store (or AMO) access fault [#1]
> CPU: 0 UID: 0 PID: 1 Comm: swapper Not tainted
> 6.12.0-rc1-00015-g8a6e02d0c00e #201
> Hardware name: Renesas SMARC EVK based on r9a07g043f01 (DT)
> epc : __memset+0x60/0x100
> ra : __dma_alloc_from_coherent+0x150/0x17a
> epc : ffffffff8062d2bc ra : ffffffff80053a94 sp : ffffffc60000ba20
> gp : ffffffff812e9938 tp : ffffffd601920000 t0 : ffffffc6000d0000
> t1 : 0000000000000000 t2 : ffffffffe9600000 s0 : ffffffc60000baa0
> s1 : ffffffc6000d0000 a0 : ffffffc6000d0000 a1 : 0000000000000000
> a2 : 0000000000001000 a3 : ffffffc6000d1000 a4 : 0000000000000000
> a5 : 0000000000000000 a6 : ffffffd601adacc0 a7 : ffffffd601a841a8
> s2 : ffffffd6018573c0 s3 : 0000000000001000 s4 : ffffffd6019541e0
> s5 : 0000000200000022 s6 : ffffffd6018f8410 s7 : ffffffd6018573e8
> s8 : 0000000000000001 s9 : 0000000000000001 s10: 0000000000000010
> s11: 0000000000000000 t3 : 0000000000000000 t4 : ffffffffdefe62d1
> t5 : 000000001cd6a3a9 t6 : ffffffd601b2aad6
> status: 0000000200000120 badaddr: ffffffc6000d0000 cause: 0000000000000007
> [<ffffffff8062d2bc>] __memset+0x60/0x100
> [<ffffffff80053e1a>] dma_alloc_from_global_coherent+0x1c/0x28
> [<ffffffff80053056>] dma_direct_alloc+0x98/0x112
> [<ffffffff8005238c>] dma_alloc_attrs+0x78/0x86
> [<ffffffff8035fdb4>] rz_dmac_probe+0x3f6/0x50a
> [<ffffffff803a0694>] platform_probe+0x4c/0x8a
> [<ffffffff8039ea16>] really_probe+0xe4/0x1c8
> [<ffffffff8039ebc4>] __driver_probe_device+0xca/0xce
> [<ffffffff8039ec48>] driver_probe_device+0x34/0x92
> [<ffffffff8039ede8>] __driver_attach+0xb4/0xbe
> [<ffffffff8039ce58>] bus_for_each_dev+0x60/0xa0
> [<ffffffff8039e26a>] driver_attach+0x1a/0x22
> [<ffffffff8039dc20>] bus_add_driver+0xa4/0x184
> [<ffffffff8039f65c>] driver_register+0x8a/0xb4
> [<ffffffff803a051c>] __platform_driver_register+0x1c/0x24
> [<ffffffff808202f6>] rz_dmac_driver_init+0x1a/0x22
> [<ffffffff80800ef6>] do_one_initcall+0x64/0x134
> [<ffffffff8080122e>] kernel_init_freeable+0x200/0x202
> [<ffffffff80638126>] kernel_init+0x1e/0x10a
> [<ffffffff8063d58e>] ret_from_fork+0xe/0x18
> Code: 1007 82b3 40e2 0797 0000 8793 00e7 8305 97ba 8782 (b023) 00b2
> ---[ end trace 0000000000000000 ]---
> Kernel panic - not syncing: Fatal exception in interrupt
> ---[ end Kernel panic - not syncing: Fatal exception in interrupt ]---
>
> Nothing really stands out in the kernel log, except for a delayed
> initialization of the reserved mem nodes (they are the same
> before/after):
>
> printk: debug: ignoring loglevel setting.
> -OF: reserved mem: 0x0000000000030000..0x000000000003ffff (64 KiB)
> nomap non-reusable mmode_resv0@30000
> -OF: reserved mem: 0x0000000000040000..0x000000000004ffff (64 KiB)
> nomap non-reusable mmode_resv1@40000
> -OF: reserved mem: 0x0000000044000000..0x000000004403ffff (256 KiB)
> nomap non-reusable mmode_resv3@44000000
> -OF: reserved mem: 0x0000000044040000..0x000000004405ffff (128 KiB)
> nomap non-reusable mmode_resv2@44040000
> +earlycon: scif0 at MMIO 0x000000001004b800 (options '115200n8')
> +printk: legacy bootconsole [scif0] enabled
> +printk: debug: skip boot console de-registration.
> Reserved memory: created DMA memory pool at 0x0000000058000000, size 128 MiB
> OF: reserved mem: initialized node pma_resv0@58000000, compatible id
> shared-dma-pool
> OF: reserved mem: 0x0000000058000000..0x000000005fffffff (131072 KiB)
> nomap non-reusable pma_resv0@58000000
> +OF: reserved mem: 0x0000000000030000..0x000000000003ffff (64 KiB)
> nomap non-reusable mmode_resv0@30000
> +OF: reserved mem: 0x0000000000040000..0x000000000004ffff (64 KiB)
> nomap non-reusable mmode_resv1@40000
> +OF: reserved mem: 0x0000000044040000..0x000000004405ffff (128 KiB)
> nomap non-reusable mmode_resv2@44040000
> +OF: reserved mem: 0x0000000044000000..0x000000004403ffff (256 KiB)
> nomap non-reusable mmode_resv3@44000000
> Zone ranges:
> DMA32 [mem 0x0000000048000000-0x000000007fffffff]
> Normal empty
>
> Reverting commits 00c9a452a235c61f ("of: reserved_mem: Add code to
> dynamically allocate reserved_mem array") and 8a6e02d0c00e7b62 fixes
> the issue.
>
> root@smarc-rzfive:/sys/firmware/devicetree/base/reserved-memory# ls -l
> total 0
> -r--r--r-- 1 root root 4 Oct 29 12:37 #address-cells
> -r--r--r-- 1 root root 4 Oct 29 12:37 #size-cells
> drwxr-xr-x 2 root root 0 Oct 29 12:37 mmode_resv0@30000
> drwxr-xr-x 2 root root 0 Oct 29 12:37 mmode_resv1@40000
> drwxr-xr-x 2 root root 0 Oct 29 12:37 mmode_resv2@44040000
> drwxr-xr-x 2 root root 0 Oct 29 12:37 mmode_resv3@44000000
> -r--r--r-- 1 root root 16 Oct 29 12:37 name
> drwxr-xr-x 2 root root 0 Oct 29 12:37 pma_resv0@58000000
> -r--r--r-- 1 root root 0 Oct 29 12:37 ranges
>
> > diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
> > index 4d528c10df3a..d0dbc8183ac4 100644
> > --- a/drivers/of/fdt.c
> > +++ b/drivers/of/fdt.c
> > @@ -511,8 +511,6 @@ void __init early_init_fdt_scan_reserved_mem(void)
> > break;
> > memblock_reserve(base, size);
> > }
> > -
> > - fdt_init_reserved_mem();
> > }
> >
> > /**
> > @@ -1212,6 +1210,9 @@ void __init unflatten_device_tree(void)
> > {
> > void *fdt = initial_boot_params;
> >
> > + /* Save the statically-placed regions in the reserved_mem array */
> > + fdt_scan_reserved_mem_reg_nodes();
> > +
> > /* Don't use the bootloader provided DTB if ACPI is enabled */
> > if (!acpi_disabled)
> > fdt = NULL;
> > diff --git a/drivers/of/of_private.h b/drivers/of/of_private.h
> > index 04aa2a91f851..29525c0b9939 100644
> > --- a/drivers/of/of_private.h
> > +++ b/drivers/of/of_private.h
> > @@ -9,6 +9,7 @@
> > */
> >
> > #define FDT_ALIGN_SIZE 8
> > +#define MAX_RESERVED_REGIONS 64
> >
> > /**
> > * struct alias_prop - Alias property in 'aliases' node
> > @@ -180,7 +181,7 @@ static inline struct device_node *__of_get_dma_parent(const struct device_node *
> > #endif
> >
> > int fdt_scan_reserved_mem(void);
> > -void fdt_init_reserved_mem(void);
> > +void __init fdt_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 46e1c3fbc769..2011174211f9 100644
> > --- a/drivers/of/of_reserved_mem.c
> > +++ b/drivers/of/of_reserved_mem.c
> > @@ -27,7 +27,6 @@
> >
> > #include "of_private.h"
> >
> > -#define MAX_RESERVED_REGIONS 64
> > static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
> > static int reserved_mem_count;
> >
> > @@ -56,6 +55,7 @@ static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
> > return err;
> > }
> >
> > +static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem);
> > /*
> > * fdt_reserved_mem_save_node() - save fdt node for second pass initialization
> > */
> > @@ -74,6 +74,9 @@ static void __init fdt_reserved_mem_save_node(unsigned long node, const char *un
> > rmem->base = base;
> > rmem->size = size;
> >
> > + /* Call the region specific initialization function */
> > + fdt_init_reserved_mem_node(rmem);
> > +
> > reserved_mem_count++;
> > return;
> > }
> > @@ -106,7 +109,6 @@ 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);
> > @@ -134,10 +136,6 @@ 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;
> > }
> > @@ -165,12 +163,77 @@ static int __init __reserved_mem_check_root(unsigned long node)
> > return 0;
> > }
> >
> > +static void __init __rmem_check_for_overlap(void);
> > +
> > +/**
> > + * fdt_scan_reserved_mem_reg_nodes() - Store info for the "reg" defined
> > + * reserved memory regions.
> > + *
> > + * This function is used to scan through the DT and store the
> > + * information for the reserved memory regions that are defined using
> > + * the "reg" property. The region node number, name, base address, and
> > + * size are all stored in the reserved_mem array by calling the
> > + * fdt_reserved_mem_save_node() function.
> > + */
> > +void __init fdt_scan_reserved_mem_reg_nodes(void)
> > +{
> > + int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
> > + const void *fdt = initial_boot_params;
> > + phys_addr_t base, size;
> > + const __be32 *prop;
> > + int node, child;
> > + int len;
> > +
> > + if (!fdt)
> > + return;
> > +
> > + node = fdt_path_offset(fdt, "/reserved-memory");
> > + if (node < 0) {
> > + pr_info("Reserved memory: No reserved-memory node in the DT\n");
> > + return;
> > + }
> > +
> > + if (__reserved_mem_check_root(node)) {
> > + pr_err("Reserved memory: unsupported node format, ignoring\n");
> > + return;
> > + }
> > +
> > + fdt_for_each_subnode(child, fdt, node) {
> > + const char *uname;
> > +
> > + prop = of_get_flat_dt_prop(child, "reg", &len);
> > + if (!prop)
> > + continue;
> > + if (!of_fdt_device_is_available(fdt, child))
> > + continue;
> > +
> > + uname = fdt_get_name(fdt, child, NULL);
> > + if (len && len % t_len != 0) {
> > + pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
> > + uname);
> > + continue;
> > + }
> > + 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(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);
> > +
> > /*
> > * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
> > */
> > int __init fdt_scan_reserved_mem(void)
> > {
> > int node, child;
> > + int dynamic_nodes_cnt = 0;
> > + int dynamic_nodes[MAX_RESERVED_REGIONS];
> > const void *fdt = initial_boot_params;
> >
> > node = fdt_path_offset(fdt, "/reserved-memory");
> > @@ -192,8 +255,24 @@ int __init fdt_scan_reserved_mem(void)
> > uname = fdt_get_name(fdt, child, NULL);
> >
> > 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);
> > + /*
> > + * Save the nodes for the dynamically-placed regions
> > + * into an array which will be used for allocation right
> > + * after all the statically-placed regions are reserved
> > + * or marked as no-map. This is done to avoid dynamically
> > + * allocating from one of the statically-placed regions.
> > + */
> > + if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL)) {
> > + dynamic_nodes[dynamic_nodes_cnt] = child;
> > + dynamic_nodes_cnt++;
> > + }
> > + }
> > + for (int i = 0; i < dynamic_nodes_cnt; i++) {
> > + const char *uname;
> > +
> > + child = dynamic_nodes[i];
> > + uname = fdt_get_name(fdt, child, NULL);
> > + __reserved_mem_alloc_size(child, uname);
> > }
> > return 0;
> > }
> > @@ -253,8 +332,7 @@ 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)
> > +static 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;
> > @@ -334,9 +412,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
> > return -ENOMEM;
> > }
> >
> > - *res_base = base;
> > - *res_size = size;
> > -
> > + /* Save region in the reserved_mem array */
> > + fdt_reserved_mem_save_node(node, uname, base, size);
> > return 0;
> > }
> >
> > @@ -425,48 +502,37 @@ static void __init __rmem_check_for_overlap(void)
> > }
> >
> > /**
> > - * fdt_init_reserved_mem() - allocate and init all saved reserved memory regions
> > + * fdt_init_reserved_mem_node() - Initialize a reserved memory region
> > + * @rmem: reserved_mem struct of the memory region to be initialized.
> > + *
> > + * This function is used to call the region specific initialization
> > + * function for a reserved memory region.
> > */
> > -void __init fdt_init_reserved_mem(void)
> > +static void __init fdt_init_reserved_mem_node(struct reserved_mem *rmem)
> > {
> > - int i;
> > -
> > - /* check for overlapping reserved regions */
> > - __rmem_check_for_overlap();
> > -
> > - for (i = 0; i < reserved_mem_count; i++) {
> > - struct reserved_mem *rmem = &reserved_mem[i];
> > - unsigned long node = rmem->fdt_node;
> > - int err = 0;
> > - bool nomap;
> > + unsigned long node = rmem->fdt_node;
> > + int err = 0;
> > + bool nomap;
> >
> > - nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
> > + nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
> >
> > - 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");
> > }
> > }
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
