[PATCH] RISC-V: Add kernel image sections to the resource tree
Atish Patra
atishp at atishpatra.org
Fri Dec 18 18:52:06 EST 2020
On Thu, Nov 5, 2020 at 10:37 AM Palmer Dabbelt <palmer at dabbelt.com> wrote:
>
> On Mon, 12 Oct 2020 07:24:10 PDT (-0700), mick at ics.forth.gr wrote:
> > This patch (previously part of my kexec/kdump series) populates
> > /proc/iomem with the various sections of the kernel image. We need
> > this for kexec-tools to be able to prepare the crashkernel image
> > for kdump to work. Since resource tree initialization is not
> > related to memory initialization I added the code to kernel/setup.c
> > and removed the original code (derived from the arm64 tree) from
> > mm/init.c.
> >
> > Signed-off-by: Nick Kossifidis <mick at ics.forth.gr>
> > ---
> > arch/riscv/kernel/setup.c | 160 ++++++++++++++++++++++++++++++++++++++
> > arch/riscv/mm/init.c | 27 -------
> > 2 files changed, 160 insertions(+), 27 deletions(-)
> >
> > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> > index 2c6dd3293..450f0142f 100644
> > --- a/arch/riscv/kernel/setup.c
> > +++ b/arch/riscv/kernel/setup.c
> > @@ -4,6 +4,8 @@
> > * Chen Liqin <liqin.chen at sunplusct.com>
> > * Lennox Wu <lennox.wu at sunplusct.com>
> > * Copyright (C) 2012 Regents of the University of California
> > + * Copyright (C) 2020 FORTH-ICS/CARV
> > + * Nick Kossifidis <mick at ics.forth.gr>
> > */
> >
> > #include <linux/init.h>
> > @@ -48,6 +50,163 @@ atomic_t hart_lottery __section(.sdata);
> > unsigned long boot_cpu_hartid;
> > static DEFINE_PER_CPU(struct cpu, cpu_devices);
> >
> > +/*
> > + * Place kernel memory regions on the resource tree so that
> > + * kexec-tools can retrieve them from /proc/iomem. While there
> > + * also add "System RAM" regions for compatibility with other
> > + * archs, and the rest of the known regions for completeness.
> > + */
> > +static struct resource code_res = { .name = "Kernel code", };
> > +static struct resource data_res = { .name = "Kernel data", };
> > +static struct resource rodata_res = { .name = "Kernel rodata", };
> > +static struct resource bss_res = { .name = "Kernel bss", };
> > +
> > +static int __init add_resource(struct resource *parent,
> > + struct resource *res)
> > +{
> > + int ret = 0;
> > +
> > + ret = insert_resource(parent, res);
> > + if (ret < 0) {
> > + pr_err("Failed to add a %s resource at %llx\n",
> > + res->name, (unsigned long long) res->start);
> > + return ret;
> > + }
> > +
> > + return 1;
> > +}
> > +
> > +static int __init add_kernel_resources(struct resource *res)
> > +{
> > + int ret = 0;
> > +
> > + /*
> > + * The memory region of the kernel image is continuous and
> > + * was reserved on setup_bootmem, find it here and register
> > + * it as a resource, then register the various segments of
> > + * the image as child nodes
> > + */
> > + if (!(res->start <= code_res.start && res->end >= data_res.end))
> > + return 0;
> > +
> > + res->name = "Kernel image";
> > + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +
> > + /*
> > + * We removed a part of this region on setup_bootmem so
> > + * we need to expand the resource for the bss to fit in.
> > + */
> > + res->end = bss_res.end;
> > +
> > + ret = add_resource(&iomem_resource, res);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = add_resource(res, &code_res);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = add_resource(res, &rodata_res);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = add_resource(res, &data_res);
> > + if (ret < 0)
> > + return ret;
> > +
> > + ret = add_resource(res, &bss_res);
> > +
> > + return ret;
> > +}
> > +
> > +static void __init init_resources(void)
> > +{
> > + struct memblock_region *region = NULL;
> > + struct resource *res = NULL;
> > + int ret = 0;
> > +
> > + code_res.start = __pa_symbol(_text);
> > + code_res.end = __pa_symbol(_etext) - 1;
> > + code_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +
> > + rodata_res.start = __pa_symbol(__start_rodata);
> > + rodata_res.end = __pa_symbol(__end_rodata) - 1;
> > + rodata_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +
> > + data_res.start = __pa_symbol(_data);
> > + data_res.end = __pa_symbol(_edata) - 1;
> > + data_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +
> > + bss_res.start = __pa_symbol(__bss_start);
> > + bss_res.end = __pa_symbol(__bss_stop) - 1;
> > + bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > +
> > + /*
> > + * Start by adding the reserved regions, if they overlap
> > + * with /memory regions, insert_resource later on will take
> > + * care of it.
> > + */
> > + for_each_memblock(reserved, region) {
> > + res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
Is there a specific reason to invoke memblock_alloc while iterating
reserved regions ?
memblock_alloc also adds calls memblock_reserve. So we are modifying
the reserved region entries
while iterating it. It resulted in below warning for rv32.
[ 0.000000] ------------[ cut here ]------------
[ 0.000000] WARNING: CPU: 0 PID: 0 at kernel/resource.c:795
__insert_resource+0x8e/0xd0
[ 0.000000] Modules linked in:
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted
5.10.0-00022-ge20097fb37e2-dirty #549
[ 0.000000] epc: c00125c2 ra : c001262c sp : c1c01f50
[ 0.000000] gp : c1d456e0 tp : c1c0a980 t0 : ffffcf20
[ 0.000000] t1 : 00000000 t2 : 00000000 s0 : c1c01f60
[ 0.000000] s1 : ffffcf00 a0 : ffffff00 a1 : c1c0c0c4
[ 0.000000] a2 : 80c12b15 a3 : 80402000 a4 : 80402000
[ 0.000000] a5 : c1c0c0c4 a6 : 80c12b15 a7 : f5faf600
[ 0.000000] s2 : c1c0c0c4 s3 : c1c0e000 s4 : c1009a80
[ 0.000000] s5 : c1c0c000 s6 : c1d48000 s7 : c1613b4c
[ 0.000000] s8 : 00000fff s9 : 80000200 s10: c1613b40
[ 0.000000] s11: 00000000 t3 : c1d4a000 t4 : ffffffff
[ 0.000000] t5 : c1008e38 t6 : 00000001
[ 0.000000] status: 00000100 badaddr: 00000000 cause: 00000003
[ 0.000000] irq event stamp: 0
[ 0.000000] hardirqs last enabled at (0): [<00000000>] 0x0
[ 0.000000] hardirqs last disabled at (0): [<00000000>] 0x0
[ 0.000000] softirqs last enabled at (0): [<00000000>] 0x0
[ 0.000000] softirqs last disabled at (0): [<00000000>] 0x0
[ 0.000000] random: get_random_bytes called from __warn+0xd8/0x11e
with crng_init=0
[ 0.000000] ---[ end trace 0000000000000000 ]---
[ 0.000000] Failed to add a Kernel code resource at 80402000
Here is the fix that works:
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -127,7 +127,9 @@ static void __init init_resources(void)
{
struct memblock_region *region = NULL;
struct resource *res = NULL;
- int ret = 0;
+ int ret = 0, i = 0;
+ int num_mem_res;
+ struct resource *mem_res;
code_res.start = __pa_symbol(_text);
code_res.end = __pa_symbol(_etext) - 1;
@@ -145,16 +147,17 @@ static void __init init_resources(void)
bss_res.end = __pa_symbol(__bss_stop) - 1;
bss_res.flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
+ num_mem_res = memblock.memory.cnt + memblock.reserved.cnt;
+ mem_res = memblock_alloc(num_mem_res * sizeof(*mem_res),
SMP_CACHE_BYTES);
+ if (!mem_res)
+ panic("%s: Failed to allocate %zu bytes\n", __func__,
num_mem_res * sizeof(*mem_res));
/*
* Start by adding the reserved regions, if they overlap
* with /memory regions, insert_resource later on will take
* care of it.
*/
for_each_reserved_mem_region(region) {
- res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
- if (!res)
- panic("%s: Failed to allocate %zu bytes\n", __func__,
- sizeof(struct resource));
+ res = &mem_res[i++];
res->name = "Reserved";
res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
@@ -181,11 +184,8 @@ static void __init init_resources(void)
/* Add /memory regions to the resource tree */
for_each_mem_region(region) {
- res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
- if (!res)
- panic("%s: Failed to allocate %zu bytes\n", __func__,
- sizeof(struct resource));
+ res = &mem_res[i++];
If this looks okay to you, I will send the patch.
> > + if (!res)
> > + panic("%s: Failed to allocate %zu bytes\n", __func__,
> > + sizeof(struct resource));
> > +
> > + res->name = "Reserved";
> > + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> > + res->start = __pfn_to_phys(memblock_region_reserved_base_pfn(region));
> > + res->end = __pfn_to_phys(memblock_region_reserved_end_pfn(region)) - 1;
> > +
> > + ret = add_kernel_resources(res);
> > + if (ret < 0)
> > + goto error;
> > + else if (ret)
> > + continue;
> > +
> > + /*
> > + * Ignore any other reserved regions within
> > + * system memory.
> > + */
> > + if (memblock_is_memory(res->start))
> > + continue;
> > +
Shouldn't we free the res in this case ? The allocated memblock is
useless as it is not going to be added
to the resource tree.
> > + ret = add_resource(&iomem_resource, res);
> > + if (ret < 0)
> > + goto error;
> > + }
> > +
> > + /* Add /memory regions to the resource tree */
> > + for_each_memblock(memory, region) {
> > + res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
> > + if (!res)
> > + panic("%s: Failed to allocate %zu bytes\n", __func__,
> > + sizeof(struct resource));
> > +
> > + if (unlikely(memblock_is_nomap(region))) {
> > + res->name = "Reserved";
> > + res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
> > + } else {
> > + res->name = "System RAM";
> > + res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > + }
> > +
> > + res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
> > + res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
> > +
> > + ret = add_resource(&iomem_resource, res);
> > + if (ret < 0)
> > + goto error;
> > + }
> > +
> > + return;
> > +
> > + error:
> > + memblock_free((phys_addr_t) res, sizeof(struct resource));
> > + /* Better an empty resource tree than an inconsistent one */
> > + release_child_resources(&iomem_resource);
> > +}
> > +
> > +
> > void __init parse_dtb(void)
> > {
> > if (early_init_dt_scan(dtb_early_va))
> > @@ -73,6 +232,7 @@ void __init setup_arch(char **cmdline_p)
> >
> > setup_bootmem();
> > paging_init();
> > + init_resources();
> > #if IS_ENABLED(CONFIG_BUILTIN_DTB)
> > unflatten_and_copy_device_tree();
> > #else
> > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > index f750e012d..05d6cf0c2 100644
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@ -541,39 +541,12 @@ void mark_rodata_ro(void)
> > }
> > #endif
> >
> > -static void __init resource_init(void)
> > -{
> > - struct memblock_region *region;
> > -
> > - for_each_memblock(memory, region) {
> > - struct resource *res;
> > -
> > - res = memblock_alloc(sizeof(struct resource), SMP_CACHE_BYTES);
> > - if (!res)
> > - panic("%s: Failed to allocate %zu bytes\n", __func__,
> > - sizeof(struct resource));
> > -
> > - if (memblock_is_nomap(region)) {
> > - res->name = "reserved";
> > - res->flags = IORESOURCE_MEM;
> > - } else {
> > - res->name = "System RAM";
> > - res->flags = IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY;
> > - }
> > - res->start = __pfn_to_phys(memblock_region_memory_base_pfn(region));
> > - res->end = __pfn_to_phys(memblock_region_memory_end_pfn(region)) - 1;
> > -
> > - request_resource(&iomem_resource, res);
> > - }
> > -}
> > -
> > void __init paging_init(void)
> > {
> > setup_vm_final();
> > sparse_init();
> > setup_zero_page();
> > zone_sizes_init();
> > - resource_init();
> > }
> >
> > #ifdef CONFIG_SPARSEMEM_VMEMMAP
>
> Thanks, this is on for-next. I had to fix up a few things, LMK if I screwed
> anything up.
>
> _______________________________________________
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--
Regards,
Atish
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