diff mbox series

[V2,2/2] riscv: Add modules to virtual kernel memory layout dump

Message ID 20220714025901.359695-3-xianting.tian@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series Improve vmcoreinfo and memory layout dump | expand

Commit Message

Xianting Tian July 14, 2022, 2:59 a.m. UTC
Modules always live before the kernel, MODULES_END is fixed but
MODULES_VADDR isn't fixed, it depends on the kernel size.
Let's add it to virtual kernel memory layout dump.

As MODULES is only defined for CONFIG_64BIT, so we dump it when
CONFIG_64BIT.

eg,
MODULES_VADDR - MODULES_END
0xffffffff01133000 - 0xffffffff80000000

Signed-off-by: Xianting Tian <xianting.tian@linux.alibaba.com>
---
 arch/riscv/mm/init.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Arnd Bergmann July 14, 2022, 8:24 a.m. UTC | #1
On Thu, Jul 14, 2022 at 4:59 AM Xianting Tian
<xianting.tian@linux.alibaba.com> wrote:
>
> As MODULES is only defined for CONFIG_64BIT, so we dump it when
> CONFIG_64BIT.

Doesn't this cause a compile-time error on 32-bit?

>                 (unsigned long)VMEMMAP_END);
>         print_ml("vmalloc", (unsigned long)VMALLOC_START,
>                 (unsigned long)VMALLOC_END);
> +       if (IS_ENABLED(CONFIG_64BIT))
> +               print_ml("modules", (unsigned long)MODULES_VADDR,
> +                       (unsigned long)MODULES_END);

The IS_ENABLED() check prevents the line from getting executed, but
unlike an #ifdef it still relies on it to be parsable.

         Arnd
Xianting Tian July 14, 2022, 9:17 a.m. UTC | #2
在 2022/7/14 下午4:24, Arnd Bergmann 写道:
> On Thu, Jul 14, 2022 at 4:59 AM Xianting Tian
> <xianting.tian@linux.alibaba.com> wrote:
>> As MODULES is only defined for CONFIG_64BIT, so we dump it when
>> CONFIG_64BIT.
> Doesn't this cause a compile-time error on 32-bit?
I tested, rv32 compile is OK.
>
>>                  (unsigned long)VMEMMAP_END);
>>          print_ml("vmalloc", (unsigned long)VMALLOC_START,
>>                  (unsigned long)VMALLOC_END);
>> +       if (IS_ENABLED(CONFIG_64BIT))
>> +               print_ml("modules", (unsigned long)MODULES_VADDR,
>> +                       (unsigned long)MODULES_END);
> The IS_ENABLED() check prevents the line from getting executed, but
> unlike an #ifdef it still relies on it to be parsable.
Thanks, I will use #ifdef instead of IS_ENABLED
>
>           Arnd
Heiko Stuebner July 14, 2022, 9:46 a.m. UTC | #3
Am Donnerstag, 14. Juli 2022, 11:17:26 CEST schrieb Xianting Tian:
> 
> 在 2022/7/14 下午4:24, Arnd Bergmann 写道:
> > On Thu, Jul 14, 2022 at 4:59 AM Xianting Tian
> > <xianting.tian@linux.alibaba.com> wrote:
> >> As MODULES is only defined for CONFIG_64BIT, so we dump it when
> >> CONFIG_64BIT.
> > Doesn't this cause a compile-time error on 32-bit?
> I tested, rv32 compile is OK.

> >>                  (unsigned long)VMEMMAP_END);
> >>          print_ml("vmalloc", (unsigned long)VMALLOC_START,
> >>                  (unsigned long)VMALLOC_END);
> >> +       if (IS_ENABLED(CONFIG_64BIT))
> >> +               print_ml("modules", (unsigned long)MODULES_VADDR,
> >> +                       (unsigned long)MODULES_END);
> > The IS_ENABLED() check prevents the line from getting executed, but
> > unlike an #ifdef it still relies on it to be parsable.
> Thanks, I will use #ifdef instead of IS_ENABLED

Patch1 also has that issue with the

      if (IS_ENABLED(CONFIG_64BIT)) {
              vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
              vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
      ....


module_alloc falls back to a weak variant [0] which is the same as the riscv variant
only then using VMALLOC_START - VMALLOC_END as range, as the riscv-variant
conditional to CONFIG_64BIT.

I'm wondering if it wouldn't be easier in the long run to just define
MODULES_VADDR, MODULES_END for 32bit to use these values and get rid of
the CONFIG_64BIT ifdef we already have for MODULES (and new ones we are
introducing now).


Heiko


[0] https://elixir.bootlin.com/linux/latest/source/kernel/module.c#L2835
Xianting Tian July 14, 2022, 11:06 a.m. UTC | #4
在 2022/7/14 下午5:46, Heiko Stübner 写道:
> Am Donnerstag, 14. Juli 2022, 11:17:26 CEST schrieb Xianting Tian:
>> 在 2022/7/14 下午4:24, Arnd Bergmann 写道:
>>> On Thu, Jul 14, 2022 at 4:59 AM Xianting Tian
>>> <xianting.tian@linux.alibaba.com> wrote:
>>>> As MODULES is only defined for CONFIG_64BIT, so we dump it when
>>>> CONFIG_64BIT.
>>> Doesn't this cause a compile-time error on 32-bit?
>> I tested, rv32 compile is OK.
>>>>                   (unsigned long)VMEMMAP_END);
>>>>           print_ml("vmalloc", (unsigned long)VMALLOC_START,
>>>>                   (unsigned long)VMALLOC_END);
>>>> +       if (IS_ENABLED(CONFIG_64BIT))
>>>> +               print_ml("modules", (unsigned long)MODULES_VADDR,
>>>> +                       (unsigned long)MODULES_END);
>>> The IS_ENABLED() check prevents the line from getting executed, but
>>> unlike an #ifdef it still relies on it to be parsable.
>> Thanks, I will use #ifdef instead of IS_ENABLED
> Patch1 also has that issue with the
thanks, I will modify it in V3.
>
>        if (IS_ENABLED(CONFIG_64BIT)) {
>                vmcoreinfo_append_str("NUMBER(MODULES_VADDR)=0x%lx\n", MODULES_VADDR);
>                vmcoreinfo_append_str("NUMBER(MODULES_END)=0x%lx\n", MODULES_END);
>        ....
>
>
> module_alloc falls back to a weak variant [0] which is the same as the riscv variant
> only then using VMALLOC_START - VMALLOC_END as range, as the riscv-variant
> conditional to CONFIG_64BIT.

yes, I ever checked, actually before 5.13, it doesn't define MODULES 
area but use VMALLOC for modules,

crash> mod
      MODULE       NAME           BASE           SIZE  OBJECT FILE
ffffffdf8167f280  galcore  ffffffdf81646000  3075841  (not loaded)  
[CONFIG_KALLSYMS]

[    0.000000]      vmalloc : 0xffffffd000000000 - 0xffffffdfffffffff   
(65535 MB)

>
> I'm wondering if it wouldn't be easier in the long run to just define
> MODULES_VADDR, MODULES_END for 32bit to use these values and get rid of
> the CONFIG_64BIT ifdef we already have for MODULES (and new ones we are
> introducing now).
>
>
> Heiko
>
>
> [0] https://elixir.bootlin.com/linux/latest/source/kernel/module.c#L2835
>
>
diff mbox series

Patch

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index d466ec670e1f..bbc9431e9042 100644
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -135,6 +135,9 @@  static void __init print_vm_layout(void)
 		(unsigned long)VMEMMAP_END);
 	print_ml("vmalloc", (unsigned long)VMALLOC_START,
 		(unsigned long)VMALLOC_END);
+	if (IS_ENABLED(CONFIG_64BIT))
+		print_ml("modules", (unsigned long)MODULES_VADDR,
+			(unsigned long)MODULES_END);
 	print_ml("lowmem", (unsigned long)PAGE_OFFSET,
 		(unsigned long)high_memory);
 	if (IS_ENABLED(CONFIG_64BIT)) {