If "capacity-dmips-mhz" is present in a CPU DT node,
topology_parse_cpu_capacity() will fail to allocate memory.
ARM64, with which this code path is shared, does not call
topology_parse_cpu_capacity() until later in boot where memory allocation
is available.

Move init_cpu_topology(), which calls topology_parse_cpu_capacity(), to a
later initialization stage, to match ARM64.

Tested on Qemu platform.

Fixes: 03f11f03dbfe ("RISC-V: Parse cpu topology during boot.")
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>

---
Changes:
v2:
- Update commit description with suggestion from Conor.
- Added Reviewed-by.
- Added Fixes.

History:
[v1]: https://patchwork.kernel.org/project/linux-riscv/patch/20230103035316.3841303-1-leyfoon.tan@starfivetech.com/

Conor also submitted patches in [1] to add "capacity-dmips-mhz" DT
parameter for RISC-V platform:

https://patchwork.kernel.org/project/linux-riscv/cover/20230104180513.1379453-1-conor@kernel.org/
---
 arch/riscv/kernel/smpboot.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 3373df413c88..ddb2afba6d25 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -39,7 +39,6 @@ static DECLARE_COMPLETION(cpu_running);
 
 void __init smp_prepare_boot_cpu(void)
 {
-	init_cpu_topology();
 }
 
 void __init smp_prepare_cpus(unsigned int max_cpus)
@@ -48,6 +47,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	int ret;
 	unsigned int curr_cpuid;
 
+	init_cpu_topology();
+
 	curr_cpuid = smp_processor_id();
 	store_cpu_topology(curr_cpuid);
 	numa_store_cpu_info(curr_cpuid);
-- 
2.25.1

Hello:

This patch was applied to riscv/linux.git (fixes)
by Palmer Dabbelt <palmer@rivosinc.com>:

On Thu, 5 Jan 2023 11:37:05 +0800 you wrote:
> If "capacity-dmips-mhz" is present in a CPU DT node,
> topology_parse_cpu_capacity() will fail to allocate memory.
> ARM64, with which this code path is shared, does not call
> topology_parse_cpu_capacity() until later in boot where memory allocation
> is available.
> 
> Move init_cpu_topology(), which calls topology_parse_cpu_capacity(), to a
> later initialization stage, to match ARM64.
> 
> [...]

Here is the summary with links:
  - [v2] riscv: Move call to init_cpu_topology() to later initialization stage
    https://git.kernel.org/riscv/c/c1d610586946

You are awesome, thank you!
-- 
Deet-doot-dot, I am a bot.
https://korg.docs.kernel.org/patchwork/pwbot.html

On Thu, 5 Jan 2023 11:37:05 +0800, Ley Foon Tan wrote:
> If "capacity-dmips-mhz" is present in a CPU DT node,
> topology_parse_cpu_capacity() will fail to allocate memory.
> ARM64, with which this code path is shared, does not call
> topology_parse_cpu_capacity() until later in boot where memory allocation
> is available.
> 
> Move init_cpu_topology(), which calls topology_parse_cpu_capacity(), to a
> later initialization stage, to match ARM64.
> 
> [...]

Applied, thanks!

[1/1] riscv: Move call to init_cpu_topology() to later initialization stage
      https://git.kernel.org/palmer/c/c1d610586946

Best regards,
-- 
Palmer Dabbelt <palmer@rivosinc.com>

Hi Ley,

On Thu, Jan 5, 2023 at 4:45 AM Ley Foon Tan
<leyfoon.tan@starfivetech.com> wrote:
> If "capacity-dmips-mhz" is present in a CPU DT node,
> topology_parse_cpu_capacity() will fail to allocate memory.
> ARM64, with which this code path is shared, does not call
> topology_parse_cpu_capacity() until later in boot where memory allocation
> is available.
>
> Move init_cpu_topology(), which calls topology_parse_cpu_capacity(), to a
> later initialization stage, to match ARM64.
>
> Tested on Qemu platform.
>
> Fixes: 03f11f03dbfe ("RISC-V: Parse cpu topology during boot.")
> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
> Signed-off-by: Ley Foon Tan <leyfoon.tan@starfivetech.com>
>
> ---
> Changes:
> v2:
> - Update commit description with suggestion from Conor.
> - Added Reviewed-by.
> - Added Fixes.

This also fixes the error message

    Early cacheinfo failed, ret = -12

seen during early boot on all my RV64 platforms.

Fixes: 5944ce092b97caed ("arch_topology: Build cacheinfo from primary CPU")
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

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