Re: [PATCH V4 13/23] RISC-V: cpufeature: Add ACPI support in riscv_fill_hwcap()

Conor Dooley
2023-04-29T10:31:28Z

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Hey Sunil,

On Tue, Apr 04, 2023 at 11:50:27PM +0530, Sunil V L wrote:

> @@ -103,14 +109,36 @@ void __init riscv_fill_hwcap(void)
>
> bitmap_zero(riscv_isa, RISCV_ISA_EXT_MAX);
>
> - for_each_of_cpu_node(node) {
> + if (!acpi_disabled) {
> + status = acpi_get_table(ACPI_SIG_RHCT, 0, &rhct);
> + if (ACPI_FAILURE(status))
> + return;
> + }
> +
> + for_each_possible_cpu(cpu) {
> unsigned long this_hwcap = 0;
> DECLARE_BITMAP(this_isa, RISCV_ISA_EXT_MAX);
> const char *temp;
>
> - if (of_property_read_string(node, "riscv,isa", &isa)) {
> - pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> - continue;
> + if (acpi_disabled) {
> + node = of_cpu_device_node_get(cpu);
> + if (node) {
> + rc = of_property_read_string(node, "riscv,isa", &isa);
> + of_node_put(node);
> + if (rc) {
> + pr_warn("Unable to find \"riscv,isa\" devicetree entry\n");
> + continue;
> + }
> + } else {
> + pr_warn("Unable to find cpu node\n");
> + continue;

I was poking at this the last few days and went back to look at the ACPI
code again. Is there a reason we don't do early-return here? IOW:

node = of_cpu_device_node_get(cpu);
if (!node) {
pr_warn()
continue;
}

rc = of_property_read_string(node, "riscv,isa", &isa);
of_node_put(node);
if (rc) {
pr_warn();
continue;
}

Cheers,
Conor.

> + }
> + } else {
> + rc = acpi_get_riscv_isa(rhct, cpu, &isa);
> + if (rc < 0) {
> + pr_warn("Unable to get ISA for the hart - %d\n", cpu);
> + continue;
> + }
> }
>
> temp = isa;
> @@ -243,6 +271,9 @@ void __init riscv_fill_hwcap(void)

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