[PATCH V5 08/21] RISC-V: ACPI: Cache and retrieve the RINTC structure

[Conor Dooley]

Hey Sunil,

On Mon, May 08, 2023 at 05:22:24PM +0530, Sunil V L wrote:
> RINTC structures in the MADT provide mapping between the hartid
> and the CPU. This is required many times even at run time like
> cpuinfo. So, instead of parsing the ACPI table every time, cache
> the RINTC structures and provide a function to get the correct
> RINTC structure for a given cpu.
> 
> Signed-off-by: Sunil V L <sunilvl at ventanamicro.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki at intel.com>

From this patch until "RISC-V: Add ACPI initialization in
setup_arch()" (which is 19/21), the series fails to build.

allmodconfig, clang-16:
../arch/riscv/include/asm/acpi.h:22:23: error: unknown type name 'acpi_physical_address'; did you mean 'efi_physical_addr_t'?
../arch/riscv/include/asm/acpi.h:22:51: error: unknown type name 'acpi_size'

rv32_defconfig, clang-16:
arch/riscv/kernel/setup.c:297:7: error: use of undeclared identifier 'acpi_disabled'; did you mean '__cpu_disable'?
arch/riscv/kernel/setup.c:297:7: warning: address of function '__cpu_disable' will always evaluate to 'true' [-Wpointer-bool-conversion]

I ballsed up a toolchain upgrade to gcc-13, so the whole series is
showing build issues on patchwork for the gcc configurations:
https://patchwork.kernel.org/project/linux-riscv/list/?series=745787

However, I suspect that the same patches that fail for clang-16 will
fail for gcc-13 too, once I have fixed that!

Cheers,
Conor.

> ---
>  arch/riscv/include/asm/acpi.h | 10 ++++++++
>  arch/riscv/kernel/acpi.c      | 45 +++++++++++++++++++++++++++++++++++
>  arch/riscv/kernel/setup.c     |  4 ++++
>  3 files changed, 59 insertions(+)
> 
> diff --git a/arch/riscv/include/asm/acpi.h b/arch/riscv/include/asm/acpi.h
> index 9be52b6ffae1..6519529c8bdf 100644
> --- a/arch/riscv/include/asm/acpi.h
> +++ b/arch/riscv/include/asm/acpi.h
> @@ -59,6 +59,16 @@ static inline bool acpi_has_cpu_in_madt(void)
>  
>  static inline void arch_fix_phys_package_id(int num, u32 slot) { }
>  
> +void acpi_init_rintc_map(void);
> +struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu);
> +u32 get_acpi_id_for_cpu(int cpu);
> +#else
> +static inline void acpi_init_rintc_map(void) { }
> +static inline struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
> +{
> +	return NULL;
> +}
> +
>  #endif /* CONFIG_ACPI */
>  
>  #endif /*_ASM_ACPI_H*/
> diff --git a/arch/riscv/kernel/acpi.c b/arch/riscv/kernel/acpi.c
> index 81d448c41714..89e142611c84 100644
> --- a/arch/riscv/kernel/acpi.c
> +++ b/arch/riscv/kernel/acpi.c
> @@ -24,6 +24,51 @@ EXPORT_SYMBOL(acpi_disabled);
>  int acpi_pci_disabled = 1;	/* skip ACPI PCI scan and IRQ initialization */
>  EXPORT_SYMBOL(acpi_pci_disabled);
>  
> +static struct acpi_madt_rintc cpu_madt_rintc[NR_CPUS];
> +
> +static int acpi_parse_madt_rintc(union acpi_subtable_headers *header, const unsigned long end)
> +{
> +	struct acpi_madt_rintc *rintc = (struct acpi_madt_rintc *)header;
> +	int cpuid;
> +
> +	if (!(rintc->flags & ACPI_MADT_ENABLED))
> +		return 0;
> +
> +	cpuid = riscv_hartid_to_cpuid(rintc->hart_id);
> +	/*
> +	 * When CONFIG_SMP is disabled, mapping won't be created for
> +	 * all cpus.
> +	 * CPUs more than num_possible_cpus, will be ignored.
> +	 */
> +	if (cpuid >= 0 && cpuid < num_possible_cpus())
> +		cpu_madt_rintc[cpuid] = *rintc;
> +
> +	return 0;
> +}
> +
> +/*
> + * Instead of parsing (and freeing) the ACPI table, cache
> + * the RINTC structures since they are frequently used
> + * like in  cpuinfo.
> + */
> +void __init acpi_init_rintc_map(void)
> +{
> +	if (acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_madt_rintc, 0) <= 0) {
> +		pr_err("No valid RINTC entries exist\n");
> +		BUG();
> +	}
> +}
> +
> +struct acpi_madt_rintc *acpi_cpu_get_madt_rintc(int cpu)
> +{
> +	return &cpu_madt_rintc[cpu];
> +}
> +
> +u32 get_acpi_id_for_cpu(int cpu)
> +{
> +	return acpi_cpu_get_madt_rintc(cpu)->uid;
> +}
> +
>  /*
>   * __acpi_map_table() will be called before paging_init(), so early_ioremap()
>   * or early_memremap() should be called here to for ACPI table mapping.
> diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> index 9fb839074e16..a44c7fcde12f 100644
> --- a/arch/riscv/kernel/setup.c
> +++ b/arch/riscv/kernel/setup.c
> @@ -21,6 +21,7 @@
>  #include <linux/efi.h>
>  #include <linux/crash_dump.h>
>  
> +#include <asm/acpi.h>
>  #include <asm/alternative.h>
>  #include <asm/cacheflush.h>
>  #include <asm/cpu_ops.h>
> @@ -293,6 +294,9 @@ void __init setup_arch(char **cmdline_p)
>  	setup_smp();
>  #endif
>  
> +	if (!acpi_disabled)
> +		acpi_init_rintc_map();
> +
>  	riscv_init_cbo_blocksizes();
>  	riscv_fill_hwcap();
>  	apply_boot_alternatives();
> -- 
> 2.34.1
> 
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