| Message ID | 20160202182657.GC15706@e104818-lin.cambridge.arm.com |
|---|---|
| State | New |
| Headers | show |
On Wed, Feb 03, 2016 at 11:21:12AM +0000, Lorenzo Pieralisi wrote: > On Tue, Feb 02, 2016 at 06:26:58PM +0000, Catalin Marinas wrote: > > On Tue, Jan 26, 2016 at 11:10:38AM +0000, Lorenzo Pieralisi wrote: > > > The SBBR and ACPI specifications allow ACPI based systems that do not > > > implement PSCI (eg systems with no EL3) to boot through the ACPI parking > > > protocol specification[1]. > > > > > > This patch implements the ACPI parking protocol CPU operations, and adds > > > code that eases parsing the parking protocol data structures to the > > > ARM64 SMP initializion carried out at the same time as cpus enumeration. > > > > > > To wake-up the CPUs from the parked state, this patch implements a > > > wakeup IPI for ARM64 (ie arch_send_wakeup_ipi_mask()) that mirrors the > > > ARM one, so that a specific IPI is sent for wake-up purpose in order > > > to distinguish it from other IPI sources. > > > > > > Given the current ACPI MADT parsing API, the patch implements a glue > > > layer that helps passing MADT GICC data structure from SMP initialization > > > code to the parking protocol implementation somewhat overriding the CPU > > > operations interfaces. This to avoid creating a completely trasparent > > > DT/ACPI CPU operations layer that would require creating opaque > > > structure handling for CPUs data (DT represents CPU through DT nodes, ACPI > > > through static MADT table entries), which seems overkill given that ACPI > > > on ARM64 mandates only two booting protocols (PSCI and parking protocol), > > > so there is no need for further protocol additions. > > > > > > Based on the original work by Mark Salter <msalter@redhat.com> > > > > > > [1] https://acpica.org/sites/acpica/files/MP%20Startup%20for%20ARM%20platforms.docx > > > > > > Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> > > > Cc: Will Deacon <will.deacon@arm.com> > > > Cc: Hanjun Guo <hanjun.guo@linaro.org> > > > Cc: Loc Ho <lho@apm.com> > > > Cc: Sudeep Holla <sudeep.holla@arm.com> > > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > > Cc: Mark Rutland <mark.rutland@arm.com> > > > Cc: Mark Salter <msalter@redhat.com> > > > Cc: Al Stone <ahs3@redhat.com> > > > > Applied, with a minor addition just to warn people from not using it in > > other configurations (#ifdef still needed otherwise the > > acpi_parking_protocol_valid symbol is not available; but I prefer uglier > > code than people starting to use this IPI in their firmware): > > It makes sense, we could include asm/acpi.h in smp.c (which is not > included by linux/acpi.h if !CONFIG_ACPI) to pull in the symbol and > remove the ifdef if you think it is cleaner. I don't think it's worth. BTW, the acpi_parking_protocol_valid() definition has an __init annotation while the declaration does not. I removed the __init altogether since I get a section mismatch warning when being called from handle_IPI. -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -767,6 +767,12 @@ void handle_IPI(int ipinr, struct pt_regs *regs) break; #endif + +#ifdef CONFIG_ARM64_ACPI_PARKING_PROTOCOL case IPI_WAKEUP: + WARN_ONCE(!acpi_parking_protocol_valid(cpu), + "CPU%u: Wake-up IPI outside the ACPI parking protocol\n", + cpu); break; +#endif default: