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powerpc: Change the doorbell IPI calling convention

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Change the doorbell callers to know about their msgsnd addressing,
rather than have them set a per-cpu target data tag at boot that gets
sent to the cause_ipi functions. The data is only used for doorbell IPI
functions, no other IPI types, so it makes sense to keep that detail
local to doorbell.

Have the platform code understand doorbell IPIs, rather than the
interrupt controller code understand them. Platform code can look at
capabilities it has available and decide which to use.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin
2017-04-13 20:16:21 +10:00
committed by Michael Ellerman
parent 9b7ff0c658
commit b866cc2199
14 changed files with 95 additions and 82 deletions
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58
arch/powerpc/kernel/dbell.c
View File

@@ -20,18 +20,60 @@
#include <asm/kvm_ppc.h>
#ifdef CONFIG_SMP
void doorbell_setup_this_cpu(void)
{
unsigned long tag = mfspr(SPRN_DOORBELL_CPUTAG) & PPC_DBELL_TAG_MASK;
smp_muxed_ipi_set_data(smp_processor_id(), tag);
}
void doorbell_cause_ipi(int cpu, unsigned long data)
/*
* Doorbells must only be used if CPU_FTR_DBELL is available.
* msgsnd is used in HV, and msgsndp is used in !HV.
*
* These should be used by platform code that is aware of restrictions.
* Other arch code should use ->cause_ipi.
*
* doorbell_global_ipi() sends a dbell to any target CPU.
* Must be used only by architectures that address msgsnd target
* by PIR/get_hard_smp_processor_id.
*/
void doorbell_global_ipi(int cpu)
{
u32 tag = get_hard_smp_processor_id(cpu);
kvmppc_set_host_ipi(cpu, 1);
/* Order previous accesses vs. msgsnd, which is treated as a store */
mb();
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, data);
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
}
/*
* doorbell_core_ipi() sends a dbell to a target CPU in the same core.
* Must be used only by architectures that address msgsnd target
* by TIR/cpu_thread_in_core.
*/
void doorbell_core_ipi(int cpu)
{
u32 tag = cpu_thread_in_core(cpu);
kvmppc_set_host_ipi(cpu, 1);
/* Order previous accesses vs. msgsnd, which is treated as a store */
mb();
ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, tag);
}
/*
* Attempt to cause a core doorbell if destination is on the same core.
* Returns 1 on success, 0 on failure.
*/
int doorbell_try_core_ipi(int cpu)
{
int this_cpu = get_cpu();
int ret = 0;
if (cpumask_test_cpu(cpu, cpu_sibling_mask(this_cpu))) {
doorbell_core_ipi(cpu);
ret = 1;
}
put_cpu();
return ret;
}
void doorbell_exception(struct pt_regs *regs)

17
arch/powerpc/kernel/smp.c
View File

@@ -39,6 +39,7 @@
#include <asm/irq.h>
#include <asm/hw_irq.h>
#include <asm/kvm_ppc.h>
#include <asm/dbell.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/prom.h>
@@ -211,17 +212,9 @@ int smp_request_message_ipi(int virq, int msg)
#ifdef CONFIG_PPC_SMP_MUXED_IPI
struct cpu_messages {
long messages; /* current messages */
unsigned long data; /* data for cause ipi */
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct cpu_messages, ipi_message);
void smp_muxed_ipi_set_data(int cpu, unsigned long data)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
info->data = data;
}
void smp_muxed_ipi_set_message(int cpu, int msg)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
@@ -236,14 +229,13 @@ void smp_muxed_ipi_set_message(int cpu, int msg)
void smp_muxed_ipi_message_pass(int cpu, int msg)
{
struct cpu_messages *info = &per_cpu(ipi_message, cpu);
smp_muxed_ipi_set_message(cpu, msg);
/*
* cause_ipi functions are required to include a full barrier
* before doing whatever causes the IPI.
*/
smp_ops->cause_ipi(cpu, info->data);
smp_ops->cause_ipi(cpu);
}
#ifdef __BIG_ENDIAN__
@@ -254,11 +246,12 @@ void smp_muxed_ipi_message_pass(int cpu, int msg)
irqreturn_t smp_ipi_demux(void)
{
struct cpu_messages *info = this_cpu_ptr(&ipi_message);
struct cpu_messages *info;
unsigned long all;
mb(); /* order any irq clear */
info = this_cpu_ptr(&ipi_message);
do {
all = xchg(&info->messages, 0);
#if defined(CONFIG_KVM_XICS) && defined(CONFIG_KVM_BOOK3S_HV_POSSIBLE)