[kvm-unit-tests PATCH v8 22/35] powerpc: add SMP and IPI support

Nicholas Piggin
2024-04-05T08:37:20Z

powerpc SMP support is very primitive and does not set up a first-class
runtime environment for secondary CPUs.

This reworks SMP support, and provides a complete C and harness
environment for the secondaries, including interrupt handling, as well
as IPI support.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
lib/powerpc/asm/processor.h | 23 +++
lib/powerpc/asm/reg.h | 1 +
lib/powerpc/asm/setup.h | 2 -
lib/powerpc/asm/smp.h | 46 +++--
lib/powerpc/io.c | 15 +-
lib/powerpc/processor.c | 7 +-
lib/powerpc/setup.c | 90 +++++++---
lib/powerpc/smp.c | 282 +++++++++++++++++++++++++----
lib/ppc64/asm-offsets.c | 7 +
lib/ppc64/asm/atomic.h | 6 +
lib/ppc64/asm/barrier.h | 3 +
lib/ppc64/asm/opal.h | 7 +
powerpc/Makefile.common | 1 +
powerpc/cstart64.S | 49 ++++-
powerpc/selftest.c | 4 +-
powerpc/smp.c | 348 ++++++++++++++++++++++++++++++++++++
powerpc/tm.c | 4 +-
powerpc/unittests.cfg | 8 +
18 files changed, 818 insertions(+), 85 deletions(-)
create mode 100644 lib/ppc64/asm/atomic.h
create mode 100644 powerpc/smp.c

diff --git a/lib/powerpc/asm/processor.h b/lib/powerpc/asm/processor.h
index eed37d1f4..a3859b5d4 100644
--- a/lib/powerpc/asm/processor.h
+++ b/lib/powerpc/asm/processor.h
@@ -16,6 +16,7 @@ extern bool cpu_has_siar;
extern bool cpu_has_heai;
extern bool cpu_has_prefix;
extern bool cpu_has_sc_lev;
+extern bool cpu_has_pause_short;

static inline uint64_t mfspr(int nr)
{
@@ -45,6 +46,28 @@ static inline void mtmsr(uint64_t msr)
asm volatile ("mtmsrd %[msr]" :: [msr] "r" (msr) : "memory");
}

+static inline void local_irq_enable(void)
+{
+ unsigned long msr;
+
+ asm volatile(
+" mfmsr %0 \n \
+ ori %0,%0,%1 \n \
+ mtmsrd %0,1 "
+ : "=r"(msr) : "i"(MSR_EE): "memory");
+}
+
+static inline void local_irq_disable(void)
+{
+ unsigned long msr;
+
+ asm volatile(
+" mfmsr %0 \n \
+ andc %0,%0,%1 \n \
+ mtmsrd %0,1 "
+ : "=r"(msr) : "r"(MSR_EE): "memory");
+}
+
/*
* This returns true on PowerNV / OPAL machines which run in hypervisor
* mode. False on pseries / PAPR machines that run in guest mode.
diff --git a/lib/powerpc/asm/reg.h b/lib/powerpc/asm/reg.h
index d6097f48f..d2ca964c4 100644
--- a/lib/powerpc/asm/reg.h
+++ b/lib/powerpc/asm/reg.h
@@ -19,6 +19,7 @@
#define SPR_SPRG1 0x111
#define SPR_SPRG2 0x112
#define SPR_SPRG3 0x113
+#define SPR_TBU40 0x11e
#define SPR_PVR 0x11f
#define PVR_VERSION_MASK UL(0xffff0000)
#define PVR_VER_970 UL(0x00390000)
diff --git a/lib/powerpc/asm/setup.h b/lib/powerpc/asm/setup.h
index cc7cf5e25..9ca318ce6 100644
--- a/lib/powerpc/asm/setup.h
+++ b/lib/powerpc/asm/setup.h
@@ -8,8 +8,6 @@
#include <libcflat.h>

#define NR_CPUS 8 /* arbitrarily set for now */
-extern u32 cpus[NR_CPUS];
-extern int nr_cpus;

extern uint64_t tb_hz;

diff --git a/lib/powerpc/asm/smp.h b/lib/powerpc/asm/smp.h
index 21940b4bc..4519e5436 100644
--- a/lib/powerpc/asm/smp.h
+++ b/lib/powerpc/asm/smp.h
@@ -2,21 +2,45 @@
#define _ASMPOWERPC_SMP_H_

#include <libcflat.h>
+#include <asm/processor.h>

-extern int nr_threads;
+typedef void (*secondary_entry_fn)(int cpu_id);

-struct start_threads {
- int nr_threads;
- int nr_started;
-};
+struct cpu {
+ unsigned long server_no;
+ unsigned long stack;
+ unsigned long exception_stack;
+ secondary_entry_fn entry;
+} __attribute__((packed)); /* used by asm */

-typedef void (*secondary_entry_fn)(void);
+extern int nr_cpus_present;
+extern int nr_cpus_online;
+extern struct cpu cpus[];

-extern void halt(void);
+register struct cpu *__current_cpu asm("r13");
+static inline struct cpu *current_cpu(void)
+{
+ return __current_cpu;
+}

-extern int start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3);
-extern struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry,
- uint32_t r3);
-extern bool start_all_cpus(secondary_entry_fn entry, uint32_t r3);
+static inline int smp_processor_id(void)
+{
+ return current_cpu()->server_no;
+}
+
+void cpu_init(struct cpu *cpu, int cpu_id);
+
+extern void halt(int cpu_id);
+
+extern bool start_all_cpus(secondary_entry_fn entry);
+extern void stop_all_cpus(void);
+
+struct pt_regs;
+void register_ipi(void (*fn)(struct pt_regs *, void *), void *data);
+void unregister_ipi(void);
+void cpu_init_ipis(void);
+void local_ipi_enable(void);
+void local_ipi_disable(void);
+void send_ipi(int cpu_id);

#endif /* _ASMPOWERPC_SMP_H_ */
diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c
index ab7bb843c..cb7f2f050 100644
--- a/lib/powerpc/io.c
+++ b/lib/powerpc/io.c
@@ -10,6 +10,7 @@
#include <asm/rtas.h>
#include <asm/setup.h>
#include <asm/processor.h>
+#include <asm/atomic.h>
#include "io.h"

static struct spinlock print_lock;
@@ -55,13 +56,17 @@ extern void halt(int code);

void exit(int code)
{
+ static int exited = 0;
+
// FIXME: change this print-exit/rtas-poweroff to chr_testdev_exit(),
// maybe by plugging chr-testdev into a spapr-vty.
- printf("\nEXIT: STATUS=%d\n", ((code) << 1) | 1);
- if (machine_is_powernv())
- opal_power_off();
- else
- rtas_power_off();
+ if (atomic_fetch_inc(&exited) == 0) {
+ printf("\nEXIT: STATUS=%d\n", ((code) << 1) | 1);
+ if (machine_is_powernv())
+ opal_power_off();
+ else
+ rtas_power_off();
+ }
halt(code);
__builtin_unreachable();
}
diff --git a/lib/powerpc/processor.c b/lib/powerpc/processor.c
index 1b4bb0d61..a6ce3c905 100644
--- a/lib/powerpc/processor.c
+++ b/lib/powerpc/processor.c
@@ -13,6 +13,7 @@
#include <asm/barrier.h>
#include <asm/hcall.h>
#include <asm/handlers.h>
+#include <asm/smp.h>

static struct {
void (*func)(struct pt_regs *, void *data);
@@ -44,6 +45,8 @@ void do_handle_exception(struct pt_regs *regs)
{
unsigned char v;

+ __current_cpu = (struct cpu *)mfspr(SPR_SPRG0);
+
v = regs->trap >> 5;

if (v < 128 && handlers[v].func) {
@@ -51,8 +54,8 @@ void do_handle_exception(struct pt_regs *regs)
return;
}

- printf("Unhandled cpu exception %#lx at NIA:0x%016lx MSR:0x%016lx\n",
- regs->trap, regs->nip, regs->msr);
+ printf("Unhandled CPU%d exception %#lx at NIA:0x%016lx MSR:0x%016lx\n",
+ smp_processor_id(), regs->trap, regs->nip, regs->msr);
dump_frame_stack((void *)regs->nip, (void *)regs->gpr[1]);
abort();
}
diff --git a/lib/powerpc/setup.c b/lib/powerpc/setup.c
index 496af40f8..16f009152 100644
--- a/lib/powerpc/setup.c
+++ b/lib/powerpc/setup.c
@@ -2,7 +2,7 @@
* Initialize machine setup information and I/O.
*
* After running setup() unit tests may query how many cpus they have
- * (nr_cpus), how much memory they have (PHYSICAL_END - PHYSICAL_START),
+ * (nr_cpus_present), how much memory they have (PHYSICAL_END - PHYSICAL_START),
* may use dynamic memory allocation (malloc, etc.), printf, and exit.
* Finally, argc and argv are also ready to be passed to main().
*
@@ -17,6 +17,7 @@
#include <alloc_phys.h>
#include <argv.h>
#include <asm/setup.h>
+#include <asm/smp.h>
#include <asm/page.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
@@ -28,8 +29,8 @@ extern unsigned long stacktop;
char *initrd;
u32 initrd_size;

-u32 cpus[NR_CPUS] = { [0 ... NR_CPUS-1] = (~0U) };
-int nr_cpus;
+u32 cpu_to_hwid[NR_CPUS] = { [0 ... NR_CPUS-1] = (~0U) };
+int nr_cpus_present;
uint64_t tb_hz;

struct mem_region mem_regions[NR_MEM_REGIONS];
@@ -44,13 +45,32 @@ struct cpu_set_params {

static void cpu_set(int fdtnode, u64 regval, void *info)
{
+ const struct fdt_property *prop;
+ u32 *threads;
static bool read_common_info = false;
struct cpu_set_params *params = info;
- int cpu = nr_cpus++;
-
- assert_msg(cpu < NR_CPUS, "Number cpus exceeds maximum supported (%d).", NR_CPUS);
-
- cpus[cpu] = regval;
+ int nr_threads;
+ int len, i;
+
+ /* Get the id array of threads on this node */
+ prop = fdt_get_property(dt_fdt(), fdtnode,
+ "ibm,ppc-interrupt-server#s", &len);
+ assert(prop);
+
+ nr_threads = len >> 2; /* Divide by 4 since 4 bytes per thread */
+ threads = (u32 *)prop->data; /* Array of valid ids */
+
+ for (i = 0; i < nr_threads; i++) {
+ if (nr_cpus_present >= NR_CPUS) {
+ static bool warned = false;
+ if (!warned) {
+ printf("Warning: Number of present CPUs exceeds maximum supported (%d).\n", NR_CPUS);
+ warned = true;
+ }
+ break;
+ }
+ cpu_to_hwid[nr_cpus_present++] = fdt32_to_cpu(threads[i]);
+ }

if (!read_common_info) {
const struct fdt_property *prop;
@@ -84,32 +104,25 @@ bool cpu_has_siar;
bool cpu_has_heai;
bool cpu_has_prefix;
bool cpu_has_sc_lev; /* sc interrupt has LEV field in SRR1 */
+bool cpu_has_pause_short;

-static void cpu_init(void)
+static void cpu_init_params(void)
{
struct cpu_set_params params;
int ret;

- nr_cpus = 0;
+ nr_cpus_present = 0;
ret = dt_for_each_cpu_node(cpu_set, &params);
assert(ret == 0);
__icache_bytes = params.icache_bytes;
__dcache_bytes = params.dcache_bytes;
tb_hz = params.tb_hz;

- /* Interrupt Endianness */
- if (machine_is_pseries()) {
-#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
- hcall(H_SET_MODE, 1, 4, 0, 0);
-#else
- hcall(H_SET_MODE, 0, 4, 0, 0);
-#endif
- }
-
switch (mfspr(SPR_PVR) & PVR_VERSION_MASK) {
case PVR_VER_POWER10:
cpu_has_prefix = true;
cpu_has_sc_lev = true;
+ cpu_has_pause_short = true;
case PVR_VER_POWER9:
case PVR_VER_POWER8E:
case PVR_VER_POWER8NVL:
@@ -175,19 +188,37 @@ static void mem_init(phys_addr_t freemem_start)
#define EXCEPTION_STACK_SIZE SZ_64K

static char boot_exception_stack[EXCEPTION_STACK_SIZE];
+struct cpu cpus[NR_CPUS];
+
+void cpu_init(struct cpu *cpu, int cpu_id)
+{
+ cpu->server_no = cpu_id;
+
+ cpu->stack = (unsigned long)memalign(SZ_4K, SZ_64K);
+ cpu->stack += SZ_64K - 64;
+ cpu->exception_stack = (unsigned long)memalign(SZ_4K, SZ_64K);
+ cpu->exception_stack += SZ_64K - 64;
+}

void setup(const void *fdt)
{
void *freemem = &stacktop;
const char *bootargs, *tmp;
+ struct cpu *cpu;
u32 fdt_size;
int ret;

cpu_has_hv = !!(mfmsr() & (1ULL << MSR_HV_BIT));

- /* set exception stack address for this CPU (in SPGR0) */
- asm volatile ("mtsprg0 %[addr]" ::
- [addr] "r" (boot_exception_stack));
+ memset(cpus, 0xff, sizeof(cpus));
+
+ cpu = &cpus[0];
+ cpu->server_no = fdt_boot_cpuid_phys(fdt);
+ cpu->exception_stack = (unsigned long)boot_exception_stack;
+ cpu->exception_stack += SZ_64K - 64;
+
+ mtspr(SPR_SPRG0, (unsigned long)cpu);
+ __current_cpu = cpu;

enable_mcheck();

@@ -230,8 +261,19 @@ void setup(const void *fdt)

assert(STACK_INT_FRAME_SIZE % 16 == 0);

- /* call init functions */
- cpu_init();
+ /* set parameters from dt */
+ cpu_init_params();
+
+ /* Interrupt Endianness */
+ if (machine_is_pseries()) {
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+ hcall(H_SET_MODE, 1, 4, 0, 0);
+#else
+ hcall(H_SET_MODE, 0, 4, 0, 0);
+#endif
+ }
+
+ cpu_init_ipis();

/* cpu_init must be called before mem_init */
mem_init(PAGE_ALIGN((unsigned long)freemem));
diff --git a/lib/powerpc/smp.c b/lib/powerpc/smp.c
index 3e211eba8..a3bf85d44 100644
--- a/lib/powerpc/smp.c
+++ b/lib/powerpc/smp.c
@@ -6,58 +6,253 @@
* This work is licensed under the terms of the GNU LGPL, version 2.
*/

+#include <alloc.h>
#include <devicetree.h>
+#include <asm/atomic.h>
+#include <asm/barrier.h>
+#include <asm/processor.h>
#include <asm/time.h>
#include <asm/setup.h>
+#include <asm/opal.h>
+#include <asm/hcall.h>
#include <asm/rtas.h>
#include <asm/smp.h>

-int nr_threads;
-
struct secondary_entry_data {
secondary_entry_fn entry;
- uint64_t r3;
- int nr_started;
};

+int nr_cpus_online = 1;
+
+static void stop_self(int cpu_id)
+{
+ if (machine_is_powernv()) {
+ if (opal_call(OPAL_RETURN_CPU, 0, 0, 0) != OPAL_SUCCESS) {
+ printf("OPAL_RETURN_CPU failed\n");
+ }
+ } else {
+ rtas_stop_self();
+ }
+
+ printf("failed to stop cpu %d\n", cpu_id);
+ assert(0);
+}
+
+void main_secondary(struct cpu *cpu);
+void main_secondary(struct cpu *cpu)
+{
+ mtspr(SPR_SPRG0, (unsigned long)cpu);
+ __current_cpu = cpu;
+
+ enable_mcheck();
+
+ cpu_init_ipis();
+
+ atomic_fetch_inc(&nr_cpus_online);
+
+ cpu->entry(cpu->server_no);
+
+ mb();
+ atomic_fetch_dec(&nr_cpus_online);
+
+ stop_self(cpu->server_no);
+}
+
+enum OpalThreadStatus {
+ OPAL_THREAD_INACTIVE = 0x0,
+ OPAL_THREAD_STARTED = 0x1,
+ OPAL_THREAD_UNAVAILABLE = 0x2 /* opal-v3 */
+};
+
+#define H_EOI 0x64
+#define H_CPPR 0x68
+#define H_IPI 0x6c
+#define H_XIRR 0x74
+
+static void (*ipi_fn)(struct pt_regs *regs, void *data);
+
+static void dbell_handler(struct pt_regs *regs, void *data)
+{
+ /* sync */
+ ipi_fn(regs, data);
+}
+
+static void extint_handler(struct pt_regs *regs, void *data)
+{
+ int32_t xirr;
+ int32_t xisr;
+ int64_t rc;
+
+ asm volatile("mr r3,%1 ; sc 1 ; mr %0,r4" : "=r"(xirr) : "r"(H_XIRR));
+ xisr = xirr & 0xffffff;
+
+ if (xisr == 2) { /* IPI */
+ rc = hcall(H_IPI, smp_processor_id(), 0xff);
+ assert(rc == H_SUCCESS);
+ }
+
+ xirr |= (5 << 24);
+ rc = hcall(H_EOI, xirr);
+ assert(rc == H_SUCCESS);
+
+ /* lower IPI */
+ ipi_fn(regs, data);
+}
+
+void cpu_init_ipis(void)
+{
+ if (machine_is_powernv()) {
+ /* skiboot can leave some messages set */
+ unsigned long rb = (5 << (63-36));
+ asm volatile("msgclr %0" :: "r"(rb) : "memory");
+ }
+}
+
+void local_ipi_enable(void)
+{
+ if (machine_is_pseries()) {
+ hcall(H_CPPR, 5);
+ }
+}
+
+void local_ipi_disable(void)
+{
+ if (machine_is_pseries()) {
+ hcall(H_CPPR, 0);
+ }
+}
+
+void register_ipi(void (*fn)(struct pt_regs *, void *), void *data)
+{
+ ipi_fn = fn;
+ if (machine_is_powernv()) {
+ handle_exception(0xe80, &dbell_handler, data);
+ } else {
+ handle_exception(0x500, &extint_handler, data);
+ }
+}
+
+void unregister_ipi(void)
+{
+ if (machine_is_powernv()) {
+ handle_exception(0xe80, NULL, NULL);
+ } else {
+ handle_exception(0x500, NULL, NULL);
+ }
+}
+
+void send_ipi(int cpu_id)
+{
+ if (machine_is_powernv()) {
+ unsigned long rb = (5 << (63-36)) | cpu_id;
+ asm volatile("lwsync" ::: "memory");
+ asm volatile("msgsnd %0" :: "r"(rb) : "memory");
+ } else {
+ hcall(H_IPI, cpu_id, 4);
+ }
+}
+
+static int nr_started = 1;
+
+extern void start_secondary(uint64_t server_no); /* asm entry point */
+
+static bool cpu_is_running(int cpu_id)
+{
+ if (machine_is_powernv()) {
+ int64_t ret;
+ uint8_t status;
+
+ ret = opal_call(OPAL_QUERY_CPU_STATUS, cpu_id, (unsigned long)&status, 0);
+ if (ret != OPAL_SUCCESS) {
+ printf("OPAL_QUERY_CPU_STATUS failed for cpu %d\n", cpu_id);
+ return false;
+ }
+ return (status != OPAL_THREAD_INACTIVE);
+ } else {
+ uint32_t query_token;
+ int outputs[1], ret;
+
+ ret = rtas_token("query-cpu-stopped-state", &query_token);
+ if (ret != 0) {
+ printf("rtas token query-cpu-stopped-state failed\n");
+ return false;
+ }
+
+ ret = rtas_call(query_token, 1, 2, outputs, cpu_id);
+ if (ret) {
+ printf("query-cpu-stopped-state failed for cpu %d\n", cpu_id);
+ return ret;
+ }
+ if (outputs[0]) /* cpu not in stopped state */
+ return true;
+ return false;
+ }
+}
+
/*
* Start stopped thread cpu_id at entry
* Returns: <0 on failure to start stopped cpu
* 0 on success
* >0 on cpu not in stopped state
*/
-int start_thread(int cpu_id, secondary_entry_fn entry, uint32_t r3)
+static int start_thread(int cpu_id, secondary_entry_fn entry)
{
- uint32_t query_token, start_token;
- int outputs[1], ret;
+ struct cpu *cpu;
+ uint64_t tb;

- ret = rtas_token("query-cpu-stopped-state", &query_token);
- assert(ret == 0);
- ret = rtas_token("start-cpu", &start_token);
- assert(ret == 0);
+ if (nr_started >= NR_CPUS) {
+ /* Reached limit */
+ return -1;
+ }
+
+ if (cpu_id == smp_processor_id()) {
+ /* Boot CPU already started */
+ return -1;
+ }

- ret = rtas_call(query_token, 1, 2, outputs, cpu_id);
- if (ret) {
- printf("query-cpu-stopped-state failed for cpu %d\n", cpu_id);
- } else if (!outputs[0]) { /* cpu in stopped state */
- ret = rtas_call(start_token, 3, 1, NULL, cpu_id, entry, r3);
- if (ret)
+ tb = get_tb();
+ while (cpu_is_running(cpu_id)) {
+ if (get_tb() - tb > 3*tb_hz) {
+ printf("Unable to start running CPU:%d\n", cpu_id);
+ return 1;
+ }
+ }
+
+ cpu = &cpus[nr_started];
+ nr_started++;
+
+ cpu_init(cpu, cpu_id);
+ cpu->entry = entry;
+
+ if (machine_is_powernv()) {
+ if (opal_call(OPAL_START_CPU, cpu_id, (unsigned long)start_secondary, 0) != OPAL_SUCCESS) {
printf("failed to start cpu %d\n", cpu_id);
- } else { /* cpu not in stopped state */
- ret = outputs[0];
+ return -1;
+ }
+ } else {
+ uint32_t start_token;
+ int ret;
+
+ ret = rtas_token("start-cpu", &start_token);
+ assert(ret == 0);
+
+ ret = rtas_call(start_token, 3, 1, NULL, cpu_id, start_secondary, cpu_id);
+ if (ret) {
+ printf("failed to start cpu %d\n", cpu_id);
+ return ret;
+ }
}

- return ret;
+ return 0;
}

/*
* Start all stopped threads (vcpus) on cpu_node
* Returns: Number of stopped cpus which were successfully started
*/
-struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry,
- uint32_t r3)
+static void start_core(int cpu_node, secondary_entry_fn entry)
{
- int len, i, nr_threads, nr_started = 0;
+ int len, i, nr_threads;
const struct fdt_property *prop;
u32 *threads;

@@ -67,23 +262,18 @@ struct start_threads start_cpu(int cpu_node, secondary_entry_fn entry,
assert(prop);

nr_threads = len >> 2; /* Divide by 4 since 4 bytes per thread */
- threads = (u32 *)prop->data; /* Array of valid ids */

- for (i = 0; i < nr_threads; i++) {
- if (!start_thread(fdt32_to_cpu(threads[i]), entry, r3))
- nr_started++;
- }
+ threads = (u32 *)prop->data; /* Array of valid ids */

- return (struct start_threads) { nr_threads, nr_started };
+ for (i = 0; i < nr_threads; i++)
+ start_thread(fdt32_to_cpu(threads[i]), entry);
}

static void start_each_secondary(int fdtnode, u64 regval __unused, void *info)
{
struct secondary_entry_data *datap = info;
- struct start_threads ret = start_cpu(fdtnode, datap->entry, datap->r3);

- nr_threads += ret.nr_threads;
- datap->nr_started += ret.nr_started;
+ start_core(fdtnode, datap->entry);
}

/*
@@ -92,14 +282,34 @@ static void start_each_secondary(int fdtnode, u64 regval __unused, void *info)
* Returns: TRUE on success
* FALSE on failure
*/
-bool start_all_cpus(secondary_entry_fn entry, uint32_t r3)
+bool start_all_cpus(secondary_entry_fn entry)
{
- struct secondary_entry_data data = { entry, r3, 0 };
+ struct secondary_entry_data data = { entry };
+ uint64_t tb;
int ret;

+ assert(nr_cpus_online == 1);
+ assert(nr_started == 1);
ret = dt_for_each_cpu_node(start_each_secondary, &data);
assert(ret == 0);
+ assert(nr_started == nr_cpus_present);

- /* We expect that we come in with one thread already started */
- return data.nr_started == nr_threads - 1;
+ tb = get_tb();
+ while (nr_cpus_online < nr_cpus_present) {
+ if (get_tb() - tb > 3*tb_hz) {
+ printf("failed to start all secondaries\n");
+ assert(0);
+ }
+ cpu_relax();
+ }
+
+ return 1;
+}
+
+void stop_all_cpus(void)
+{
+ while (nr_cpus_online > 1)
+ cpu_relax();
+ mb();
+ nr_started = 1;
}
diff --git a/lib/ppc64/asm-offsets.c b/lib/ppc64/asm-offsets.c
index 7843a20b4..0ac2c9a75 100644
--- a/lib/ppc64/asm-offsets.c
+++ b/lib/ppc64/asm-offsets.c
@@ -6,6 +6,8 @@
#include <libcflat.h>
#include <kbuild.h>
#include <asm/ptrace.h>
+#include <asm/setup.h>
+#include <asm/smp.h>

int main(void)
{
@@ -50,5 +52,10 @@ int main(void)
DEFINE(_XER, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, xer));
DEFINE(_CCR, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, ccr));
DEFINE(_TRAP, STACK_FRAME_OVERHEAD+offsetof(struct pt_regs, trap));
+
+ DEFINE(SIZEOF_STRUCT_CPU, sizeof(struct cpu));
+ DEFINE(EXCEPTION_STACK, offsetof(struct cpu, exception_stack));
+ DEFINE(MAX_CPUS, NR_CPUS);
+
return 0;
}
diff --git a/lib/ppc64/asm/atomic.h b/lib/ppc64/asm/atomic.h
new file mode 100644
index 000000000..0f461b9ce
--- /dev/null
+++ b/lib/ppc64/asm/atomic.h
@@ -0,0 +1,6 @@
+#ifndef _POWERPC_ATOMIC_H_
+#define _POWERPC_ATOMIC_H_
+
+#include "asm-generic/atomic.h"
+
+#endif /* _POWERPC_ATOMIC_H_ */
diff --git a/lib/ppc64/asm/barrier.h b/lib/ppc64/asm/barrier.h
index 76f6efa78..475434b6a 100644
--- a/lib/ppc64/asm/barrier.h
+++ b/lib/ppc64/asm/barrier.h
@@ -1,6 +1,9 @@
#ifndef _ASMPPC64_BARRIER_H_
#define _ASMPPC64_BARRIER_H_

+#define cpu_relax() asm volatile("or 1,1,1 ; or 2,2,2" ::: "memory")
+#define pause_short() asm volatile(".long 0x7c40003c" ::: "memory")
+
#define mb() asm volatile("sync":::"memory")
#define rmb() asm volatile("sync":::"memory")
#define wmb() asm volatile("sync":::"memory")
diff --git a/lib/ppc64/asm/opal.h b/lib/ppc64/asm/opal.h
index de64e2c8d..6c3e9ffe2 100644
--- a/lib/ppc64/asm/opal.h
+++ b/lib/ppc64/asm/opal.h
@@ -2,14 +2,21 @@
#ifndef _ASMPPC64_OPAL_H_
#define _ASMPPC64_OPAL_H_

+#include <stdint.h>
+
#define OPAL_SUCCESS 0

#define OPAL_CONSOLE_WRITE 1
#define OPAL_CONSOLE_READ 2
#define OPAL_CEC_POWER_DOWN 5
#define OPAL_POLL_EVENTS 10
+#define OPAL_START_CPU 41
+#define OPAL_QUERY_CPU_STATUS 42
+#define OPAL_RETURN_CPU 69
#define OPAL_REINIT_CPUS 70
# define OPAL_REINIT_CPUS_HILE_BE (1 << 0)
# define OPAL_REINIT_CPUS_HILE_LE (1 << 1)

+int64_t opal_call(int64_t token, int64_t arg1, int64_t arg2, int64_t arg3);
+
#endif
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 68165fc25..744dfc1f7 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -12,6 +12,7 @@ tests-common = \
$(TEST_DIR)/rtas.elf \
$(TEST_DIR)/emulator.elf \
$(TEST_DIR)/tm.elf \
+ $(TEST_DIR)/smp.elf \
$(TEST_DIR)/sprs.elf \
$(TEST_DIR)/interrupts.elf

diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index 405cb0561..8c4da65bc 100644
--- a/powerpc/cstart64.S
+++ b/powerpc/cstart64.S
@@ -125,6 +125,49 @@ start:
bl exit
b halt

+/*
+ * start_secondary is the secondary entry point. r3 contains the cpu id
+ */
+.globl start_secondary
+start_secondary:
+ FIXUP_ENDIAN
+ /* Switch to 64-bit mode */
+ mfmsr r1
+ li r2,1
+ sldi r2,r2,MSR_SF_BIT
+ or r1,r1,r2
+ mtmsrd r1
+
+ bl 0f
+0: mflr r31
+ subi r31, r31, 0b - start /* QEMU's kernel load address */
+
+ ld r2, (p_toc - start)(r31)
+
+ LOAD_REG_ADDR(r9, cpus)
+ li r8,0
+ li r7,0
+1: ldx r6,r9,r7
+ cmpd r6,r3
+ beq 2f
+ addi r7,r7,SIZEOF_STRUCT_CPU
+ addi r8,r8,1
+ cmpdi r8,MAX_CPUS
+ bne 1b
+ b .
+
+2: add r3,r9,r7
+ ld r1,8(r3)
+
+ /* Zero backpointers in initial stack frame so backtrace() stops */
+ li r0,0
+ std r0,0(r1)
+ std r0,16(r1)
+
+ bl main_secondary
+ bl exit
+ b halt
+
.align 3
p_stack: .llong stackptr
p_toc: .llong tocptr
@@ -257,7 +300,8 @@ do_handle_exception_return:
. = \vec

mtsprg1 r1 /* save r1 */
- mfsprg0 r1 /* get exception stack address */
+ mfsprg0 r1 /* get struct cpu address */
+ ld r1,EXCEPTION_STACK(r1) /* get exception stack address */
subi r1,r1, INT_FRAME_SIZE

/* save r0 and ctr to call generic handler */
@@ -273,7 +317,8 @@ do_handle_exception_return:
. = \vec

mtsprg1 r1 /* save r1 */
- mfsprg0 r1 /* get exception stack address */
+ mfsprg0 r1 /* get struct cpu address */
+ ld r1,EXCEPTION_STACK(r1) /* get exception stack address */
subi r1,r1, INT_FRAME_SIZE

/* save r0 and ctr to call generic handler */
diff --git a/powerpc/selftest.c b/powerpc/selftest.c
index 7acff7104..8d1a2c767 100644
--- a/powerpc/selftest.c
+++ b/powerpc/selftest.c
@@ -8,6 +8,7 @@
#include <libcflat.h>
#include <util.h>
#include <asm/setup.h>
+#include <asm/smp.h>

static void check_setup(int argc, char **argv)
{
@@ -34,7 +35,8 @@ static void check_setup(int argc, char **argv)

} else if (strcmp(argv[i], "smp") == 0) {

- report(nr_cpus == (int)val, "nr_cpus = %d", nr_cpus);
+ report(nr_cpus_present == (int)val,
+ "nr_cpus_present = %d", nr_cpus_present);
++nr_tests;
}

diff --git a/powerpc/smp.c b/powerpc/smp.c
new file mode 100644
index 000000000..644cf1c75
--- /dev/null
+++ b/powerpc/smp.c
@@ -0,0 +1,348 @@
+/* SPDX-License-Identifier: LGPL-2.0-only */
+/*
+ * SMP and IPI Tests
+ *
+ * Copyright 2024 Nicholas Piggin, IBM Corp.
+ */
+#include <libcflat.h>
+#include <asm/atomic.h>
+#include <asm/barrier.h>
+#include <asm/processor.h>
+#include <asm/time.h>
+#include <asm/smp.h>
+#include <asm/setup.h>
+#include <asm/ppc_asm.h>
+#include <devicetree.h>
+
+static volatile bool start_test_running = true;
+static volatile int nr_cpus_started;
+
+static void start_fn(int cpu_id)
+{
+ atomic_fetch_inc(&nr_cpus_started);
+ while (start_test_running)
+ cpu_relax();
+ atomic_fetch_dec(&nr_cpus_started);
+}
+
+static void test_start_cpus(int argc, char **argv)
+{
+ uint64_t tb;
+
+ if (argc > 2)
+ report_abort("Unsupported argument: '%s'", argv[2]);
+
+ nr_cpus_started = 1;
+ if (!start_all_cpus(start_fn))
+ report_abort("Failed to start secondary cpus");
+
+ tb = get_tb();
+ while (nr_cpus_started < nr_cpus_present) {
+ cpu_relax();
+ if (get_tb() - tb > tb_hz * 5)
+ report_abort("Failed to start all secondaries");
+ }
+
+ if (nr_cpus_started != nr_cpus_online)
+ report_abort("Started CPUs does not match online");
+
+ barrier();
+ start_test_running = false;
+ barrier();
+
+ tb = get_tb();
+ while (nr_cpus_started > 1) {
+ cpu_relax();
+ if (get_tb() - tb > tb_hz * 5)
+ report_abort("Failed to stop all secondaries");
+ }
+
+ stop_all_cpus();
+
+ report(true, "start cpus");
+}
+
+static volatile int nr_cpus_ipi = 0;
+
+static void ipi_handler(struct pt_regs *regs, void *data)
+{
+ atomic_fetch_inc(&nr_cpus_ipi);
+}
+
+static volatile bool ipi_test_running = true;
+
+static void ipi_fn(int cpu_id)
+{
+ local_ipi_enable();
+
+ mtspr(SPR_DEC, 0x7fffffff);
+ local_irq_enable();
+ while (ipi_test_running)
+ cpu_relax();
+ local_irq_disable();
+
+ local_ipi_disable();
+}
+
+static void test_ipi_cpus(int argc, char **argv)
+{
+ uint64_t tb;
+ int i;
+
+ if (argc > 2)
+ report_abort("Unsupported argument: '%s'", argv[2]);
+
+ if (nr_cpus_present < 2) {
+ report_skip("Requires SMP (2 or more CPUs)");
+ return;
+ }
+
+ register_ipi(ipi_handler, NULL);
+
+ if (!start_all_cpus(ipi_fn))
+ report_abort("Failed to start secondary cpus");
+
+ for (i = 1; i < nr_cpus_online; i++)
+ send_ipi(cpus[i].server_no);
+
+ tb = get_tb();
+ while (nr_cpus_ipi < nr_cpus_online - 1) {
+ cpu_relax();
+ if (get_tb() - tb > tb_hz * 5)
+ report_abort("Secondaries failed to respond to IPIs");
+ }
+
+ send_ipi(cpus[1].server_no);
+
+ tb = get_tb();
+ while (nr_cpus_ipi < nr_cpus_online) {
+ cpu_relax();
+ if (get_tb() - tb > tb_hz * 5)
+ report_abort("Secondaries failed to respond to IPIs");
+ }
+
+ ipi_test_running = false;
+
+ stop_all_cpus();
+
+ assert(nr_cpus_ipi == nr_cpus_present);
+
+ unregister_ipi();
+
+ report(true, "IPI cpus");
+}
+
+static uint64_t time;
+static bool time_went_backward;
+
+static void check_and_record_time(void)
+{
+ uint64_t tb;
+ uint64_t t;
+ uint64_t old;
+
+ t = time;
+again:
+ barrier();
+ tb = get_tb();
+ asm volatile("1: ldarx %0,0,%1 ; cmpd %0,%2 ; bne 2f ; stdcx. %3,0,%1 ; bne- 1b; 2:" : "=&r"(old) : "r"(&time), "r"(t), "r"(tb) : "memory", "cr0");
+ assert(tb >= t);
+ if (old != t) {
+ t = old;
+ goto again;
+ }
+ if (old > tb)
+ time_went_backward = true;
+}
+
+static void update_time(int64_t tb_offset)
+{
+ uint64_t new_tb;
+
+ new_tb = get_tb() + tb_offset;
+ mtspr(SPR_TBU40, new_tb);
+ if ((get_tb() & 0xFFFFFF) < (new_tb & 0xFFFFFF)) {
+ new_tb += 0x1000000;
+ mtspr(SPR_TBU40, new_tb);
+ }
+}
+
+static void time_sync_fn(int cpu_id)
+{
+ uint64_t start = get_tb();
+
+ while (!time_went_backward && get_tb() - start < tb_hz*2) {
+ check_and_record_time();
+ cpu_relax();
+ }
+
+ while (!time_went_backward && get_tb() - start < tb_hz*2) {
+ check_and_record_time();
+ udelay(1);
+ }
+
+ if (machine_is_powernv()) {
+ while (!time_went_backward && get_tb() - start < tb_hz*2) {
+ check_and_record_time();
+ update_time(0x1234000000);
+ cpu_relax();
+ update_time(-0x1234000000);
+ }
+ }
+}
+
+static void test_time_sync(int argc, char **argv)
+{
+ if (argc > 2)
+ report_abort("Unsupported argument: '%s'", argv[2]);
+
+ if (nr_cpus_present < 2) {
+ report_skip("Requires SMP (2 or more CPUs)");
+ return;
+ }
+
+ time_went_backward = false;
+
+ if (!start_all_cpus(time_sync_fn))
+ report_abort("Failed to start secondary cpus");
+
+ time_sync_fn(-1);
+
+ stop_all_cpus();
+
+ report(!time_went_backward, "time sync");
+}
+
+static volatile bool relax_test_running = true;
+
+static int relax_loop_count[NR_CPUS];
+
+static void relax_fn(int cpu_id)
+{
+ volatile int i = 0;
+
+ while (relax_test_running) {
+ cpu_relax();
+ i++;
+ }
+
+ relax_loop_count[cpu_id] = i;
+}
+
+#define ITERS 1000000
+
+static void test_relax(int argc, char **argv)
+{
+ volatile int i;
+ int count;
+
+ if (argc > 2)
+ report_abort("Unsupported argument: '%s'", argv[2]);
+
+ if (nr_cpus_present < 2) {
+ report_skip("Requires SMP (2 or more CPUs)");
+ return;
+ }
+
+ if (!start_all_cpus(relax_fn))
+ report_abort("Failed to start secondary cpus");
+
+ for (i = 0; i < ITERS; i++)
+ ;
+
+ relax_test_running = false;
+
+ stop_all_cpus();
+
+ count = 0;
+ for (i = 0; i < NR_CPUS; i++)
+ count += relax_loop_count[i];
+ if (count == 0)
+ count = 1;
+
+ report(true, "busy-loops on CPU:%d vs cpu_relax-loops on others %ld%%", smp_processor_id(), (long)ITERS * 100 / count);
+}
+
+static volatile bool pause_test_running = true;
+
+static int pause_loop_count[NR_CPUS];
+
+static void pause_fn(int cpu_id)
+{
+ volatile int i = 0;
+
+ while (pause_test_running) {
+ pause_short();
+ i++;
+ }
+
+ pause_loop_count[cpu_id] = i;
+}
+
+#define ITERS 1000000
+
+static void test_pause(int argc, char **argv)
+{
+ volatile int i;
+ int count;
+
+ if (argc > 2)
+ report_abort("Unsupported argument: '%s'", argv[2]);
+
+ if (!cpu_has_pause_short)
+ return;
+
+ if (nr_cpus_present < 2) {
+ report_skip("Requires SMP (2 or more CPUs)");
+ return;
+ }
+
+ if (!start_all_cpus(pause_fn))
+ report_abort("Failed to start secondary cpus");
+
+ for (i = 0; i < ITERS; i++)
+ ;
+
+ pause_test_running = false;
+
+ stop_all_cpus();
+
+ count = 0;
+ for (i = 0; i < NR_CPUS; i++)
+ count += pause_loop_count[i];
+
+ report(true, "busy-loops on CPU:%d vs pause_short-loops on others %ld%%", smp_processor_id(), (long)ITERS * 100 / count);
+}
+
+struct {
+ const char *name;
+ void (*func)(int argc, char **argv);
+} hctests[] = {
+ { "start_cpus", test_start_cpus },
+ { "ipi_cpus", test_ipi_cpus },
+ { "time_sync", test_time_sync },
+ { "cpu_relax", test_relax },
+ { "pause", test_pause },
+ { NULL, NULL }
+};
+
+int main(int argc, char **argv)
+{
+ bool all;
+ int i;
+
+ all = argc == 1 || !strcmp(argv[1], "all");
+
+ report_prefix_push("smp");
+
+ for (i = 0; hctests[i].name != NULL; i++) {
+ if (all || strcmp(argv[1], hctests[i].name) == 0) {
+ report_prefix_push(hctests[i].name);
+ hctests[i].func(argc, argv);
+ report_prefix_pop();
+ }
+ }
+
+ report_prefix_pop();
+ return report_summary();
+}
diff --git a/powerpc/tm.c b/powerpc/tm.c
index 6b1ceeb6e..efbcf1f12 100644
--- a/powerpc/tm.c
+++ b/powerpc/tm.c
@@ -89,7 +89,7 @@ static void test_h_cede_tm(int argc, char **argv)
if (argc > 2)
report_abort("Unsupported argument: '%s'", argv[2]);

- if (!start_all_cpus(halt, 0))
+ if (!start_all_cpus(halt))
report_abort("Failed to start secondary cpus");

if (!enable_tm())
@@ -133,7 +133,7 @@ int main(int argc, char **argv)
report_skip("TM is not available");
goto done;
}
- report(cpus_with_tm == nr_cpus,
+ report(cpus_with_tm == nr_cpus_present,
"TM available in all 'ibm,pa-features' properties");

all = argc == 1 || !strcmp(argv[1], "all");
diff --git a/powerpc/unittests.cfg b/powerpc/unittests.cfg
index 9fdc86b66..ddce409a8 100644
--- a/powerpc/unittests.cfg
+++ b/powerpc/unittests.cfg
@@ -74,6 +74,14 @@ file = emulator.elf
[interrupts]
file = interrupts.elf

+[smp]
+file = smp.elf
+smp = 2
+
+[smp-smt]
+file = smp.elf
+smp = 8,threads=4
+
[h_cede_tm]
file = tm.elf
machine = pseries
--
2.43.0