Commit 245a7868 authored by Paul Burton's avatar Paul Burton

MIPS: smp-cps: rework core/VPE initialisation

When hotplug and/or a powered down idle state are supported cases will
arise where a non-zero VPE must be brought online without VPE 0, and it
where multiple VPEs must be onlined simultaneously. This patch prepares
for that by:

  - Splitting struct boot_config into core & VPE boot config structures,
    allocated one per core or VPE respectively. This allows for multiple
    VPEs to be onlined simultaneously without clobbering each others
    configuration.

  - Indicating which VPEs should be online within a core at any given
    time using a bitmap. This allows multiple VPEs to be brought online
    simultaneously and also indicates to VPE 0 whether it should halt
    after starting any non-zero VPEs that should be online within the
    core. For example if all VPEs within a core are offlined via hotplug
    and the user onlines the second VPE within that core:

      1) The core will be powered up.

      2) VPE 0 will run from the BEV (ie. mips_cps_core_entry) to
         initialise the core.

      3) VPE 0 will start VPE 1 because its bit is set in the cores
         bitmap.

      4) VPE 0 will halt itself because its bit is clear in the cores
         bitmap.

  - Moving the core & VPE initialisation to assembly code which does not
    make any use of the stack. This is because if a non-zero VPE is to
    be brought online in a powered down core then when VPE 0 of that
    core runs it may not have a valid stack, and even if it did then
    it's messy to run through parts of generic kernel code on VPE 0
    before starting the correct VPE.
Signed-off-by: default avatarPaul Burton <paul.burton@imgtec.com>
parent d674dd14
......@@ -13,17 +13,23 @@
#ifndef __ASSEMBLY__
struct boot_config {
unsigned int core;
unsigned int vpe;
struct vpe_boot_config {
unsigned long pc;
unsigned long sp;
unsigned long gp;
};
extern struct boot_config mips_cps_bootcfg;
struct core_boot_config {
atomic_t vpe_mask;
struct vpe_boot_config *vpe_config;
};
extern struct core_boot_config *mips_cps_core_bootcfg;
extern void mips_cps_core_entry(void);
extern void mips_cps_core_init(void);
extern struct vpe_boot_config *mips_cps_boot_vpes(void);
#else /* __ASSEMBLY__ */
......
......@@ -487,10 +487,14 @@ void output_kvm_defines(void)
void output_cps_defines(void)
{
COMMENT(" MIPS CPS offsets. ");
OFFSET(BOOTCFG_CORE, boot_config, core);
OFFSET(BOOTCFG_VPE, boot_config, vpe);
OFFSET(BOOTCFG_PC, boot_config, pc);
OFFSET(BOOTCFG_SP, boot_config, sp);
OFFSET(BOOTCFG_GP, boot_config, gp);
OFFSET(COREBOOTCFG_VPEMASK, core_boot_config, vpe_mask);
OFFSET(COREBOOTCFG_VPECONFIG, core_boot_config, vpe_config);
DEFINE(COREBOOTCFG_SIZE, sizeof(struct core_boot_config));
OFFSET(VPEBOOTCFG_PC, vpe_boot_config, pc);
OFFSET(VPEBOOTCFG_SP, vpe_boot_config, sp);
OFFSET(VPEBOOTCFG_GP, vpe_boot_config, gp);
DEFINE(VPEBOOTCFG_SIZE, sizeof(struct vpe_boot_config));
}
#endif
......@@ -14,12 +14,33 @@
#include <asm/asmmacro.h>
#include <asm/cacheops.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#define GCR_CL_COHERENCE_OFS 0x2008
#define GCR_CL_ID_OFS 0x2028
.extern mips_cm_base
.set noreorder
/*
* Set dest to non-zero if the core supports the MT ASE, else zero. If
* MT is not supported then branch to nomt.
*/
.macro has_mt dest, nomt
mfc0 \dest, CP0_CONFIG
bgez \dest, \nomt
mfc0 \dest, CP0_CONFIG, 1
bgez \dest, \nomt
mfc0 \dest, CP0_CONFIG, 2
bgez \dest, \nomt
mfc0 \dest, CP0_CONFIG, 3
andi \dest, \dest, MIPS_CONF3_MT
beqz \dest, \nomt
.endm
.section .text.cps-vec
.balign 0x1000
.set noreorder
LEAF(mips_cps_core_entry)
/*
......@@ -134,21 +155,24 @@ dcache_done:
jr t0
nop
1: /* We're up, cached & coherent */
/*
* We're up, cached & coherent. Perform any further required core-level
* initialisation.
*/
1: jal mips_cps_core_init
nop
/*
* TODO: We should check the VPE number we intended to boot here, and
* if non-zero we should start that VPE and stop this one. For
* the moment this doesn't matter since CPUs are brought up
* sequentially and in order, but once hotplug is implemented
* this will need revisiting.
* Boot any other VPEs within this core that should be online, and
* deactivate this VPE if it should be offline.
*/
jal mips_cps_boot_vpes
nop
/* Off we go! */
la t0, mips_cps_bootcfg
lw t1, BOOTCFG_PC(t0)
lw gp, BOOTCFG_GP(t0)
lw sp, BOOTCFG_SP(t0)
lw t1, VPEBOOTCFG_PC(v0)
lw gp, VPEBOOTCFG_GP(v0)
lw sp, VPEBOOTCFG_SP(v0)
jr t1
nop
END(mips_cps_core_entry)
......@@ -189,3 +213,237 @@ LEAF(excep_ejtag)
jr k0
nop
END(excep_ejtag)
LEAF(mips_cps_core_init)
#ifdef CONFIG_MIPS_MT
/* Check that the core implements the MT ASE */
has_mt t0, 3f
nop
.set push
.set mt
/* Only allow 1 TC per VPE to execute... */
dmt
/* ...and for the moment only 1 VPE */
dvpe
la t1, 1f
jr.hb t1
nop
/* Enter VPE configuration state */
1: mfc0 t0, CP0_MVPCONTROL
ori t0, t0, MVPCONTROL_VPC
mtc0 t0, CP0_MVPCONTROL
/* Retrieve the number of VPEs within the core */
mfc0 t0, CP0_MVPCONF0
srl t0, t0, MVPCONF0_PVPE_SHIFT
andi t0, t0, (MVPCONF0_PVPE >> MVPCONF0_PVPE_SHIFT)
addi t7, t0, 1
/* If there's only 1, we're done */
beqz t0, 2f
nop
/* Loop through each VPE within this core */
li t5, 1
1: /* Operate on the appropriate TC */
mtc0 t5, CP0_VPECONTROL
ehb
/* Bind TC to VPE (1:1 TC:VPE mapping) */
mttc0 t5, CP0_TCBIND
/* Set exclusive TC, non-active, master */
li t0, VPECONF0_MVP
sll t1, t5, VPECONF0_XTC_SHIFT
or t0, t0, t1
mttc0 t0, CP0_VPECONF0
/* Set TC non-active, non-allocatable */
mttc0 zero, CP0_TCSTATUS
/* Set TC halted */
li t0, TCHALT_H
mttc0 t0, CP0_TCHALT
/* Next VPE */
addi t5, t5, 1
slt t0, t5, t7
bnez t0, 1b
nop
/* Leave VPE configuration state */
2: mfc0 t0, CP0_MVPCONTROL
xori t0, t0, MVPCONTROL_VPC
mtc0 t0, CP0_MVPCONTROL
3: .set pop
#endif
jr ra
nop
END(mips_cps_core_init)
LEAF(mips_cps_boot_vpes)
/* Retrieve CM base address */
la t0, mips_cm_base
lw t0, 0(t0)
/* Calculate a pointer to this cores struct core_boot_config */
lw t0, GCR_CL_ID_OFS(t0)
li t1, COREBOOTCFG_SIZE
mul t0, t0, t1
la t1, mips_cps_core_bootcfg
lw t1, 0(t1)
addu t0, t0, t1
/* Calculate this VPEs ID. If the core doesn't support MT use 0 */
has_mt t6, 1f
li t9, 0
/* Find the number of VPEs present in the core */
mfc0 t1, CP0_MVPCONF0
srl t1, t1, MVPCONF0_PVPE_SHIFT
andi t1, t1, MVPCONF0_PVPE >> MVPCONF0_PVPE_SHIFT
addi t1, t1, 1
/* Calculate a mask for the VPE ID from EBase.CPUNum */
clz t1, t1
li t2, 31
subu t1, t2, t1
li t2, 1
sll t1, t2, t1
addiu t1, t1, -1
/* Retrieve the VPE ID from EBase.CPUNum */
mfc0 t9, $15, 1
and t9, t9, t1
1: /* Calculate a pointer to this VPEs struct vpe_boot_config */
li t1, VPEBOOTCFG_SIZE
mul v0, t9, t1
lw t7, COREBOOTCFG_VPECONFIG(t0)
addu v0, v0, t7
#ifdef CONFIG_MIPS_MT
/* If the core doesn't support MT then return */
bnez t6, 1f
nop
jr ra
nop
.set push
.set mt
1: /* Enter VPE configuration state */
dvpe
la t1, 1f
jr.hb t1
nop
1: mfc0 t1, CP0_MVPCONTROL
ori t1, t1, MVPCONTROL_VPC
mtc0 t1, CP0_MVPCONTROL
ehb
/* Loop through each VPE */
lw t6, COREBOOTCFG_VPEMASK(t0)
move t8, t6
li t5, 0
/* Check whether the VPE should be running. If not, skip it */
1: andi t0, t6, 1
beqz t0, 2f
nop
/* Operate on the appropriate TC */
mfc0 t0, CP0_VPECONTROL
ori t0, t0, VPECONTROL_TARGTC
xori t0, t0, VPECONTROL_TARGTC
or t0, t0, t5
mtc0 t0, CP0_VPECONTROL
ehb
/* Skip the VPE if its TC is not halted */
mftc0 t0, CP0_TCHALT
beqz t0, 2f
nop
/* Calculate a pointer to the VPEs struct vpe_boot_config */
li t0, VPEBOOTCFG_SIZE
mul t0, t0, t5
addu t0, t0, t7
/* Set the TC restart PC */
lw t1, VPEBOOTCFG_PC(t0)
mttc0 t1, CP0_TCRESTART
/* Set the TC stack pointer */
lw t1, VPEBOOTCFG_SP(t0)
mttgpr t1, sp
/* Set the TC global pointer */
lw t1, VPEBOOTCFG_GP(t0)
mttgpr t1, gp
/* Copy config from this VPE */
mfc0 t0, CP0_CONFIG
mttc0 t0, CP0_CONFIG
/* Ensure no software interrupts are pending */
mttc0 zero, CP0_CAUSE
mttc0 zero, CP0_STATUS
/* Set TC active, not interrupt exempt */
mftc0 t0, CP0_TCSTATUS
li t1, ~TCSTATUS_IXMT
and t0, t0, t1
ori t0, t0, TCSTATUS_A
mttc0 t0, CP0_TCSTATUS
/* Clear the TC halt bit */
mttc0 zero, CP0_TCHALT
/* Set VPE active */
mftc0 t0, CP0_VPECONF0
ori t0, t0, VPECONF0_VPA
mttc0 t0, CP0_VPECONF0
/* Next VPE */
2: srl t6, t6, 1
addi t5, t5, 1
bnez t6, 1b
nop
/* Leave VPE configuration state */
mfc0 t1, CP0_MVPCONTROL
xori t1, t1, MVPCONTROL_VPC
mtc0 t1, CP0_MVPCONTROL
ehb
evpe
/* Check whether this VPE is meant to be running */
li t0, 1
sll t0, t0, t9
and t0, t0, t8
bnez t0, 2f
nop
/* This VPE should be offline, halt the TC */
li t0, TCHALT_H
mtc0 t0, CP0_TCHALT
la t0, 1f
1: jr.hb t0
nop
2: .set pop
#endif /* CONFIG_MIPS_MT */
/* Return */
jr ra
nop
END(mips_cps_boot_vpes)
......@@ -9,6 +9,8 @@
*/
#include <linux/errno.h>
#include <linux/percpu.h>
#include <linux/spinlock.h>
#include <asm/mips-cm.h>
#include <asm/mips-cpc.h>
......
......@@ -26,98 +26,37 @@
static DECLARE_BITMAP(core_power, NR_CPUS);
struct boot_config mips_cps_bootcfg;
struct core_boot_config *mips_cps_core_bootcfg;
static void init_core(void)
static unsigned core_vpe_count(unsigned core)
{
unsigned int nvpes, t;
u32 mvpconf0, vpeconf0, vpecontrol, tcstatus, tcbind, status;
unsigned cfg;
if (!cpu_has_mipsmt)
return;
/* Enter VPE configuration state */
dvpe();
set_c0_mvpcontrol(MVPCONTROL_VPC);
/* Retrieve the count of VPEs in this core */
mvpconf0 = read_c0_mvpconf0();
nvpes = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
smp_num_siblings = nvpes;
for (t = 1; t < nvpes; t++) {
/* Use a 1:1 mapping of TC index to VPE index */
settc(t);
/* Bind 1 TC to this VPE */
tcbind = read_tc_c0_tcbind();
tcbind &= ~TCBIND_CURVPE;
tcbind |= t << TCBIND_CURVPE_SHIFT;
write_tc_c0_tcbind(tcbind);
/* Set exclusive TC, non-active, master */
vpeconf0 = read_vpe_c0_vpeconf0();
vpeconf0 &= ~(VPECONF0_XTC | VPECONF0_VPA);
vpeconf0 |= t << VPECONF0_XTC_SHIFT;
vpeconf0 |= VPECONF0_MVP;
write_vpe_c0_vpeconf0(vpeconf0);
/* Declare TC non-active, non-allocatable & interrupt exempt */
tcstatus = read_tc_c0_tcstatus();
tcstatus &= ~(TCSTATUS_A | TCSTATUS_DA);
tcstatus |= TCSTATUS_IXMT;
write_tc_c0_tcstatus(tcstatus);
/* Halt the TC */
write_tc_c0_tchalt(TCHALT_H);
/* Allow only 1 TC to execute */
vpecontrol = read_vpe_c0_vpecontrol();
vpecontrol &= ~VPECONTROL_TE;
write_vpe_c0_vpecontrol(vpecontrol);
/* Copy (most of) Status from VPE 0 */
status = read_c0_status();
status &= ~(ST0_IM | ST0_IE | ST0_KSU);
status |= ST0_CU0;
write_vpe_c0_status(status);
/* Copy Config from VPE 0 */
write_vpe_c0_config(read_c0_config());
write_vpe_c0_config7(read_c0_config7());
/* Ensure no software interrupts are pending */
write_vpe_c0_cause(0);
/* Sync Count */
write_vpe_c0_count(read_c0_count());
}
if (!config_enabled(CONFIG_MIPS_MT_SMP) || !cpu_has_mipsmt)
return 1;
/* Leave VPE configuration state */
clear_c0_mvpcontrol(MVPCONTROL_VPC);
write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF);
cfg = read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK;
return (cfg >> CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
}
static void __init cps_smp_setup(void)
{
unsigned int ncores, nvpes, core_vpes;
int c, v;
u32 core_cfg, *entry_code;
u32 *entry_code;
/* Detect & record VPE topology */
ncores = mips_cm_numcores();
pr_info("VPE topology ");
for (c = nvpes = 0; c < ncores; c++) {
if (cpu_has_mipsmt && config_enabled(CONFIG_MIPS_MT_SMP)) {
write_gcr_cl_other(c << CM_GCR_Cx_OTHER_CORENUM_SHF);
core_cfg = read_gcr_co_config();
core_vpes = ((core_cfg & CM_GCR_Cx_CONFIG_PVPE_MSK) >>
CM_GCR_Cx_CONFIG_PVPE_SHF) + 1;
} else {
core_vpes = 1;
}
core_vpes = core_vpe_count(c);
pr_cont("%c%u", c ? ',' : '{', core_vpes);
/* Use the number of VPEs in core 0 for smp_num_siblings */
if (!c)
smp_num_siblings = core_vpes;
for (v = 0; v < min_t(int, core_vpes, NR_CPUS - nvpes); v++) {
cpu_data[nvpes + v].core = c;
#ifdef CONFIG_MIPS_MT_SMP
......@@ -140,12 +79,8 @@ static void __init cps_smp_setup(void)
/* Core 0 is powered up (we're running on it) */
bitmap_set(core_power, 0, 1);
/* Disable MT - we only want to run 1 TC per VPE */
if (cpu_has_mipsmt)
dmt();
/* Initialise core 0 */
init_core();
mips_cps_core_init();
/* Patch the start of mips_cps_core_entry to provide the CM base */
entry_code = (u32 *)&mips_cps_core_entry;
......@@ -157,15 +92,60 @@ static void __init cps_smp_setup(void)
static void __init cps_prepare_cpus(unsigned int max_cpus)
{
unsigned ncores, core_vpes, c;
mips_mt_set_cpuoptions();
/* Allocate core boot configuration structs */
ncores = mips_cm_numcores();
mips_cps_core_bootcfg = kcalloc(ncores, sizeof(*mips_cps_core_bootcfg),
GFP_KERNEL);
if (!mips_cps_core_bootcfg) {
pr_err("Failed to allocate boot config for %u cores\n", ncores);
goto err_out;
}
/* Allocate VPE boot configuration structs */
for (c = 0; c < ncores; c++) {
core_vpes = core_vpe_count(c);
mips_cps_core_bootcfg[c].vpe_config = kcalloc(core_vpes,
sizeof(*mips_cps_core_bootcfg[c].vpe_config),
GFP_KERNEL);
if (!mips_cps_core_bootcfg[c].vpe_config) {
pr_err("Failed to allocate %u VPE boot configs\n",
core_vpes);
goto err_out;
}
}
/* Mark this CPU as booted */
atomic_set(&mips_cps_core_bootcfg[current_cpu_data.core].vpe_mask,
1 << cpu_vpe_id(&current_cpu_data));
return;
err_out:
/* Clean up allocations */
if (mips_cps_core_bootcfg) {
for (c = 0; c < ncores; c++)
kfree(mips_cps_core_bootcfg[c].vpe_config);
kfree(mips_cps_core_bootcfg);
mips_cps_core_bootcfg = NULL;
}
/* Effectively disable SMP by declaring CPUs not present */
for_each_possible_cpu(c) {
if (c == 0)
continue;
set_cpu_present(c, false);
}
}
static void boot_core(struct boot_config *cfg)
static void boot_core(unsigned core)
{
u32 access;
/* Select the appropriate core */
write_gcr_cl_other(cfg->core << CM_GCR_Cx_OTHER_CORENUM_SHF);
write_gcr_cl_other(core << CM_GCR_Cx_OTHER_CORENUM_SHF);
/* Set its reset vector */
write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry));
......@@ -175,15 +155,12 @@ static void boot_core(struct boot_config *cfg)
/* Ensure the core can access the GCRs */
access = read_gcr_access();
access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + cfg->core);
access |= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF + core);
write_gcr_access(access);
/* Copy cfg */
mips_cps_bootcfg = *cfg;
if (mips_cpc_present()) {
/* Select the appropriate core */
write_cpc_cl_other(cfg->core << CPC_Cx_OTHER_CORENUM_SHF);
write_cpc_cl_other(core << CPC_Cx_OTHER_CORENUM_SHF);
/* Reset the core */
write_cpc_co_cmd(CPC_Cx_CMD_RESET);
......@@ -193,77 +170,47 @@ static void boot_core(struct boot_config *cfg)
}
/* The core is now powered up */
bitmap_set(core_power, cfg->core, 1);
bitmap_set(core_power, core, 1);
}
static void boot_vpe(void *info)
static void remote_vpe_boot(void *dummy)
{
struct boot_config *cfg = info;
u32 tcstatus, vpeconf0;
/* Enter VPE configuration state */
dvpe();
set_c0_mvpcontrol(MVPCONTROL_VPC);
settc(cfg->vpe);
/* Set the TC restart PC */
write_tc_c0_tcrestart((unsigned long)&smp_bootstrap);
/* Activate the TC, allow interrupts */
tcstatus = read_tc_c0_tcstatus();
tcstatus &= ~TCSTATUS_IXMT;
tcstatus |= TCSTATUS_A;
write_tc_c0_tcstatus(tcstatus);
/* Clear the TC halt bit */
write_tc_c0_tchalt(0);
/* Activate the VPE */
vpeconf0 = read_vpe_c0_vpeconf0();
vpeconf0 |= VPECONF0_VPA;
write_vpe_c0_vpeconf0(vpeconf0);
/* Set the stack & global pointer registers */
write_tc_gpr_sp(cfg->sp);
write_tc_gpr_gp(cfg->gp);
/* Leave VPE configuration state */
clear_c0_mvpcontrol(MVPCONTROL_VPC);
/* Enable other VPEs to execute */
evpe(EVPE_ENABLE);
mips_cps_boot_vpes();
}
static void cps_boot_secondary(int cpu, struct task_struct *idle)
{
struct boot_config cfg;
unsigned core = cpu_data[cpu].core;
unsigned vpe_id = cpu_vpe_id(&cpu_data[cpu]);
struct core_boot_config *core_cfg = &mips_cps_core_bootcfg[core];
struct vpe_boot_config *vpe_cfg = &core_cfg->vpe_config[vpe_id];
unsigned int remote;
int err;
cfg.core = cpu_data[cpu].core;
cfg.vpe = cpu_vpe_id(&cpu_data[cpu]);
cfg.pc = (unsigned long)&smp_bootstrap;
cfg.sp = __KSTK_TOS(idle);
cfg.gp = (unsigned long)task_thread_info(idle);
vpe_cfg->pc = (unsigned long)&smp_bootstrap;
vpe_cfg->sp = __KSTK_TOS(idle);
vpe_cfg->gp = (unsigned long)task_thread_info(idle);
if (!test_bit(cfg.core, core_power)) {
atomic_or(1 << cpu_vpe_id(&cpu_data[cpu]), &core_cfg->vpe_mask);
if (!test_bit(core, core_power)) {
/* Boot a VPE on a powered down core */
boot_core(&cfg);
boot_core(core);
return;
}
if (cfg.core != current_cpu_data.core) {
if (core != current_cpu_data.core) {
/* Boot a VPE on another powered up core */
for (remote = 0; remote < NR_CPUS; remote++) {
if (cpu_data[remote].core != cfg.core)
if (cpu_data[remote].core != core)
continue;
if (cpu_online(remote))
break;
}
BUG_ON(remote >= NR_CPUS);
err = smp_call_function_single(remote, boot_vpe, &cfg, 1);
err = smp_call_function_single(remote, remote_vpe_boot,
NULL, 1);
if (err)
panic("Failed to call remote CPU\n");
return;
......@@ -272,7 +219,7 @@ static void cps_boot_secondary(int cpu, struct task_struct *idle)
BUG_ON(!cpu_has_mipsmt);
/* Boot a VPE on this core */
boot_vpe(&cfg);
mips_cps_boot_vpes();
}
static void cps_init_secondary(void)
......@@ -281,10 +228,6 @@ static void cps_init_secondary(void)
if (cpu_has_mipsmt)
dmt();
/* TODO: revisit this assumption once hotplug is implemented */
if (cpu_vpe_id(&current_cpu_data) == 0)
init_core();
change_c0_status(ST0_IM, STATUSF_IP3 | STATUSF_IP4 |
STATUSF_IP6 | STATUSF_IP7);
}
......
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