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elfloader: add support for PSCI functions via HVC #239

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elfloader: add support for PSCI functions via HVC
Ivan-Velickovic Oct 23, 2025
80ae668
cmake-tool: support QEMU simulation for SMP
Ivan-Velickovic Oct 23, 2025
8c7a9b4
elfloader: allow HVC PSCI on 32-bit ARM, broken
Ivan-Velickovic Nov 6, 2025
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3 changes: 2 additions & 1 deletion cmake-tool/helpers/simulation.cmake
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Original file line number Diff line number Diff line change
Expand Up @@ -57,6 +57,7 @@ function(GenerateSimulateScript)
set(sim_cpu_opt "")
set(sim_machine "")
set(qemu_sim_extra_args "")
set(sim_smp "${KernelMaxNumNodes}")
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@Ivan-Velickovic Ivan-Velickovic Oct 23, 2025

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This will apply to all simulation targets, but I have only tested ARM.

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@Indanz Indanz Nov 5, 2025

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If the Qemu argument is the same, it should work. If not, we're not worse off than before.

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@Ivan-Velickovic Ivan-Velickovic Nov 6, 2025

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It is the same across all architectures so yes it should be fine.

if(KernelArchX86)
# Try and simulate the correct micro architecture and features
if(KernelX86MicroArchNehalem)
Expand Down Expand Up @@ -202,7 +203,7 @@ function(GenerateSimulateScript)
COMMAND
${CMAKE_COMMAND} -DCONFIGURE_INPUT_FILE=${SIMULATE_SCRIPT}
-DCONFIGURE_OUTPUT_FILE=${sim_path} -DQEMU_SIM_BINARY=${QemuBinaryMachine}
-DQEMU_SIM_CPU=${sim_cpu} -DQEMU_SIM_MACHINE=${sim_machine}
-DQEMU_SIM_CPU=${sim_cpu} -DQEMU_SIM_SMP=${sim_smp} -DQEMU_SIM_MACHINE=${sim_machine}
-DQEMU_SIM_CPU_OPT=${sim_cpu_opt} -DQEMU_SIM_GRAPHIC_OPT=${sim_graphic_opt}
-DQEMU_SIM_SERIAL_OPT=${sim_serial_opt} -DQEMU_SIM_MEM_SIZE_OPT=${QemuMemSize}
-DQEMU_SIM_KERNEL_FILE=${KERNEL_IMAGE_NAME} -DQEMU_SIM_INITRD_FILE=${IMAGE_NAME}
Expand Down
8 changes: 7 additions & 1 deletion cmake-tool/simulate_scripts/simulate.py
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Expand Up @@ -23,6 +23,8 @@ def parse_args():
help="QEMU CPU", default="@QEMU_SIM_CPU@")
parser.add_argument('-o', '--cpu-opt', dest='qemu_sim_cpu_opt', type=str,
help="QEMU CPU Options", default="@QEMU_SIM_CPU_OPT@")
parser.add_argument('--smp', dest='qemu_sim_smp', type=str,
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@Ivan-Velickovic Ivan-Velickovic Oct 23, 2025

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All the other main arguments have a single letter variant, -s is already taken though so I didn't know what to put here.

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@Indanz Indanz Nov 5, 2025

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Maybe -j, like make does?

help="QEMU SMP", default="@QEMU_SIM_SMP@")
parser.add_argument('-g', '--graphic', dest='qemu_sim_graphic_opt', type=str,
help="QEMU Graphic Options", default="@QEMU_SIM_GRAPHIC_OPT@")
parser.add_argument('-s', '--serial', dest='qemu_sim_serial_opt', type=str,
Expand Down Expand Up @@ -79,7 +81,11 @@ def notice(message):

qemu_sim_mem_size_entry = "-m size=" + args.qemu_sim_mem_size

qemu_simulate_command_opts = [args.qemu_sim_binary, qemu_sim_machine_entry, qemu_sim_cpu_entry, args.qemu_sim_graphic_opt,
qemu_sim_smp_entry = ""
if args.qemu_sim_smp:
qemu_sim_smp_entry = "-smp " + args.qemu_sim_smp

qemu_simulate_command_opts = [args.qemu_sim_binary, qemu_sim_machine_entry, qemu_sim_cpu_entry, qemu_sim_smp_entry, args.qemu_sim_graphic_opt,
args.qemu_sim_serial_opt, qemu_sim_mem_size_entry, args.qemu_sim_extra_args, qemu_sim_images_entry,
qemu_gdbserver_command]
qemu_simulate_command = " ".join(qemu_simulate_command_opts)
Expand Down
10 changes: 5 additions & 5 deletions elfloader-tool/include/arch-arm/psci.h
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Expand Up @@ -21,11 +21,11 @@
#define PSCI_METHOD_SMC 1
#define PSCI_METHOD_HVC 2

int psci_version(void);
int psci_cpu_suspend(int power_state, unsigned long entry_point,
int psci_version(unsigned int method);
int psci_cpu_suspend(unsigned int method, int power_state, unsigned long entry_point,
unsigned long context_id);
/* this function does not return when successful */
int psci_cpu_off(void);
int psci_cpu_on(unsigned long target_cpu, unsigned long entry_point,
int psci_cpu_off(unsigned int method);
int psci_cpu_on(unsigned int method, unsigned long target_cpu, unsigned long entry_point,
unsigned long context_id);
int psci_system_reset(void);
int psci_system_reset(unsigned int method);
12 changes: 9 additions & 3 deletions elfloader-tool/src/arch-arm/armv/armv7-a/32/smc.S
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@Ivan-Velickovic Ivan-Velickovic Oct 23, 2025

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I should investigate into HVC on 32-bit ARM.

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@Indanz Indanz Oct 23, 2025

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Seems to be the same as for 64-bit Arm.

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@Ivan-Velickovic Ivan-Velickovic Oct 24, 2025

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I initially tried that but it failed for 32-bit ARM on QEMU. Will have to debug.

Original file line number Diff line number Diff line change
Expand Up @@ -16,12 +16,18 @@ BEGIN_FUNC(smc)
ldmfd sp!, {r3-r11, pc}
END_FUNC(smc)

BEGIN_FUNC(psci_func)
BEGIN_FUNC(psci_smc_func)
.arch_extension sec
stmfd sp!, {r3-r11, lr}
dsb
smc #0
ldmfd sp!, {r3-r11, pc}
END_FUNC(psci_func)

END_FUNC(psci_smc_func)

BEGIN_FUNC(psci_hvc_func)
.arch_extension sec
stmfd sp!, {r3-r11, lr}
dsb
hvc #0
ldmfd sp!, {r3-r11, pc}
END_FUNC(psci_hvc_func)
9 changes: 7 additions & 2 deletions elfloader-tool/src/arch-arm/armv/armv8-a/64/psci_asm.S
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Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,12 @@

.text

BEGIN_FUNC(psci_func)
BEGIN_FUNC(psci_smc_func)
smc #0
ret
END_FUNC(psci_func)
END_FUNC(psci_smc_func)

BEGIN_FUNC(psci_hvc_func)
hvc #0
ret
END_FUNC(psci_hvc_func)
6 changes: 1 addition & 5 deletions elfloader-tool/src/arch-arm/drivers/smp-psci.c
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Expand Up @@ -18,14 +18,10 @@ static int smp_psci_cpu_on(UNUSED struct elfloader_device *dev,
UNUSED struct elfloader_cpu *cpu, UNUSED void *entry, UNUSED void *stack)
{
#if CONFIG_MAX_NUM_NODES > 1
if (cpu->extra_data == PSCI_METHOD_HVC) {
printf("HVC is not supported for PSCI!\n");
return -1;
}
secondary_data.entry = entry;
secondary_data.stack = stack;
dmb();
int ret = psci_cpu_on(cpu->cpu_id, (unsigned long)&secondary_startup, 0);
int ret = psci_cpu_on(cpu->extra_data, cpu->cpu_id, (unsigned long)&secondary_startup, 0);
if (ret != PSCI_SUCCESS) {
printf("Failed to bring up core 0x%x with error %d\n", cpu->cpu_id, ret);
return -1;
Expand Down
41 changes: 29 additions & 12 deletions elfloader-tool/src/arch-arm/psci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -7,6 +7,7 @@
#include <autoconf.h>
#include <elfloader/gen_config.h>
#include <printf.h>
#include <psci.h>

#ifdef CONFIG_ARCH_AARCH64
#define SMC_FID_VER 0x84000000
Expand All @@ -23,40 +24,56 @@
#endif


extern int psci_func(unsigned int id, unsigned long param1,
unsigned long param2, unsigned long param3);
extern int psci_smc_func(unsigned int id, unsigned long param1,
unsigned long param2, unsigned long param3);

int psci_version(void)
extern int psci_hvc_func(unsigned int id, unsigned long param1,
unsigned long param2, unsigned long param3);

int psci_func(unsigned int method, unsigned int id, unsigned long param1,
unsigned long param2, unsigned long param3)
{
if (method == PSCI_METHOD_HVC) {
return psci_hvc_func(id, param1, param2, param3);
} else if (method == PSCI_METHOD_SMC) {
return psci_smc_func(id, param1, param2, param3);
} else {
printf("ERROR: PSCI method %u is unsupported\n", method);
return -1;
}
}

int psci_version(unsigned int method)
{
int ver = psci_func(SMC_FID_VER, 0, 0, 0);
int ver = psci_func(method, SMC_FID_VER, 0, 0, 0);
return ver;
}


int psci_cpu_suspend(int power_state, unsigned long entry_point,
int psci_cpu_suspend(unsigned int method, int power_state, unsigned long entry_point,
unsigned long context_id)
{
int ret = psci_func(SMC_FID_CPU_SUSPEND, power_state, entry_point, context_id);
int ret = psci_func(method, SMC_FID_CPU_SUSPEND, power_state, entry_point, context_id);
return ret;
}

/* this function does not return when successful */
int psci_cpu_off(void)
int psci_cpu_off(unsigned int method)
{
int ret = psci_func(SMC_FID_CPU_OFF, 0, 0, 0);
int ret = psci_func(method, SMC_FID_CPU_OFF, 0, 0, 0);
return ret;
}

int psci_cpu_on(unsigned long target_cpu, unsigned long entry_point,
int psci_cpu_on(unsigned int method, unsigned long target_cpu, unsigned long entry_point,
unsigned long context_id)
{
int ret = psci_func(SMC_FID_CPU_ON, target_cpu, entry_point, context_id);
int ret = psci_func(method, SMC_FID_CPU_ON, target_cpu, entry_point, context_id);
return ret;
}

int psci_system_reset(void)
int psci_system_reset(unsigned int method)
{
int ret = psci_func(SMC_FID_SYSTEM_RESET, 0, 0, 0);
int ret = psci_func(method, SMC_FID_SYSTEM_RESET, 0, 0, 0);
return ret;
}

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