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hw/arm/boot: Don't write secondary boot stub if using PSCI

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If we're using PSCI emulation to start secondary CPUs, there is no
point in writing the "secondary boot" stub code, because it will
never be used -- secondary CPUs start powered-off, and when powered
on are set to begin execution at the address specified by the guest's
power-on PSCI call, not at the stub.

Move the call to the hook that writes the secondary boot stub code so
that we can do it only if we're starting a Linux kernel and not using
PSCI.

(None of the users of the hook care about the ordering of its call
relative to anything else: they only use it to write a rom blob to
guest memory.)

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Tested-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20220127154639.2090164-14-peter.maydell@linaro.org
This commit is contained in:
Peter Maydell 2022-01-27 15:46:36 +00:00
parent dc888dd43b
commit d4a29ed6db
2 changed files with 27 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
hw/arm/boot.c
View File

@ -804,7 +804,7 @@ static void do_cpu_reset(void *opaque)
set_kernel_args(info, as);
}
}
} else {
} else if (info->secondary_cpu_reset_hook) {
info->secondary_cpu_reset_hook(cpu, info);
}
}
@ -1030,13 +1030,6 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
elf_machine = EM_ARM;
}
if (!info->secondary_cpu_reset_hook) {
info->secondary_cpu_reset_hook = default_reset_secondary;
}
if (!info->write_secondary_boot) {
info->write_secondary_boot = default_write_secondary;
}
if (info->nb_cpus == 0)
info->nb_cpus = 1;
@ -1216,9 +1209,6 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
write_bootloader("bootloader", info->loader_start,
primary_loader, fixupcontext, as);
if (info->nb_cpus > 1) {
info->write_secondary_boot(cpu, info);
}
if (info->write_board_setup) {
info->write_board_setup(cpu, info);
}
@ -1385,6 +1375,29 @@ void arm_load_kernel(ARMCPU *cpu, MachineState *ms, struct arm_boot_info *info)
}
}
if (info->psci_conduit == QEMU_PSCI_CONDUIT_DISABLED &&
info->is_linux && info->nb_cpus > 1) {
/*
* We're booting Linux but not using PSCI, so for SMP we need
* to write a custom secondary CPU boot loader stub, and arrange
* for the secondary CPU reset to make the accompanying initialization.
*/
if (!info->secondary_cpu_reset_hook) {
info->secondary_cpu_reset_hook = default_reset_secondary;
}
if (!info->write_secondary_boot) {
info->write_secondary_boot = default_write_secondary;
}
info->write_secondary_boot(cpu, info);
} else {
/*
* No secondary boot stub; don't use the reset hook that would
* have set the CPU up to call it
*/
info->write_secondary_boot = NULL;
info->secondary_cpu_reset_hook = NULL;
}
/*
* arm_load_dtb() may add a PSCI node so it must be called after we have
* decided whether to enable PSCI and set the psci-conduit CPU properties.

3
include/hw/arm/boot.h
View File

@ -70,6 +70,9 @@ struct arm_boot_info {
* boot loader/boot ROM code, and secondary_cpu_reset_hook() should
* perform any necessary CPU reset handling and set the PC for the
* secondary CPUs to point at this boot blob.
*
* These hooks won't be called if secondary CPUs are booting via
* emulated PSCI (see psci_conduit below).
*/
void (*write_secondary_boot)(ARMCPU *cpu,
const struct arm_boot_info *info);