The SMP release mechanism for FSL book3e is different from when booting with normal hardware. In theory we could simulate the normal spin table mechanism, but not at the addresses U-Boot put in the device tree -- so there'd need to be even more communication between the kernel and kexec to set that up. Instead, kexec-tools will set a boolean property linux,booted-from-kexec in the /chosen node. Signed-off-by: Scott Wood <scottwood@xxxxxxxxxxxxx> Cc: devicetree@xxxxxxxxxxxxxxx --- v2: Use a device tree property instead of a flag in the kernel image This depends on the kexec-tools patch v2 "ppc64: Add a flag to tell the kernel it's booting from kexec": http://patchwork.ozlabs.org/patch/527050/ --- Documentation/devicetree/bindings/chosen.txt | 8 ++++++++ arch/powerpc/kernel/setup_64.c | 17 ++++++++++++++++- 2 files changed, 24 insertions(+), 1 deletion(-) diff --git a/Documentation/devicetree/bindings/chosen.txt b/Documentation/devicetree/bindings/chosen.txt index ed838f4..6ae9d82 100644 --- a/Documentation/devicetree/bindings/chosen.txt +++ b/Documentation/devicetree/bindings/chosen.txt @@ -44,3 +44,11 @@ Implementation note: Linux will look for the property "linux,stdout-path" or on PowerPC "stdout" if "stdout-path" is not found. However, the "linux,stdout-path" and "stdout" properties are deprecated. New platforms should only use the "stdout-path" property. + +linux,booted-from-kexec +----------------------- + +This property is set (currently only on PowerPC, and only needed on +book3e) by some versions of kexec-tools to tell the new kernel that it +is being booted by kexec, as the booting environment may differ (e.g. +a different secondary CPU release mechanism) diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c index 505ec2c..5c03a6a 100644 --- a/arch/powerpc/kernel/setup_64.c +++ b/arch/powerpc/kernel/setup_64.c @@ -340,11 +340,26 @@ void early_setup_secondary(void) #endif /* CONFIG_SMP */ #if defined(CONFIG_SMP) || defined(CONFIG_KEXEC) +static bool use_spinloop(void) +{ + if (!IS_ENABLED(CONFIG_PPC_BOOK3E)) + return true; + + /* + * When book3e boots from kexec, the ePAPR spin table does + * not get used. + */ + return of_property_read_bool(of_chosen, "linux,booted-from-kexec"); +} + void smp_release_cpus(void) { unsigned long *ptr; int i; + if (!use_spinloop()) + return; + DBG(" -> smp_release_cpus()\n"); /* All secondary cpus are spinning on a common spinloop, release them @@ -524,7 +539,7 @@ void __init setup_system(void) * Freescale Book3e parts spin in a loop provided by firmware, * so smp_release_cpus() does nothing for them */ -#if defined(CONFIG_SMP) && !defined(CONFIG_PPC_FSL_BOOK3E) +#if defined(CONFIG_SMP) /* Release secondary cpus out of their spinloops at 0x60 now that * we can map physical -> logical CPU ids */ -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
