On Fri, 15 Jan 2016, Shannon Zhao wrote: > From: Shannon Zhao <shannon.zhao@xxxxxxxxxx> > > Move xen_early_init() before efi_init(), then when calling efi_init() > could initialize Xen specific UEFI. > > Check if it runs on Xen hypervisor through the flat dts. > > Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx> > --- > arch/arm/xen/enlighten.c | 56 ++++++++++++++++++++++++++++++++++------------- > arch/arm64/kernel/setup.c | 2 +- > 2 files changed, 42 insertions(+), 16 deletions(-) > > diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c > index 4e78c49..5d0fe68 100644 > --- a/arch/arm/xen/enlighten.c > +++ b/arch/arm/xen/enlighten.c > @@ -19,6 +19,7 @@ > #include <linux/irqreturn.h> > #include <linux/module.h> > #include <linux/of.h> > +#include <linux/of_fdt.h> > #include <linux/of_irq.h> > #include <linux/of_address.h> > #include <linux/cpuidle.h> > @@ -52,8 +53,6 @@ struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata; > > static __read_mostly unsigned int xen_events_irq; > > -static __initdata struct device_node *xen_node; > - > int xen_remap_domain_gfn_array(struct vm_area_struct *vma, > unsigned long addr, > xen_pfn_t *gfn, int nr, > @@ -222,6 +221,33 @@ static irqreturn_t xen_arm_callback(int irq, void *arg) > return IRQ_HANDLED; > } > > +static __initdata struct { > + const char *compat; > + const char *prefix; > + const char *version; > + bool found; > +} xen_node = {"xen,xen", "xen,xen-", NULL, false}; > + > +static int __init fdt_find_xen_node(unsigned long node, const char *uname, > + int depth, void *data) > +{ > + const void *s = NULL; > + int len; > + > + if (depth != 1 || strcmp(uname, "hypervisor") != 0) > + return 0; > + > + if (of_flat_dt_is_compatible(node, xen_node.compat)) > + xen_node.found = true; > + > + s = of_get_flat_dt_prop(node, "compatible", &len); > + if (strlen(xen_node.prefix) + 3 < len && > + !strncmp(xen_node.prefix, s, strlen(xen_node.prefix))) > + xen_node.version = s + strlen(xen_node.prefix); > + > + return 0; > +} > + > /* > * see Documentation/devicetree/bindings/arm/xen.txt for the > * documentation of the Xen Device Tree format. > @@ -229,26 +255,18 @@ static irqreturn_t xen_arm_callback(int irq, void *arg) > #define GRANT_TABLE_PHYSADDR 0 > void __init xen_early_init(void) > { > - int len; > - const char *s = NULL; > - const char *version = NULL; > - const char *xen_prefix = "xen,xen-"; > - > - xen_node = of_find_compatible_node(NULL, NULL, "xen,xen"); > - if (!xen_node) { > + of_scan_flat_dt(fdt_find_xen_node, NULL); > + if (!xen_node.found) { > pr_debug("No Xen support\n"); > return; > } > - s = of_get_property(xen_node, "compatible", &len); > - if (strlen(xen_prefix) + 3 < len && > - !strncmp(xen_prefix, s, strlen(xen_prefix))) > - version = s + strlen(xen_prefix); > - if (version == NULL) { > + > + if (xen_node.version == NULL) { > pr_debug("Xen version not found\n"); > return; > } This is going to access data within the fdt, after it has been unflattened (by the unflatten_device_tree call). Is that allowed? If that's not allowed, then you could copy the version string to xen_node.version, rather than just copying the pointer. Otherwise you could move the version check entirely within fdt_find_xen_node and remove the version field from xen_node. > - pr_info("Xen %s support found\n", version); > + pr_info("Xen %s support found\n", xen_node.version); > > xen_domain_type = XEN_HVM_DOMAIN; > > @@ -296,6 +314,14 @@ static int __init xen_guest_init(void) > } > #endif > } else { > + struct device_node *xen_node; > + > + xen_node = of_find_compatible_node(NULL, NULL, "xen,xen"); > + if (!xen_node) { > + pr_debug("No Xen support\n"); > + return -ENODEV; > + } It makes sense to move this into a DT specific init function called from xen_guest_init. Also, given that at this point we know that a Xen node should be present, it makes sense to return EFAULT on error, instead of ENODEV. The error message could be changed to something like: "Xen support was detected before, but it has disappeared" and should be pr_err. > xen_events_irq = irq_of_parse_and_map(xen_node, 0); > } > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c > index 8119479..a4a2878 100644 > --- a/arch/arm64/kernel/setup.c > +++ b/arch/arm64/kernel/setup.c > @@ -313,6 +313,7 @@ void __init setup_arch(char **cmdline_p) > */ > local_async_enable(); > > + xen_early_init(); > efi_init(); > arm64_memblock_init(); > > @@ -334,7 +335,6 @@ void __init setup_arch(char **cmdline_p) > } else { > psci_acpi_init(); > } > - xen_early_init(); > > cpu_read_bootcpu_ops(); > smp_init_cpus(); -- 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