Re: [Xen-devel] [PATCH 13/13] ARM: XEN: Move xen_early_init() before efi_init()

[Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>]

On Tue, 17 Nov 2015, shannon.zhao@xxxxxxxxxx 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  | 62 
> ++++++++++++++++++++++++++++++++++++-----------
>  arch/arm64/kernel/setup.c |  2 +-
>  2 files changed, 49 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
> index b8e9db8..d4f884c 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>
> @@ -48,8 +49,6 @@ 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,
> @@ -142,6 +141,34 @@ static irqreturn_t xen_arm_callback(int irq, void *arg)
>       return IRQ_HANDLED;
>  }
>  
> +struct xen_node_info {
> +     const char *compat;
> +     const char *prefix;
> +     const char *version;
> +     bool found;
> +};
> +
> +static int __init fdt_find_xen_node(unsigned long node, const char *uname,
> +                                 int depth, void *data)
> +{
> +     struct xen_node_info *info = data;
> +     const void *s = NULL;
> +     int len;
> +
> +     if (depth != 1 || strcmp(uname, "hypervisor") != 0)
> +             return 0;
> +
> +     if (of_flat_dt_is_compatible(node, info->compat))
> +             info->found = true;
> +
> +     s = of_get_flat_dt_prop(node, "compatible", &len);
> +     if (strlen(info->prefix) + 3  < len &&
> +                        !strncmp(info->prefix, s, strlen(info->prefix)))
> +                info->version = s + strlen(info->prefix);
> +     return 0;
> +}
> +
>  /*
>   * see Documentation/devicetree/bindings/arm/xen.txt for the
>   * documentation of the Xen Device Tree format.
> @@ -149,26 +176,25 @@ 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-";
> +     struct xen_node_info info;
> +
> +     info.compat = "xen,xen";
> +     info.prefix = "xen,xen-";
> +     info.version = NULL;
> +     info.found = false;

Can you initialize the fields directly when you define xen_node_info and
make it static?

The rest looks good.


> -     xen_node = of_find_compatible_node(NULL, NULL, "xen,xen");
> -     if (!xen_node) {
> +     of_scan_flat_dt(fdt_find_xen_node, &info);
> +     if (!info.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 (info.version == NULL) {
>               pr_debug("Xen version not found\n");
>               return;
>       }
>  
> -     pr_info("Xen %s support found\n", version);
> +     pr_info("Xen %s support found\n", info.version);
>  
>       xen_domain_type = XEN_HVM_DOMAIN;
>  
> @@ -204,6 +230,14 @@ static int __init xen_guest_init(void)
>               }
>               xen_events_irq = a.value & 0xff;
>       } 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;
> +             }
> +
>               xen_events_irq = irq_of_parse_and_map(xen_node, 0);
>               if (!xen_events_irq) {
>                       pr_err("Xen event channel interrupt not found\n");
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index 2322479..ee95593 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -428,6 +428,7 @@ void __init setup_arch(char **cmdline_p)
>        */
>       local_async_enable();
>  
> +     xen_early_init();
>       efi_init();
>       arm64_memblock_init();
>  
> @@ -446,7 +447,6 @@ void __init setup_arch(char **cmdline_p)
>       } else {
>               psci_acpi_init();
>       }
> -     xen_early_init();
>  
>       cpu_read_bootcpu_ops();
>       smp_init_cpus();
> -- 
> 2.1.0
> 

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