[Xen-devel] [PATCH v4] xen: arm: introduce uImage probe function for Dom0

[Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>]

Patch adds a possibility to boot dom0 kernel from uImage.
This is needed to improve boot-time. Comparing to zImage,
uImage is not packed, therefore we can save time needed
to unpack.

uImage header format:
http://git.denx.de/cgi-bin/gitweb.cgi?p=u-boot.git;a=blob;f=include/image.h

Signed-off-by: Oleksandr Dmytryshyn <oleksandr.dmytryshyn@xxxxxxxxxxxxxxx>
---
Changed since v1:
 * fixed commit message
 * added uimage structure definition
 * removed checking of the append device tree

Changed since v2:
 * removed "32" in the uimage constants name
 * added printing a warning if the uimage 'load' field != 0
 * added checking of the uimage 'arch' field to know the kernel is 32 or 64 bits

Changed since v3:
 * removed unused CPU Architecture Codes
 * fixed wrong uimage data size comparison
 * added switch() operator instead of the cascade of else if

 xen/arch/arm/kernel.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)

diff --git a/xen/arch/arm/kernel.c b/xen/arch/arm/kernel.c
index d635a7e..6d6c637 100644
--- a/xen/arch/arm/kernel.c
+++ b/xen/arch/arm/kernel.c
@@ -16,6 +16,9 @@
 
 #include "kernel.h"
 
+#define UIMAGE_MAGIC          0x27051956
+#define UIMAGE_NMLEN          32
+
 #define ZIMAGE32_MAGIC_OFFSET 0x24
 #define ZIMAGE32_START_OFFSET 0x28
 #define ZIMAGE32_END_OFFSET   0x2c
@@ -188,6 +191,77 @@ static void kernel_zimage_load(struct kernel_info *info)
     }
 }
 
+/*
+ * Uimage CPU Architecture Codes
+ */
+#define IH_ARCH_ARM             2       /* ARM          */
+#define IH_ARCH_ARM64           22      /* ARM64        */
+
+/*
+ * Check if the image is a uImage and setup kernel_info
+ */
+static int kernel_uimage_probe(struct kernel_info *info,
+                                 paddr_t addr, paddr_t size)
+{
+    struct {
+        __be32 magic;   /* Image Header Magic Number */
+        __be32 hcrc;    /* Image Header CRC Checksum */
+        __be32 time;    /* Image Creation Timestamp  */
+        __be32 size;    /* Image Data Size           */
+        __be32 load;    /* Data Load Address         */
+        __be32 ep;      /* Entry Point Address       */
+        __be32 dcrc;    /* Image Data CRC Checksum   */
+        uint8_t os;     /* Operating System          */
+        uint8_t arch;   /* CPU architecture          */
+        uint8_t type;   /* Image Type                */
+        uint8_t comp;   /* Compression Type          */
+        uint8_t name[UIMAGE_NMLEN]; /* Image Name  */
+    } uimage;
+
+    uint32_t start, len;
+
+    if ( size < sizeof(uimage) )
+        return -EINVAL;
+
+    copy_from_paddr(&uimage, addr, sizeof(uimage));
+
+    if ( be32_to_cpu(uimage.magic) != UIMAGE_MAGIC )
+        return -EINVAL;
+
+    start = be32_to_cpu(uimage.load);
+    len = be32_to_cpu(uimage.size);
+
+    if ( len > size - sizeof(uimage) )
+        return -EINVAL;
+
+    if ( start == 0 )
+        printk(XENLOG_ERR "uImage start position is not defined\n");
+
+    info->zimage.start = start;
+    info->zimage.kernel_addr = addr + sizeof(uimage);
+    info->zimage.len = len;
+
+    info->entry = info->zimage.start;
+    info->load = kernel_zimage_load;
+
+#ifdef CONFIG_ARM_64
+    switch ( uimage->arch )
+    {
+    case IH_ARCH_ARM:
+        info->type = DOMAIN_32BIT;
+        break;
+    case IH_ARCH_ARM64:
+        info->type = DOMAIN_64BIT;
+        break;
+    default:
+        printk(XENLOG_ERR "Not supported uImage arch type %d\n", uimage->arch);
+        return -EINVAL;
+    }
+#endif
+
+    return 0;
+}
+
 #ifdef CONFIG_ARM_64
 /*
  * Check if the image is a 64-bit Image.
@@ -398,6 +472,8 @@ int kernel_probe(struct kernel_info *info)
     rc = kernel_zimage64_probe(info, start, size);
     if (rc < 0)
 #endif
+        rc = kernel_uimage_probe(info, start, size);
+    if(rc < 0 )
         rc = kernel_zimage32_probe(info, start, size);
     if (rc < 0)
         rc = kernel_elf_probe(info, start, size);
-- 
1.9.1


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