From: "Richard W.M. Jones" <rjones@redhat.com>
Date: Tue, 19 Aug 2014 18:56:28 +0100
Subject: [PATCH] aarch64: Allow -kernel option to take a gzip-compressed
 kernel.
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On aarch64 it is the bootloader's job to uncompress the kernel.  UEFI
and u-boot bootloaders do this automatically when the kernel is
gzip-compressed.

However the qemu -kernel option does not do this.  The following
command does not work:

  qemu-system-aarch64 [...] -kernel /boot/vmlinuz

because it tries to execute the gzip-compressed data.

This commit lets gzip-compressed kernels be uncompressed
transparently.

Currently this is only done when emulating aarch64.

Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Crosthwaite <peter.crosthwaite@xilinx.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1407831259-2115-3-git-send-email-rjones@redhat.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
(cherry picked from commit 6f5d3cbe8892367026526a7deed0ceecc700a7ad)
---
 hw/arm/boot.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 3d1f4a2..b7d60aa 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -510,6 +510,13 @@ void arm_load_kernel(ARMCPU *cpu, struct arm_boot_info *info)
         kernel_size = load_uimage(info->kernel_filename, &entry, NULL,
                                   &is_linux);
     }
+    /* On aarch64, it's the bootloader's job to uncompress the kernel. */
+    if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) && kernel_size < 0) {
+        entry = info->loader_start + kernel_load_offset;
+        kernel_size = load_image_gzipped(info->kernel_filename, entry,
+                                         info->ram_size - kernel_load_offset);
+        is_linux = 1;
+    }
     if (kernel_size < 0) {
         entry = info->loader_start + kernel_load_offset;
         kernel_size = load_image_targphys(info->kernel_filename, entry,