In the Arm kernel/initrd loading code, in some places we make the
incorrect assumption that info->ram_size can be treated as the
address of the end of RAM, as for instance when we calculate the
available space for the initrd using "info->ram_size - info->initrd_start".
This is wrong, because many Arm boards (including "virt") specify
a non-zero info->loader_start to indicate that their RAM area
starts at a non-zero physical address.

Correct the places which make this incorrect assumption.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/arm/boot.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index a830655e1af..0bb9a7d5b5c 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -976,6 +976,7 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
     int elf_machine;
     hwaddr entry;
     static const ARMInsnFixup *primary_loader;
+    uint64_t ram_end = info->loader_start + info->ram_size;
 
     if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
         primary_loader = bootloader_aarch64;
@@ -1047,8 +1048,7 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
         /* 32-bit ARM */
         entry = info->loader_start + KERNEL_LOAD_ADDR;
         kernel_size = load_image_targphys_as(info->kernel_filename, entry,
-                                             info->ram_size - KERNEL_LOAD_ADDR,
-                                             as);
+                                             ram_end - KERNEL_LOAD_ADDR, as);
         is_linux = 1;
     }
     if (kernel_size < 0) {
@@ -1062,12 +1062,11 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
         if (info->initrd_filename) {
             initrd_size = load_ramdisk_as(info->initrd_filename,
                                           info->initrd_start,
-                                          info->ram_size - info->initrd_start,
-                                          as);
+                                          ram_end - info->initrd_start, as);
             if (initrd_size < 0) {
                 initrd_size = load_image_targphys_as(info->initrd_filename,
                                                      info->initrd_start,
-                                                     info->ram_size -
+                                                     ram_end -
                                                      info->initrd_start,
                                                      as);
             }
-- 
2.20.1

Peter Maydell <peter.maydell@linaro.org> writes:

> In the Arm kernel/initrd loading code, in some places we make the
> incorrect assumption that info->ram_size can be treated as the
> address of the end of RAM, as for instance when we calculate the
> available space for the initrd using "info->ram_size - info->initrd_start".
> This is wrong, because many Arm boards (including "virt") specify
> a non-zero info->loader_start to indicate that their RAM area
> starts at a non-zero physical address.
>
> Correct the places which make this incorrect assumption.
>
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

> ---
>  hw/arm/boot.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/hw/arm/boot.c b/hw/arm/boot.c
> index a830655e1af..0bb9a7d5b5c 100644
> --- a/hw/arm/boot.c
> +++ b/hw/arm/boot.c
> @@ -976,6 +976,7 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
>      int elf_machine;
>      hwaddr entry;
>      static const ARMInsnFixup *primary_loader;
> +    uint64_t ram_end = info->loader_start + info->ram_size;
>
>      if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64)) {
>          primary_loader = bootloader_aarch64;
> @@ -1047,8 +1048,7 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
>          /* 32-bit ARM */
>          entry = info->loader_start + KERNEL_LOAD_ADDR;
>          kernel_size = load_image_targphys_as(info->kernel_filename, entry,
> -                                             info->ram_size - KERNEL_LOAD_ADDR,
> -                                             as);
> +                                             ram_end - KERNEL_LOAD_ADDR, as);
>          is_linux = 1;
>      }
>      if (kernel_size < 0) {
> @@ -1062,12 +1062,11 @@ static void arm_setup_direct_kernel_boot(ARMCPU *cpu,
>          if (info->initrd_filename) {
>              initrd_size = load_ramdisk_as(info->initrd_filename,
>                                            info->initrd_start,
> -                                          info->ram_size - info->initrd_start,
> -                                          as);
> +                                          ram_end - info->initrd_start, as);
>              if (initrd_size < 0) {
>                  initrd_size = load_image_targphys_as(info->initrd_filename,
>                                                       info->initrd_start,
> -                                                     info->ram_size -
> +                                                     ram_end -
>                                                       info->initrd_start,
>                                                       as);
>              }


--
Alex Bennée