Merge "Backport arm_boot: Change initrd load address to "halfway through RAM"" into studio-1.2-dev automerge: f912613master-soong

automerge: e503215

* commit 'e5032154b6c89c89879048e51f09a8085b4ed042':
  Backport arm_boot: Change initrd load address to "halfway through RAM"

2 files changed, 21 insertions, 8 deletions

diff --git a/hw/arm/boot.c b/hw/arm/boot.c
index 4c901485f8..b4fb9e9a58 100644
--- a/hw/arm/boot.c
+++ b/hw/arm/boot.c
@@ -13,7 +13,6 @@
 
 #define KERNEL_ARGS_ADDR 0x100
 #define KERNEL_LOAD_ADDR 0x00010000
-#define INITRD_LOAD_ADDR 0x00800000
 
 /* The worlds second smallest bootloader.  Set r0-r2, then jump to kernel.  */
 static uint32_t bootloader[] = {
@@ -80,7 +79,7 @@ static void set_kernel_args(const struct arm_boot_info *info,
         /* ATAG_INITRD2 */
         WRITE_WORD(p, 4);
         WRITE_WORD(p, 0x54420005);
-        WRITE_WORD(p, info->loader_start + INITRD_LOAD_ADDR);
+        WRITE_WORD(p, info->initrd_start);
         WRITE_WORD(p, initrd_size);
     }
     if (info->kernel_cmdline && *info->kernel_cmdline) {
@@ -156,10 +155,11 @@ static void set_kernel_args_old(const struct arm_boot_info *info,
     /* pages_in_vram */
     WRITE_WORD(p, 0);
     /* initrd_start */
-    if (initrd_size)
-        WRITE_WORD(p, info->loader_start + INITRD_LOAD_ADDR);
-    else
+    if (initrd_size) {
+        WRITE_WORD(p, info->initrd_start);
+    } else {
         WRITE_WORD(p, 0);
+    }
     /* initrd_size */
     WRITE_WORD(p, initrd_size);
     /* rd_start */
@@ -203,6 +203,19 @@ void arm_load_kernel(CPUARMState *env, struct arm_boot_info *info)
     nb_cpus = info->nb_cpus ? info->nb_cpus : 1;
     env->boot_info = info;
 
+     /* We want to put the initrd far enough into RAM that when the
+      * kernel is uncompressed it will not clobber the initrd. However
+      * on boards without much RAM we must ensure that we still leave
+      * enough room for a decent sized initrd, and on boards with large
+      * amounts of RAM we must avoid the initrd being so far up in RAM
+      * that it is outside lowmem and inaccessible to the kernel.
+      * So for boards with less than 256MB of RAM we put the initrd
+      * halfway into RAM, and for boards with 256MB of RAM or more we put
+      * the initrd at 128MB.
+      */
+    info->initrd_start = info->loader_start +
+        MIN(info->ram_size / 2, 128 * 1024 * 1024);
+
     /* Assume that raw images are linux kernels, and ELF images are not.  */
     kernel_size = load_elf(info->kernel_filename, 0, &elf_entry, NULL, NULL);
     entry = elf_entry;
@@ -228,9 +241,8 @@ void arm_load_kernel(CPUARMState *env, struct arm_boot_info *info)
     } else {
         if (info->initrd_filename) {
             initrd_size = load_image_targphys(info->initrd_filename,
-                                              info->loader_start
-                                              + INITRD_LOAD_ADDR,
-                                              ram_size - INITRD_LOAD_ADDR);
+                                              info->initrd_start,
+                                              ram_size - info->initrd_start);
             if (initrd_size < 0) {
                 fprintf(stderr, "qemu: could not load initrd '%s'\n",
                         info->initrd_filename);
diff --git a/include/hw/arm/arm.h b/include/hw/arm/arm.h
index a4983331dc..2a11ee84b2 100644
--- a/include/hw/arm/arm.h
+++ b/include/hw/arm/arm.h
@@ -37,6 +37,7 @@ struct arm_boot_info {
     int (*atag_board)(const struct arm_boot_info *info, void *p);
     /* Used internally by arm_boot.c */
     int is_linux;
+    hwaddr initrd_start;
     hwaddr initrd_size;
     hwaddr entry;
 };