[Qemu-devel] [PATCH 0/9] target-xtensa: linux booting improvements

[Qemu-devel] [PATCH 0/9] target-xtensa: linux booting improvements

[Max Filippov]

Hi,

this series refactors boot parameters handling for xtensa xtfpga boards
and implements uImage, FDT and initrd loading.

Max Filippov (9):
  hw/xtensa: remove extraneous xtensa_ prefix from file names
  hw/xtensa: replace fprintfs with error_report
  hw/xtensa/xtfpga: retrieve parameters from machine_opts
  hw/xtensa/xtfpga: use symbolic constants for bootparam tags
  hw/xtensa/xtfpga: refactor bootparameters filling
  hw/xtensa/xtfpga: add memory info to bootparam
  hw/xtensa/xtfpga: implement uImage loading
  hw/xtensa/xtfpga: implement DTB loading
  hw/xtensa/xtfpga: implement initrd loading

 hw/xtensa/Makefile.objs               |   4 +-
 hw/xtensa/bootparam.h                 |  49 ++++++++++++++
 hw/xtensa/{xtensa_sim.c => sim.c}     |   6 +-
 hw/xtensa/xtensa_bootparam.h          |  25 -------
 hw/xtensa/{xtensa_lx60.c => xtfpga.c} | 120 +++++++++++++++++++++++++++++-----
 5 files changed, 157 insertions(+), 47 deletions(-)
 create mode 100644 hw/xtensa/bootparam.h
 rename hw/xtensa/{xtensa_sim.c => sim.c} (96%)
 delete mode 100644 hw/xtensa/xtensa_bootparam.h
 rename hw/xtensa/{xtensa_lx60.c => xtfpga.c} (70%)

-- 
1.8.1.4

[Qemu-devel] [PATCH 1/9] hw/xtensa: remove extraneous xtensa_ prefix from file names

[Max Filippov]

While at it rename lx60 (named after the first board of the family) to
more generic xtfpga (the family name).

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/Makefile.objs                       | 4 ++--
 hw/xtensa/{xtensa_bootparam.h => bootparam.h} | 0
 hw/xtensa/{xtensa_sim.c => sim.c}             | 0
 hw/xtensa/{xtensa_lx60.c => xtfpga.c}         | 2 +-
 4 files changed, 3 insertions(+), 3 deletions(-)
 rename hw/xtensa/{xtensa_bootparam.h => bootparam.h} (100%)
 rename hw/xtensa/{xtensa_sim.c => sim.c} (100%)
 rename hw/xtensa/{xtensa_lx60.c => xtfpga.c} (99%)

diff --git a/hw/xtensa/Makefile.objs b/hw/xtensa/Makefile.objs
index 6ead782..cb77dc3 100644
--- a/hw/xtensa/Makefile.objs
+++ b/hw/xtensa/Makefile.objs
@@ -1,3 +1,3 @@
 obj-y += pic_cpu.o
-obj-y += xtensa_sim.o
-obj-y += xtensa_lx60.o
+obj-y += sim.o
+obj-y += xtfpga.o
diff --git a/hw/xtensa/xtensa_bootparam.h b/hw/xtensa/bootparam.h
similarity index 100%
rename from hw/xtensa/xtensa_bootparam.h
rename to hw/xtensa/bootparam.h
diff --git a/hw/xtensa/xtensa_sim.c b/hw/xtensa/sim.c
similarity index 100%
rename from hw/xtensa/xtensa_sim.c
rename to hw/xtensa/sim.c
diff --git a/hw/xtensa/xtensa_lx60.c b/hw/xtensa/xtfpga.c
similarity index 99%
rename from hw/xtensa/xtensa_lx60.c
rename to hw/xtensa/xtfpga.c
index 183527f..0b8a2ed 100644
--- a/hw/xtensa/xtensa_lx60.c
+++ b/hw/xtensa/xtfpga.c
@@ -37,7 +37,7 @@
 #include "hw/block/flash.h"
 #include "sysemu/blockdev.h"
 #include "sysemu/char.h"
-#include "xtensa_bootparam.h"
+#include "bootparam.h"
 
 typedef struct LxBoardDesc {
     hwaddr flash_base;
-- 
1.8.1.4

[Qemu-devel] [PATCH 2/9] hw/xtensa: replace fprintfs with error_report

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/sim.c    |  6 ++++--
 hw/xtensa/xtfpga.c | 10 ++++++----
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/hw/xtensa/sim.c b/hw/xtensa/sim.c
index 89da43c..9642bf5 100644
--- a/hw/xtensa/sim.c
+++ b/hw/xtensa/sim.c
@@ -31,6 +31,7 @@
 #include "elf.h"
 #include "exec/memory.h"
 #include "exec/address-spaces.h"
+#include "qemu/error-report.h"
 
 static uint64_t translate_phys_addr(void *opaque, uint64_t addr)
 {
@@ -63,8 +64,9 @@ static void xtensa_sim_init(MachineState *machine)
     for (n = 0; n < smp_cpus; n++) {
         cpu = cpu_xtensa_init(cpu_model);
         if (cpu == NULL) {
-            fprintf(stderr, "Unable to find CPU definition\n");
-            exit(1);
+            error_report("unable to find CPU definition '%s'\n",
+                         cpu_model);
+            exit(EXIT_FAILURE);
         }
         env = &cpu->env;
 
diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 0b8a2ed..75bc479 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -37,6 +37,7 @@
 #include "hw/block/flash.h"
 #include "sysemu/blockdev.h"
 #include "sysemu/char.h"
+#include "qemu/error-report.h"
 #include "bootparam.h"
 
 typedef struct LxBoardDesc {
@@ -185,8 +186,9 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
     for (n = 0; n < smp_cpus; n++) {
         cpu = cpu_xtensa_init(cpu_model);
         if (cpu == NULL) {
-            fprintf(stderr, "Unable to find CPU definition\n");
-            exit(1);
+            error_report("unable to find CPU definition '%s'\n",
+                         cpu_model);
+            exit(EXIT_FAILURE);
         }
         env = &cpu->env;
 
@@ -227,8 +229,8 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
                 board->flash_size / board->flash_sector_size,
                 4, 0x0000, 0x0000, 0x0000, 0x0000, be);
         if (flash == NULL) {
-            fprintf(stderr, "Unable to mount pflash\n");
-            exit(1);
+            error_report("unable to mount pflash\n");
+            exit(EXIT_FAILURE);
         }
     }
 
-- 
1.8.1.4

[Qemu-devel] [PATCH 3/9] hw/xtensa/xtfpga: retrieve parameters from machine_opts

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/xtfpga.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 75bc479..0aa3eeb 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -174,9 +174,10 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
     MemoryRegion *ram, *rom, *system_io;
     DriveInfo *dinfo;
     pflash_t *flash = NULL;
+    QemuOpts *machine_opts = qemu_get_machine_opts();
     const char *cpu_model = machine->cpu_model;
-    const char *kernel_filename = machine->kernel_filename;
-    const char *kernel_cmdline = machine->kernel_cmdline;
+    const char *kernel_filename = qemu_opt_get(machine_opts, "kernel");
+    const char *kernel_cmdline = qemu_opt_get(machine_opts, "append");
     int n;
 
     if (!cpu_model) {
-- 
1.8.1.4

[Qemu-devel] [PATCH 4/9] hw/xtensa/xtfpga: use symbolic constants for bootparam tags

[Max Filippov]

Import bootparam tag names from linux/arch/xtensa/include/asm/bootparam.h
No functional changes.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/bootparam.h | 10 ++++++++++
 hw/xtensa/xtfpga.c    |  6 +++---
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/hw/xtensa/bootparam.h b/hw/xtensa/bootparam.h
index 38ef32b..e6cf3b1 100644
--- a/hw/xtensa/bootparam.h
+++ b/hw/xtensa/bootparam.h
@@ -1,6 +1,16 @@
 #ifndef HW_XTENSA_BOOTPARAM
 #define HW_XTENSA_BOOTPARAM
 
+#define BP_TAG_COMMAND_LINE     0x1001  /* command line (0-terminated string)*/
+#define BP_TAG_INITRD           0x1002  /* ramdisk addr and size (bp_meminfo) */
+#define BP_TAG_MEMORY           0x1003  /* memory addr and size (bp_meminfo) */
+#define BP_TAG_SERIAL_BAUDRATE  0x1004  /* baud rate of current console. */
+#define BP_TAG_SERIAL_PORT      0x1005  /* serial device of current console */
+#define BP_TAG_FDT              0x1006  /* flat device tree addr */
+
+#define BP_TAG_FIRST            0x7B0B  /* first tag with a version number */
+#define BP_TAG_LAST             0x7E0B  /* last tag */
+
 typedef struct BpTag {
     uint16_t tag;
     uint16_t size;
diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 0aa3eeb..6d070b0 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -250,12 +250,12 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
 
             env->regs[2] = tagptr;
 
-            tagptr = put_tag(tagptr, 0x7b0b, 0, NULL);
+            tagptr = put_tag(tagptr, BP_TAG_FIRST, 0, NULL);
             if (cmdline_size > 1) {
-                tagptr = put_tag(tagptr, 0x1001,
+                tagptr = put_tag(tagptr, BP_TAG_COMMAND_LINE,
                         cmdline_size, kernel_cmdline);
             }
-            tagptr = put_tag(tagptr, 0x7e0b, 0, NULL);
+            tagptr = put_tag(tagptr, BP_TAG_LAST, 0, NULL);
         }
         uint64_t elf_entry;
         uint64_t elf_lowaddr;
-- 
1.8.1.4

[Qemu-devel] [PATCH 5/9] hw/xtensa/xtfpga: refactor bootparameters filling

[Max Filippov]

Separate filling first/last tag and size calculation from the kernel
command line setup.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/bootparam.h |  5 +++++
 hw/xtensa/xtfpga.c    | 28 ++++++++++++++++------------
 2 files changed, 21 insertions(+), 12 deletions(-)

diff --git a/hw/xtensa/bootparam.h b/hw/xtensa/bootparam.h
index e6cf3b1..e839bee 100644
--- a/hw/xtensa/bootparam.h
+++ b/hw/xtensa/bootparam.h
@@ -16,6 +16,11 @@ typedef struct BpTag {
     uint16_t size;
 } BpTag;
 
+static inline size_t get_tag_size(size_t data_size)
+{
+    return data_size + sizeof(BpTag) + 4;
+}
+
 static inline ram_addr_t put_tag(ram_addr_t addr, uint16_t tag,
         size_t size, const void *data)
 {
diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 6d070b0..689d078 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -237,26 +237,30 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
 
     /* Use presence of kernel file name as 'boot from SRAM' switch. */
     if (kernel_filename) {
+        size_t bp_size = 2 * get_tag_size(0);
+        uint32_t tagptr = 0xfe000000 + board->sram_size;
+        uint32_t cur_tagptr;
+
         rom = g_malloc(sizeof(*rom));
         memory_region_init_ram(rom, NULL, "lx60.sram", board->sram_size);
         vmstate_register_ram_global(rom);
         memory_region_add_subregion(system_memory, 0xfe000000, rom);
 
+        if (kernel_cmdline) {
+            bp_size += get_tag_size(strlen(kernel_cmdline) + 1);
+        }
+
         /* Put kernel bootparameters to the end of that SRAM */
+        tagptr = (tagptr - bp_size) & ~0xff;
+        cur_tagptr = put_tag(tagptr, BP_TAG_FIRST, 0, NULL);
+
         if (kernel_cmdline) {
-            size_t cmdline_size = strlen(kernel_cmdline) + 1;
-            size_t bp_size = sizeof(BpTag[4]) + cmdline_size;
-            uint32_t tagptr = (0xfe000000 + board->sram_size - bp_size) & ~0xff;
-
-            env->regs[2] = tagptr;
-
-            tagptr = put_tag(tagptr, BP_TAG_FIRST, 0, NULL);
-            if (cmdline_size > 1) {
-                tagptr = put_tag(tagptr, BP_TAG_COMMAND_LINE,
-                        cmdline_size, kernel_cmdline);
-            }
-            tagptr = put_tag(tagptr, BP_TAG_LAST, 0, NULL);
+            cur_tagptr = put_tag(cur_tagptr, BP_TAG_COMMAND_LINE,
+                                 strlen(kernel_cmdline) + 1, kernel_cmdline);
         }
+        cur_tagptr = put_tag(cur_tagptr, BP_TAG_LAST, 0, NULL);
+        env->regs[2] = tagptr;
+
         uint64_t elf_entry;
         uint64_t elf_lowaddr;
         int success = load_elf(kernel_filename, translate_phys_addr, cpu,
-- 
1.8.1.4

[Qemu-devel] [PATCH 6/9] hw/xtensa/xtfpga: add memory info to bootparam

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/bootparam.h | 9 +++++++++
 hw/xtensa/xtfpga.c    | 9 ++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/hw/xtensa/bootparam.h b/hw/xtensa/bootparam.h
index e839bee..955f4e8 100644
--- a/hw/xtensa/bootparam.h
+++ b/hw/xtensa/bootparam.h
@@ -16,6 +16,15 @@ typedef struct BpTag {
     uint16_t size;
 } BpTag;
 
+typedef struct BpMemInfo {
+    uint32_t type;
+    uint32_t start;
+    uint32_t end;
+} BpMemInfo;
+
+#define MEMORY_TYPE_CONVENTIONAL        0x1000
+#define MEMORY_TYPE_NONE                0x2000
+
 static inline size_t get_tag_size(size_t data_size)
 {
     return data_size + sizeof(BpTag) + 4;
diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 689d078..97e5842 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -237,9 +237,14 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
 
     /* Use presence of kernel file name as 'boot from SRAM' switch. */
     if (kernel_filename) {
-        size_t bp_size = 2 * get_tag_size(0);
+        size_t bp_size = 3 * get_tag_size(0); /* first/last and memory tags */
         uint32_t tagptr = 0xfe000000 + board->sram_size;
         uint32_t cur_tagptr;
+        BpMemInfo memory_location = {
+            .type = tswap32(MEMORY_TYPE_CONVENTIONAL),
+            .start = tswap32(0),
+            .end = tswap32(machine->ram_size),
+        };
 
         rom = g_malloc(sizeof(*rom));
         memory_region_init_ram(rom, NULL, "lx60.sram", board->sram_size);
@@ -253,6 +258,8 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
         /* Put kernel bootparameters to the end of that SRAM */
         tagptr = (tagptr - bp_size) & ~0xff;
         cur_tagptr = put_tag(tagptr, BP_TAG_FIRST, 0, NULL);
+        cur_tagptr = put_tag(cur_tagptr, BP_TAG_MEMORY,
+                             sizeof(memory_location), &memory_location);
 
         if (kernel_cmdline) {
             cur_tagptr = put_tag(cur_tagptr, BP_TAG_COMMAND_LINE,
-- 
1.8.1.4

[Qemu-devel] [PATCH 7/9] hw/xtensa/xtfpga: implement uImage loading

[Max Filippov]

Provide a simple bootloader code at the reset address that jumps to the
loaded image entry point when it's not equal to the reset address. This
is needed because the old method of setting pc doesn't work due to cpu
reset done after the machine setup.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/xtfpga.c | 25 ++++++++++++++++++++++++-
 1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 97e5842..0e0d825 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -237,6 +237,7 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
 
     /* Use presence of kernel file name as 'boot from SRAM' switch. */
     if (kernel_filename) {
+        uint32_t entry_point = env->pc;
         size_t bp_size = 3 * get_tag_size(0); /* first/last and memory tags */
         uint32_t tagptr = 0xfe000000 + board->sram_size;
         uint32_t cur_tagptr;
@@ -273,7 +274,29 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
         int success = load_elf(kernel_filename, translate_phys_addr, cpu,
                 &elf_entry, &elf_lowaddr, NULL, be, ELF_MACHINE, 0);
         if (success > 0) {
-            env->pc = elf_entry;
+            entry_point = elf_entry;
+        } else {
+            hwaddr ep;
+            int is_linux;
+            success = load_uimage(kernel_filename, &ep, NULL, &is_linux);
+            if (success > 0 && is_linux) {
+                entry_point = ep;
+            } else {
+                error_report("could not load kernel '%s'\n",
+                             kernel_filename);
+                exit(EXIT_FAILURE);
+            }
+        }
+        if (entry_point != env->pc) {
+            static const uint8_t jx_a0[] = {
+#ifdef TARGET_WORDS_BIGENDIAN
+                0x0a, 0, 0,
+#else
+                0xa0, 0, 0,
+#endif
+            };
+            env->regs[0] = entry_point;
+            cpu_physical_memory_write(env->pc, jx_a0, sizeof(jx_a0));
         }
     } else {
         if (flash) {
-- 
1.8.1.4

[Qemu-devel] [PATCH 8/9] hw/xtensa/xtfpga: implement DTB loading

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/xtfpga.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 0e0d825..01825d6 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -37,6 +37,7 @@
 #include "hw/block/flash.h"
 #include "sysemu/blockdev.h"
 #include "sysemu/char.h"
+#include "sysemu/device_tree.h"
 #include "qemu/error-report.h"
 #include "bootparam.h"
 
@@ -178,6 +179,7 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
     const char *cpu_model = machine->cpu_model;
     const char *kernel_filename = qemu_opt_get(machine_opts, "kernel");
     const char *kernel_cmdline = qemu_opt_get(machine_opts, "append");
+    const char *dtb_filename = qemu_opt_get(machine_opts, "dtb");
     int n;
 
     if (!cpu_model) {
@@ -246,6 +248,9 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
             .start = tswap32(0),
             .end = tswap32(machine->ram_size),
         };
+        uint32_t lowmem_end = machine->ram_size < 0x08000000 ?
+            machine->ram_size : 0x08000000;
+        uint32_t cur_lowmem = QEMU_ALIGN_UP(lowmem_end / 2, 4096);
 
         rom = g_malloc(sizeof(*rom));
         memory_region_init_ram(rom, NULL, "lx60.sram", board->sram_size);
@@ -255,6 +260,9 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
         if (kernel_cmdline) {
             bp_size += get_tag_size(strlen(kernel_cmdline) + 1);
         }
+        if (dtb_filename) {
+            bp_size += get_tag_size(sizeof(uint32_t));
+        }
 
         /* Put kernel bootparameters to the end of that SRAM */
         tagptr = (tagptr - bp_size) & ~0xff;
@@ -266,6 +274,21 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
             cur_tagptr = put_tag(cur_tagptr, BP_TAG_COMMAND_LINE,
                                  strlen(kernel_cmdline) + 1, kernel_cmdline);
         }
+        if (dtb_filename) {
+            int fdt_size;
+            void *fdt = load_device_tree(dtb_filename, &fdt_size);
+            uint32_t dtb_addr = tswap32(cur_lowmem);
+
+            if (!fdt) {
+                error_report("could not load DTB '%s'\n", dtb_filename);
+                exit(EXIT_FAILURE);
+            }
+
+            cpu_physical_memory_write(cur_lowmem, fdt, fdt_size);
+            cur_tagptr = put_tag(cur_tagptr, BP_TAG_FDT,
+                                 sizeof(dtb_addr), &dtb_addr);
+            cur_lowmem = QEMU_ALIGN_UP(cur_lowmem + fdt_size, 4096);
+        }
         cur_tagptr = put_tag(cur_tagptr, BP_TAG_LAST, 0, NULL);
         env->regs[2] = tagptr;
 
-- 
1.8.1.4

[Qemu-devel] [PATCH 9/9] hw/xtensa/xtfpga: implement initrd loading

[Max Filippov]

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 hw/xtensa/xtfpga.c | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/hw/xtensa/xtfpga.c b/hw/xtensa/xtfpga.c
index 01825d6..a2dff5a 100644
--- a/hw/xtensa/xtfpga.c
+++ b/hw/xtensa/xtfpga.c
@@ -180,6 +180,7 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
     const char *kernel_filename = qemu_opt_get(machine_opts, "kernel");
     const char *kernel_cmdline = qemu_opt_get(machine_opts, "append");
     const char *dtb_filename = qemu_opt_get(machine_opts, "dtb");
+    const char *initrd_filename = qemu_opt_get(machine_opts, "initrd");
     int n;
 
     if (!cpu_model) {
@@ -263,6 +264,9 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
         if (dtb_filename) {
             bp_size += get_tag_size(sizeof(uint32_t));
         }
+        if (initrd_filename) {
+            bp_size += get_tag_size(sizeof(BpMemInfo));
+        }
 
         /* Put kernel bootparameters to the end of that SRAM */
         tagptr = (tagptr - bp_size) & ~0xff;
@@ -289,6 +293,26 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
                                  sizeof(dtb_addr), &dtb_addr);
             cur_lowmem = QEMU_ALIGN_UP(cur_lowmem + fdt_size, 4096);
         }
+        if (initrd_filename) {
+            BpMemInfo initrd_location = { 0 };
+            int initrd_size = load_ramdisk(initrd_filename, cur_lowmem,
+                                           lowmem_end - cur_lowmem);
+
+            if (initrd_size < 0) {
+                initrd_size = load_image_targphys(initrd_filename,
+                                                  cur_lowmem,
+                                                  lowmem_end - cur_lowmem);
+            }
+            if (initrd_size < 0) {
+                error_report("could not load initrd '%s'\n", initrd_filename);
+                exit(EXIT_FAILURE);
+            }
+            initrd_location.start = tswap32(cur_lowmem);
+            initrd_location.end = tswap32(cur_lowmem + initrd_size);
+            cur_tagptr = put_tag(cur_tagptr, BP_TAG_INITRD,
+                                 sizeof(initrd_location), &initrd_location);
+            cur_lowmem = QEMU_ALIGN_UP(cur_lowmem + initrd_size, 4096);
+        }
         cur_tagptr = put_tag(cur_tagptr, BP_TAG_LAST, 0, NULL);
         env->regs[2] = tagptr;
 
-- 
1.8.1.4