hw/riscv: Support to load DTB after 3GB memory on 64-bit system.

Larger initrd image will overlap the DTB at 3GB address. Since 64-bit
system doesn't have 32-bit addressable issue, we just load DTB to the end
of dram in 64-bit system.

Signed-off-by: Jim Shu <jim.shu@sifive.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-ID: <20241120153935.24706-2-jim.shu@sifive.com>
[ Changes by AF
 -  Store fdt_load_addr_hi32 in the reset vector
]
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/riscv/boot.c

@@ -293,7 +293,7 @@ out:
  * The FDT is fdt_packed() during the calculation.
  */
 uint64_t riscv_compute_fdt_addr(hwaddr dram_base, hwaddr dram_size,
-                                MachineState *ms)
+                                MachineState *ms, RISCVHartArrayState *harts)
 {
     int ret = fdt_pack(ms->fdt);
     hwaddr dram_end, temp;
@@ -317,11 +317,15 @@ uint64_t riscv_compute_fdt_addr(hwaddr dram_base, hwaddr dram_size,
 
     /*
      * We should put fdt as far as possible to avoid kernel/initrd overwriting
-     * its content. But it should be addressable by 32 bit system as well.
+     * its content. But it should be addressable by 32 bit system as well in RV32.
-     * Thus, put it at an 2MB aligned address that less than fdt size from the
+     * Thus, put it near to the end of dram in RV64, and put it near to the end
-     * end of dram or 3GB whichever is lesser.
+     * of dram or 3GB whichever is lesser in RV32.
      */
-    temp = (dram_base < 3072 * MiB) ? MIN(dram_end, 3072 * MiB) : dram_end;
+    if (!riscv_is_32bit(harts)) {
+        temp = dram_end;
+    } else {
+        temp = (dram_base < 3072 * MiB) ? MIN(dram_end, 3072 * MiB) : dram_end;
+    }
 
     return QEMU_ALIGN_DOWN(temp - fdtsize, 2 * MiB);
 }

hw/riscv/microchip_pfsoc.c

@@ -519,7 +519,7 @@ static void microchip_icicle_kit_machine_init(MachineState *machine)
     bool kernel_as_payload = false;
     target_ulong firmware_end_addr, kernel_start_addr;
     uint64_t kernel_entry;
-    uint32_t fdt_load_addr;
+    uint64_t fdt_load_addr;
     DriveInfo *dinfo = drive_get(IF_SD, 0, 0);
 
     /* Sanity check on RAM size */
@@ -625,7 +625,7 @@ static void microchip_icicle_kit_machine_init(MachineState *machine)
         /* Compute the fdt load address in dram */
         fdt_load_addr = riscv_compute_fdt_addr(memmap[MICROCHIP_PFSOC_DRAM_LO].base,
                                                memmap[MICROCHIP_PFSOC_DRAM_LO].size,
-                                               machine);
+                                               machine, &s->soc.u_cpus);
         riscv_load_fdt(fdt_load_addr, machine->fdt);
 
         /* Load the reset vector */

hw/riscv/sifive_u.c

@@ -518,8 +518,9 @@ static void sifive_u_machine_init(MachineState *machine)
     target_ulong firmware_end_addr, kernel_start_addr;
     const char *firmware_name;
     uint32_t start_addr_hi32 = 0x00000000;
+    uint32_t fdt_load_addr_hi32 = 0x00000000;
     int i;
-    uint32_t fdt_load_addr;
+    uint64_t fdt_load_addr;
     uint64_t kernel_entry;
     DriveInfo *dinfo;
     BlockBackend *blk;
@@ -606,11 +607,12 @@ static void sifive_u_machine_init(MachineState *machine)
 
     fdt_load_addr = riscv_compute_fdt_addr(memmap[SIFIVE_U_DEV_DRAM].base,
                                            memmap[SIFIVE_U_DEV_DRAM].size,
-                                           machine);
+                                           machine, &s->soc.u_cpus);
     riscv_load_fdt(fdt_load_addr, machine->fdt);
 
     if (!riscv_is_32bit(&s->soc.u_cpus)) {
         start_addr_hi32 = (uint64_t)start_addr >> 32;
+        fdt_load_addr_hi32 = fdt_load_addr >> 32;
     }
 
     /* reset vector */
@@ -625,7 +627,7 @@ static void sifive_u_machine_init(MachineState *machine)
         start_addr,                    /* start: .dword */
         start_addr_hi32,
         fdt_load_addr,                 /* fdt_laddr: .dword */
-        0x00000000,
+        fdt_load_addr_hi32,
         0x00000000,
                                        /* fw_dyn: */
     };

hw/riscv/spike.c

@@ -201,7 +201,7 @@ static void spike_board_init(MachineState *machine)
     hwaddr firmware_load_addr = memmap[SPIKE_DRAM].base;
     target_ulong kernel_start_addr;
     char *firmware_name;
-    uint32_t fdt_load_addr;
+    uint64_t fdt_load_addr;
     uint64_t kernel_entry;
     char *soc_name;
     int i, base_hartid, hart_count;
@@ -317,7 +317,7 @@ static void spike_board_init(MachineState *machine)
 
     fdt_load_addr = riscv_compute_fdt_addr(memmap[SPIKE_DRAM].base,
                                            memmap[SPIKE_DRAM].size,
-                                           machine);
+                                           machine, &s->soc[0]);
     riscv_load_fdt(fdt_load_addr, machine->fdt);
 
     /* load the reset vector */

hw/riscv/virt.c

@@ -1492,7 +1492,7 @@ static void virt_machine_done(Notifier *notifier, void *data)
 
     fdt_load_addr = riscv_compute_fdt_addr(memmap[VIRT_DRAM].base,
                                            memmap[VIRT_DRAM].size,
-                                           machine);
+                                           machine, &s->soc[0]);
     riscv_load_fdt(fdt_load_addr, machine->fdt);
 
     /* load the reset vector */

include/hw/riscv/boot.h

@@ -49,7 +49,7 @@ target_ulong riscv_load_kernel(MachineState *machine,
                                bool load_initrd,
                                symbol_fn_t sym_cb);
 uint64_t riscv_compute_fdt_addr(hwaddr dram_start, uint64_t dram_size,
-                                MachineState *ms);
+                                MachineState *ms, RISCVHartArrayState *harts);
 void riscv_load_fdt(hwaddr fdt_addr, void *fdt);
 void riscv_setup_rom_reset_vec(MachineState *machine, RISCVHartArrayState *harts,
                                hwaddr saddr,