hw/riscv: spike: Decouple create_fdt() dependency to ELF loading

At present create_fdt() calls htif_uses_elf_symbols() to determine
whether to insert a <reg> property for the HTIF. This unfortunately
creates a hidden dependency to riscv_load_{firmware,kernel} that
create_fdt() must be called after the ELF {firmware,kernel} image
has been loaded.

Decouple such dependency be adding a new parameter to create_fdt(),
whether custom HTIF base address is used. The flag will be set if
non ELF {firmware,kernel} image is given by user.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Message-Id: <20221229091828.1945072-13-bmeng@tinylab.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

hw/char/riscv_htif.c

@@ -52,20 +52,17 @@
 #define PK_SYS_WRITE            64
 
 static uint64_t fromhost_addr, tohost_addr;
-static int address_symbol_set;
 
 void htif_symbol_callback(const char *st_name, int st_info, uint64_t st_value,
                           uint64_t st_size)
 {
     if (strcmp("fromhost", st_name) == 0) {
-        address_symbol_set |= 1;
         fromhost_addr = st_value;
         if (st_size != 8) {
             error_report("HTIF fromhost must be 8 bytes");
             exit(1);
         }
     } else if (strcmp("tohost", st_name) == 0) {
-        address_symbol_set |= 2;
         tohost_addr = st_value;
         if (st_size != 8) {
             error_report("HTIF tohost must be 8 bytes");
@@ -275,19 +272,19 @@ static const MemoryRegionOps htif_mm_ops = {
     .write = htif_mm_write,
 };
 
-bool htif_uses_elf_symbols(void)
-{
-    return (address_symbol_set == 3) ? true : false;
-}
-
 HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
-                        uint64_t nonelf_base)
+                        uint64_t nonelf_base, bool custom_base)
 {
     uint64_t base, size, tohost_offset, fromhost_offset;
 
-    if (!htif_uses_elf_symbols()) {
+    if (custom_base) {
         fromhost_addr = nonelf_base;
         tohost_addr = nonelf_base + 8;
+    } else {
+        if (!fromhost_addr || !tohost_addr) {
+            error_report("Invalid HTIF fromhost or tohost address");
+            exit(1);
+        }
     }
 
     base = MIN(tohost_addr, fromhost_addr);

hw/riscv/spike.c

@@ -49,7 +49,8 @@ static const MemMapEntry spike_memmap[] = {
 };
 
 static void create_fdt(SpikeState *s, const MemMapEntry *memmap,
-                       uint64_t mem_size, const char *cmdline, bool is_32_bit)
+                       uint64_t mem_size, const char *cmdline,
+                       bool is_32_bit, bool htif_custom_base)
 {
     void *fdt;
     uint64_t addr, size;
@@ -77,7 +78,7 @@ static void create_fdt(SpikeState *s, const MemMapEntry *memmap,
 
     qemu_fdt_add_subnode(fdt, "/htif");
     qemu_fdt_setprop_string(fdt, "/htif", "compatible", "ucb,htif0");
-    if (!htif_uses_elf_symbols()) {
+    if (htif_custom_base) {
         qemu_fdt_setprop_cells(fdt, "/htif", "reg",
             0x0, memmap[SPIKE_HTIF].base, 0x0, memmap[SPIKE_HTIF].size);
     }
@@ -183,18 +184,33 @@ static void create_fdt(SpikeState *s, const MemMapEntry *memmap,
     }
 }
 
+static bool spike_test_elf_image(char *filename)
+{
+    Error *err = NULL;
+
+    load_elf_hdr(filename, NULL, NULL, &err);
+    if (err) {
+        error_free(err);
+        return false;
+    } else {
+        return true;
+    }
+}
+
 static void spike_board_init(MachineState *machine)
 {
     const MemMapEntry *memmap = spike_memmap;
     SpikeState *s = SPIKE_MACHINE(machine);
     MemoryRegion *system_memory = get_system_memory();
     MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
-    target_ulong firmware_end_addr, kernel_start_addr;
+    target_ulong firmware_end_addr = memmap[SPIKE_DRAM].base;
-    const char *firmware_name;
+    target_ulong kernel_start_addr;
+    char *firmware_name;
     uint32_t fdt_load_addr;
     uint64_t kernel_entry;
     char *soc_name;
     int i, base_hartid, hart_count;
+    bool htif_custom_base = false;
 
     /* Check socket count limit */
     if (SPIKE_SOCKETS_MAX < riscv_socket_count(machine)) {
@@ -256,10 +272,34 @@ static void spike_board_init(MachineState *machine)
     memory_region_add_subregion(system_memory, memmap[SPIKE_MROM].base,
                                 mask_rom);
 
-    firmware_name = riscv_default_firmware_name(&s->soc[0]);
+    /* Find firmware */
-    firmware_end_addr = riscv_find_and_load_firmware(machine, firmware_name,
+    firmware_name = riscv_find_firmware(machine->firmware,
-                                                     memmap[SPIKE_DRAM].base,
+                        riscv_default_firmware_name(&s->soc[0]));
-                                                     htif_symbol_callback);
+
+    /*
+     * Test the given firmware or kernel file to see if it is an ELF image.
+     * If it is an ELF, we assume it contains the symbols required for
+     * the HTIF console, otherwise we fall back to use the custom base
+     * passed from device tree for the HTIF console.
+     */
+    if (!firmware_name && !machine->kernel_filename) {
+        htif_custom_base = true;
+    } else {
+        if (firmware_name) {
+            htif_custom_base = !spike_test_elf_image(firmware_name);
+        }
+        if (!htif_custom_base && machine->kernel_filename) {
+            htif_custom_base = !spike_test_elf_image(machine->kernel_filename);
+        }
+    }
+
+    /* Load firmware */
+    if (firmware_name) {
+        firmware_end_addr = riscv_load_firmware(firmware_name,
+                                                memmap[SPIKE_DRAM].base,
+                                                htif_symbol_callback);
+        g_free(firmware_name);
+    }
 
     /* Load kernel */
     if (machine->kernel_filename) {
@@ -279,7 +319,7 @@ static void spike_board_init(MachineState *machine)
 
     /* Create device tree */
     create_fdt(s, memmap, machine->ram_size, machine->kernel_cmdline,
-               riscv_is_32bit(&s->soc[0]));
+               riscv_is_32bit(&s->soc[0]), htif_custom_base);
 
     /* Load initrd */
     if (machine->kernel_filename && machine->initrd_filename) {
@@ -307,7 +347,8 @@ static void spike_board_init(MachineState *machine)
                               fdt_load_addr);
 
     /* initialize HTIF using symbols found in load_kernel */
-    htif_mm_init(system_memory, serial_hd(0), memmap[SPIKE_HTIF].base);
+    htif_mm_init(system_memory, serial_hd(0), memmap[SPIKE_HTIF].base,
+                 htif_custom_base);
 }
 
 static void spike_machine_instance_init(Object *obj)

include/hw/char/riscv_htif.h

@@ -44,11 +44,8 @@ typedef struct HTIFState {
 void htif_symbol_callback(const char *st_name, int st_info, uint64_t st_value,
     uint64_t st_size);
 
-/* Check if HTIF uses ELF symbols */
-bool htif_uses_elf_symbols(void);
-
 /* legacy pre qom */
 HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
-                        uint64_t nonelf_base);
+                        uint64_t nonelf_base, bool custom_base);
 
 #endif