hw/loongarch/virt: Add BSP support with aux boot code

If system boots directly from Linux kernel, BSP core jumps to kernel
entry of Linux kernel image and other APs jump to aux boot code. Instead
BSP and APs can all jump to aux boot code like UEFI bios.

With aux boot code, BSP core is judged from physical cpu id, whose
cpu id is 0. With BSP core, load data to register A0-A2 and PC.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-ID: <20250906070200.3749326-2-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>

diff --git a/hw/loongarch/boot.c b/hw/loongarch/boot.c
index 14d6c52d4e4d5ae0f30ad10ae356d8c403b8d908..4962668e5ac664c46846a26c0b483808c0e455fc 100644 (file)
--- a/hw/loongarch/boot.c
+++ b/hw/loongarch/boot.c
@@ -35,13 +35,19 @@ struct loongarch_linux_hdr {
     uint32_t pe_header_offset;
 } QEMU_PACKED;
 
-static const unsigned int slave_boot_code[] = {
+static const unsigned int aux_boot_code[] = {
                   /* Configure reset ebase.                    */
     0x0400302c,   /* csrwr      $t0, LOONGARCH_CSR_EENTRY      */
 
                   /* Disable interrupt.                        */
     0x0380100c,   /* ori        $t0, $zero,0x4                 */
     0x04000180,   /* csrxchg    $zero, $t0, LOONGARCH_CSR_CRMD */
+    0x03400000,   /* nop                                       */
+
+    0x0400800c,   /* csrrd      $t0, LOONGARCH_CSR_CPUNUM      */
+    0x034ffd8c,   /* andi       $t0, $t0, 0x3ff                */
+    0x0015000d,   /* move       $t1, $zero                     */
+    0x5800718d,   /* beq        $t0, $t1, 112                  */
 
                   /* Clear mailbox.                            */
     0x1400002d,   /* lu12i.w    $t1, 1(0x1)                    */
@@ -81,6 +87,26 @@ static const unsigned int slave_boot_code[] = {
     0x06480dac,   /* iocsrrd.d  $t0, $t1                       */
     0x00150181,   /* move       $ra, $t0                       */
     0x4c000020,   /* jirl       $zero, $ra,0                   */
+                  /* BSP Core                                  */
+    0x03400000,   /* nop                                       */
+    0x1800000d,   /* pcaddi     $t1, 0                         */
+    0x28c0a1a4,   /* ld.d       $a0, $t1, 40                   */
+    0x1800000d,   /* pcaddi     $t1, 0                         */
+    0x28c0a1a5,   /* ld.d       $a1, $t1, 40                   */
+    0x1800000d,   /* pcaddi     $t1, 0                         */
+    0x28c0a1a6,   /* ld.d       $a2, $t1, 40                   */
+    0x1800000d,   /* pcaddi     $t1, 0                         */
+    0x28c0a1ac,   /* ld.d       $t0, $t1, 40                   */
+    0x00150181,   /* move       $ra, $t0                       */
+    0x4c000020,   /* jirl       $zero, $ra,0                   */
+    0x00000000,   /* .dword 0   A0                             */
+    0x00000000,
+    0x00000000,   /* .dword 0   A1                             */
+    0x00000000,
+    0x00000000,   /* .dword 0   A2                             */
+    0x00000000,
+    0x00000000,   /* .dword 0   PC                             */
+    0x00000000,
 };
 
 static inline void *guidcpy(void *dst, const void *src)
@@ -391,6 +417,7 @@ static void loongarch_direct_kernel_boot(MachineState *ms,
     int64_t kernel_addr = VIRT_FLASH0_BASE;
     LoongArchCPU *lacpu;
     CPUState *cs;
+    uint64_t *data;
 
     if (info->kernel_filename) {
         kernel_addr = load_kernel_info(info);
@@ -408,7 +435,12 @@ static void loongarch_direct_kernel_boot(MachineState *ms,
 
     /* Load slave boot code at pflash0 . */
     void *boot_code = g_malloc0(VIRT_FLASH0_SIZE);
-    memcpy(boot_code, &slave_boot_code, sizeof(slave_boot_code));
+    memcpy(boot_code, &aux_boot_code, sizeof(aux_boot_code));
+    data = (uint64_t *)(boot_code + sizeof(aux_boot_code));
+    *(data - 4) = cpu_to_le64(info->a0);
+    *(data - 3) = cpu_to_le64(info->a1);
+    *(data - 2) = cpu_to_le64(info->a2);
+    *(data - 1) = cpu_to_le64(kernel_addr);
     rom_add_blob_fixed("boot_code", boot_code, VIRT_FLASH0_SIZE, VIRT_FLASH0_BASE);
 
     CPU_FOREACH(cs) {