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hw/xtensa/xtfpga: rewrite mini bootloader

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Don't load jump target into the CPU config, instead put it and initial
a2 as literals into the mini bootloader and use l32r to load them
natively. With these changes it should be possible to do warm reboot of
the guest.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2017-12-21 20:51:05 -08:00
parent 997eba28a3
commit 339ef8fb6a
1 changed files with 23 additions and 5 deletions
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28
hw/xtensa/xtfpga.c
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@ -372,15 +372,33 @@ static void lx_init(const LxBoardDesc *board, MachineState *machine)
}
}
if (entry_point != env->pc) {
static const uint8_t jx_a0[] = {
uint8_t boot[] = {
#ifdef TARGET_WORDS_BIGENDIAN
0x0a, 0, 0,
0x60, 0x00, 0x08, /* j 1f */
0x00, /* .literal_position */
0x00, 0x00, 0x00, 0x00, /* .literal entry_pc */
0x00, 0x00, 0x00, 0x00, /* .literal entry_a2 */
/* 1: */
0x10, 0xff, 0xfe, /* l32r a0, entry_pc */
0x12, 0xff, 0xfe, /* l32r a2, entry_a2 */
0x0a, 0x00, 0x00, /* jx a0 */
#else
0xa0, 0, 0,
0x06, 0x02, 0x00, /* j 1f */
0x00, /* .literal_position */
0x00, 0x00, 0x00, 0x00, /* .literal entry_pc */
0x00, 0x00, 0x00, 0x00, /* .literal entry_a2 */
/* 1: */
0x01, 0xfe, 0xff, /* l32r a0, entry_pc */
0x21, 0xfe, 0xff, /* l32r a2, entry_a2 */
0xa0, 0x00, 0x00, /* jx a0 */
#endif
};
env->regs[0] = entry_point;
cpu_physical_memory_write(env->pc, jx_a0, sizeof(jx_a0));
uint32_t entry_pc = tswap32(entry_point);
uint32_t entry_a2 = tswap32(tagptr);
memcpy(boot + 4, &entry_pc, sizeof(entry_pc));
memcpy(boot + 8, &entry_a2, sizeof(entry_a2));
cpu_physical_memory_write(env->pc, boot, sizeof(boot));
}
} else {
if (flash) {