On 6/8/21 9:54 AM, Kunihiko Hayashi wrote:
Hi,
[...]
I would expect that after relocation, if all you have is env_nowhere
driver, the env_nowhere_init() is called again from the first
for() loop
of env_init() [1], which would set gd->env_valid to ENV_INVALID
[1], and
that for() loop would exit with ret = -ENOENT [2], so then the
last part
of env_init() would check for ret == -ENOENT and update
gd->env_addr to
relocated default_environment [3].
324 int env_init(void)
325 {
326 struct env_driver *drv;
327 int ret = -ENOENT;
328 int prio;
329
330 for (prio = 0; (drv = env_driver_lookup(ENVOP_INIT, prio));
prio++) {
/* Part [1] */
331 if (!drv->init || !(ret = drv->init()))
332 env_set_inited(drv->location);
333 if (ret == -ENOENT)
334 env_set_inited(drv->location);
335
336 debug("%s: Environment %s init done (ret=%d)\n", __func__,
337 drv->name, ret);
338
/* Part [2] */
339 if (gd->env_valid == ENV_INVALID)
340 ret = -ENOENT;
341 }
342
343 if (!prio)
344 return -ENODEV;
345
/* Part [3] */
346 if (ret == -ENOENT) {
/* This should be relocated default_environment address */
347 gd->env_addr = (ulong)&default_environment[0];
348 gd->env_valid = ENV_VALID;
349
350 return 0;
351 }
352
353 return ret;
354 }
Or am I missing something obvious ?
These are called before relocation, and update gd->env_addr to
non-relocated
default_environment by [3].
After that, gd->env_addr is relocated in initr_reloc_global_data()
if CONFIG_SYS_RELOC_GD_ENV_ADDR is defined.
| #ifdef CONFIG_SYS_RELOC_GD_ENV_ADDR
| /*
| * Relocate the early env_addr pointer unless we know it is
not inside
| * the binary. Some systems need this and for the rest, it
doesn't hurt.
| */
| gd->env_addr += gd->reloc_off;
| #endif
Shouldn't the post-relocation env update happen in env_relocate() ?
Usually env_relocate() calls env_load() that uses relocated
gd->env_addr.
It's no problem.
If CONFIG_SYS_TEXT_BASE is zero, gd->reloc_off becomes illegal.
CONFIG_SYS_RELOC_GD_ENV_ADDR should be disabled in that case.
Sorry this isn't wrong.
But then, if CONFIG_SYS_TEXT_BASE is zero, the env shouldn't be
relocated or how should it behave ?
I think the env should be relocated if CONFIG_SYS_RELOC_GD_ENV_ADDR=y
regardless of CONFIG_SYS_TEXT_BASE.
If CONFIG_POSITION_INDEPENDENT=y and CONFIG_SYS_TEXT_BASE is zero,
there is something wrong with the calculation of the relocation address
about env.
Ah, got it.
gd->reloc_off is relocated address offset from zero, however,
gd->env_addr has still non-relocated address.
>>>> | gd->env_addr += gd->reloc_off;
I think the env should be relocated if CONFIG_SYS_RELOC_GD_ENV_ADDR=y.
But this code sets gd->env_addr incorrectly.
In that case, there is a non-relocated <textbase> address instead of
CONFIG_SYS_TEXT_BASE.
This should be "gd->env_addr = (gd->env_addr - <textbase>) +
gd->reloc_off",
However, I'm not sure how we get non-relocated <textbase> address.
Maybe what you need to do is store current $pc register when you enter
U-Boot very early on, in _start function, and then use it here ?
Although, I am not entirely sure whether this is still possible on arm64.
