On Sat, Nov 21, 2015 at 10:14 PM, Ben Gardner gardner.ben@gmail.com wrote:
I think I found the issue, but won't be able to test for another week.
car_get_var_ptr() assumes that the migrated base is the same as _car_data_start. On FSP 1.0, that isn't true. _car_data_start is 0x0c00 bytes past migrated base.
The last two lines of car_get_var_ptr() read as follows: offset = (char *)var - (char *)_car_data_start; return &migrated_base[offset];
However, migrated base matches 0xfef00000 (DCACHE_RAM_BASE), while _car_data_start is 0xfef00c00. So, when the data is migrated, the migrated offset is wrong and cbmem_console_p is fairly random.
It worked when I moved _preram_cbmem_console because that put _car_data_start at 0xfef00000 again. A simple fix would be to use CONFIG_DCACHE_RAM_BASE instead of _car_data_start when calculating the base.
I think we may also need Aaron's earlier patch proposed in this thread, as _preram_cbmem_console is not between _car_data_start and _car_data_end.
Yes. We should bring that patch in.
The fix might be something like the following: (gmail ate my tabs).
What do you think?
--- a/src/cpu/x86/car.c +++ b/src/cpu/x86/car.c @@ -63,15 +63,15 @@ void *car_get_var_ptr(void *var) #if IS_ENABLED(CONFIG_PLATFORM_USES_FSP1_0) migrated_base=(char *)find_saved_temp_mem( *(void **)CBMEM_FSP_HOB_PTR);
offset = (char *)var - (char *)CONFIG_DCACHE_RAM_BASE;#else migrated_base = cbmem_find(CBMEM_ID_CAR_GLOBALS);
offset = (char *)var - (char *)_car_start;#endif
if (migrated_base == NULL) die( "CAR: Could not find migration base!\n");
offset = (char *)var - (char *)_car_start;return &migrated_base[offset];}
That makes sense. FSP 1.0 moves entire CAR region while coreboot only moves the CAR_GLOBALs proper. So the relative offset changes depending on object layout.
On Fri, Nov 20, 2015 at 5:11 PM, Ben Gardner gardner.ben@gmail.com wrote:
On Fri, Nov 20, 2015 at 4:56 PM, Ben Gardner gardner.ben@gmail.com wrote:
Ug. I was looking at the wrong log. Time for a break.
The output from the log was: Stack: fef03fc4 or fef03fcc
That seems to match the settings: CONFIG_DCACHE_RAM_BASE=0xfef00000 CONFIG_DCACHE_RAM_SIZE=0x4000
For what it is worth, I verified that ECX = 0xfef00000 and EDX = 0xfef04000 when the FSP's TempRamIinitEntry() function returns. The CAR global data makes more sense now, as that is mapped to the bottom of the temporary stack area. The CAR data location is correct and the stack data does indeed appear to have been copied correctly to 0x7ae230a0. I think I'm looking in the wrong area.
Oh, well. I'll look at it again after the Thanksgiving holiday.
Ben
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Aaron Durbin