Hello,
I'm new to PowerPC and encounter some problems booting Linux on a custom
MPC8270 board.
The boot sequence goes wrong at the begining of the MMU init, in MMU_init_hw().
[arch/powerpc/mm/ppc_mmu_32.c]
...
if (!cpu_has_feature(CPU_FTR_HPTE_TABLE)) {
/*
* Put a blr (procedure return) instruction at the
* start of hash_page, since we can still get DSI
* exceptions on a 603.
*/
hash_page[0] = 0x4e800020;
flush_icache_range((unsigned long) &hash_page[0], <- Never returns
(unsigned long) &hash_page[1]);
return;
}
...
the problem in flush_icache_range occurs when the first cache block is copied
to memory, at dcbst instruction:
[arch/powerpc/kernel/misc_32.S]
...
_KPROBE(__flush_icache_range)
BEGIN_FTR_SECTION
blr /* for 601, do nothing */
END_FTR_SECTION_IFSET(CPU_FTR_COHERENT_ICACHE)
li r5,L1_CACHE_BYTES-1
andc r3,r3,r5
subf r4,r3,r4
add r4,r4,r5
srwi. r4,r4,L1_CACHE_SHIFT
beqlr
mtctr r4
mr r6,r3
1: dcbst 0,r3 <- Control is lost here
addi r3,r3,L1_CACHE_BYTES
bdnz 1b
sync
...
By stepping, I lose debugger control at this point. No exception seems to
occur. No more log is stored in the log buffer. The instruction seems to
never end.
L1_CACHE_BYTES has the value (1 << 5), corresponding the CONFIG_PPC32
config.
R0 00030040
R1 C0311FC0
R2 C02F7578
R3 C0014B20
R4 1
R5 1F
R6 C031B456
R7 C0320000
Any idea on possible causes or ways to improve my investigations would be
greatly appreciated.
Best regards,
Rémi Lefevre
---
Versions:
(U-Boot 1.3.4)
linux-2.6-denx.git from today
(linux-2.6-denx-63646fc60b177cfc511d8d35a9134902f41f9898)
Kernel configuration is identical to pq2fads:
CONFIG_6xx=y
CONFIG_PPC_FPU=y
CONFIG_PPC_STD_MMU=y
CONFIG_PPC_STD_MMU_32=y
CONFIG_PPC32=y
CONFIG_WORD_SIZE=32
CONFIG_PPC_MERGE=y
CONFIG_MMU=y
CONFIG_GENERIC_CMOS_UPDATE=y
CONFIG_GENERIC_TIME=y
CONFIG_GENERIC_TIME_VSYSCALL=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_HARDIRQS=y
CONFIG_IRQ_PER_CPU=y
CONFIG_RWSEM_XCHGADD_ALGORITHM=y
CONFIG_ARCH_HAS_ILOG2_U32=y
CONFIG_GENERIC_HWEIGHT=y
CONFIG_GENERIC_CALIBRATE_DELAY=y
CONFIG_GENERIC_FIND_NEXT_BIT=y
CONFIG_PPC=y
CONFIG_EARLY_PRINTK=y
CONFIG_GENERIC_NVRAM=y
CONFIG_SCHED_NO_NO_OMIT_FRAME_POINTER=y
CONFIG_ARCH_MAY_HAVE_PC_FDC=y
CONFIG_PPC_OF=y
CONFIG_OF=y
CONFIG_AUDIT_ARCH=y
CONFIG_GENERIC_BUG=y
CONFIG_DEFAULT_UIMAGE=y
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