Hi,
we have an issue using QEMUs MIPS user space emulation
running programs compiled with mipsel glibc based
crosscompiler [1]. Because I'm not sure if it's a QEMU or
toolchain (or anything else?) issue, I'd like to ask the
experts here.
Up to now, the conclusion from [1] is that QEMUs mipsel user
space emulation fails executing a simple hello world program
if compiled with glibc based mipsel toolchain build with
crosstool and linked dynamically. Compiled with toolchain
using uClib or same program linked statically (-static) is okay.
For example, hello world compiled with mipsel toolchain
build with crosstool-0.42 configuration
cat mipsel.dat gcc-3.4.1-glibc-2.3.2.dat
fails if dynamically linked. As mentioned above, using
-static is okay.
If failing, debug output shows that code
...
0x401fa00c: lw t9,-32600(gp)
0x401fa010: addiu a0,a0,30820
0x401fa014: addiu a1,a1,29452
0x401fa018: addiu a3,a3,25856
0x401fa01c: jalr t9
0x401fa020: li a2,161
...
fails because it seems that it gets a wrong jump address in t9:
pc=0x00012a2c HI=0x00000000 LO=0x00000000 ds 0003 00000000 0
GPR00: r0 00000000 at 00000000 v0 401f60d4 v1 00000008
GPR04: a0 00017864 a1 0001730c a2 000000a1 a3 00016500
GPR08: t0 90000000 t1 401f6000 t2 40000000 t3 6fffffff
GPR12: t4 70000053 t5 401f3c20 t6 401f3f20 t7 00000063
GPR16: s0 6fffff72 s1 00000000 s2 00000000 s3 00000000
GPR20: s4 00000000 s5 00000000 s6 00000000 s7 00000000
GPR24: t8 6ffffdff t9 00012a2c k0 00000000 k1 00000000
GPR28: gp 40257020 sp 401f3c08 s8 00000000 ra 401fa024
CP0 Status 0x30400014 Cause 0x00000000 EPC 0x00000000
Config0 0x80000082 Config1 0x1e190c8b LLAddr 0x00000000
CP1 FCR0 0x00000110 FCR31 0x00000000 SR.FR 0
...
cpu_mips_handle_mmu_fault pc 00012a2c ad 00012a2c rw 0
is_user 1 smmu 0
Any ideas or hints where to search?
Many thanks
Dirk
[1] Thread "MIPS little endian user space emulation" on QEMU
devel mailinglist
http://lists.gnu.org/archive/html/qemu-devel/2006-09/msg00090.html
