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--- etc:users:jcmvbkbc:mpc85xx-qemu-linux [2010/01/09 04:50] – создано jcmvbkbc
+++ etc:users:jcmvbkbc:mpc85xx-qemu-linux [2016/08/08 20:53] (current) – ↷ Page moved from users:jcmvbkbc:mpc85xx-qemu-linux to etc:users:jcmvbkbc:mpc85xx-qemu-linux kel
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 ====== Booting linux on qemu-mpc85xx on x86 ======
+Even though qemu have ppce500_mpc8544ds board inside, it relies on kvm to manage MMU stuff. Thus to run it one need PPC host (correct me if I'm wrong).
+Let's try to emulate BookE MMU in qemu and boot linux.
+===== Plan =====
+  * build ppc linux kernel for mpc8544;
+  * build qemu that can boot this kernel;
+  * try to boot it and fix all that's broken along the way;
+===== PPC kernel =====
+  * need dtc to compile it;
+  * description of FDT and how kernel expects it: Documentation/powerpc/booting-without-of.txt;
+  * modify arch/powerpc/boot/wrapper -- link_address is too low (0x400000 -> 0x800000);
+  * boot sequence:
+<code>
+arch/powerpc/boot/crt0.S (basic platform init)
+arch/powerpc/boot/main.c (unzip kernel to PA 0 and jump to it)
+arch/powerpc/kernel/head_fsl_booke.S (MMU/vectors setup)
+</code>
+  * use x/s sprint_buf to see what kernel prints (unless you see serial port output -- I don't);
+===== Qemu that can boot -M mpc8544ds -kernel =====
+  * need libfdt: take it from scripts/dtc/libfdt, use Makefile:
+<file>
+# Makefile.libfdt
+#
+# This is not a complete Makefile of itself.  Instead, it is designed to
+# be easily embeddable into other systems of Makefiles.
+#
+LIBFDT_INCLUDES = fdt.h libfdt.h
+LIBFDT_SRCS = fdt.c fdt_ro.c fdt_wip.c fdt_sw.c fdt_rw.c fdt_strerror.c
+LIBFDT_OBJS = $(LIBFDT_SRCS:%.c=%.o)
+LIBFDT_SRCS = fdt.c fdt_ro.c fdt_wip.c fdt_sw.c fdt_rw.c fdt_strerror.c
+LIBFDT_INCLUDES = fdt.h libfdt.h
+LIBFDT_EXTRA = libfdt_internal.h
+LIBFDT_LIB = libfdt/libfdt.a
+LIBFDT_SHARED_LIB=libfdt.so
+LIBFDT_OBJS = $(LIBFDT_SRCS:%.c=%.o)
+CFLAGS += -fPIC -I .
+$(LIBFDT_objdir)/$(LIBFDT_LIB): $(addprefix $(LIBFDT_objdir)/,$(LIBFDT_OBJS))
+$(LIBFDT_SHARED_LIB): $(LIBFDT_OBJS)
+        $(CC) -shared -o $(LIBFDT_SHARED_LIB) $^
+clean:
+        rm -f $(LIBFDT_SHARED_LIB) $(LIBFDT_OBJS)
+</file>
+  * install libfdt.so, fdt.h, libfdt.h, libfdt_env.h
+  * configure qemu: ../qemu/configure --enable-system --disable-linux-user --enable-fdt --target-list=ppc-softmmu --prefix=`pwd`/root "$@"
+  * apply some patches :TODO:
+===== Next steps =====
+Ok, we've got to _start, but somehow stuck here.
+  * what's the initial MMU setup on entry to kernel? see arch/powerpc/kvm/e500_tlb.c, esp. kvmppc_e500_tlb_setup;
+  * why exception in the first mfmsr? mmu_idx, mem_idx -- ??
+  * implement tlbsx (done), tlbre (done), tlbwe (done), tlbivax (done) for BookE (needed by arch/powerpc/kernel/head_fsl_booke.S)
+  * how softmmu works? how to substitute existing PPC softmmu by TLB-based one?
+  * what is hardware TLB entry replacement policy/hash function?
+  * need to refactor the whole TLB thing for BookE PPC
+===== References =====
+  * [[http://www.power.org/resources/downloads/PowerISA_V2.06_PUBLIC.pdf|PowerISA 2.06]]
+  * [[http://www.google.ru/url?sa=t&source=web&ct=res&cd=3&ved=0CBMQFjAC&url=http%3A%2F%2Fwww.freescale.com%2Ffiles%2F32bit%2Fdoc%2Fref_manual%2FE500CORERM.pdf&rct=j&q=e500corerm.pdf&ei=BbNbS7WpOsyF-AaL1tD4CQ&usg=AFQjCNHTUfqYcCfN1rAgkHpbeyJnSCF-WQ|E500 core reference manual (e500corerm.pdf)]]