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3b65b74254
The current qemu hppa emulation emulates a PA1.1 CPU, which can only execute the 32-bit instruction set. For unknown 64-bit instructions, a instruction trap is sent to the virtual CPU. This behaviour is correct in the sense that we emulate what the PA1.1 specification says. But when trying to boot older Linux installation images, e.g. ftp://parisc.parisc-linux.org/debian-cd/debian-5.0/lenny-5.0.10-hppa-iso-cd/cdimage.debian.org/debian-5010-hppa-netinst.iso one finds that qemu fails to boot those images. The problem is, that in the Linux kernel (e.g. 2.6.26) of those old images 64-bit instructions were used by mistake in the fault handlers. The relevant instructions (the ",*" indicates that it's a 64-bit instruction) I see are: 0: 09 3e 04 29 sub,* sp,r9,r9 0: 08 3d 06 3d add,* ret1,r1,ret1 0: 0a 09 02 61 or,* r9,r16,r1 0: 0a ba 00 3a andcm,* r26,r21,r26 0: 08 33 02 33 and,* r19,r1,r19 The interesting part is, that real physical 32-bit machines (like the 700/64 and B160L - which is the one we emulate) do boot those images and thus seem to simply ignore the 64-bit flag on those instructions. The patch below modifies the qemu instruction decoder to ignore the 64-bit flag too - which is what real 32-bit hardware seems to do. With this modification qemu now successfully boots those older images too. I suggest to apply the patch below - even if it does not reflect what the SPEC says. Instead it increases the compatibility to really existing hardware and seem to not create problems if we add real PA2.0 support anytime later. Signed-off-by: Helge Deller <deller@gmx.de> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> |
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| .. | ||
| cpu-param.h | ||
| cpu-qom.h | ||
| cpu.c | ||
| cpu.h | ||
| gdbstub.c | ||
| helper.c | ||
| helper.h | ||
| insns.decode | ||
| int_helper.c | ||
| machine.c | ||
| mem_helper.c | ||
| meson.build | ||
| op_helper.c | ||
| trace-events | ||
| trace.h | ||
| translate.c | ||