On 10/22/2013 10:14 AM, Christian Menard wrote:
On October 21st, 2013, 12:20 p.m. UTC, *Andreas Sandberg* wrote:
It seems like the diff doesn't apply cleanly in RB. It happens from
time to time, it's kinda crap.
I think you probably don't want to add the 'default: Inst::INT(Ib);' to
the SE-mode case, just using 'Inst::INT(Ib)' as the default when FullSystemInt
!= 0 should suffice. I'd be very surprised if taking an interrupt in SE mode is
going to do anything sensible.
I think you should be able to do 'limm t1, imm, dataSize=8' instead of
clearing t1 first.
Also, are you sure the long mode test is correct? Isn't it supposed to
be something like this:
andi t0, t5, 0x1, flags=(EZF,)
br rom_label("longModeSoftInterrupt"), flags=(nCEZF,)
IIRC, the least significant bit of the handy m5 reg is 0 for long mode
and 1 for the the legacy modes.
You are right about 'default: Inst::INT(Ib);', I just put it into the wrong
block.
I thought about using 'limm t1, imm, dataSize=8' too. But I'm not sure how the
byte sized immediate is treated. I think it will be sign extended this way.
You're right, it seems like the immediate is sign extended in the
decode. It seems like the "right" way to solve it in that case is this
(stolen from OUT_I_R):
.adjust_imm trimImm(8)
limm t1, imm, dataSize=8
The .adjust_imm statement masks out the lower 8 bits of the immediate
when the macro instruction is created, which means that the limm
statement will load 0 into the high 56 bits of t1.
The long mode test is correct. It does not check the IIRC but the 3 bits left
of it. They represent the submode, in 64-bit mode these bits are 0. But just
checking the least significant bit should do the same trick. But in the 'br'
instruction ypu have to check for the 'CEZF', because the result of the 'andi'
is 0 in long mode.
I might be wrong here, but I really don't think that's the case. For
example, X86FaultBase::invoke() only checks the mode field (the least
significant bit) when selecting which interrupt delivery entry point to
use. If I understand the x86 modes correctly, you would be in LongMode
and submode CompatabilityMode (submode 1) when running 32-bit code on a
64-bit kernel. In this case, you probably want to run the long-mode
code. Your code would run the legacy mode interrupt code in that case,
which I believe to be wrong.
//Andreas
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