QEMU installs a custom U-Boot in-memory descriptor to share board
information with Linux, which means that the QEMU machine was
initially designed to support booting Linux directly without using the
loaded FW. But, it's not that simple because the CPU still starts at
address 0xfffffffc where nothing is currently mapped. Support must
have been broken these last years.
Since we can not find a "ppc405_rom.bin" firmware file, request one to
be specified on the command line. A consequence of this change is that
the machine can be booted directly from Linux without any FW being
loaded. This is still broken and the CPU start address will be fixed
in the next changes.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-10-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
It is currently impossible to find a "ppc405_rom.bin" firmware file or
a full flash image for the PPC405EP evalution board. Even if it should
be technically possible to recreate such an image, it's unlikely that
anyone will do it since the board is obsolete and support in QEMU has
been broken for about 10 years.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-9-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
It was introduced in commit b8d3f5d126 ("Add flags to support
PowerPC 405 bootinfos variations.") but since its value has always
been set to '1'.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20211206103712.1866296-6-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
The PPC 405 CPU is a system-on-a-chip, so all 405 machines are very similar,
except for some external periphery. However, the periphery of the 'taihu'
machine is hardly emulated at all (e.g. neither the LCD nor the USB part had
been implemented), so there is not much value added by this board. The users
can use the 'ref405ep' machine to test their PPC405 code instead.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Message-Id: <20211203164904.290954-2-thuth@redhat.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-3-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
The default addresses to load the kernel, fdt, initrd of AMCC boards
in U-Boot v2015.10 are :
"kernel_addr_r=1000000\0"
"fdt_addr_r=1800000\0"
"ramdisk_addr_r=1900000\0"
The taihu is one of these boards, the ref405ep is not but we don't
have much information on it and both boards have a very similar
address space layout.
Also, if loaded at address 0, U-Boot will partially overwrite the
uImage because of a bug in get_ram_size() (U-Boot v2015.10) not
restoring properly the probed RAM contents and because the exception
vectors are installed in the same range. Finally, a gzipped kernel
image will be uncompressed at 0x0. These are all good reasons for not
mappping a kernel image at this address.
Change the kernel load address to match U-Boot expectations and fix
loading.
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20211202191446.1292125-1-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211206103712.1866296-2-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
(Applies to 7441, 7445, 7450, 7451, 7455, 7457, 7447, 7447a and 7448)
The QEMU-side software TLB implementation for the 7450 family of CPUs
is being removed due to lack of known users in the real world. The
last users in the code were removed by the two previous commits.
A brief history:
The feature was added in QEMU by commit 7dbe11acd8 ("Handle all MMU
models in switches...") with the mention that Linux was not able to
handle the TLB miss interrupts and the MMU model would be kept
disabled.
At some point later, commit 8ca3f6c382 ("Allow selection of all
defined PowerPC 74xx (aka G4) CPUs.") enabled the model for the 7450
family without further justification.
We have since the year 2011 [1] been unable to run OpenBIOS in the
7450s and have not heard of any other software that is used with those
CPUs in QEMU. Attempts were made to find a guest OS that implemented
the TLB miss handlers and none were found among Linux 5.15, FreeBSD 13,
MacOS9, MacOSX and MorphOS 3.15.
All CPUs that registered this feature were moved to an MMU model that
replaces the software TLB with a QEMU hardware TLB
implementation. They can now run the same software as the 7400 CPUs,
including the OSes mentioned above.
References:
- https://bugs.launchpad.net/qemu/+bug/812398https://gitlab.com/qemu-project/qemu/-/issues/86
- https://lists.nongnu.org/archive/html/qemu-ppc/2021-11/msg00289.html
message id: 20211119134431.406753-1-farosas@linux.ibm.com
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211130230123.781844-4-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
The e600 CPU is a successor of the 7448 and like all the 7450s CPUs,
it has an optional software TLB feature.
We have determined that there is no OS software support for the 7450
software TLB available these days. See the previous commit for more
information.
This patch disables the SPRs and instructions related to software TLB
from the e600 CPU.
No functional change intended. These facilities should be used by the
OS in interrupt handlers for interrupts that QEMU never generates.
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211130230123.781844-3-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
(Applies to 7441, 7445, 7450, 7451, 7455, 7457, 7447 and 7447a)*
We have since 2011 [1] been unable to run OpenBIOS in the 7450s and
have not heard of any other software that is used with those CPUs in
QEMU. A current discussion [2] shows that the 7450 software TLB is
unsupported in Linux 5.15, FreeBSD 13, MacOS9, MacOSX and MorphOS
3.15. With no known support in firmware or OS, this means that no code
for any of the 7450 CPUs is ever ran in QEMU.
Since the implementation in QEMU of the 7400 MMU is the same as the
7450, except for the software TLB vs. hardware TLB search, this patch
changes all 7450 cpus to the 7400 MMU model. This has the practical
effect of disabling the software TLB feature while keeping other
aspects of address translation working as expected.
This allow us to run software on the 7450 family again.
*- note that the 7448 is currently aliased in QEMU for a 7400, so it
is unaffected by this change.
1- https://bugs.launchpad.net/qemu/+bug/812398https://gitlab.com/qemu-project/qemu/-/issues/86
2- https://lists.nongnu.org/archive/html/qemu-ppc/2021-11/msg00289.html
message id: 20211119134431.406753-1-farosas@linux.ibm.com
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Message-Id: <20211130230123.781844-2-farosas@linux.ibm.com>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
When computing the predicate "is this value currently formatted
for single precision", we do not want to round the value according
to the current rounding mode, nor perform a floating-point equality.
We want to see if the N bits that make up single-precision are the
only ones set within the register, and then a bitwise equality.
Fixes a bug in which a single-precision NaN is considered !SP,
because float64_eq(nan, nan) is always false.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-35-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
There is no double-rounding bug here, because the result is
merely an estimate to within 1 part in 256, but perform the
operation with float64r32_div for consistency.
Use float_flag_invalid_snan instead of recomputing the
snan-ness of the operand.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-34-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
These variants take a float64 as input, compute the result to
infinite precision (as we do with FloatParts), round the result
to the precision and dynamic range of float32, and then return
the result in the format of float64.
This is the operation PowerPC requires for its float32 operations.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-28-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Now that vxsqrt and vxsnan are computed directly by softfloat,
we don't need to recompute it. Split out float_invalid_op_sqrt
to be used in several places. This fixes VSX_SQRT, which did
not order its tests correctly to eliminate NaN with sign set.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-25-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Now that vximz, vxisi, and vxsnan are computed directly by
softfloat, we don't need to recompute it. This replaces the
separate float{32,64}_maddsub_update_excp functions with a
single float_invalid_op_madd function.
Fix VSX_MADD by passing sfprf to float_invalid_op_madd,
whereas the previous *_maddsub_update_excp assumed it true.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-19-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Fixes a bug in which e.g XE enabled causes inexact to be raised
before the writeback to the architectural register.
All of the users of GEN_FLOAT_B either set set_fprf, or are one
of the convert-to-integer instructions that require this behaviour.
Split out the two gen_helper_* calls in gen_compute_fprf_float64
and protect only the first with set_fprf.
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211119160502.17432-12-richard.henderson@linaro.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Cédric Le Goater
Thomas Huth
Fabiano Rosas
Richard Henderson