Hi, Philippe, On Mon, Dec 14, 2020 at 9:49 PM Philippe Mathieu-Daudé <f4...@amsat.org> wrote: > > On 12/14/20 3:37 AM, Huacai Chen wrote: > > Hi, Philippe, > > > > On Mon, Dec 14, 2020 at 7:09 AM Philippe Mathieu-Daudé <f4...@amsat.org> > > wrote: > >> > >> On 12/13/20 11:17 PM, Philippe Mathieu-Daudé wrote: > >>> On 12/11/20 12:32 PM, Philippe Mathieu-Daudé wrote: > >>>> On 12/11/20 3:46 AM, Huacai Chen wrote: > >>>>> Hi, Rechard and Peter, > >>>>> > >>>>> On Wed, Dec 2, 2020 at 5:32 PM Philippe Mathieu-Daudé <f4...@amsat.org> > >>>>> wrote: > >>>>>> > >>>>>> On 12/2/20 2:14 AM, Huacai Chen wrote: > >>>>>>> Hi, Phillippe, > >>>>>>> > >>>>>>> On Tue, Nov 24, 2020 at 6:25 AM Philippe Mathieu-Daudé > >>>>>>> <f4...@amsat.org> wrote: > >>>>>>>> > >>>>>>>> On 11/6/20 5:21 AM, Huacai Chen wrote: > >>>>>>>>> Preparing to add Loongson-3 machine support, add Loongson-3's LEFI > >>>>>>>>> (a > >>>>>>>>> UEFI-like interface for BIOS-Kernel boot parameters) helpers first. > >>>>>>>>> > >>>>>>>>> Reviewed-by: Philippe Mathieu-Daudé <f4...@amsat.org> > >>>>>>>>> Signed-off-by: Huacai Chen <che...@lemote.com> > >>>>>>>>> Co-developed-by: Jiaxun Yang <jiaxun.y...@flygoat.com> > >>>>>>>>> Signed-off-by: Jiaxun Yang <jiaxun.y...@flygoat.com> > >>>>>>>>> --- > >>>>>>>>> hw/mips/loongson3_bootp.c | 165 +++++++++++++++++++++++++++++++ > >>>>>>>>> hw/mips/loongson3_bootp.h | 241 > >>>>>>>>> ++++++++++++++++++++++++++++++++++++++++++++++ > >>>>>>>>> hw/mips/meson.build | 1 + > >>>>>>>>> 3 files changed, 407 insertions(+) > >>>>>>>>> create mode 100644 hw/mips/loongson3_bootp.c > >>>>>>>>> create mode 100644 hw/mips/loongson3_bootp.h > >>>>>>>>> > >>>>>>>>> diff --git a/hw/mips/loongson3_bootp.c b/hw/mips/loongson3_bootp.c > >>>>>>>>> new file mode 100644 > >>>>>>>>> index 0000000..3a16081 > >>>>>>>>> --- /dev/null > >>>>>>>>> +++ b/hw/mips/loongson3_bootp.c > >>>>>>>>> @@ -0,0 +1,165 @@ > >>>>>>>>> +/* > >>>>>>>>> + * LEFI (a UEFI-like interface for BIOS-Kernel boot parameters) > >>>>>>>>> helpers > >>>>>>>>> + * > >>>>>>>>> + * Copyright (c) 2018-2020 Huacai Chen (che...@lemote.com) > >>>>>>>>> + * Copyright (c) 2018-2020 Jiaxun Yang <jiaxun.y...@flygoat.com> > >>>>>>>>> + * > >>>>>>>>> + * This program is free software: you can redistribute it and/or > >>>>>>>>> modify > >>>>>>>>> + * it under the terms of the GNU General Public License as > >>>>>>>>> published by > >>>>>>>>> + * the Free Software Foundation, either version 2 of the License, > >>>>>>>>> or > >>>>>>>>> + * (at your option) any later version. > >>>>>>>>> + * > >>>>>>>>> + * This program is distributed in the hope that it will be useful, > >>>>>>>>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of > >>>>>>>>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > >>>>>>>>> + * GNU General Public License for more details. > >>>>>>>>> + * > >>>>>>>>> + * You should have received a copy of the GNU General Public > >>>>>>>>> License > >>>>>>>>> + * along with this program. If not, see > >>>>>>>>> <https://www.gnu.org/licenses/>. > >>>>>>>>> + */ > >>>>>>>>> + > >>>>>>>>> +#include "qemu/osdep.h" > >>>>>>>>> +#include "qemu/units.h" > >>>>>>>>> +#include "qemu/cutils.h" > >>>>>>>>> +#include "cpu.h" > >>>>>>>>> +#include "hw/boards.h" > >>>>>>>>> +#include "hw/mips/loongson3_bootp.h" > >>>>>>>>> + > >>>>>>>>> +#define LOONGSON3_CORE_PER_NODE 4 > >>>>>>>>> + > >>>>>>>>> +static struct efi_cpuinfo_loongson *init_cpu_info(void *g_cpuinfo, > >>>>>>>>> uint64_t cpu_freq) > >>>>>>>>> +{ > >>>>>>>>> + struct efi_cpuinfo_loongson *c = g_cpuinfo; > >>>>>>>>> + > >>>>>>>>> + stl_le_p(&c->cputype, Loongson_3A); > >>>>>>>>> + stl_le_p(&c->processor_id, MIPS_CPU(first_cpu)->env.CP0_PRid); > >>>>>>>> > >>>>>>>> Build failing with Clang: > >>>>>>>> > >>>>>>>> FAILED: libqemu-mips64el-softmmu.fa.p/hw_mips_loongson3_bootp.c.o > >>>>>>>> hw/mips/loongson3_bootp.c:35:15: error: taking address of packed > >>>>>>>> member > >>>>>>>> 'processor_id' of class or structure 'efi_cpuinfo_loongson' may > >>>>>>>> result > >>>>>>>> in an unaligned pointer value [-Werror,-Waddress-of-packed-member] > >>>>>>>> stl_le_p(&c->processor_id, MIPS_CPU(first_cpu)->env.CP0_PRid); > >>>>>>>> ^~~~~~~~~~~~~~~ > >>>>>>>> 1 error generated. > >>>>>>> We cannot reproduce it on X86/MIPS with clang... > >>>>>> > >>>>>> You can reproduce running the Clang job on Gitlab-CI: > >>>>>> > >>>>>> https://wiki.qemu.org/Testing/CI/GitLabCI > >>>>>> > >>>>>>> And I found that > >>>>>>> stl_le_p() will be __builtin_memcpy(), I don't think memcpy() will > >>>>>>> cause unaligned access. So, any suggestions? > >>>> > >>>> My understanding is the compiler is complaining for the argument > >>>> passed to the caller, with no knowledge of the callee implementation. > >>>> > >>>> Which makes me wonder if these functions are really inlined... > >>>> > >>>> Do we need to use QEMU_ALWAYS_INLINE for these LDST helpers? > >>> > >>> No, this doesn't work neither. > >> > >> Well, this works: > >> > >> -- >8 -- > >> @@ -32,7 +32,7 @@ static struct efi_cpuinfo_loongson *init_cpu_info(void > >> *g_cpuinfo, uint64_t cpu_ > >> struct efi_cpuinfo_loongson *c = g_cpuinfo; > >> > >> stl_le_p(&c->cputype, Loongson_3A); > >> - stl_le_p(&c->processor_id, MIPS_CPU(first_cpu)->env.CP0_PRid); > >> + c->processor_id = cpu_to_le32(MIPS_CPU(first_cpu)->env.CP0_PRid); > >> if (cpu_freq > UINT_MAX) { > >> stl_le_p(&c->cpu_clock_freq, UINT_MAX); > >> } else { > > > > This seems not allowed. In include/qemu/bswap.h it says: > > * Do an in-place conversion of the value pointed to by @v from the > > * native endianness of the host CPU to the specified format. > > * > > * Both X_to_cpu() and cpu_to_X() perform the same operation; you > > * should use whichever one is better documenting of the function your > > * code is performing. > > * > > * Do not use these functions for conversion of values which are in guest > > * memory, since the data may not be sufficiently aligned for the host CPU's > > * load and store instructions. Instead you should use the ld*_p() and > > * st*_p() functions, which perform loads and stores of data of any > > * required size and endianness and handle possible misalignment. > > > > And there is a very strange problem, nearly all 32bit members are > > after a 16bit vers member, why only processor_id is special? Compiler > > bug? > > This is what I wonder since some time but I don't have the knowledge > to confirm. > > Indeed I commented the "stl_le_p(&c->processor_id, ...);" line, > and there is no error for the following 32-bit values, which are > similarly unlikely 32-bit aligned. > > FWIW I am using Fedora release 32 (Thirty Two), and 'cc -v': > > clang version 10.0.1 (Fedora 10.0.1-3.fc32) > Target: x86_64-unknown-linux-gnu > clang -cc1 version 10.0.1 based upon LLVM 10.0.1 default target > x86_64-unknown-linux-gnu > Since cpu_to_le32() "solve" the problem here, I want to use cpu_to_lexx() for all members, do you agree?
Huacai > > > > Huacai > >> --- > >> > >>> > >>>> > >>>> I see Richard used it in commit 80d9d1c6785 ("cputlb: Split out > >>>> load/store_memop"). > >>>> > >>>>>> > >>>>>> I'll defer this question to Richard/Peter who have deeper > >>>>>> understanding. > >>>>> Any sugguestions? Other patches are updated, except this one. > >>>> > >>>> Searching on the list, I see Marc-André resolved that by > >>>> using a copy on the stack: > >>>> https://www.mail-archive.com/qemu-devel@nongnu.org/msg614482.html