[U-Boot] [PATCH v3 00/11] SMP support for RISC-V

[Auer, Lukas <lukas.auer@aisec.fraunhofer.de>]

On Wed, 2019-03-20 at 05:37 -0700, Palmer Dabbelt wrote:
> On Sun, 17 Mar 2019 11:28:31 PDT (-0700), 
> lukas.auer at aisec.fraunhofer.de wrote:
> > This patch series adds SMP support for RISC-V to U-Boot. It allows
> > U-Boot to run on multi-hart systems (hart is the RISC-V terminology
> > for
> > hardware thread). Images passed to bootm will be started on all
> > harts.
> > The bootm command is currently the only one that will boot images
> > on all
> > harts, bootefi is not yet supported.
> > 
> > The patches have been successfully tested on both QEMU (machine and
> > supervisor mode) and the HiFive Unleashed board (supervisor mode),
> > using
> > BBL and OpenSBI.
> > Mainline QEMU requires two patches [1, 2] to run in this
> > configuration.
> > Patch [1] has been dropped and will be replaced with a U-Boot
> > patch.
> > 
> > [1]: https://patchwork.ozlabs.org/patch/1039493/
> 
> As far as I understand it we're taking a different approach here, so
> this patch 
> won't be going in.
> 
> > [2]: https://patchwork.ozlabs.org/patch/1039082/
> 
> This should be in rc0, LMK if I screwed something up.
> 
> Thanks for the patches, and also for testing on the board :)
> 

Everything looks good, thanks for merging the patch!

U-Boot with the SMP patches now runs in supervisor mode on mainline
QEMU. I will send a U-Boot patch later this week to get it running in
machine mode on mainline QEMU as well.

Thanks,
Lukas

> > Changes in v3:
> > - Print error if riscv_send_ipi() fails
> > - Adjust error message for failures of riscv_clear_ipi() to match
> > error
> > message for failures of riscv_send_ipi()
> > - New patch to save the hart ID in register tp instead of s0
> > - Adjust patch to use the new location of the hart ID (register tp)
> > - New patch to hang if relocation of secondary harts fails
> > 
> > Changes in v2:
> > - Remove unneeded quotes from NR_CPUS Kconfig entry
> > - Move memory barrier from send_ipi_many() to handle_ipi()
> > - Add check in send_ipi_many so that IPIs are only sent to
> > available
> > harts as indicated by the available_harts mask
> > - Implement hart lottery to pick main hart to run U-Boot
> > - Remove CONFIG_MAIN_HART as it is not required anymore
> > - Register available harts in the available_harts mask
> > - New patch to populate register a0 with the hart ID from the
> > mhartid
> > CSR in machine-mode
> > - New patch to enable SMP on the SiFive FU540, which was previously
> > sent
> > independently
> > 
> > Lukas Auer (11):
> >   riscv: add infrastructure for calling functions on other harts
> >   riscv: import the supervisor binary interface header file
> >   riscv: implement IPI platform functions using SBI
> >   riscv: delay initialization of caches and debug UART
> >   riscv: save hart ID in register tp instead of s0
> >   riscv: add support for multi-hart systems
> >   riscv: boot images passed to bootm on all harts
> >   riscv: do not rely on hart ID passed by previous boot stage
> >   riscv: hang if relocation of secondary harts fails
> >   riscv: fu540: enable SMP
> >   riscv: qemu: enable SMP
> > 
> >  arch/riscv/Kconfig                   |  28 +++++
> >  arch/riscv/cpu/cpu.c                 |   9 +-
> >  arch/riscv/cpu/start.S               | 167
> > +++++++++++++++++++++++++--
> >  arch/riscv/include/asm/csr.h         |   1 +
> >  arch/riscv/include/asm/global_data.h |   6 +
> >  arch/riscv/include/asm/sbi.h         |  94 +++++++++++++++
> >  arch/riscv/include/asm/smp.h         |  53 +++++++++
> >  arch/riscv/lib/Makefile              |   2 +
> >  arch/riscv/lib/asm-offsets.c         |   1 +
> >  arch/riscv/lib/bootm.c               |  13 ++-
> >  arch/riscv/lib/sbi_ipi.c             |  25 ++++
> >  arch/riscv/lib/smp.c                 | 118 +++++++++++++++++++
> >  board/emulation/qemu-riscv/Kconfig   |   1 +
> >  board/sifive/fu540/Kconfig           |   1 +
> >  14 files changed, 507 insertions(+), 12 deletions(-)
> >  create mode 100644 arch/riscv/include/asm/sbi.h
> >  create mode 100644 arch/riscv/include/asm/smp.h
> >  create mode 100644 arch/riscv/lib/sbi_ipi.c
> >  create mode 100644 arch/riscv/lib/smp.c