On Thu, Jun 18, 2020 at 1:26 AM Bin Meng <bmeng...@gmail.com> wrote:
>
> On Wed, Jun 17, 2020 at 3:29 AM Atish Patra <atish.pa...@wdc.com> wrote:
> >
> > Currently, the fdt is copied to the ROM after the reset vector. The firmware
> > has to copy it to DRAM. Instead of this, directly copy the device tree to a
> > pre-computed dram address. The device tree load address should be as far as
> > possible from kernel and initrd images. That's why it is kept at the end of
> > the DRAM or 4GB whichever is lesser.
> >
> > Signed-off-by: Atish Patra <atish.pa...@wdc.com>
> > ---
> > hw/riscv/boot.c | 45 ++++++++++++++++++++++++++++++-----------
> > hw/riscv/sifive_u.c | 14 ++++++++++++-
> > hw/riscv/spike.c | 14 ++++++++++++-
> > hw/riscv/virt.c | 13 +++++++++++-
> > include/hw/riscv/boot.h | 5 ++++-
> > 5 files changed, 75 insertions(+), 16 deletions(-)
> >
> > diff --git a/hw/riscv/boot.c b/hw/riscv/boot.c
> > index 8ed96da600c9..0378b7f1bd58 100644
> > --- a/hw/riscv/boot.c
> > +++ b/hw/riscv/boot.c
> > @@ -160,25 +160,51 @@ hwaddr riscv_load_initrd(const char *filename,
> > uint64_t mem_size,
> > return *start + size;
> > }
> >
> > +hwaddr riscv_calc_fdt_load_addr(hwaddr dram_base, uint64_t mem_size, void
> > *fdt)
> > +{
> > + hwaddr temp, fdt_addr;
> > + hwaddr dram_end = dram_base + mem_size;
> > + int fdtsize = fdt_totalsize(fdt);
> > +
> > + if (fdtsize <= 0) {
> > + error_report("invalid device-tree");
> > + exit(1);
> > + }
> > + /*
> > + * We should put fdt as far as possible to avoid kernel/initrd
> > overwriting
> > + * its content. But it should be addressable by 32 bit system as well.
> > + * Thus, put it at an aligned address that less than fdt size from end
> > of
> > + * dram or 4GB whichever is lesser.
> > + */
> > + temp = MIN(dram_end, 4096 * MiB);
> > + fdt_addr = QEMU_ALIGN_DOWN(temp - fdtsize, 2 * MiB);
> > +
> > + return fdt_addr;
> > +}
> > +
> > void riscv_setup_rom_reset_vec(hwaddr start_addr, hwaddr rom_base,
> > - hwaddr rom_size, void *fdt)
> > + hwaddr rom_size,
> > + hwaddr fdt_load_addr, void *fdt)
> > {
> > int i;
> > /* reset vector */
> > - uint32_t reset_vec[8] = {
> > - 0x00000297, /* 1: auipc t0, %pcrel_hi(dtb) */
> > - 0x02028593, /* addi a1, t0, %pcrel_lo(1b) */
> > + uint32_t reset_vec[10] = {
> > + 0x00000297, /* 1: auipc t0, %pcrel_hi(fw_dyn) */
> > 0xf1402573, /* csrr a0, mhartid */
> > #if defined(TARGET_RISCV32)
> > + 0x0202a583, /* lw a1, 32(t0) */
> > 0x0182a283, /* lw t0, 24(t0) */
> > #elif defined(TARGET_RISCV64)
> > + 0x0202b583, /* ld a1, 32(t0) */
> > 0x0182b283, /* ld t0, 24(t0) */
> > #endif
> > 0x00028067, /* jr t0 */
> > 0x00000000,
> > start_addr, /* start: .dword */
> > 0x00000000,
> > - /* dtb: */
> > + fdt_load_addr, /* fdt_laddr: .dword */
> > + 0x00000000,
> > + /* fw_dyn: */
> > };
> >
> > /* copy in the reset vector in little_endian byte order */
> > @@ -189,14 +215,9 @@ void riscv_setup_rom_reset_vec(hwaddr start_addr,
> > hwaddr rom_base,
> > rom_base, &address_space_memory);
> >
> > /* copy in the device tree */
> > - if (fdt_pack(fdt) || fdt_totalsize(fdt) >
> > - rom_size - sizeof(reset_vec)) {
> > - error_report("not enough space to store device-tree");
> > - exit(1);
> > - }
> > qemu_fdt_dumpdtb(fdt, fdt_totalsize(fdt));
> > - rom_add_blob_fixed_as("mrom.fdt", fdt, fdt_totalsize(fdt),
> > - rom_base + sizeof(reset_vec),
> > +
> > + rom_add_blob_fixed_as("fdt", fdt, fdt_totalsize(fdt), fdt_load_addr,
> > &address_space_memory);
> >
> > return;
> > diff --git a/hw/riscv/sifive_u.c b/hw/riscv/sifive_u.c
> > index c2712570e0d9..1a1540c7f98d 100644
> > --- a/hw/riscv/sifive_u.c
> > +++ b/hw/riscv/sifive_u.c
> > @@ -31,6 +31,7 @@
> > */
> >
> > #include "qemu/osdep.h"
> > +#include "qemu/units.h"
> > #include "qemu/log.h"
> > #include "qemu/error-report.h"
> > #include "qapi/error.h"
> > @@ -325,6 +326,7 @@ static void sifive_u_machine_init(MachineState *machine)
> > MemoryRegion *main_mem = g_new(MemoryRegion, 1);
> > MemoryRegion *flash0 = g_new(MemoryRegion, 1);
> > target_ulong start_addr = memmap[SIFIVE_U_DRAM].base;
> > + hwaddr fdt_load_addr;
> >
> > /* Initialize SoC */
> > object_initialize_child(OBJECT(machine), "soc", &s->soc,
> > @@ -369,13 +371,23 @@ static void sifive_u_machine_init(MachineState
> > *machine)
> > }
> > }
> >
> > + /* Compute the fdt load address in dram */
> > + fdt_load_addr = riscv_calc_fdt_load_addr(memmap[SIFIVE_U_DRAM].base,
> > + machine->ram_size, s->fdt);
> > +
> > + if (fdt_load_addr >= (memmap[SIFIVE_U_DRAM].base + machine->ram_size))
> > {
>
> This check is unnecessary as the parameter passed to
> riscv_calc_fdt_load_addr() guarantees that this won't happen.
>
Sure. I will remove that.
> > + error_report("Not enough space for FDT after kernel + initrd");
> > + exit(1);
> > + }
> > +
> > if (s->start_in_flash) {
> > start_addr = memmap[SIFIVE_U_FLASH0].base;
> > }
> >
> > /* load the reset vector */
> > riscv_setup_rom_reset_vec(start_addr, memmap[SIFIVE_U_MROM].base,
> > - memmap[SIFIVE_U_MROM].size, s->fdt);
> > + memmap[SIFIVE_U_MROM].size,
> > + fdt_load_addr, s->fdt);
> > }
> >
> > static bool sifive_u_machine_get_start_in_flash(Object *obj, Error **errp)
> > diff --git a/hw/riscv/spike.c b/hw/riscv/spike.c
> > index 238eae48716a..2a34a1382487 100644
> > --- a/hw/riscv/spike.c
> > +++ b/hw/riscv/spike.c
> > @@ -24,6 +24,7 @@
> > */
> >
> > #include "qemu/osdep.h"
> > +#include "qemu/units.h"
> > #include "qemu/log.h"
> > #include "qemu/error-report.h"
> > #include "qapi/error.h"
> > @@ -166,6 +167,7 @@ static void spike_board_init(MachineState *machine)
> > MemoryRegion *main_mem = g_new(MemoryRegion, 1);
> > MemoryRegion *mask_rom = g_new(MemoryRegion, 1);
> > unsigned int smp_cpus = machine->smp.cpus;
> > + hwaddr fdt_load_addr;
> >
> > /* Initialize SOC */
> > object_initialize_child(OBJECT(machine), "soc", &s->soc,
> > sizeof(s->soc),
> > @@ -212,9 +214,19 @@ static void spike_board_init(MachineState *machine)
> > }
> > }
> >
> > + /* Compute the fdt load address in dram */
> > + fdt_load_addr = riscv_calc_fdt_load_addr(memmap[SPIKE_DRAM].base,
> > + machine->ram_size, s->fdt);
> > +
> > + if (fdt_load_addr >= (memmap[SPIKE_DRAM].base + machine->ram_size)) {
> > + error_report("Not enough space for FDT after kernel + initrd");
> > + exit(1);
> > + }
> > +
> > /* load the reset vector */
> > riscv_setup_rom_reset_vec(memmap[SPIKE_DRAM].base,
> > memmap[SPIKE_MROM].base,
> > - memmap[SPIKE_MROM].size, s->fdt);
> > + memmap[SPIKE_MROM].size,
> > + fdt_load_addr, s->fdt);
> >
> > /* initialize HTIF using symbols found in load_kernel */
> > htif_mm_init(system_memory, mask_rom, &s->soc.harts[0].env,
> > serial_hd(0));
> > diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
> > index a8e2d58cc067..ebb5dd5c8c1c 100644
> > --- a/hw/riscv/virt.c
> > +++ b/hw/riscv/virt.c
> > @@ -481,6 +481,7 @@ static void virt_machine_init(MachineState *machine)
> > char *plic_hart_config;
> > size_t plic_hart_config_len;
> > target_ulong start_addr = memmap[VIRT_DRAM].base;
> > + hwaddr fdt_load_addr;
> > int i;
> > unsigned int smp_cpus = machine->smp.cpus;
> >
> > @@ -536,9 +537,19 @@ static void virt_machine_init(MachineState *machine)
> > start_addr = virt_memmap[VIRT_FLASH].base;
> > }
> >
> > + /* Compute the fdt load address in dram */
> > + fdt_load_addr = riscv_calc_fdt_load_addr(memmap[VIRT_DRAM].base,
> > + machine->ram_size, s->fdt);
> > + if (fdt_load_addr >= (memmap[VIRT_DRAM].base + machine->ram_size)) {
> > + error_report("Not enough space for FDT after kernel + initrd");
> > + exit(1);
> > + }
> > +
> > +
> > /* load the reset vector */
> > riscv_setup_rom_reset_vec(start_addr, virt_memmap[VIRT_MROM].base,
> > - virt_memmap[VIRT_MROM].size, s->fdt);
> > + virt_memmap[VIRT_MROM].size,
> > + fdt_load_addr, s->fdt);
> >
> > /* create PLIC hart topology configuration string */
> > plic_hart_config_len = (strlen(VIRT_PLIC_HART_CONFIG) + 1) * smp_cpus;
> > diff --git a/include/hw/riscv/boot.h b/include/hw/riscv/boot.h
> > index 3e9759c89aa2..b6289a05d952 100644
> > --- a/include/hw/riscv/boot.h
> > +++ b/include/hw/riscv/boot.h
> > @@ -35,7 +35,10 @@ target_ulong riscv_load_kernel(const char
> > *kernel_filename,
> > symbol_fn_t sym_cb);
> > hwaddr riscv_load_initrd(const char *filename, uint64_t mem_size,
> > uint64_t kernel_entry, hwaddr *start);
> > +hwaddr riscv_calc_fdt_load_addr(hwaddr dram_start, uint64_t dram_size,
> > + void *fdt);
> > void riscv_setup_rom_reset_vec(hwaddr saddr, hwaddr rom_base,
> > - hwaddr rom_size, void *fdt);
> > + hwaddr rom_size,
> > + hwaddr fdt_load_addr, void *fdt);
> >
> > #endif /* RISCV_BOOT_H */
>
> Regards,
> Bin
>
--
Regards,
Atish
