hw/char: riscv_htif: Support console output via proxy syscall

At present the HTIF proxy syscall is unsupported. On RV32, only
device 0 is supported so there is no console device for RV32.
The only way to implement console funtionality on RV32 is to
support the SYS_WRITE syscall.

With this commit, the Spike machine is able to boot the 32-bit
OpenSBI generic image.

Signed-off-by: Bin Meng <bmeng@tinylab.org>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <20221229091828.1945072-8-bmeng@tinylab.org>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Bin Meng 2022-12-29 17:18:23 +08:00 committed by Alistair Francis
parent 03ef1899dd
commit a6e13e31d5

View file

@ -48,6 +48,9 @@
#define HTIF_CONSOLE_CMD_GETC 0
#define HTIF_CONSOLE_CMD_PUTC 1
/* PK system call number */
#define PK_SYS_WRITE 64
static uint64_t fromhost_addr, tohost_addr;
static int address_symbol_set;
@ -165,7 +168,19 @@ static void htif_handle_tohost_write(HTIFState *s, uint64_t val_written)
int exit_code = payload >> 1;
exit(exit_code);
} else {
qemu_log_mask(LOG_UNIMP, "pk syscall proxy not supported\n");
uint64_t syscall[8];
cpu_physical_memory_read(payload, syscall, sizeof(syscall));
if (syscall[0] == PK_SYS_WRITE &&
syscall[1] == HTIF_DEV_CONSOLE &&
syscall[3] == HTIF_CONSOLE_CMD_PUTC) {
uint8_t ch;
cpu_physical_memory_read(syscall[2], &ch, 1);
qemu_chr_fe_write(&s->chr, &ch, 1);
resp = 0x100 | (uint8_t)payload;
} else {
qemu_log_mask(LOG_UNIMP,
"pk syscall proxy not supported\n");
}
}
} else {
qemu_log("HTIF device %d: unknown command\n", device);