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| author | Andrew Waterman <waterman@cs.berkeley.edu> | 2016-05-02 14:30:48 -0700 |
|---|---|---|
| committer | Andrew Waterman <waterman@cs.berkeley.edu> | 2016-05-02 14:30:48 -0700 |
| commit | 2001632142a11d9a940eee7e3bfbe7c0186fe6ce (patch) | |
| tree | c4128fd12cc967332cfb956d5a291923ef078036 /machine/mtrap.c | |
| parent | 06dfae8a04c1fb51416472e6e29ec3e926b6cf9b (diff) | |
| download | riscv-pk-2001632142a11d9a940eee7e3bfbe7c0186fe6ce.zip riscv-pk-2001632142a11d9a940eee7e3bfbe7c0186fe6ce.tar.gz riscv-pk-2001632142a11d9a940eee7e3bfbe7c0186fe6ce.tar.bz2 | |
Don't use tohost/fromhost registers; communicate with host via memory
Diffstat (limited to 'machine/mtrap.c')
| -rw-r--r-- | machine/mtrap.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/machine/mtrap.c b/machine/mtrap.c index 4087a67..15ecf8f 100644 --- a/machine/mtrap.c +++ b/machine/mtrap.c @@ -7,6 +7,9 @@ #include <stdarg.h> #include <stdio.h> +volatile uint64_t tohost __attribute__((aligned(64))); +volatile uint64_t fromhost __attribute__((aligned(64))); + void __attribute__((noreturn)) bad_trap() { die("machine mode: unhandlable trap %d @ %p", read_csr(mcause), read_csr(mepc)); @@ -19,31 +22,33 @@ static uintptr_t mcall_hart_id() static void request_htif_keyboard_interrupt() { - uintptr_t old_tohost = swap_csr(mtohost, TOHOST_CMD(1, 0, 0)); - assert(old_tohost == 0); + assert(tohost == 0); + tohost = TOHOST_CMD(1, 0, 0); } -void htif_interrupt() +static void htif_interrupt() { - uintptr_t fromhost = swap_csr(mfromhost, 0); // we should only be interrupted by keypresses - if (!(FROMHOST_DEV(fromhost) == 1 && FROMHOST_CMD(fromhost) == 0)) + uint64_t fh = fromhost; + if (!(FROMHOST_DEV(fh) == 1 && FROMHOST_CMD(fh) == 0)) die("unexpected htif interrupt"); - HLS()->console_ibuf = 1 + (uint8_t)FROMHOST_DATA(fromhost); + HLS()->console_ibuf = 1 + (uint8_t)FROMHOST_DATA(fh); + fromhost = 0; set_csr(mip, MIP_SSIP); } static void do_tohost_fromhost(uintptr_t dev, uintptr_t cmd, uintptr_t data) { - while (swap_csr(mtohost, TOHOST_CMD(dev, cmd, data)) != 0) - if (read_csr(mfromhost)) + while (tohost) + if (fromhost) htif_interrupt(); + tohost = TOHOST_CMD(dev, cmd, data); while (1) { - uintptr_t fromhost = read_csr(mfromhost); - if (fromhost) { - if (FROMHOST_DEV(fromhost) == dev && FROMHOST_CMD(fromhost) == cmd) { - write_csr(mfromhost, 0); + uint64_t fh = fromhost; + if (fh) { + if (FROMHOST_DEV(fh) == dev && FROMHOST_CMD(fh) == cmd) { + fromhost = 0; break; } htif_interrupt(); @@ -66,7 +71,7 @@ static uintptr_t mcall_htif_syscall(uintptr_t magic_mem) void poweroff() { while (1) - write_csr(mtohost, 1); + tohost = 1; } void putstring(const char* s) |