diff options
| -rw-r--r-- | src/fw/coreboot.c | 21 |
1 files changed, 15 insertions, 6 deletions
diff --git a/src/fw/coreboot.c b/src/fw/coreboot.c index 4957b80d..7214f8ae 100644 --- a/src/fw/coreboot.c +++ b/src/fw/coreboot.c @@ -80,10 +80,12 @@ struct cb_cbmem_ref { #define CB_TAG_CBMEM_CONSOLE 0x17 struct cbmem_console { - u32 buffer_size; - u32 buffer_cursor; - u8 buffer_body[0]; + u32 size; + u32 cursor; + u8 body[0]; } PACKED; +#define CBMC_CURSOR_MASK ((1 << 28) - 1) +#define CBMC_OVERFLOW (1 << 31) static struct cbmem_console *cbcon = NULL; static u16 @@ -220,9 +222,16 @@ void coreboot_debug_putc(char c) return; if (!cbcon) return; - u32 cursor = cbcon->buffer_cursor++; - if (cursor < cbcon->buffer_size) - cbcon->buffer_body[cursor] = c; + u32 cursor = cbcon->cursor & CBMC_CURSOR_MASK; + u32 flags = cbcon->cursor & ~CBMC_CURSOR_MASK; + if (cursor >= cbcon->size) + return; // Old coreboot version with legacy overflow mechanism. + cbcon->body[cursor++] = c; + if (cursor >= cbcon->size) { + cursor = 0; + flags |= CBMC_OVERFLOW; + } + cbcon->cursor = flags | cursor; } /**************************************************************** |