d67c6876b5
This patch allows the CBMEM console to persist across reboots, which should greatly help post factum debugging of issues involving multiple reboots. In order to prevent the console from filling up, it will instead operate as a ring buffer that continues to evict the oldest lines once full. (This means that if even a single boot doesn't fit into the buffer, we will now drop the oldest lines whereas previous code would've dropped the newest lines instead.) The console control structure is modified in a sorta backwards-compatible way, so that new readers can continue to work with old console buffers and vice versa. When an old reader reads a new buffer that has already once overflowed (i.e. is operating in true ring buffer mode) it will print lines out of order, but it will at least still print out the whole console content and not do any illegal memory accesses (assuming it correctly implemented cursor overflow as it was already possible before this patch). BUG=chromium:651966 TEST=Rebooted and confirmed output repeatedly on a Kevin and a Falco. Also confirmed correct behavior across suspend/resume for the latter. Change-Id: Ifcbf59d58e1ad20995b98d111c4647281fbb45ff Signed-off-by: Julius Werner <jwerner@chromium.org> Reviewed-on: https://review.coreboot.org/18301 Tested-by: build bot (Jenkins) Reviewed-by: Aaron Durbin <adurbin@chromium.org>
77 lines
2.6 KiB
C
77 lines
2.6 KiB
C
/*
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* This file is part of the libpayload project.
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*
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* Copyright (c) 2012 Google Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <libpayload.h>
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#include <stdint.h>
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struct cbmem_console {
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uint32_t size;
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uint32_t cursor;
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uint8_t body[0];
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} __attribute__ ((__packed__));
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#define CURSOR_MASK ((1 << 28) - 1)
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#define OVERFLOW (1 << 31)
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static struct cbmem_console *cbmem_console_p;
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static struct console_output_driver cbmem_console_driver =
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{
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.write = &cbmem_console_write,
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};
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static void do_write(const void *buffer, size_t count)
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{
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memcpy(cbmem_console_p->body + (cbmem_console_p->cursor & CURSOR_MASK),
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buffer, count);
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cbmem_console_p->cursor += count;
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}
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void cbmem_console_init(void)
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{
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cbmem_console_p = lib_sysinfo.cbmem_cons;
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if (cbmem_console_p && cbmem_console_p->size)
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console_add_output_driver(&cbmem_console_driver);
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}
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void cbmem_console_write(const void *buffer, size_t count)
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{
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while ((cbmem_console_p->cursor & CURSOR_MASK) + count >=
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cbmem_console_p->size) {
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size_t still_fits = cbmem_console_p->size -
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(cbmem_console_p->cursor & CURSOR_MASK);
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do_write(buffer, still_fits);
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cbmem_console_p->cursor &= ~CURSOR_MASK;
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cbmem_console_p->cursor |= OVERFLOW;
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buffer += still_fits;
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count -= still_fits;
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}
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do_write(buffer, count);
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}
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