f0a08324d0
The Microsoft spec for SPCR says "The base address of the Serial Port register set described using the ACPI Generic Address Structure, or 0 if console redirection is disabled". So, return early if redirection is disabled (base address = 0). If this check is not done we may get invalid ports on machines with redirection disabled and boot may hang when reading the grub.cfg file. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: Leo Sandoval <lsandova@redhat.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
97 lines
3.0 KiB
C
97 lines
3.0 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2022 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#if !defined(GRUB_MACHINE_IEEE1275) && !defined(GRUB_MACHINE_QEMU)
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#include <grub/misc.h>
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#include <grub/serial.h>
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#include <grub/ns8250.h>
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#include <grub/types.h>
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#include <grub/dl.h>
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#include <grub/acpi.h>
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struct grub_serial_port *
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grub_ns8250_spcr_init (void)
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{
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struct grub_acpi_spcr *spcr;
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struct grub_serial_config config;
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spcr = grub_acpi_find_table (GRUB_ACPI_SPCR_SIGNATURE);
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if (spcr == NULL)
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return NULL;
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if (spcr->hdr.revision < 2)
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grub_dprintf ("serial", "SPCR table revision %d < 2, continuing anyway\n",
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(int) spcr->hdr.revision);
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if (spcr->intf_type != GRUB_ACPI_SPCR_INTF_TYPE_16550 &&
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spcr->intf_type != GRUB_ACPI_SPCR_INTF_TYPE_16550_DBGP &&
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spcr->intf_type != GRUB_ACPI_SPCR_INTF_TYPE_16550_DBG2)
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return NULL;
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/* For now, we only support byte accesses. */
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if (spcr->base_addr.access_size != GRUB_ACPI_GENADDR_SIZE_BYTE &&
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spcr->base_addr.access_size != GRUB_ACPI_GENADDR_SIZE_LGCY)
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return NULL;
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config.word_len = 8;
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config.parity = GRUB_SERIAL_PARITY_NONE;
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config.stop_bits = GRUB_SERIAL_STOP_BITS_1;
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config.base_clock = UART_DEFAULT_BASE_CLOCK;
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if (spcr->flow_control & GRUB_ACPI_SPCR_FC_RTSCTS)
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config.rtscts = 1;
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else
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config.rtscts = 0;
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switch (spcr->baud_rate)
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{
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case GRUB_ACPI_SPCR_BAUD_9600:
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config.speed = 9600;
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break;
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case GRUB_ACPI_SPCR_BAUD_19200:
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config.speed = 19200;
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break;
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case GRUB_ACPI_SPCR_BAUD_57600:
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config.speed = 57600;
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break;
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case GRUB_ACPI_SPCR_BAUD_115200:
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config.speed = 115200;
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break;
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case GRUB_ACPI_SPCR_BAUD_CURRENT:
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default:
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/*
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* We don't (yet) have a way to read the currently
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* configured speed in HW, so let's use a sane default.
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*/
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config.speed = 115200;
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break;
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};
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/* If base address is 0 it means redirection is disabled. */
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if (spcr->base_addr.addr == 0)
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return NULL;
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switch (spcr->base_addr.space_id)
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{
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case GRUB_ACPI_GENADDR_MEM_SPACE:
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return grub_serial_ns8250_add_mmio (spcr->base_addr.addr,
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spcr->base_addr.access_size, &config);
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case GRUB_ACPI_GENADDR_IO_SPACE:
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return grub_serial_ns8250_add_port (spcr->base_addr.addr, &config);
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default:
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return NULL;
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};
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}
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#endif
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