48f569c78a
During attempts to configure a serial console, a Page Fault Exception and system reset were encountered, specifically on release 2.12~rc1. This issue was not present in prior versions and seemed to affect only a specific machine, potentially pointing to hardware or firmware flaw. After investigation, it was discovered that the invalid page access occurred during the discovery of serial MMIO ports as specified by ACPI's SPCR table [1]. The recent change uncovered an issue in GRUB's ACPI driver. In certain cases, the XSDT/RSDT root table might contain a NULL entry as a terminator, depending on how the tables are assembled. GRUB cannot blindly trust the address in the root table to be valid and should perform a sanity check for NULL entries. This patch introduces this simple check. This fix is also inspired by a related Linux kernel fix [2]. [1] 7b192ec4c term/ns8250: Use ACPI SPCR table when available to configure serial [2] 0f929fbf0 ACPICA: Tables: Add new mechanism to skip NULL entries in RSDT and XSDT. Signed-off-by: Michael Chang <mchang@suse.com> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
136 lines
3.4 KiB
C
136 lines
3.4 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2012 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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#include <grub/types.h>
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#include <grub/time.h>
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#include <grub/misc.h>
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#include <grub/mm.h>
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#include <grub/acpi.h>
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/* Simple checksum by summing all bytes. Used by ACPI and SMBIOS. */
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grub_uint8_t
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grub_byte_checksum (void *base, grub_size_t size)
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{
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grub_uint8_t *ptr;
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grub_uint8_t ret = 0;
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for (ptr = (grub_uint8_t *) base; ptr < ((grub_uint8_t *) base) + size;
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ptr++)
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ret += *ptr;
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return ret;
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}
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static void *
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grub_acpi_rsdt_find_table (struct grub_acpi_table_header *rsdt, const char *sig)
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{
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grub_size_t s;
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grub_unaligned_uint32_t *ptr;
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if (!rsdt)
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return 0;
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if (grub_memcmp (rsdt->signature, "RSDT", 4) != 0)
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return 0;
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ptr = (grub_unaligned_uint32_t *) (rsdt + 1);
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s = (rsdt->length - sizeof (*rsdt)) / sizeof (grub_uint32_t);
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for (; s; s--, ptr++)
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{
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struct grub_acpi_table_header *tbl;
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/* Skip NULL entries in RSDT/XSDT. */
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if (!ptr->val)
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continue;
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tbl = (struct grub_acpi_table_header *) (grub_addr_t) ptr->val;
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if (grub_memcmp (tbl->signature, sig, 4) == 0)
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return tbl;
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}
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return 0;
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}
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static void *
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grub_acpi_xsdt_find_table (struct grub_acpi_table_header *xsdt, const char *sig)
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{
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grub_size_t s;
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grub_unaligned_uint64_t *ptr;
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if (!xsdt)
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return 0;
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if (grub_memcmp (xsdt->signature, "XSDT", 4) != 0)
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return 0;
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ptr = (grub_unaligned_uint64_t *) (xsdt + 1);
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s = (xsdt->length - sizeof (*xsdt)) / sizeof (grub_uint32_t);
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for (; s; s--, ptr++)
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{
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struct grub_acpi_table_header *tbl;
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/* Skip NULL entries in RSDT/XSDT. */
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if (!ptr->val)
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continue;
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#if GRUB_CPU_SIZEOF_VOID_P != 8
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if (ptr->val >> 32)
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continue;
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#endif
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tbl = (struct grub_acpi_table_header *) (grub_addr_t) ptr->val;
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if (grub_memcmp (tbl->signature, sig, 4) == 0)
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return tbl;
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}
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return 0;
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}
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void *
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grub_acpi_find_table (const char *sig)
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{
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struct grub_acpi_fadt *r = NULL;
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struct grub_acpi_rsdp_v10 *rsdpv1;
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struct grub_acpi_rsdp_v20 *rsdpv2;
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rsdpv1 = grub_machine_acpi_get_rsdpv1 ();
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if (rsdpv1)
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r = grub_acpi_rsdt_find_table ((struct grub_acpi_table_header *)
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(grub_addr_t) rsdpv1->rsdt_addr,
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sig);
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if (r)
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return r;
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rsdpv2 = grub_machine_acpi_get_rsdpv2 ();
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if (rsdpv2
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#if GRUB_CPU_SIZEOF_VOID_P != 8
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&& !(rsdpv2->xsdt_addr >> 32)
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#endif
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)
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r = grub_acpi_xsdt_find_table ((struct grub_acpi_table_header *)
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(grub_addr_t) rsdpv2->xsdt_addr,
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sig);
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if (r)
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return r;
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if (rsdpv2)
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r = grub_acpi_rsdt_find_table ((struct grub_acpi_table_header *)
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(grub_addr_t) rsdpv2->rsdpv1.rsdt_addr,
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sig);
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if (r)
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return r;
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return 0;
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}
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struct grub_acpi_fadt *
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grub_acpi_find_fadt (void)
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{
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return grub_acpi_find_table (GRUB_ACPI_FADT_SIGNATURE);
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}
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