cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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iscsi_ibft_find.c (2195B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 *  Copyright 2007-2010 Red Hat, Inc.
      4 *  by Peter Jones <pjones@redhat.com>
      5 *  Copyright 2007 IBM, Inc.
      6 *  by Konrad Rzeszutek <konradr@linux.vnet.ibm.com>
      7 *  Copyright 2008
      8 *  by Konrad Rzeszutek <ketuzsezr@darnok.org>
      9 *
     10 * This code finds the iSCSI Boot Format Table.
     11 */
     12
     13#include <linux/memblock.h>
     14#include <linux/blkdev.h>
     15#include <linux/ctype.h>
     16#include <linux/device.h>
     17#include <linux/efi.h>
     18#include <linux/err.h>
     19#include <linux/init.h>
     20#include <linux/limits.h>
     21#include <linux/module.h>
     22#include <linux/pci.h>
     23#include <linux/stat.h>
     24#include <linux/string.h>
     25#include <linux/types.h>
     26#include <linux/acpi.h>
     27#include <linux/iscsi_ibft.h>
     28
     29#include <asm/mmzone.h>
     30
     31/*
     32 * Physical location of iSCSI Boot Format Table.
     33 */
     34phys_addr_t ibft_phys_addr;
     35EXPORT_SYMBOL_GPL(ibft_phys_addr);
     36
     37static const struct {
     38	char *sign;
     39} ibft_signs[] = {
     40	{ "iBFT" },
     41	{ "BIFT" },	/* Broadcom iSCSI Offload */
     42};
     43
     44#define IBFT_SIGN_LEN 4
     45#define IBFT_START 0x80000 /* 512kB */
     46#define IBFT_END 0x100000 /* 1MB */
     47#define VGA_MEM 0xA0000 /* VGA buffer */
     48#define VGA_SIZE 0x20000 /* 128kB */
     49
     50/*
     51 * Routine used to find and reserve the iSCSI Boot Format Table
     52 */
     53void __init reserve_ibft_region(void)
     54{
     55	unsigned long pos;
     56	unsigned int len = 0;
     57	void *virt;
     58	int i;
     59
     60	ibft_phys_addr = 0;
     61
     62	/* iBFT 1.03 section 1.4.3.1 mandates that UEFI machines will
     63	 * only use ACPI for this
     64	 */
     65	if (efi_enabled(EFI_BOOT))
     66		return;
     67
     68	for (pos = IBFT_START; pos < IBFT_END; pos += 16) {
     69		/* The table can't be inside the VGA BIOS reserved space,
     70		 * so skip that area */
     71		if (pos == VGA_MEM)
     72			pos += VGA_SIZE;
     73		virt = isa_bus_to_virt(pos);
     74
     75		for (i = 0; i < ARRAY_SIZE(ibft_signs); i++) {
     76			if (memcmp(virt, ibft_signs[i].sign, IBFT_SIGN_LEN) ==
     77			    0) {
     78				unsigned long *addr =
     79				    (unsigned long *)isa_bus_to_virt(pos + 4);
     80				len = *addr;
     81				/* if the length of the table extends past 1M,
     82				 * the table cannot be valid. */
     83				if (pos + len <= (IBFT_END-1)) {
     84					ibft_phys_addr = pos;
     85					memblock_reserve(ibft_phys_addr, PAGE_ALIGN(len));
     86					pr_info("iBFT found at %pa.\n", &ibft_phys_addr);
     87					return;
     88				}
     89			}
     90		}
     91	}
     92}