// SPDX-License-Identifier: GPL-2.0-only
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#define pr_fmt(fmt) "efi: " fmt
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/efi.h>
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#include <linux/libfdt.h>
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#include <linux/of_fdt.h>
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#include <asm/unaligned.h>
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enum {
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SYSTAB,
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MMBASE,
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MMSIZE,
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DCSIZE,
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DCVERS,
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PARAMCOUNT
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};
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static __initconst const char name[][22] = {
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[SYSTAB] = "System Table ",
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[MMBASE] = "MemMap Address ",
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[MMSIZE] = "MemMap Size ",
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[DCSIZE] = "MemMap Desc. Size ",
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[DCVERS] = "MemMap Desc. Version ",
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};
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static __initconst const struct {
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const char path[17];
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const char params[PARAMCOUNT][26];
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} dt_params[] = {
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{
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#ifdef CONFIG_XEN // <-------17------>
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.path = "/hypervisor/uefi",
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.params = {
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[SYSTAB] = "xen,uefi-system-table",
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[MMBASE] = "xen,uefi-mmap-start",
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[MMSIZE] = "xen,uefi-mmap-size",
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[DCSIZE] = "xen,uefi-mmap-desc-size",
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[DCVERS] = "xen,uefi-mmap-desc-ver",
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}
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}, {
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#endif
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.path = "/chosen",
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.params = { // <-----------26----------->
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[SYSTAB] = "linux,uefi-system-table",
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[MMBASE] = "linux,uefi-mmap-start",
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[MMSIZE] = "linux,uefi-mmap-size",
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[DCSIZE] = "linux,uefi-mmap-desc-size",
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[DCVERS] = "linux,uefi-mmap-desc-ver",
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}
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}
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};
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static int __init efi_get_fdt_prop(const void *fdt, int node, const char *pname,
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const char *rname, void *var, int size)
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{
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const void *prop;
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int len;
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u64 val;
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prop = fdt_getprop(fdt, node, pname, &len);
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if (!prop)
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return 1;
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val = (len == 4) ? (u64)be32_to_cpup(prop) : get_unaligned_be64(prop);
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if (size == 8)
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*(u64 *)var = val;
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else
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*(u32 *)var = (val < U32_MAX) ? val : U32_MAX; // saturate
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if (efi_enabled(EFI_DBG))
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pr_info(" %s: 0x%0*llx\n", rname, size * 2, val);
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return 0;
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}
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u64 __init efi_get_fdt_params(struct efi_memory_map_data *mm)
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{
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const void *fdt = initial_boot_params;
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unsigned long systab;
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int i, j, node;
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struct {
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void *var;
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int size;
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} target[] = {
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[SYSTAB] = { &systab, sizeof(systab) },
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[MMBASE] = { &mm->phys_map, sizeof(mm->phys_map) },
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[MMSIZE] = { &mm->size, sizeof(mm->size) },
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[DCSIZE] = { &mm->desc_size, sizeof(mm->desc_size) },
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[DCVERS] = { &mm->desc_version, sizeof(mm->desc_version) },
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};
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BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(name));
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BUILD_BUG_ON(ARRAY_SIZE(target) != ARRAY_SIZE(dt_params[0].params));
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if (!fdt)
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return 0;
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for (i = 0; i < ARRAY_SIZE(dt_params); i++) {
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node = fdt_path_offset(fdt, dt_params[i].path);
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if (node < 0)
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continue;
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if (efi_enabled(EFI_DBG))
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pr_info("Getting UEFI parameters from %s in DT:\n",
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dt_params[i].path);
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for (j = 0; j < ARRAY_SIZE(target); j++) {
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const char *pname = dt_params[i].params[j];
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if (!efi_get_fdt_prop(fdt, node, pname, name[j],
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target[j].var, target[j].size))
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continue;
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if (!j)
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goto notfound;
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pr_err("Can't find property '%s' in DT!\n", pname);
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return 0;
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}
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return systab;
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}
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notfound:
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pr_info("UEFI not found.\n");
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return 0;
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}
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