2017-07-18 05:10:03 +08:00
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/*
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* AMD Memory Encryption Support
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*
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* Copyright (C) 2016 Advanced Micro Devices, Inc.
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*
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* Author: Tom Lendacky <thomas.lendacky@amd.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/linkage.h>
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2017-07-18 05:10:05 +08:00
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#include <linux/init.h>
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2017-07-18 05:10:07 +08:00
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#include <linux/mm.h>
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2017-07-18 05:10:03 +08:00
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2017-07-18 05:10:10 +08:00
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#include <asm/tlbflush.h>
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#include <asm/fixmap.h>
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2017-07-18 05:10:11 +08:00
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#include <asm/setup.h>
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#include <asm/bootparam.h>
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2017-07-18 05:10:10 +08:00
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2017-07-18 05:10:03 +08:00
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/*
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* Since SME related variables are set early in the boot process they must
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* reside in the .data section so as not to be zeroed out when the .bss
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* section is later cleared.
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*/
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unsigned long sme_me_mask __section(.data) = 0;
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EXPORT_SYMBOL_GPL(sme_me_mask);
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2017-07-18 05:10:05 +08:00
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2017-07-18 05:10:10 +08:00
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/* Buffer used for early in-place encryption by BSP, no locking needed */
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static char sme_early_buffer[PAGE_SIZE] __aligned(PAGE_SIZE);
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/*
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* This routine does not change the underlying encryption setting of the
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* page(s) that map this memory. It assumes that eventually the memory is
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* meant to be accessed as either encrypted or decrypted but the contents
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* are currently not in the desired state.
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*
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* This routine follows the steps outlined in the AMD64 Architecture
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* Programmer's Manual Volume 2, Section 7.10.8 Encrypt-in-Place.
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*/
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static void __init __sme_early_enc_dec(resource_size_t paddr,
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unsigned long size, bool enc)
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{
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void *src, *dst;
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size_t len;
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if (!sme_me_mask)
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return;
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local_flush_tlb();
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wbinvd();
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/*
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* There are limited number of early mapping slots, so map (at most)
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* one page at time.
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*/
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while (size) {
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len = min_t(size_t, sizeof(sme_early_buffer), size);
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/*
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* Create mappings for the current and desired format of
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* the memory. Use a write-protected mapping for the source.
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*/
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src = enc ? early_memremap_decrypted_wp(paddr, len) :
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early_memremap_encrypted_wp(paddr, len);
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dst = enc ? early_memremap_encrypted(paddr, len) :
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early_memremap_decrypted(paddr, len);
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/*
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* If a mapping can't be obtained to perform the operation,
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* then eventual access of that area in the desired mode
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* will cause a crash.
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*/
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BUG_ON(!src || !dst);
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/*
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* Use a temporary buffer, of cache-line multiple size, to
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* avoid data corruption as documented in the APM.
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*/
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memcpy(sme_early_buffer, src, len);
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memcpy(dst, sme_early_buffer, len);
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early_memunmap(dst, len);
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early_memunmap(src, len);
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paddr += len;
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size -= len;
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}
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}
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void __init sme_early_encrypt(resource_size_t paddr, unsigned long size)
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{
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__sme_early_enc_dec(paddr, size, true);
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}
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void __init sme_early_decrypt(resource_size_t paddr, unsigned long size)
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{
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__sme_early_enc_dec(paddr, size, false);
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}
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2017-07-18 05:10:11 +08:00
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static void __init __sme_early_map_unmap_mem(void *vaddr, unsigned long size,
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bool map)
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{
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unsigned long paddr = (unsigned long)vaddr - __PAGE_OFFSET;
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pmdval_t pmd_flags, pmd;
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/* Use early_pmd_flags but remove the encryption mask */
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pmd_flags = __sme_clr(early_pmd_flags);
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do {
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pmd = map ? (paddr & PMD_MASK) + pmd_flags : 0;
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__early_make_pgtable((unsigned long)vaddr, pmd);
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vaddr += PMD_SIZE;
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paddr += PMD_SIZE;
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size = (size <= PMD_SIZE) ? 0 : size - PMD_SIZE;
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} while (size);
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__native_flush_tlb();
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}
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void __init sme_unmap_bootdata(char *real_mode_data)
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{
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struct boot_params *boot_data;
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unsigned long cmdline_paddr;
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if (!sme_active())
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return;
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/* Get the command line address before unmapping the real_mode_data */
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boot_data = (struct boot_params *)real_mode_data;
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cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
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__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), false);
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if (!cmdline_paddr)
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return;
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__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, false);
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}
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void __init sme_map_bootdata(char *real_mode_data)
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{
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struct boot_params *boot_data;
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unsigned long cmdline_paddr;
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if (!sme_active())
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return;
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__sme_early_map_unmap_mem(real_mode_data, sizeof(boot_params), true);
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/* Get the command line address after mapping the real_mode_data */
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boot_data = (struct boot_params *)real_mode_data;
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cmdline_paddr = boot_data->hdr.cmd_line_ptr | ((u64)boot_data->ext_cmd_line_ptr << 32);
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if (!cmdline_paddr)
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return;
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__sme_early_map_unmap_mem(__va(cmdline_paddr), COMMAND_LINE_SIZE, true);
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}
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2017-07-18 05:10:07 +08:00
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void __init sme_early_init(void)
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{
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unsigned int i;
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if (!sme_me_mask)
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return;
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early_pmd_flags = __sme_set(early_pmd_flags);
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__supported_pte_mask = __sme_set(__supported_pte_mask);
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/* Update the protection map with memory encryption mask */
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for (i = 0; i < ARRAY_SIZE(protection_map); i++)
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protection_map[i] = pgprot_encrypted(protection_map[i]);
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}
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2017-07-18 05:10:05 +08:00
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void __init sme_encrypt_kernel(void)
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{
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}
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void __init sme_enable(void)
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{
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}
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