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Subject[tip: x86/seves] x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.c
The following commit has been merged into the x86/seves branch of tip:

Commit-ID: 5f2bb01682b7b067783207994c7b8a3dbeb1cd83
Gitweb: https://git.kernel.org/tip/5f2bb01682b7b067783207994c7b8a3dbeb1cd83
Author: Joerg Roedel <jroedel@suse.de>
AuthorDate: Mon, 07 Sep 2020 15:15:15 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Mon, 07 Sep 2020 19:45:25 +02:00

x86/boot/compressed/64: Rename kaslr_64.c to ident_map_64.c

The file contains only code related to identity-mapped page tables.
Rename the file and compile it always in.

Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lkml.kernel.org/r/20200907131613.12703-15-joro@8bytes.org
---
arch/x86/boot/compressed/Makefile | 2 +-
arch/x86/boot/compressed/ident_map_64.c | 162 +++++++++++++++++++++++-
arch/x86/boot/compressed/kaslr.c | 9 +-
arch/x86/boot/compressed/kaslr_64.c | 153 +----------------------
arch/x86/boot/compressed/misc.h | 8 +-
5 files changed, 171 insertions(+), 163 deletions(-)
create mode 100644 arch/x86/boot/compressed/ident_map_64.c
delete mode 100644 arch/x86/boot/compressed/kaslr_64.c

diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index c661dc5..e7f3eba 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -84,7 +84,7 @@ vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/kernel_info.o $(obj)/head_$(BITS).o
vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr.o
ifdef CONFIG_X86_64
- vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/kaslr_64.o
+ vmlinux-objs-y += $(obj)/ident_map_64.o
vmlinux-objs-y += $(obj)/idt_64.o $(obj)/idt_handlers_64.o
vmlinux-objs-y += $(obj)/mem_encrypt.o
vmlinux-objs-y += $(obj)/pgtable_64.o
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c
new file mode 100644
index 0000000..d9932a1
--- /dev/null
+++ b/arch/x86/boot/compressed/ident_map_64.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * This code is used on x86_64 to create page table identity mappings on
+ * demand by building up a new set of page tables (or appending to the
+ * existing ones), and then switching over to them when ready.
+ *
+ * Copyright (C) 2015-2016 Yinghai Lu
+ * Copyright (C) 2016 Kees Cook
+ */
+
+/*
+ * Since we're dealing with identity mappings, physical and virtual
+ * addresses are the same, so override these defines which are ultimately
+ * used by the headers in misc.h.
+ */
+#define __pa(x) ((unsigned long)(x))
+#define __va(x) ((void *)((unsigned long)(x)))
+
+/* No PAGE_TABLE_ISOLATION support needed either: */
+#undef CONFIG_PAGE_TABLE_ISOLATION
+
+#include "misc.h"
+
+/* These actually do the work of building the kernel identity maps. */
+#include <linux/pgtable.h>
+#include <asm/init.h>
+/* Use the static base for this part of the boot process */
+#undef __PAGE_OFFSET
+#define __PAGE_OFFSET __PAGE_OFFSET_BASE
+#include "../../mm/ident_map.c"
+
+#ifdef CONFIG_X86_5LEVEL
+unsigned int __pgtable_l5_enabled;
+unsigned int pgdir_shift = 39;
+unsigned int ptrs_per_p4d = 1;
+#endif
+
+/* Used by PAGE_KERN* macros: */
+pteval_t __default_kernel_pte_mask __read_mostly = ~0;
+
+/* Used to track our page table allocation area. */
+struct alloc_pgt_data {
+ unsigned char *pgt_buf;
+ unsigned long pgt_buf_size;
+ unsigned long pgt_buf_offset;
+};
+
+/*
+ * Allocates space for a page table entry, using struct alloc_pgt_data
+ * above. Besides the local callers, this is used as the allocation
+ * callback in mapping_info below.
+ */
+static void *alloc_pgt_page(void *context)
+{
+ struct alloc_pgt_data *pages = (struct alloc_pgt_data *)context;
+ unsigned char *entry;
+
+ /* Validate there is space available for a new page. */
+ if (pages->pgt_buf_offset >= pages->pgt_buf_size) {
+ debug_putstr("out of pgt_buf in " __FILE__ "!?\n");
+ debug_putaddr(pages->pgt_buf_offset);
+ debug_putaddr(pages->pgt_buf_size);
+ return NULL;
+ }
+
+ entry = pages->pgt_buf + pages->pgt_buf_offset;
+ pages->pgt_buf_offset += PAGE_SIZE;
+
+ return entry;
+}
+
+/* Used to track our allocated page tables. */
+static struct alloc_pgt_data pgt_data;
+
+/* The top level page table entry pointer. */
+static unsigned long top_level_pgt;
+
+phys_addr_t physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
+
+/*
+ * Mapping information structure passed to kernel_ident_mapping_init().
+ * Due to relocation, pointers must be assigned at run time not build time.
+ */
+static struct x86_mapping_info mapping_info;
+
+/* Locates and clears a region for a new top level page table. */
+void initialize_identity_maps(void)
+{
+ /* If running as an SEV guest, the encryption mask is required. */
+ set_sev_encryption_mask();
+
+ /* Exclude the encryption mask from __PHYSICAL_MASK */
+ physical_mask &= ~sme_me_mask;
+
+ /* Init mapping_info with run-time function/buffer pointers. */
+ mapping_info.alloc_pgt_page = alloc_pgt_page;
+ mapping_info.context = &pgt_data;
+ mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sme_me_mask;
+ mapping_info.kernpg_flag = _KERNPG_TABLE;
+
+ /*
+ * It should be impossible for this not to already be true,
+ * but since calling this a second time would rewind the other
+ * counters, let's just make sure this is reset too.
+ */
+ pgt_data.pgt_buf_offset = 0;
+
+ /*
+ * If we came here via startup_32(), cr3 will be _pgtable already
+ * and we must append to the existing area instead of entirely
+ * overwriting it.
+ *
+ * With 5-level paging, we use '_pgtable' to allocate the p4d page table,
+ * the top-level page table is allocated separately.
+ *
+ * p4d_offset(top_level_pgt, 0) would cover both the 4- and 5-level
+ * cases. On 4-level paging it's equal to 'top_level_pgt'.
+ */
+ top_level_pgt = read_cr3_pa();
+ if (p4d_offset((pgd_t *)top_level_pgt, 0) == (p4d_t *)_pgtable) {
+ debug_putstr("booted via startup_32()\n");
+ pgt_data.pgt_buf = _pgtable + BOOT_INIT_PGT_SIZE;
+ pgt_data.pgt_buf_size = BOOT_PGT_SIZE - BOOT_INIT_PGT_SIZE;
+ memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
+ } else {
+ debug_putstr("booted via startup_64()\n");
+ pgt_data.pgt_buf = _pgtable;
+ pgt_data.pgt_buf_size = BOOT_PGT_SIZE;
+ memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
+ top_level_pgt = (unsigned long)alloc_pgt_page(&pgt_data);
+ }
+}
+
+/*
+ * Adds the specified range to what will become the new identity mappings.
+ * Once all ranges have been added, the new mapping is activated by calling
+ * finalize_identity_maps() below.
+ */
+void add_identity_map(unsigned long start, unsigned long size)
+{
+ unsigned long end = start + size;
+
+ /* Align boundary to 2M. */
+ start = round_down(start, PMD_SIZE);
+ end = round_up(end, PMD_SIZE);
+ if (start >= end)
+ return;
+
+ /* Build the mapping. */
+ kernel_ident_mapping_init(&mapping_info, (pgd_t *)top_level_pgt,
+ start, end);
+}
+
+/*
+ * This switches the page tables to the new level4 that has been built
+ * via calls to add_identity_map() above. If booted via startup_32(),
+ * this is effectively a no-op.
+ */
+void finalize_identity_maps(void)
+{
+ write_cr3(top_level_pgt);
+}
diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
index 877970d..e27de98 100644
--- a/arch/x86/boot/compressed/kaslr.c
+++ b/arch/x86/boot/compressed/kaslr.c
@@ -40,17 +40,8 @@
#include <asm/setup.h> /* For COMMAND_LINE_SIZE */
#undef _SETUP

-#ifdef CONFIG_X86_5LEVEL
-unsigned int __pgtable_l5_enabled;
-unsigned int pgdir_shift __ro_after_init = 39;
-unsigned int ptrs_per_p4d __ro_after_init = 1;
-#endif
-
extern unsigned long get_cmd_line_ptr(void);

-/* Used by PAGE_KERN* macros: */
-pteval_t __default_kernel_pte_mask __read_mostly = ~0;
-
/* Simplified build-specific string for starting entropy. */
static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
diff --git a/arch/x86/boot/compressed/kaslr_64.c b/arch/x86/boot/compressed/kaslr_64.c
deleted file mode 100644
index f9c5c13..0000000
--- a/arch/x86/boot/compressed/kaslr_64.c
+++ /dev/null
@@ -1,153 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * This code is used on x86_64 to create page table identity mappings on
- * demand by building up a new set of page tables (or appending to the
- * existing ones), and then switching over to them when ready.
- *
- * Copyright (C) 2015-2016 Yinghai Lu
- * Copyright (C) 2016 Kees Cook
- */
-
-/*
- * Since we're dealing with identity mappings, physical and virtual
- * addresses are the same, so override these defines which are ultimately
- * used by the headers in misc.h.
- */
-#define __pa(x) ((unsigned long)(x))
-#define __va(x) ((void *)((unsigned long)(x)))
-
-/* No PAGE_TABLE_ISOLATION support needed either: */
-#undef CONFIG_PAGE_TABLE_ISOLATION
-
-#include "misc.h"
-
-/* These actually do the work of building the kernel identity maps. */
-#include <linux/pgtable.h>
-#include <asm/init.h>
-/* Use the static base for this part of the boot process */
-#undef __PAGE_OFFSET
-#define __PAGE_OFFSET __PAGE_OFFSET_BASE
-#include "../../mm/ident_map.c"
-
-/* Used to track our page table allocation area. */
-struct alloc_pgt_data {
- unsigned char *pgt_buf;
- unsigned long pgt_buf_size;
- unsigned long pgt_buf_offset;
-};
-
-/*
- * Allocates space for a page table entry, using struct alloc_pgt_data
- * above. Besides the local callers, this is used as the allocation
- * callback in mapping_info below.
- */
-static void *alloc_pgt_page(void *context)
-{
- struct alloc_pgt_data *pages = (struct alloc_pgt_data *)context;
- unsigned char *entry;
-
- /* Validate there is space available for a new page. */
- if (pages->pgt_buf_offset >= pages->pgt_buf_size) {
- debug_putstr("out of pgt_buf in " __FILE__ "!?\n");
- debug_putaddr(pages->pgt_buf_offset);
- debug_putaddr(pages->pgt_buf_size);
- return NULL;
- }
-
- entry = pages->pgt_buf + pages->pgt_buf_offset;
- pages->pgt_buf_offset += PAGE_SIZE;
-
- return entry;
-}
-
-/* Used to track our allocated page tables. */
-static struct alloc_pgt_data pgt_data;
-
-/* The top level page table entry pointer. */
-static unsigned long top_level_pgt;
-
-phys_addr_t physical_mask = (1ULL << __PHYSICAL_MASK_SHIFT) - 1;
-
-/*
- * Mapping information structure passed to kernel_ident_mapping_init().
- * Due to relocation, pointers must be assigned at run time not build time.
- */
-static struct x86_mapping_info mapping_info;
-
-/* Locates and clears a region for a new top level page table. */
-void initialize_identity_maps(void)
-{
- /* If running as an SEV guest, the encryption mask is required. */
- set_sev_encryption_mask();
-
- /* Exclude the encryption mask from __PHYSICAL_MASK */
- physical_mask &= ~sme_me_mask;
-
- /* Init mapping_info with run-time function/buffer pointers. */
- mapping_info.alloc_pgt_page = alloc_pgt_page;
- mapping_info.context = &pgt_data;
- mapping_info.page_flag = __PAGE_KERNEL_LARGE_EXEC | sme_me_mask;
- mapping_info.kernpg_flag = _KERNPG_TABLE;
-
- /*
- * It should be impossible for this not to already be true,
- * but since calling this a second time would rewind the other
- * counters, let's just make sure this is reset too.
- */
- pgt_data.pgt_buf_offset = 0;
-
- /*
- * If we came here via startup_32(), cr3 will be _pgtable already
- * and we must append to the existing area instead of entirely
- * overwriting it.
- *
- * With 5-level paging, we use '_pgtable' to allocate the p4d page table,
- * the top-level page table is allocated separately.
- *
- * p4d_offset(top_level_pgt, 0) would cover both the 4- and 5-level
- * cases. On 4-level paging it's equal to 'top_level_pgt'.
- */
- top_level_pgt = read_cr3_pa();
- if (p4d_offset((pgd_t *)top_level_pgt, 0) == (p4d_t *)_pgtable) {
- debug_putstr("booted via startup_32()\n");
- pgt_data.pgt_buf = _pgtable + BOOT_INIT_PGT_SIZE;
- pgt_data.pgt_buf_size = BOOT_PGT_SIZE - BOOT_INIT_PGT_SIZE;
- memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
- } else {
- debug_putstr("booted via startup_64()\n");
- pgt_data.pgt_buf = _pgtable;
- pgt_data.pgt_buf_size = BOOT_PGT_SIZE;
- memset(pgt_data.pgt_buf, 0, pgt_data.pgt_buf_size);
- top_level_pgt = (unsigned long)alloc_pgt_page(&pgt_data);
- }
-}
-
-/*
- * Adds the specified range to what will become the new identity mappings.
- * Once all ranges have been added, the new mapping is activated by calling
- * finalize_identity_maps() below.
- */
-void add_identity_map(unsigned long start, unsigned long size)
-{
- unsigned long end = start + size;
-
- /* Align boundary to 2M. */
- start = round_down(start, PMD_SIZE);
- end = round_up(end, PMD_SIZE);
- if (start >= end)
- return;
-
- /* Build the mapping. */
- kernel_ident_mapping_init(&mapping_info, (pgd_t *)top_level_pgt,
- start, end);
-}
-
-/*
- * This switches the page tables to the new level4 that has been built
- * via calls to add_identity_map() above. If booted via startup_32(),
- * this is effectively a no-op.
- */
-void finalize_identity_maps(void)
-{
- write_cr3(top_level_pgt);
-}
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 8feb5f6..98b7a1d 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -134,6 +134,14 @@ int count_immovable_mem_regions(void);
static inline int count_immovable_mem_regions(void) { return 0; }
#endif

+/* ident_map_64.c */
+#ifdef CONFIG_X86_5LEVEL
+extern unsigned int __pgtable_l5_enabled, pgdir_shift, ptrs_per_p4d;
+#endif
+
+/* Used by PAGE_KERN* macros: */
+extern pteval_t __default_kernel_pte_mask;
+
/* idt_64.c */
extern gate_desc boot_idt[BOOT_IDT_ENTRIES];
extern struct desc_ptr boot_idt_desc;
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