From b1bd27b9ad45d77a2924e2168c6982c8ff1d8083 Mon Sep 17 00:00:00 2001 From: Jiri Slaby Date: Fri, 11 Oct 2019 13:50:51 +0200 Subject: [PATCH] x86/asm/head: Annotate data appropriately Use the new SYM_DATA, SYM_DATA_START, and SYM_DATA_END in both 32 and 64 bit head_*.S. In the 64-bit version, define also SYM_DATA_START_PAGE_ALIGNED locally using the new SYM_START. It is used in the code instead of NEXT_PAGE() which was defined in this file and had been using the obsolete macro GLOBAL(). Now, the data in the 64-bit object file look sane: Value Size Type Bind Vis Ndx Name 0000 4096 OBJECT GLOBAL DEFAULT 15 init_level4_pgt 1000 4096 OBJECT GLOBAL DEFAULT 15 level3_kernel_pgt 2000 2048 OBJECT GLOBAL DEFAULT 15 level2_kernel_pgt 3000 4096 OBJECT GLOBAL DEFAULT 15 level2_fixmap_pgt 4000 4096 OBJECT GLOBAL DEFAULT 15 level1_fixmap_pgt 5000 2 OBJECT GLOBAL DEFAULT 15 early_gdt_descr 5002 8 OBJECT LOCAL DEFAULT 15 early_gdt_descr_base 500a 8 OBJECT GLOBAL DEFAULT 15 phys_base 0000 8 OBJECT GLOBAL DEFAULT 17 initial_code 0008 8 OBJECT GLOBAL DEFAULT 17 initial_gs 0010 8 OBJECT GLOBAL DEFAULT 17 initial_stack 0000 4 OBJECT GLOBAL DEFAULT 19 early_recursion_flag 1000 4096 OBJECT GLOBAL DEFAULT 19 early_level4_pgt 2000 0x40000 OBJECT GLOBAL DEFAULT 19 early_dynamic_pgts 0000 4096 OBJECT GLOBAL DEFAULT 22 empty_zero_page All have correct size and type now. Note that this also removes implicit 16B alignment previously inserted by ENTRY: * initial_code, setup_once_ref, initial_page_table, initial_stack, boot_gdt are still aligned * early_gdt_descr is now properly aligned as was intended before ENTRY was added there long time ago * phys_base's alignment is kept by an explicitly added new alignment Signed-off-by: Jiri Slaby Signed-off-by: Borislav Petkov Cc: Andy Lutomirski Cc: Cao jin Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Josh Poimboeuf Cc: Juergen Gross Cc: linux-arch@vger.kernel.org Cc: Maran Wilson Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20191011115108.12392-12-jslaby@suse.cz --- arch/x86/kernel/head_32.S | 35 ++++++++++--------- arch/x86/kernel/head_64.S | 87 +++++++++++++++++++++++++---------------------- 2 files changed, 65 insertions(+), 57 deletions(-) diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S index aec1fdb..e2b3e6c 100644 --- a/arch/x86/kernel/head_32.S +++ b/arch/x86/kernel/head_32.S @@ -502,15 +502,12 @@ ENDPROC(early_ignore_irq) __INITDATA .align 4 -GLOBAL(early_recursion_flag) - .long 0 +SYM_DATA(early_recursion_flag, .long 0) __REFDATA .align 4 -ENTRY(initial_code) - .long i386_start_kernel -ENTRY(setup_once_ref) - .long setup_once +SYM_DATA(initial_code, .long i386_start_kernel) +SYM_DATA(setup_once_ref, .long setup_once) #ifdef CONFIG_PAGE_TABLE_ISOLATION #define PGD_ALIGN (2 * PAGE_SIZE) @@ -553,7 +550,7 @@ EXPORT_SYMBOL(empty_zero_page) __PAGE_ALIGNED_DATA /* Page-aligned for the benefit of paravirt? */ .align PGD_ALIGN -ENTRY(initial_page_table) +SYM_DATA_START(initial_page_table) .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 /* low identity map */ # if KPMDS == 3 .long pa(initial_pg_pmd+PGD_IDENT_ATTR),0 @@ -571,17 +568,18 @@ ENTRY(initial_page_table) # error "Kernel PMDs should be 1, 2 or 3" # endif .align PAGE_SIZE /* needs to be page-sized too */ +SYM_DATA_END(initial_page_table) #endif .data .balign 4 -ENTRY(initial_stack) - /* - * The SIZEOF_PTREGS gap is a convention which helps the in-kernel - * unwinder reliably detect the end of the stack. - */ - .long init_thread_union + THREAD_SIZE - SIZEOF_PTREGS - \ - TOP_OF_KERNEL_STACK_PADDING; +/* + * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder + * reliably detect the end of the stack. + */ +SYM_DATA(initial_stack, + .long init_thread_union + THREAD_SIZE - + SIZEOF_PTREGS - TOP_OF_KERNEL_STACK_PADDING) __INITRODATA int_msg: @@ -600,22 +598,25 @@ int_msg: ALIGN # early boot GDT descriptor (must use 1:1 address mapping) .word 0 # 32 bit align gdt_desc.address -boot_gdt_descr: +SYM_DATA_START_LOCAL(boot_gdt_descr) .word __BOOT_DS+7 .long boot_gdt - __PAGE_OFFSET +SYM_DATA_END(boot_gdt_descr) # boot GDT descriptor (later on used by CPU#0): .word 0 # 32 bit align gdt_desc.address -ENTRY(early_gdt_descr) +SYM_DATA_START(early_gdt_descr) .word GDT_ENTRIES*8-1 .long gdt_page /* Overwritten for secondary CPUs */ +SYM_DATA_END(early_gdt_descr) /* * The boot_gdt must mirror the equivalent in setup.S and is * used only for booting. */ .align L1_CACHE_BYTES -ENTRY(boot_gdt) +SYM_DATA_START(boot_gdt) .fill GDT_ENTRY_BOOT_CS,8,0 .quad 0x00cf9a000000ffff /* kernel 4GB code at 0x00000000 */ .quad 0x00cf92000000ffff /* kernel 4GB data at 0x00000000 */ +SYM_DATA_END(boot_gdt) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 5b42552..8b0926a 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -260,16 +260,14 @@ END(start_cpu0) /* Both SMP bootup and ACPI suspend change these variables */ __REFDATA .balign 8 - GLOBAL(initial_code) - .quad x86_64_start_kernel - GLOBAL(initial_gs) - .quad INIT_PER_CPU_VAR(fixed_percpu_data) - GLOBAL(initial_stack) - /* - * The SIZEOF_PTREGS gap is a convention which helps the in-kernel - * unwinder reliably detect the end of the stack. - */ - .quad init_thread_union + THREAD_SIZE - SIZEOF_PTREGS +SYM_DATA(initial_code, .quad x86_64_start_kernel) +SYM_DATA(initial_gs, .quad INIT_PER_CPU_VAR(fixed_percpu_data)) + +/* + * The SIZEOF_PTREGS gap is a convention which helps the in-kernel unwinder + * reliably detect the end of the stack. + */ +SYM_DATA(initial_stack, .quad init_thread_union + THREAD_SIZE - SIZEOF_PTREGS) __FINITDATA __INIT @@ -335,9 +333,9 @@ SYM_CODE_START_LOCAL(early_idt_handler_common) jmp restore_regs_and_return_to_kernel SYM_CODE_END(early_idt_handler_common) -#define NEXT_PAGE(name) \ - .balign PAGE_SIZE; \ -GLOBAL(name) + +#define SYM_DATA_START_PAGE_ALIGNED(name) \ + SYM_START(name, SYM_L_GLOBAL, .balign PAGE_SIZE) #ifdef CONFIG_PAGE_TABLE_ISOLATION /* @@ -352,11 +350,11 @@ GLOBAL(name) */ #define PTI_USER_PGD_FILL 512 /* This ensures they are 8k-aligned: */ -#define NEXT_PGD_PAGE(name) \ - .balign 2 * PAGE_SIZE; \ -GLOBAL(name) +#define SYM_DATA_START_PTI_ALIGNED(name) \ + SYM_START(name, SYM_L_GLOBAL, .balign 2 * PAGE_SIZE) #else -#define NEXT_PGD_PAGE(name) NEXT_PAGE(name) +#define SYM_DATA_START_PTI_ALIGNED(name) \ + SYM_DATA_START_PAGE_ALIGNED(name) #define PTI_USER_PGD_FILL 0 #endif @@ -371,20 +369,21 @@ GLOBAL(name) __INITDATA .balign 4 -NEXT_PGD_PAGE(early_top_pgt) +SYM_DATA_START_PTI_ALIGNED(early_top_pgt) .fill 512,8,0 .fill PTI_USER_PGD_FILL,8,0 +SYM_DATA_END(early_top_pgt) -NEXT_PAGE(early_dynamic_pgts) +SYM_DATA_START_PAGE_ALIGNED(early_dynamic_pgts) .fill 512*EARLY_DYNAMIC_PAGE_TABLES,8,0 +SYM_DATA_END(early_dynamic_pgts) -GLOBAL(early_recursion_flag) - .long 0 +SYM_DATA(early_recursion_flag, .long 0) .data #if defined(CONFIG_XEN_PV) || defined(CONFIG_PVH) -NEXT_PGD_PAGE(init_top_pgt) +SYM_DATA_START_PTI_ALIGNED(init_top_pgt) .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC .org init_top_pgt + L4_PAGE_OFFSET*8, 0 .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC @@ -392,11 +391,13 @@ NEXT_PGD_PAGE(init_top_pgt) /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC .fill PTI_USER_PGD_FILL,8,0 +SYM_DATA_END(init_top_pgt) -NEXT_PAGE(level3_ident_pgt) +SYM_DATA_START_PAGE_ALIGNED(level3_ident_pgt) .quad level2_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC .fill 511, 8, 0 -NEXT_PAGE(level2_ident_pgt) +SYM_DATA_END(level3_ident_pgt) +SYM_DATA_START_PAGE_ALIGNED(level2_ident_pgt) /* * Since I easily can, map the first 1G. * Don't set NX because code runs from these pages. @@ -406,25 +407,29 @@ NEXT_PAGE(level2_ident_pgt) * the CPU should ignore the bit. */ PMDS(0, __PAGE_KERNEL_IDENT_LARGE_EXEC, PTRS_PER_PMD) +SYM_DATA_END(level2_ident_pgt) #else -NEXT_PGD_PAGE(init_top_pgt) +SYM_DATA_START_PTI_ALIGNED(init_top_pgt) .fill 512,8,0 .fill PTI_USER_PGD_FILL,8,0 +SYM_DATA_END(init_top_pgt) #endif #ifdef CONFIG_X86_5LEVEL -NEXT_PAGE(level4_kernel_pgt) +SYM_DATA_START_PAGE_ALIGNED(level4_kernel_pgt) .fill 511,8,0 .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC +SYM_DATA_END(level4_kernel_pgt) #endif -NEXT_PAGE(level3_kernel_pgt) +SYM_DATA_START_PAGE_ALIGNED(level3_kernel_pgt) .fill L3_START_KERNEL,8,0 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ .quad level2_kernel_pgt - __START_KERNEL_map + _KERNPG_TABLE_NOENC .quad level2_fixmap_pgt - __START_KERNEL_map + _PAGE_TABLE_NOENC +SYM_DATA_END(level3_kernel_pgt) -NEXT_PAGE(level2_kernel_pgt) +SYM_DATA_START_PAGE_ALIGNED(level2_kernel_pgt) /* * 512 MB kernel mapping. We spend a full page on this pagetable * anyway. @@ -441,8 +446,9 @@ NEXT_PAGE(level2_kernel_pgt) */ PMDS(0, __PAGE_KERNEL_LARGE_EXEC, KERNEL_IMAGE_SIZE/PMD_SIZE) +SYM_DATA_END(level2_kernel_pgt) -NEXT_PAGE(level2_fixmap_pgt) +SYM_DATA_START_PAGE_ALIGNED(level2_fixmap_pgt) .fill (512 - 4 - FIXMAP_PMD_NUM),8,0 pgtno = 0 .rept (FIXMAP_PMD_NUM) @@ -452,31 +458,32 @@ NEXT_PAGE(level2_fixmap_pgt) .endr /* 6 MB reserved space + a 2MB hole */ .fill 4,8,0 +SYM_DATA_END(level2_fixmap_pgt) -NEXT_PAGE(level1_fixmap_pgt) +SYM_DATA_START_PAGE_ALIGNED(level1_fixmap_pgt) .rept (FIXMAP_PMD_NUM) .fill 512,8,0 .endr +SYM_DATA_END(level1_fixmap_pgt) #undef PMDS .data .align 16 - .globl early_gdt_descr -early_gdt_descr: - .word GDT_ENTRIES*8-1 -early_gdt_descr_base: - .quad INIT_PER_CPU_VAR(gdt_page) - -ENTRY(phys_base) - /* This must match the first entry in level2_kernel_pgt */ - .quad 0x0000000000000000 + +SYM_DATA(early_gdt_descr, .word GDT_ENTRIES*8-1) +SYM_DATA_LOCAL(early_gdt_descr_base, .quad INIT_PER_CPU_VAR(gdt_page)) + + .align 16 +/* This must match the first entry in level2_kernel_pgt */ +SYM_DATA(phys_base, .quad 0x0) EXPORT_SYMBOL(phys_base) #include "../../x86/xen/xen-head.S" __PAGE_ALIGNED_BSS -NEXT_PAGE(empty_zero_page) +SYM_DATA_START_PAGE_ALIGNED(empty_zero_page) .skip PAGE_SIZE +SYM_DATA_END(empty_zero_page) EXPORT_SYMBOL(empty_zero_page) -- 2.7.4