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 <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Cao jin <caoj.fnst@cn.fujitsu.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: linux-arch@vger.kernel.org
Cc: Maran Wilson <maran.wilson@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191011115108.12392-12-jslaby@suse.cz

diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
index aec1fdb..e2b3e6c 100644 (file)
--- 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 (file)
--- 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)