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    Subject[GIT PULL] x86: add brk allocator for very early allocations
    Aggregate patch below.

    The following changes since commit 11f5585820ae805c48f41c09bc260d0e51744792:
    Ingo Molnar (1):
    Merge branch 'tracing/ftrace'

    are available in the git repository at:

    git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git push/x86/brk

    Jeremy Fitzhardinge (4):
    x86: make section delimiter symbols part of their section
    x86: add brk allocation for very, very early allocations
    x86-32: use brk segment for allocating initial kernel pagetable
    x86: use brk allocation for DMI

    arch/x86/include/asm/dmi.h | 14 +-----
    arch/x86/include/asm/pgtable_32.h | 3 -
    arch/x86/include/asm/sections.h | 7 +++
    arch/x86/include/asm/setup.h | 7 ++-
    arch/x86/kernel/head32.c | 5 +--
    arch/x86/kernel/head64.c | 2 +-
    arch/x86/kernel/head_32.S | 14 +++---
    arch/x86/kernel/setup.c | 51 ++++++++++++++-------
    arch/x86/kernel/vmlinux_32.lds.S | 9 +++-
    arch/x86/kernel/vmlinux_64.lds.S | 90 ++++++++++++++++++++----------------
    arch/x86/lguest/boot.c | 8 ---
    arch/x86/mm/pageattr.c | 5 +-
    arch/x86/xen/mmu.c | 6 +-
    13 files changed, 118 insertions(+), 103 deletions(-)

    diff --git a/arch/x86/include/asm/dmi.h b/arch/x86/include/asm/dmi.h
    index bc68212..aa32f7e 100644
    --- a/arch/x86/include/asm/dmi.h
    +++ b/arch/x86/include/asm/dmi.h
    @@ -2,21 +2,11 @@
    #define _ASM_X86_DMI_H

    #include <asm/io.h>
    +#include <asm/setup.h>

    -#define DMI_MAX_DATA 2048
    -
    -extern int dmi_alloc_index;
    -extern char dmi_alloc_data[DMI_MAX_DATA];
    -
    -/* This is so early that there is no good way to allocate dynamic memory.
    - Allocate data in an BSS array. */
    static inline void *dmi_alloc(unsigned len)
    {
    - int idx = dmi_alloc_index;
    - if ((dmi_alloc_index + len) > DMI_MAX_DATA)
    - return NULL;
    - dmi_alloc_index += len;
    - return dmi_alloc_data + idx;
    + return extend_brk(len, sizeof(int));
    }

    /* Use early IO mappings for DMI because it's initialized early */
    diff --git a/arch/x86/include/asm/pgtable_32.h b/arch/x86/include/asm/pgtable_32.h
    index 97612fc..31bd120 100644
    --- a/arch/x86/include/asm/pgtable_32.h
    +++ b/arch/x86/include/asm/pgtable_32.h
    @@ -42,9 +42,6 @@ extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t);
    */
    #undef TEST_ACCESS_OK

    -/* The boot page tables (all created as a single array) */
    -extern unsigned long pg0[];
    -
    #ifdef CONFIG_X86_PAE
    # include <asm/pgtable-3level.h>
    #else
    diff --git a/arch/x86/include/asm/sections.h b/arch/x86/include/asm/sections.h
    index 2b8c516..1b7ee5d 100644
    --- a/arch/x86/include/asm/sections.h
    +++ b/arch/x86/include/asm/sections.h
    @@ -1 +1,8 @@
    +#ifndef _ASM_X86_SECTIONS_H
    +#define _ASM_X86_SECTIONS_H
    +
    #include <asm-generic/sections.h>
    +
    +extern char __brk_base[], __brk_limit[];
    +
    +#endif /* _ASM_X86_SECTIONS_H */
    diff --git a/arch/x86/include/asm/setup.h b/arch/x86/include/asm/setup.h
    index 05c6f6b..366d366 100644
    --- a/arch/x86/include/asm/setup.h
    +++ b/arch/x86/include/asm/setup.h
    @@ -100,14 +100,15 @@ extern struct boot_params boot_params;
    */
    #define LOWMEMSIZE() (0x9f000)

    +/* exceedingly early brk-like allocator */
    +extern unsigned long _brk_end;
    +void *extend_brk(size_t size, size_t align);
    +
    #ifdef __i386__

    void __init i386_start_kernel(void);
    extern void probe_roms(void);

    -extern unsigned long init_pg_tables_start;
    -extern unsigned long init_pg_tables_end;
    -
    #else
    void __init x86_64_start_kernel(char *real_mode);
    void __init x86_64_start_reservations(char *real_mode_data);
    diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
    index ac108d1..3f8579f 100644
    --- a/arch/x86/kernel/head32.c
    +++ b/arch/x86/kernel/head32.c
    @@ -18,7 +18,7 @@ void __init i386_start_kernel(void)
    {
    reserve_trampoline_memory();

    - reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
    + reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

    #ifdef CONFIG_BLK_DEV_INITRD
    /* Reserve INITRD */
    @@ -29,9 +29,6 @@ void __init i386_start_kernel(void)
    reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
    }
    #endif
    - reserve_early(init_pg_tables_start, init_pg_tables_end,
    - "INIT_PG_TABLE");
    -
    reserve_ebda_region();

    /*
    diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
    index f5b2722..70eaa85 100644
    --- a/arch/x86/kernel/head64.c
    +++ b/arch/x86/kernel/head64.c
    @@ -100,7 +100,7 @@ void __init x86_64_start_reservations(char *real_mode_data)

    reserve_trampoline_memory();

    - reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");
    + reserve_early(__pa_symbol(&_text), __pa_symbol(&__bss_stop), "TEXT DATA BSS");

    #ifdef CONFIG_BLK_DEV_INITRD
    /* Reserve INITRD */
    diff --git a/arch/x86/kernel/head_32.S b/arch/x86/kernel/head_32.S
    index 6219259..d243437 100644
    --- a/arch/x86/kernel/head_32.S
    +++ b/arch/x86/kernel/head_32.S
    @@ -167,7 +167,7 @@ num_subarch_entries = (. - subarch_entries) / 4
    /*
    * Initialize page tables. This creates a PDE and a set of page
    * tables, which are located immediately beyond _end. The variable
    - * init_pg_tables_end is set up to point to the first "safe" location.
    + * _brk_end is set up to point to the first "safe" location.
    * Mappings are created both at virtual address 0 (identity mapping)
    * and PAGE_OFFSET for up to _end+sizeof(page tables)+INIT_MAP_BEYOND_END.
    *
    @@ -190,8 +190,7 @@ default_entry:

    xorl %ebx,%ebx /* %ebx is kept at zero */

    - movl $pa(pg0), %edi
    - movl %edi, pa(init_pg_tables_start)
    + movl $pa(__brk_base), %edi
    movl $pa(swapper_pg_pmd), %edx
    movl $PTE_IDENT_ATTR, %eax
    10:
    @@ -216,7 +215,8 @@ default_entry:
    cmpl %ebp,%eax
    jb 10b
    1:
    - movl %edi,pa(init_pg_tables_end)
    + addl $__PAGE_OFFSET, %edi
    + movl %edi, pa(_brk_end)
    shrl $12, %eax
    movl %eax, pa(max_pfn_mapped)

    @@ -227,8 +227,7 @@ default_entry:

    page_pde_offset = (__PAGE_OFFSET >> 20);

    - movl $pa(pg0), %edi
    - movl %edi, pa(init_pg_tables_start)
    + movl $pa(__brk_base), %edi
    movl $pa(swapper_pg_dir), %edx
    movl $PTE_IDENT_ATTR, %eax
    10:
    @@ -249,7 +248,8 @@ page_pde_offset = (__PAGE_OFFSET >> 20);
    leal (INIT_MAP_BEYOND_END+PTE_IDENT_ATTR)(%edi),%ebp
    cmpl %ebp,%eax
    jb 10b
    - movl %edi,pa(init_pg_tables_end)
    + addl $__PAGE_OFFSET, %edi
    + movl %edi, pa(_brk_end)
    shrl $12, %eax
    movl %eax, pa(max_pfn_mapped)

    diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
    index ce9e888..b344908 100644
    --- a/arch/x86/kernel/setup.c
    +++ b/arch/x86/kernel/setup.c
    @@ -114,6 +114,9 @@

    unsigned int boot_cpu_id __read_mostly;

    +static __initdata unsigned long _brk_start = (unsigned long)__brk_base;
    +unsigned long _brk_end = (unsigned long)__brk_base;
    +
    #ifdef CONFIG_X86_64
    int default_cpu_present_to_apicid(int mps_cpu)
    {
    @@ -158,12 +161,6 @@ static struct resource bss_resource = {


    #ifdef CONFIG_X86_32
    -/* This value is set up by the early boot code to point to the value
    - immediately after the boot time page tables. It contains a *physical*
    - address, and must not be in the .bss segment! */
    -unsigned long init_pg_tables_start __initdata = ~0UL;
    -unsigned long init_pg_tables_end __initdata = ~0UL;
    -
    static struct resource video_ram_resource = {
    .name = "Video RAM area",
    .start = 0xa0000,
    @@ -219,12 +216,6 @@ unsigned long mmu_cr4_features = X86_CR4_PAE;
    int bootloader_type;

    /*
    - * Early DMI memory
    - */
    -int dmi_alloc_index;
    -char dmi_alloc_data[DMI_MAX_DATA];
    -
    -/*
    * Setup options
    */
    struct screen_info screen_info;
    @@ -337,6 +328,34 @@ static void __init relocate_initrd(void)
    }
    #endif

    +void * __init extend_brk(size_t size, size_t align)
    +{
    + size_t mask = align - 1;
    + void *ret;
    +
    + BUG_ON(_brk_start == 0);
    + BUG_ON(align & mask);
    +
    + _brk_end = (_brk_end + mask) & ~mask;
    + BUG_ON((char *)(_brk_end + size) > __brk_limit);
    +
    + ret = (void *)_brk_end;
    + _brk_end += size;
    +
    + memset(ret, 0, size);
    +
    + return ret;
    +}
    +
    +static void __init reserve_brk(void)
    +{
    + if (_brk_end > _brk_start)
    + reserve_early(__pa(_brk_start), __pa(_brk_end), "BRK");
    +
    + /* Mark brk area as locked down and no longer taking any new allocations */
    + _brk_start = 0;
    +}
    +
    static void __init reserve_initrd(void)
    {
    u64 ramdisk_image = boot_params.hdr.ramdisk_image;
    @@ -717,11 +736,7 @@ void __init setup_arch(char **cmdline_p)
    init_mm.start_code = (unsigned long) _text;
    init_mm.end_code = (unsigned long) _etext;
    init_mm.end_data = (unsigned long) _edata;
    -#ifdef CONFIG_X86_32
    - init_mm.brk = init_pg_tables_end + PAGE_OFFSET;
    -#else
    - init_mm.brk = (unsigned long) &_end;
    -#endif
    + init_mm.brk = _brk_end;

    code_resource.start = virt_to_phys(_text);
    code_resource.end = virt_to_phys(_etext)-1;
    @@ -842,6 +857,8 @@ void __init setup_arch(char **cmdline_p)
    setup_bios_corruption_check();
    #endif

    + reserve_brk();
    +
    /* max_pfn_mapped is updated here */
    max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT);
    max_pfn_mapped = max_low_pfn_mapped;
    diff --git a/arch/x86/kernel/vmlinux_32.lds.S b/arch/x86/kernel/vmlinux_32.lds.S
    index 0d86096..1063fbe 100644
    --- a/arch/x86/kernel/vmlinux_32.lds.S
    +++ b/arch/x86/kernel/vmlinux_32.lds.S
    @@ -189,10 +189,13 @@ SECTIONS
    *(.bss)
    . = ALIGN(4);
    __bss_stop = .;
    - _end = . ;
    - /* This is where the kernel creates the early boot page tables */
    +
    . = ALIGN(PAGE_SIZE);
    - pg0 = . ;
    + __brk_base = . ;
    + . += 1024 * 1024 ;
    + __brk_limit = . ;
    +
    + _end = . ;
    }

    /* Sections to be discarded */
    diff --git a/arch/x86/kernel/vmlinux_64.lds.S b/arch/x86/kernel/vmlinux_64.lds.S
    index fbfced6..b8b83e4 100644
    --- a/arch/x86/kernel/vmlinux_64.lds.S
    +++ b/arch/x86/kernel/vmlinux_64.lds.S
    @@ -29,8 +29,8 @@ SECTIONS
    {
    . = __START_KERNEL;
    phys_startup_64 = startup_64 - LOAD_OFFSET;
    - _text = .; /* Text and read-only data */
    .text : AT(ADDR(.text) - LOAD_OFFSET) {
    + _text = .; /* Text and read-only data */
    /* First the code that has to be first for bootstrapping */
    *(.text.head)
    _stext = .;
    @@ -61,13 +61,13 @@ SECTIONS
    .data : AT(ADDR(.data) - LOAD_OFFSET) {
    DATA_DATA
    CONSTRUCTORS
    + _edata = .; /* End of data section */
    } :data

    - _edata = .; /* End of data section */

    - . = ALIGN(PAGE_SIZE);
    - . = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
    .data.cacheline_aligned : AT(ADDR(.data.cacheline_aligned) - LOAD_OFFSET) {
    + . = ALIGN(PAGE_SIZE);
    + . = ALIGN(CONFIG_X86_L1_CACHE_BYTES);
    *(.data.cacheline_aligned)
    }
    . = ALIGN(CONFIG_X86_INTERNODE_CACHE_BYTES);
    @@ -125,29 +125,29 @@ SECTIONS
    #undef VVIRT_OFFSET
    #undef VVIRT

    - . = ALIGN(THREAD_SIZE); /* init_task */
    .data.init_task : AT(ADDR(.data.init_task) - LOAD_OFFSET) {
    + . = ALIGN(THREAD_SIZE); /* init_task */
    *(.data.init_task)
    }:data.init

    - . = ALIGN(PAGE_SIZE);
    .data.page_aligned : AT(ADDR(.data.page_aligned) - LOAD_OFFSET) {
    + . = ALIGN(PAGE_SIZE);
    *(.data.page_aligned)
    }

    - /* might get freed after init */
    - . = ALIGN(PAGE_SIZE);
    - __smp_alt_begin = .;
    - __smp_locks = .;
    .smp_locks : AT(ADDR(.smp_locks) - LOAD_OFFSET) {
    + /* might get freed after init */
    + . = ALIGN(PAGE_SIZE);
    + __smp_alt_begin = .;
    + __smp_locks = .;
    *(.smp_locks)
    + __smp_locks_end = .;
    + . = ALIGN(PAGE_SIZE);
    + __smp_alt_end = .;
    }
    - __smp_locks_end = .;
    - . = ALIGN(PAGE_SIZE);
    - __smp_alt_end = .;

    . = ALIGN(PAGE_SIZE); /* Init code and data */
    - __init_begin = .;
    + __init_begin = .; /* paired with __init_end */
    .init.text : AT(ADDR(.init.text) - LOAD_OFFSET) {
    _sinittext = .;
    INIT_TEXT
    @@ -159,40 +159,42 @@ SECTIONS
    __initdata_end = .;
    }

    - . = ALIGN(16);
    - __setup_start = .;
    - .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) { *(.init.setup) }
    - __setup_end = .;
    - __initcall_start = .;
    + .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
    + . = ALIGN(16);
    + __setup_start = .;
    + *(.init.setup)
    + __setup_end = .;
    + }
    .initcall.init : AT(ADDR(.initcall.init) - LOAD_OFFSET) {
    + __initcall_start = .;
    INITCALLS
    + __initcall_end = .;
    }
    - __initcall_end = .;
    - __con_initcall_start = .;
    .con_initcall.init : AT(ADDR(.con_initcall.init) - LOAD_OFFSET) {
    + __con_initcall_start = .;
    *(.con_initcall.init)
    + __con_initcall_end = .;
    }
    - __con_initcall_end = .;
    - __x86_cpu_dev_start = .;
    .x86_cpu_dev.init : AT(ADDR(.x86_cpu_dev.init) - LOAD_OFFSET) {
    + __x86_cpu_dev_start = .;
    *(.x86_cpu_dev.init)
    + __x86_cpu_dev_end = .;
    }
    - __x86_cpu_dev_end = .;
    SECURITY_INIT

    . = ALIGN(8);
    .parainstructions : AT(ADDR(.parainstructions) - LOAD_OFFSET) {
    - __parainstructions = .;
    + __parainstructions = .;
    *(.parainstructions)
    - __parainstructions_end = .;
    + __parainstructions_end = .;
    }

    - . = ALIGN(8);
    - __alt_instructions = .;
    .altinstructions : AT(ADDR(.altinstructions) - LOAD_OFFSET) {
    + . = ALIGN(8);
    + __alt_instructions = .;
    *(.altinstructions)
    + __alt_instructions_end = .;
    }
    - __alt_instructions_end = .;
    .altinstr_replacement : AT(ADDR(.altinstr_replacement) - LOAD_OFFSET) {
    *(.altinstr_replacement)
    }
    @@ -207,9 +209,11 @@ SECTIONS

    #ifdef CONFIG_BLK_DEV_INITRD
    . = ALIGN(PAGE_SIZE);
    - __initramfs_start = .;
    - .init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) { *(.init.ramfs) }
    - __initramfs_end = .;
    + .init.ramfs : AT(ADDR(.init.ramfs) - LOAD_OFFSET) {
    + __initramfs_start = .;
    + *(.init.ramfs)
    + __initramfs_end = .;
    + }
    #endif

    #ifdef CONFIG_SMP
    @@ -229,20 +233,26 @@ SECTIONS
    . = ALIGN(PAGE_SIZE);
    __init_end = .;

    - . = ALIGN(PAGE_SIZE);
    - __nosave_begin = .;
    .data_nosave : AT(ADDR(.data_nosave) - LOAD_OFFSET) {
    - *(.data.nosave)
    + . = ALIGN(PAGE_SIZE);
    + __nosave_begin = .;
    + *(.data.nosave)
    + . = ALIGN(PAGE_SIZE);
    + __nosave_end = .;
    } :data.init2 /* use another section data.init2, see PERCPU_VADDR() above */
    - . = ALIGN(PAGE_SIZE);
    - __nosave_end = .;

    - __bss_start = .; /* BSS */
    .bss : AT(ADDR(.bss) - LOAD_OFFSET) {
    + . = ALIGN(PAGE_SIZE);
    + __bss_start = .; /* BSS */
    *(.bss.page_aligned)
    *(.bss)
    - }
    - __bss_stop = .;
    + __bss_stop = .;
    +
    + . = ALIGN(PAGE_SIZE);
    + __brk_base = . ;
    + . += 1024 * 1024 ;
    + __brk_limit = . ;
    + }

    _end = . ;

    diff --git a/arch/x86/lguest/boot.c b/arch/x86/lguest/boot.c
    index 9fe4dda..90e44a1 100644
    --- a/arch/x86/lguest/boot.c
    +++ b/arch/x86/lguest/boot.c
    @@ -1058,14 +1058,6 @@ __init void lguest_init(void)
    * lguest_init() where the rest of the fairly chaotic boot setup
    * occurs. */

    - /* The native boot code sets up initial page tables immediately after
    - * the kernel itself, and sets init_pg_tables_end so they're not
    - * clobbered. The Launcher places our initial pagetables somewhere at
    - * the top of our physical memory, so we don't need extra space: set
    - * init_pg_tables_end to the end of the kernel. */
    - init_pg_tables_start = __pa(pg0);
    - init_pg_tables_end = __pa(pg0);
    -
    /* As described in head_32.S, we map the first 128M of memory. */
    max_pfn_mapped = (128*1024*1024) >> PAGE_SHIFT;

    diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
    index 4629a87..8eb4eaa 100644
    --- a/arch/x86/mm/pageattr.c
    +++ b/arch/x86/mm/pageattr.c
    @@ -16,6 +16,7 @@
    #include <asm/processor.h>
    #include <asm/tlbflush.h>
    #include <asm/sections.h>
    +#include <asm/setup.h>
    #include <asm/uaccess.h>
    #include <asm/pgalloc.h>
    #include <asm/proto.h>
    @@ -95,7 +96,7 @@ static inline unsigned long highmap_start_pfn(void)

    static inline unsigned long highmap_end_pfn(void)
    {
    - return __pa(roundup((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
    + return __pa(roundup(_brk_end, PMD_SIZE)) >> PAGE_SHIFT;
    }

    #endif
    @@ -700,7 +701,7 @@ static int cpa_process_alias(struct cpa_data *cpa)
    * No need to redo, when the primary call touched the high
    * mapping already:
    */
    - if (within(vaddr, (unsigned long) _text, (unsigned long) _end))
    + if (within(vaddr, (unsigned long) _text, _brk_end))
    return 0;

    /*
    diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
    index cb6afa4..72f6a76 100644
    --- a/arch/x86/xen/mmu.c
    +++ b/arch/x86/xen/mmu.c
    @@ -1723,9 +1723,9 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
    {
    pmd_t *kernel_pmd;

    - init_pg_tables_start = __pa(pgd);
    - init_pg_tables_end = __pa(pgd) + xen_start_info->nr_pt_frames*PAGE_SIZE;
    - max_pfn_mapped = PFN_DOWN(init_pg_tables_end + 512*1024);
    + max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
    + xen_start_info->nr_pt_frames * PAGE_SIZE +
    + 512*1024);

    kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
    memcpy(level2_kernel_pgt, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);



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