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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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