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Commit a4c81cf6 authored by Yinghai Lu's avatar Yinghai Lu Committed by Thomas Gleixner
Browse files

x86: extend e820 ealy_res support 32bit



move early_res related from e820_64.c to e820.c
make edba detection to be done in head32.c
remove smp_alloc_memory, because we have fixed trampoline address now.

Signed-off-by: default avatarYinghai Lu <yhlu.kernel@gmail.com>

 arch/x86/kernel/e820.c              |  214 ++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/e820_64.c           |  196 --------------------------------
 arch/x86/kernel/head32.c            |   76 ++++++++++++
 arch/x86/kernel/setup_32.c          |  109 +++---------------
 arch/x86/kernel/smpboot.c           |   17 --
 arch/x86/kernel/trampoline.c        |    2
 arch/x86/mach-voyager/voyager_smp.c |    9 -
 include/asm-x86/e820.h              |    6 +
 include/asm-x86/e820_64.h           |    9 -
 include/asm-x86/smp.h               |    1
 arch/x86/kernel/e820.c              |  214 ++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/e820_64.c           |  196 --------------------------------
 arch/x86/kernel/head32.c            |   76 ++++++++++++
 arch/x86/kernel/setup_32.c          |  109 +++---------------
 arch/x86/kernel/smpboot.c           |   17 --
 arch/x86/kernel/trampoline.c        |    2
 arch/x86/mach-voyager/voyager_smp.c |    9 -
 include/asm-x86/e820.h              |    6 +
 include/asm-x86/e820_64.h           |    9 -
 include/asm-x86/smp.h               |    1
 arch/x86/kernel/e820.c              |  214 ++++++++++++++++++++++++++++++++++++
 arch/x86/kernel/e820_64.c           |  196 --------------------------------
 arch/x86/kernel/head32.c            |   76 ++++++++++++
 arch/x86/kernel/setup_32.c          |  109 +++---------------
 arch/x86/kernel/smpboot.c           |   17 --
 arch/x86/kernel/trampoline.c        |    2
 arch/x86/mach-voyager/voyager_smp.c |    9 -
 include/asm-x86/e820.h              |    6 +
 include/asm-x86/e820_64.h           |    9 -
 include/asm-x86/smp.h               |    1
 10 files changed, 320 insertions(+), 319 deletions(-)

Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 69c91893
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+214 −0
Original line number Diff line number Diff line
@@ -22,7 +22,9 @@
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/e820.h>
#include <asm/proto.h>
#include <asm/setup.h>
#include <asm/trampoline.h>

struct e820map e820;

@@ -493,3 +495,215 @@ __init void e820_setup_gap(void)
	       pci_mem_start, gapstart, gapsize);
}


/*
 * Early reserved memory areas.
 */
#define MAX_EARLY_RES 20

struct early_res {
	u64 start, end;
	char name[16];
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
	{ 0, PAGE_SIZE, "BIOS data page" },	/* BIOS data page */
#if defined(CONFIG_X86_64) && defined(CONFIG_X86_TRAMPOLINE)
	{ TRAMPOLINE_BASE, TRAMPOLINE_BASE + 2 * PAGE_SIZE, "TRAMPOLINE" },
#endif
#if defined(CONFIG_X86_32) && defined(CONFIG_SMP)
	/*
	 * But first pinch a few for the stack/trampoline stuff
	 * FIXME: Don't need the extra page at 4K, but need to fix
	 * trampoline before removing it. (see the GDT stuff)
	 */
	{ PAGE_SIZE, PAGE_SIZE + PAGE_SIZE, "EX TRAMPOLINE" },
	/*
	 * Has to be in very low memory so we can execute
	 * real-mode AP code.
	 */
	{ TRAMPOLINE_BASE, TRAMPOLINE_BASE + PAGE_SIZE, "TRAMPOLINE" },
#endif
	{}
};

void __init reserve_early(u64 start, u64 end, char *name)
{
	int i;
	struct early_res *r;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		r = &early_res[i];
		if (end > r->start && start < r->end)
			panic("Overlapping early reservations %llx-%llx %s to %llx-%llx %s\n",
			      start, end - 1, name?name:"", r->start,
			      r->end - 1, r->name);
	}
	if (i >= MAX_EARLY_RES)
		panic("Too many early reservations");
	r = &early_res[i];
	r->start = start;
	r->end = end;
	if (name)
		strncpy(r->name, name, sizeof(r->name) - 1);
}

void __init free_early(u64 start, u64 end)
{
	struct early_res *r;
	int i, j;

	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		r = &early_res[i];
		if (start == r->start && end == r->end)
			break;
	}
	if (i >= MAX_EARLY_RES || !early_res[i].end)
		panic("free_early on not reserved area: %llx-%llx!",
			 start, end);

	for (j = i + 1; j < MAX_EARLY_RES && early_res[j].end; j++)
		;

	memmove(&early_res[i], &early_res[i + 1],
	       (j - 1 - i) * sizeof(struct early_res));

	early_res[j - 1].end = 0;
}

void __init early_res_to_bootmem(u64 start, u64 end)
{
	int i;
	u64 final_start, final_end;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		final_start = max(start, r->start);
		final_end = min(end, r->end);
		if (final_start >= final_end)
			continue;
		printk(KERN_INFO "  early res: %d [%llx-%llx] %s\n", i,
			final_start, final_end - 1, r->name);
#ifdef CONFIG_X86_64
		reserve_bootmem_generic(final_start, final_end - final_start);
#else
		reserve_bootmem(final_start, final_end - final_start,
				BOOTMEM_DEFAULT);
#endif
	}
}

/* Check for already reserved areas */
static inline int __init bad_addr(u64 *addrp, u64 size, u64 align)
{
	int i;
	u64 addr = *addrp, last;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last >= r->start && addr < r->end) {
			*addrp = addr = round_up(r->end, align);
			changed = 1;
			goto again;
		}
	}
	return changed;
}

/* Check for already reserved areas */
static inline int __init bad_addr_size(u64 *addrp, u64 *sizep, u64 align)
{
	int i;
	u64 addr = *addrp, last;
	u64 size = *sizep;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last > r->start && addr < r->start) {
			size = r->start - addr;
			changed = 1;
			goto again;
		}
		if (last > r->end && addr < r->end) {
			addr = round_up(r->end, align);
			size = last - addr;
			changed = 1;
			goto again;
		}
		if (last <= r->end && addr >= r->start) {
			(*sizep)++;
			return 0;
		}
	}
	if (changed) {
		*addrp = addr;
		*sizep = size;
	}
	return changed;
}

/*
 * Find a free area with specified alignment in a specific range.
 */
u64 __init find_e820_area(u64 start, u64 end, u64 size, u64 align)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		u64 addr, last;
		u64 ei_last;

		if (ei->type != E820_RAM)
			continue;
		addr = round_up(ei->addr, align);
		ei_last = ei->addr + ei->size;
		if (addr < start)
			addr = round_up(start, align);
		if (addr >= ei_last)
			continue;
		while (bad_addr(&addr, size, align) && addr+size <= ei_last)
			;
		last = addr + size;
		if (last > ei_last)
			continue;
		if (last > end)
			continue;
		return addr;
	}
	return -1ULL;
}

/*
 * Find next free range after *start
 */
u64 __init find_e820_area_size(u64 start, u64 *sizep, u64 align)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		u64 addr, last;
		u64 ei_last;

		if (ei->type != E820_RAM)
			continue;
		addr = round_up(ei->addr, align);
		ei_last = ei->addr + ei->size;
		if (addr < start)
			addr = round_up(start, align);
		if (addr >= ei_last)
			continue;
		*sizep = ei_last - addr;
		while (bad_addr_size(&addr, sizep, align) &&
			addr + *sizep <= ei_last)
			;
		last = addr + *sizep;
		if (last > ei_last)
			continue;
		return addr;
	}
	return -1UL;

}
+0 −196
Original line number Diff line number Diff line
@@ -46,202 +46,6 @@ unsigned long max_pfn_mapped;
 */
static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;

/*
 * Early reserved memory areas.
 */
#define MAX_EARLY_RES 20

struct early_res {
	unsigned long start, end;
	char name[16];
};
static struct early_res early_res[MAX_EARLY_RES] __initdata = {
	{ 0, PAGE_SIZE, "BIOS data page" },			/* BIOS data page */
#ifdef CONFIG_X86_TRAMPOLINE
	{ TRAMPOLINE_BASE, TRAMPOLINE_BASE + 2 * PAGE_SIZE, "TRAMPOLINE" },
#endif
	{}
};

void __init reserve_early(unsigned long start, unsigned long end, char *name)
{
	int i;
	struct early_res *r;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		r = &early_res[i];
		if (end > r->start && start < r->end)
			panic("Overlapping early reservations %lx-%lx %s to %lx-%lx %s\n",
			      start, end - 1, name?name:"", r->start, r->end - 1, r->name);
	}
	if (i >= MAX_EARLY_RES)
		panic("Too many early reservations");
	r = &early_res[i];
	r->start = start;
	r->end = end;
	if (name)
		strncpy(r->name, name, sizeof(r->name) - 1);
}

void __init free_early(unsigned long start, unsigned long end)
{
	struct early_res *r;
	int i, j;

	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		r = &early_res[i];
		if (start == r->start && end == r->end)
			break;
	}
	if (i >= MAX_EARLY_RES || !early_res[i].end)
		panic("free_early on not reserved area: %lx-%lx!", start, end);

	for (j = i + 1; j < MAX_EARLY_RES && early_res[j].end; j++)
		;

	memmove(&early_res[i], &early_res[i + 1],
	       (j - 1 - i) * sizeof(struct early_res));

	early_res[j - 1].end = 0;
}

void __init early_res_to_bootmem(unsigned long start, unsigned long end)
{
	int i;
	unsigned long final_start, final_end;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		final_start = max(start, r->start);
		final_end = min(end, r->end);
		if (final_start >= final_end)
			continue;
		printk(KERN_INFO "  early res: %d [%lx-%lx] %s\n", i,
			final_start, final_end - 1, r->name);
		reserve_bootmem_generic(final_start, final_end - final_start);
	}
}

/* Check for already reserved areas */
static inline int __init
bad_addr(unsigned long *addrp, unsigned long size, unsigned long align)
{
	int i;
	unsigned long addr = *addrp, last;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last >= r->start && addr < r->end) {
			*addrp = addr = round_up(r->end, align);
			changed = 1;
			goto again;
		}
	}
	return changed;
}

/* Check for already reserved areas */
static inline int __init
bad_addr_size(unsigned long *addrp, unsigned long *sizep, unsigned long align)
{
	int i;
	unsigned long addr = *addrp, last;
	unsigned long size = *sizep;
	int changed = 0;
again:
	last = addr + size;
	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
		struct early_res *r = &early_res[i];
		if (last > r->start && addr < r->start) {
			size = r->start - addr;
			changed = 1;
			goto again;
		}
		if (last > r->end && addr < r->end) {
			addr = round_up(r->end, align);
			size = last - addr;
			changed = 1;
			goto again;
		}
		if (last <= r->end && addr >= r->start) {
			(*sizep)++;
			return 0;
		}
	}
	if (changed) {
		*addrp = addr;
		*sizep = size;
	}
	return changed;
}

/*
 * Find a free area with specified alignment in a specific range.
 */
unsigned long __init find_e820_area(unsigned long start, unsigned long end,
				    unsigned long size, unsigned long align)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		unsigned long addr, last;
		unsigned long ei_last;

		if (ei->type != E820_RAM)
			continue;
		addr = round_up(ei->addr, align);
		ei_last = ei->addr + ei->size;
		if (addr < start)
			addr = round_up(start, align);
		if (addr >= ei_last)
			continue;
		while (bad_addr(&addr, size, align) && addr+size <= ei_last)
			;
		last = addr + size;
		if (last > ei_last)
			continue;
		if (last > end)
			continue;
		return addr;
	}
	return -1UL;
}

/*
 * Find next free range after *start
 */
unsigned long __init find_e820_area_size(unsigned long start,
					 unsigned long *sizep,
					 unsigned long align)
{
	int i;

	for (i = 0; i < e820.nr_map; i++) {
		struct e820entry *ei = &e820.map[i];
		unsigned long addr, last;
		unsigned long ei_last;

		if (ei->type != E820_RAM)
			continue;
		addr = round_up(ei->addr, align);
		ei_last = ei->addr + ei->size;
		if (addr < start)
			addr = round_up(start, align);
		if (addr >= ei_last)
			continue;
		*sizep = ei_last - addr;
		while (bad_addr_size(&addr, sizep, align) &&
			addr + *sizep <= ei_last)
			;
		last = addr + *sizep;
		if (last > ei_last)
			continue;
		return addr;
	}
	return -1UL;

}
/*
 * Find the highest page frame number we have available
 */
+76 −0
Original line number Diff line number Diff line
@@ -8,7 +8,83 @@
#include <linux/init.h>
#include <linux/start_kernel.h>

#include <asm/setup.h>
#include <asm/sections.h>
#include <asm/e820.h>
#include <asm/bios_ebda.h>

#define BIOS_LOWMEM_KILOBYTES 0x413

/*
 * The BIOS places the EBDA/XBDA at the top of conventional
 * memory, and usually decreases the reported amount of
 * conventional memory (int 0x12) too. This also contains a
 * workaround for Dell systems that neglect to reserve EBDA.
 * The same workaround also avoids a problem with the AMD768MPX
 * chipset: reserve a page before VGA to prevent PCI prefetch
 * into it (errata #56). Usually the page is reserved anyways,
 * unless you have no PS/2 mouse plugged in.
 */
static void __init reserve_ebda_region(void)
{
	unsigned int lowmem, ebda_addr;

	/* To determine the position of the EBDA and the */
	/* end of conventional memory, we need to look at */
	/* the BIOS data area. In a paravirtual environment */
	/* that area is absent. We'll just have to assume */
	/* that the paravirt case can handle memory setup */
	/* correctly, without our help. */
	if (paravirt_enabled())
		return;

	/* end of low (conventional) memory */
	lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
	lowmem <<= 10;

	/* start of EBDA area */
	ebda_addr = get_bios_ebda();

	/* Fixup: bios puts an EBDA in the top 64K segment */
	/* of conventional memory, but does not adjust lowmem. */
	if ((lowmem - ebda_addr) <= 0x10000)
		lowmem = ebda_addr;

	/* Fixup: bios does not report an EBDA at all. */
	/* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
	if ((ebda_addr == 0) && (lowmem >= 0x9f000))
		lowmem = 0x9f000;

	/* Paranoia: should never happen, but... */
	if ((lowmem == 0) || (lowmem >= 0x100000))
		lowmem = 0x9f000;

	/* reserve all memory between lowmem and the 1MB mark */
	reserve_early(lowmem, 0x100000, "BIOS reserved");
}

void __init i386_start_kernel(void)
{
	reserve_early(__pa_symbol(&_text), __pa_symbol(&_end), "TEXT DATA BSS");

#ifdef CONFIG_BLK_DEV_INITRD
	/* Reserve INITRD */
	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
		u64 ramdisk_image = boot_params.hdr.ramdisk_image;
		u64 ramdisk_size  = boot_params.hdr.ramdisk_size;
		u64 ramdisk_end   = ramdisk_image + ramdisk_size;
		reserve_early(ramdisk_image, ramdisk_end, "RAMDISK");
	}
#endif
	reserve_early(__pa_symbol(&_end), init_pg_tables_end, "INIT_PG_TABLE");

	reserve_ebda_region();

	/*
	 * At this point everything still needed from the boot loader
	 * or BIOS or kernel text should be early reserved or marked not
	 * RAM in e820. All other memory is free game.
	 */

	start_kernel();
}
+23 −86
Original line number Diff line number Diff line
@@ -359,56 +359,6 @@ unsigned long __init find_max_low_pfn(void)
	return max_low_pfn;
}

#define BIOS_LOWMEM_KILOBYTES 0x413

/*
 * The BIOS places the EBDA/XBDA at the top of conventional
 * memory, and usually decreases the reported amount of
 * conventional memory (int 0x12) too. This also contains a
 * workaround for Dell systems that neglect to reserve EBDA.
 * The same workaround also avoids a problem with the AMD768MPX
 * chipset: reserve a page before VGA to prevent PCI prefetch
 * into it (errata #56). Usually the page is reserved anyways,
 * unless you have no PS/2 mouse plugged in.
 */
static void __init reserve_ebda_region(void)
{
	unsigned int lowmem, ebda_addr;

	/* To determine the position of the EBDA and the */
	/* end of conventional memory, we need to look at */
	/* the BIOS data area. In a paravirtual environment */
	/* that area is absent. We'll just have to assume */
	/* that the paravirt case can handle memory setup */
	/* correctly, without our help. */
	if (paravirt_enabled())
		return;

	/* end of low (conventional) memory */
	lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES);
	lowmem <<= 10;

	/* start of EBDA area */
	ebda_addr = get_bios_ebda();

	/* Fixup: bios puts an EBDA in the top 64K segment */
	/* of conventional memory, but does not adjust lowmem. */
	if ((lowmem - ebda_addr) <= 0x10000)
		lowmem = ebda_addr;

	/* Fixup: bios does not report an EBDA at all. */
	/* Some old Dells seem to need 4k anyhow (bugzilla 2990) */
	if ((ebda_addr == 0) && (lowmem >= 0x9f000))
		lowmem = 0x9f000;

	/* Paranoia: should never happen, but... */
	if ((lowmem == 0) || (lowmem >= 0x100000))
		lowmem = 0x9f000;

	/* reserve all memory between lowmem and the 1MB mark */
	reserve_bootmem(lowmem, 0x100000 - lowmem, BOOTMEM_DEFAULT);
}

#ifndef CONFIG_NEED_MULTIPLE_NODES
static void __init setup_bootmem_allocator(void);
static unsigned long __init setup_memory(void)
@@ -522,25 +472,32 @@ static void __init reserve_initrd(void)
	unsigned long end_of_lowmem = max_low_pfn << PAGE_SHIFT;
	unsigned long ramdisk_here;

	initrd_start = 0;

	if (!boot_params.hdr.type_of_loader ||
	    !ramdisk_image || !ramdisk_size)
		return;		/* No initrd provided by bootloader */

	initrd_start = 0;

	if (ramdisk_end < ramdisk_image) {
		free_bootmem(ramdisk_image, ramdisk_size);
		printk(KERN_ERR "initrd wraps around end of memory, "
		       "disabling initrd\n");
		return;
	}
	if (ramdisk_size >= end_of_lowmem/2) {
		free_bootmem(ramdisk_image, ramdisk_size);
		printk(KERN_ERR "initrd too large to handle, "
		       "disabling initrd\n");
		return;
	}

	if (ramdisk_end <= end_of_lowmem) {
		/* All in lowmem, easy case */
		reserve_bootmem(ramdisk_image, ramdisk_size, BOOTMEM_DEFAULT);
		/*
		 * don't need to reserve again, already reserved early
		 * in i386_start_kernel, and early_res_to_bootmem
		 * convert that to reserved in bootmem
		 */
		initrd_start = ramdisk_image + PAGE_OFFSET;
		initrd_end = initrd_start+ramdisk_size;
		return;
@@ -582,6 +539,8 @@ static void __init relocate_initrd(void)
		p = (char *)__va(ramdisk_image);
		memcpy(q, p, clen);
		q += clen;
		/* need to free these low pages...*/
		free_bootmem(ramdisk_image, clen);
		ramdisk_image += clen;
		ramdisk_size  -= clen;
	}
@@ -600,47 +559,28 @@ static void __init relocate_initrd(void)
		ramdisk_image += clen;
		ramdisk_size  -= clen;
	}
	/* high pages is not converted by early_res_to_bootmem */
}

#endif /* CONFIG_BLK_DEV_INITRD */

void __init setup_bootmem_allocator(void)
{
	unsigned long bootmap_size;
	unsigned long bootmap_size, bootmap;
	/*
	 * Initialize the boot-time allocator (with low memory only):
	 */
	bootmap_size = init_bootmem(min_low_pfn, max_low_pfn);

	bootmap_size = bootmem_bootmap_pages(max_low_pfn)<<PAGE_SHIFT;
	bootmap = find_e820_area(min_low_pfn<<PAGE_SHIFT,
				 max_low_pfn<<PAGE_SHIFT, bootmap_size,
				 PAGE_SIZE);
	if (bootmap == -1L)
		panic("Cannot find bootmem map of size %ld\n", bootmap_size);
	bootmap_size = init_bootmem(bootmap >> PAGE_SHIFT, max_low_pfn);
	register_bootmem_low_pages(max_low_pfn);
	early_res_to_bootmem(0, max_low_pfn<<PAGE_SHIFT);
	reserve_bootmem(bootmap, bootmap_size, BOOTMEM_DEFAULT);

	/*
	 * Reserve the bootmem bitmap itself as well. We do this in two
	 * steps (first step was init_bootmem()) because this catches
	 * the (very unlikely) case of us accidentally initializing the
	 * bootmem allocator with an invalid RAM area.
	 */
	reserve_bootmem(__pa_symbol(_text), (PFN_PHYS(min_low_pfn) +
			 bootmap_size + PAGE_SIZE-1) - __pa_symbol(_text),
			 BOOTMEM_DEFAULT);

	/*
	 * reserve physical page 0 - it's a special BIOS page on many boxes,
	 * enabling clean reboots, SMP operation, laptop functions.
	 */
	reserve_bootmem(0, PAGE_SIZE, BOOTMEM_DEFAULT);

	/* reserve EBDA region */
	reserve_ebda_region();

#ifdef CONFIG_SMP
	/*
	 * But first pinch a few for the stack/trampoline stuff
	 * FIXME: Don't need the extra page at 4K, but need to fix
	 * trampoline before removing it. (see the GDT stuff)
	 */
	reserve_bootmem(PAGE_SIZE, PAGE_SIZE, BOOTMEM_DEFAULT);
#endif
#ifdef CONFIG_ACPI_SLEEP
	/*
	 * Reserve low memory region for sleep support.
@@ -803,9 +743,6 @@ void __init setup_arch(char **cmdline_p)
	 * not to exceed the 8Mb limit.
	 */

#ifdef CONFIG_SMP
	smp_alloc_memory(); /* AP processor realmode stacks in low memory*/
#endif
	paging_init();

	/*
+0 −17
Original line number Diff line number Diff line
@@ -555,23 +555,6 @@ cpumask_t cpu_coregroup_map(int cpu)
		return c->llc_shared_map;
}

#ifdef CONFIG_X86_32
/*
 * We are called very early to get the low memory for the
 * SMP bootup trampoline page.
 */
void __init smp_alloc_memory(void)
{
	trampoline_base = alloc_bootmem_low_pages(PAGE_SIZE);
	/*
	 * Has to be in very low memory so we can execute
	 * real-mode AP code.
	 */
	if (__pa(trampoline_base) >= 0x9F000)
		BUG();
}
#endif

static void impress_friends(void)
{
	int cpu;
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