Re: [PATCH x86] [5/16] Replace hard coded reservations in x86-64 early boot code with dynamic table

[Cyrill Gorcunov <gorcunov@gmail.com>]

[Andi Kleen - Thu, Jan 03, 2008 at 04:42:18PM +0100]
| 
| On x86-64 there are several memory allocations before bootmem. To avoid
| them stomping on each other they used to be all hard coded in bad_area().
| Replace this with an array that is filled as needed.
| 
| This cleans up the code considerably and allows to expand its use.
| 
| Cc: peterz@infradead.org
| 
| Signed-off-by: Andi Kleen <ak@suse.de>
| 
| ---
|  arch/x86/kernel/e820_64.c  |   97 ++++++++++++++++++++++++---------------------
|  arch/x86/kernel/head64.c   |   48 ++++++++++++++++++++++
|  arch/x86/kernel/setup_64.c |   67 +------------------------------
|  arch/x86/mm/init_64.c      |    5 +-
|  arch/x86/mm/numa_64.c      |    1 
|  include/asm-x86/e820_64.h  |    5 +-
|  include/asm-x86/proto.h    |    2 
|  7 files changed, 112 insertions(+), 113 deletions(-)
| 
| Index: linux/arch/x86/kernel/e820_64.c
| ===================================================================
| --- linux.orig/arch/x86/kernel/e820_64.c
| +++ linux/arch/x86/kernel/e820_64.c
| @@ -47,56 +47,65 @@ unsigned long end_pfn_map;
|   */
|  static unsigned long __initdata end_user_pfn = MAXMEM>>PAGE_SHIFT;
|  
| -/* Check for some hardcoded bad areas that early boot is not allowed to touch */
| -static inline int bad_addr(unsigned long *addrp, unsigned long size)
| -{
| -	unsigned long addr = *addrp, last = addr + size;
| +/*
| + * Early reserved memory areas.
| + */
| +#define MAX_EARLY_RES 20
|  
| -	/* various gunk below that needed for SMP startup */
| -	if (addr < 0x8000) {
| -		*addrp = PAGE_ALIGN(0x8000);
| -		return 1;
| -	}
| +struct early_res {
| +	unsigned long start, end;
| +};
| +static struct early_res early_res[MAX_EARLY_RES] __initdata = {
| +	{ 0, PAGE_SIZE },			/* BIOS data page */
| +#ifdef CONFIG_SMP
| +	{ SMP_TRAMPOLINE_BASE, SMP_TRAMPOLINE_BASE + 2*PAGE_SIZE },
| +#endif
| +	{}
| +};
|  
| -	/* direct mapping tables of the kernel */
| -	if (last >= table_start<<PAGE_SHIFT && addr < table_end<<PAGE_SHIFT) {
| -		*addrp = PAGE_ALIGN(table_end << PAGE_SHIFT);
| -		return 1;
| +void __init reserve_early(unsigned long start, unsigned long end)
| +{
| +	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("Duplicated early reservation %lx-%lx\n",
| +			      start, end);
|  	}
| +	if (i >= MAX_EARLY_RES)
| +		panic("Too many early reservations");
| +	r = &early_res[i];
| +	r->start = start;
| +	r->end = end;
| +}
|  
| -	/* initrd */
| -#ifdef CONFIG_BLK_DEV_INITRD
| -	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
| -		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
| -		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
| -		unsigned long ramdisk_end   = ramdisk_image+ramdisk_size;
| +void __init early_res_to_bootmem(void)
| +{
| +	int i;
| +	for (i = 0; i < MAX_EARLY_RES && early_res[i].end; i++) {
| +	struct early_res *r = &early_res[i];
	^^^^^^
--->	just one tab used?

	Andi, it seems that is a point Ingo complained about?

| +		reserve_bootmem_generic(r->start, r->end - r->start);
| + 	}
| +}
|  
| -		if (last >= ramdisk_image && addr < ramdisk_end) {
| -			*addrp = PAGE_ALIGN(ramdisk_end);
| -			return 1;
| +/* Check for already reserved areas */
| +static inline int bad_addr(unsigned long *addrp, unsigned long size)
| +{
| +	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 = r->end;
| +			changed = 1;
| +			goto again;
|  		}
| -	}
| -#endif
| -	/* kernel code */
| -	if (last >= __pa_symbol(&_text) && addr < __pa_symbol(&_end)) {
| -		*addrp = PAGE_ALIGN(__pa_symbol(&_end));
| -		return 1;
| -	}
| -
| -	if (last >= ebda_addr && addr < ebda_addr + ebda_size) {
| -		*addrp = PAGE_ALIGN(ebda_addr + ebda_size);
| -		return 1;
| -	}
| -
| -#ifdef CONFIG_NUMA
| -	/* NUMA memory to node map */
| -	if (last >= nodemap_addr && addr < nodemap_addr + nodemap_size) {
| -		*addrp = nodemap_addr + nodemap_size;
| -		return 1;
| -	}
| -#endif
| -	/* XXX ramdisk image here? */
| -	return 0;
| + 	}
| +	return changed;
|  }
|  
|  /*
| Index: linux/arch/x86/kernel/head64.c
| ===================================================================
| --- linux.orig/arch/x86/kernel/head64.c
| +++ linux/arch/x86/kernel/head64.c
| @@ -21,6 +21,7 @@
|  #include <asm/tlbflush.h>
|  #include <asm/sections.h>
|  #include <asm/kdebug.h>
| +#include <asm/e820.h>
|  
|  static void __init zap_identity_mappings(void)
|  {
| @@ -48,6 +49,35 @@ static void __init copy_bootdata(char *r
|  	}
|  }
|  
| +#define EBDA_ADDR_POINTER 0x40E
| +
| +static __init void reserve_ebda(void)
| +{
| +	unsigned ebda_addr, ebda_size;
| +
| +	/*
| +	 * there is a real-mode segmented pointer pointing to the
| +	 * 4K EBDA area at 0x40E
| +	 */
| +	ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
| +	ebda_addr <<= 4;
| +
| +	if (!ebda_addr)
| +		return;
| +
| +	ebda_size = *(unsigned short *)__va(ebda_addr);
| +
| +	/* Round EBDA up to pages */
| +	if (ebda_size == 0)
| +		ebda_size = 1;
| +	ebda_size <<= 10;
| +	ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
| +	if (ebda_size > 64*1024)
| +		ebda_size = 64*1024;
| +
| +	reserve_early(ebda_addr, ebda_addr + ebda_size);
| +}
| +
|  void __init x86_64_start_kernel(char * real_mode_data)
|  {
|  	int i;
| @@ -70,5 +100,23 @@ void __init x86_64_start_kernel(char * r
|  	pda_init(0);
|  	copy_bootdata(__va(real_mode_data));
|  
| +	reserve_early(__pa_symbol(&_text), __pa_symbol(&_end));
| +
| +	/* Reserve INITRD */
| +	if (boot_params.hdr.type_of_loader && boot_params.hdr.ramdisk_image) {
| +		unsigned long ramdisk_image = boot_params.hdr.ramdisk_image;
| +		unsigned long ramdisk_size  = boot_params.hdr.ramdisk_size;
| +		unsigned long ramdisk_end   = ramdisk_image + ramdisk_size;
| +		reserve_early(ramdisk_image, ramdisk_end);
| +	}
| +
| +	reserve_ebda();
| +
| +	/*
| +	 * 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();
|  }
| Index: linux/arch/x86/kernel/setup_64.c
| ===================================================================
| --- linux.orig/arch/x86/kernel/setup_64.c
| +++ linux/arch/x86/kernel/setup_64.c
| @@ -243,41 +243,6 @@ static inline void __init reserve_crashk
|  {}
|  #endif
|  
| -#define EBDA_ADDR_POINTER 0x40E
| -
| -unsigned __initdata ebda_addr;
| -unsigned __initdata ebda_size;
| -
| -static void discover_ebda(void)
| -{
| -	/*
| -	 * there is a real-mode segmented pointer pointing to the
| -	 * 4K EBDA area at 0x40E
| -	 */
| -	ebda_addr = *(unsigned short *)__va(EBDA_ADDR_POINTER);
| -	/*
| -	 * There can be some situations, like paravirtualized guests,
| -	 * in which there is no available ebda information. In such
| -	 * case, just skip it
| -	 */
| -	if (!ebda_addr) {
| -		ebda_size = 0;
| -		return;
| -	}
| -
| -	ebda_addr <<= 4;
| -
| -	ebda_size = *(unsigned short *)__va(ebda_addr);
| -
| -	/* Round EBDA up to pages */
| -	if (ebda_size == 0)
| -		ebda_size = 1;
| -	ebda_size <<= 10;
| -	ebda_size = round_up(ebda_size + (ebda_addr & ~PAGE_MASK), PAGE_SIZE);
| -	if (ebda_size > 64*1024)
| -		ebda_size = 64*1024;
| -}
| -
|  /* Overridden in paravirt.c if CONFIG_PARAVIRT */
|  void __attribute__((weak)) memory_setup(void)
|  {
| @@ -355,8 +320,6 @@ void __init setup_arch(char **cmdline_p)
|  
|  	check_efer();
|  
| -	discover_ebda();
| -
|  	init_memory_mapping(0, (end_pfn_map << PAGE_SHIFT));
|  	if (efi_enabled)
|  		efi_init();
| @@ -399,33 +362,7 @@ void __init setup_arch(char **cmdline_p)
|  	contig_initmem_init(0, end_pfn);
|  #endif
|  
| -	/* Reserve direct mapping */
| -	reserve_bootmem_generic(table_start << PAGE_SHIFT,
| -				(table_end - table_start) << PAGE_SHIFT);
| -
| -	/* reserve kernel */
| -	reserve_bootmem_generic(__pa_symbol(&_text),
| -				__pa_symbol(&_end) - __pa_symbol(&_text));
| -
| -	/*
| -	 * reserve physical page 0 - it's a special BIOS page on many boxes,
| -	 * enabling clean reboots, SMP operation, laptop functions.
| -	 */
| -	reserve_bootmem_generic(0, PAGE_SIZE);
| -
| -	/* reserve ebda region */
| -	if (ebda_addr)
| -		reserve_bootmem_generic(ebda_addr, ebda_size);
| -#ifdef CONFIG_NUMA
| -	/* reserve nodemap region */
| -	if (nodemap_addr)
| -		reserve_bootmem_generic(nodemap_addr, nodemap_size);
| -#endif
| -
| -#ifdef CONFIG_SMP
| -	/* Reserve SMP trampoline */
| -	reserve_bootmem_generic(SMP_TRAMPOLINE_BASE, 2*PAGE_SIZE);
| -#endif
| +	early_res_to_bootmem();
|  
|  #ifdef CONFIG_ACPI_SLEEP
|  	/*
| @@ -455,6 +392,8 @@ void __init setup_arch(char **cmdline_p)
|  			initrd_start = ramdisk_image + PAGE_OFFSET;
|  			initrd_end = initrd_start+ramdisk_size;
|  		} else {
| +			/* Assumes everything on node 0 */
| +			free_bootmem(ramdisk_image, ramdisk_size);
|  			printk(KERN_ERR "initrd extends beyond end of memory "
|  			       "(0x%08lx > 0x%08lx)\ndisabling initrd\n",
|  			       ramdisk_end, end_of_mem);
| Index: linux/arch/x86/mm/numa_64.c
| ===================================================================
| --- linux.orig/arch/x86/mm/numa_64.c
| +++ linux/arch/x86/mm/numa_64.c
| @@ -99,6 +99,7 @@ static int __init allocate_cachealigned_
|  	}
|  	pad_addr = (nodemap_addr + pad) & ~pad;
|  	memnodemap = phys_to_virt(pad_addr);
| +	reserve_early(nodemap_addr, nodemap_addr + nodemap_size);
|  
|  	printk(KERN_DEBUG "NUMA: Allocated memnodemap from %lx - %lx\n",
|  	       nodemap_addr, nodemap_addr + nodemap_size);
| Index: linux/include/asm-x86/e820_64.h
| ===================================================================
| --- linux.orig/include/asm-x86/e820_64.h
| +++ linux/include/asm-x86/e820_64.h
| @@ -36,8 +36,9 @@ extern void finish_e820_parsing(void);
|  
|  extern struct e820map e820;
|  
| -extern unsigned ebda_addr, ebda_size;
| -extern unsigned long nodemap_addr, nodemap_size;
| +extern void reserve_early(unsigned long start, unsigned long end);
| +extern void early_res_to_bootmem(void);
| +
|  #endif/*!__ASSEMBLY__*/
|  
|  #endif/*__E820_HEADER*/
| Index: linux/arch/x86/mm/init_64.c
| ===================================================================
| --- linux.orig/arch/x86/mm/init_64.c
| +++ linux/arch/x86/mm/init_64.c
| @@ -176,7 +176,8 @@ __set_fixmap (enum fixed_addresses idx, 
|  	set_pte_phys(address, phys, prot);
|  }
|  
| -unsigned long __meminitdata table_start, table_end;
| +static unsigned long __initdata table_start;
| +static unsigned long __meminitdata table_end;
|  
|  static __meminit void *alloc_low_page(unsigned long *phys)
|  { 
| @@ -387,6 +388,8 @@ void __init_refok init_memory_mapping(un
|  	if (!after_bootmem)
|  		mmu_cr4_features = read_cr4();
|  	__flush_tlb_all();
| +
| +	reserve_early(table_start << PAGE_SHIFT, table_end << PAGE_SHIFT);
|  }
|  
|  #ifndef CONFIG_NUMA
| Index: linux/include/asm-x86/proto.h
| ===================================================================
| --- linux.orig/include/asm-x86/proto.h
| +++ linux/include/asm-x86/proto.h
| @@ -22,8 +22,6 @@ extern void syscall32_cpu_init(void);
|  
|  extern void check_efer(void);
|  
| -extern unsigned long table_start, table_end;
| -
|  extern int reboot_force;
|  
|  long do_arch_prctl(struct task_struct *task, int code, unsigned long addr);
| --
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		- Cyrill -