diff options
Diffstat (limited to 'arch/x86/mm/init_32.c')
| -rw-r--r-- | arch/x86/mm/init_32.c | 89 |
1 files changed, 88 insertions, 1 deletions
diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index 98080782ee47..d1017336f1b5 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -540,8 +540,95 @@ static void __init set_nx(void) } #endif +/* user-defined highmem size */ +static unsigned int highmem_pages = -1; + +/* + * highmem=size forces highmem to be exactly 'size' bytes. + * This works even on boxes that have no highmem otherwise. + * This also works to reduce highmem size on bigger boxes. + */ +static int __init parse_highmem(char *arg) +{ + if (!arg) + return -EINVAL; + + highmem_pages = memparse(arg, &arg) >> PAGE_SHIFT; + return 0; +} +early_param("highmem", parse_highmem); + +/* + * Determine low and high memory ranges: + */ +unsigned long __init find_max_low_pfn(void) +{ + unsigned long max_low_pfn; + + max_low_pfn = max_pfn; + if (max_low_pfn > MAXMEM_PFN) { + if (highmem_pages == -1) + highmem_pages = max_pfn - MAXMEM_PFN; + if (highmem_pages + MAXMEM_PFN < max_pfn) + max_pfn = MAXMEM_PFN + highmem_pages; + if (highmem_pages + MAXMEM_PFN > max_pfn) { + printk(KERN_WARNING "only %luMB highmem pages " + "available, ignoring highmem size of %uMB.\n", + pages_to_mb(max_pfn - MAXMEM_PFN), + pages_to_mb(highmem_pages)); + highmem_pages = 0; + } + max_low_pfn = MAXMEM_PFN; +#ifndef CONFIG_HIGHMEM + /* Maximum memory usable is what is directly addressable */ + printk(KERN_WARNING "Warning only %ldMB will be used.\n", + MAXMEM>>20); + if (max_pfn > MAX_NONPAE_PFN) + printk(KERN_WARNING + "Use a HIGHMEM64G enabled kernel.\n"); + else + printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); + max_pfn = MAXMEM_PFN; +#else /* !CONFIG_HIGHMEM */ +#ifndef CONFIG_HIGHMEM64G + if (max_pfn > MAX_NONPAE_PFN) { + max_pfn = MAX_NONPAE_PFN; + printk(KERN_WARNING "Warning only 4GB will be used." + "Use a HIGHMEM64G enabled kernel.\n"); + } +#endif /* !CONFIG_HIGHMEM64G */ +#endif /* !CONFIG_HIGHMEM */ + } else { + if (highmem_pages == -1) + highmem_pages = 0; +#ifdef CONFIG_HIGHMEM + if (highmem_pages >= max_pfn) { + printk(KERN_ERR "highmem size specified (%uMB) is " + "bigger than pages available (%luMB)!.\n", + pages_to_mb(highmem_pages), + pages_to_mb(max_pfn)); + highmem_pages = 0; + } + if (highmem_pages) { + if (max_low_pfn - highmem_pages < + 64*1024*1024/PAGE_SIZE){ + printk(KERN_ERR "highmem size %uMB results in " + "smaller than 64MB lowmem, ignoring it.\n" + , pages_to_mb(highmem_pages)); + highmem_pages = 0; + } + max_low_pfn -= highmem_pages; + } +#else + if (highmem_pages) + printk(KERN_ERR "ignoring highmem size on non-highmem" + " kernel!\n"); +#endif + } + return max_low_pfn; +} + #ifndef CONFIG_NEED_MULTIPLE_NODES -extern unsigned long find_max_low_pfn(void); unsigned long __init initmem_init(unsigned long start_pfn, unsigned long end_pfn) { |