From e621bd18958ef5dbace3129ebe17a0a475e127d9 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Wed, 20 Aug 2008 16:43:03 -0700 Subject: [PATCH] i386: vmalloc size fix Booting kernel with vmalloc=[any size<=16m] will oops on my pc (i386/1G memory). BUG_ON in arch/x86/mm/init_32.c triggered: BUG_ON((unsigned long)high_memory > VMALLOC_START); It's due to the vm area hole. In include/asm-x86/pgtable_32.h: #define VMALLOC_OFFSET (8 * 1024 * 1024) #define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \ & ~(VMALLOC_OFFSET - 1)) There's several related point: 1. MAXMEM : (-__PAGE_OFFSET - __VMALLOC_RESERVE). The space after VMALLOC_END is included as well, I set it to (VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE) 2. VMALLOC_OFFSET is not considered in __VMALLOC_RESERVE fixed by adding VMALLOC_OFFSET to it. 3. VMALLOC_START : (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) & ~(VMALLOC_OFFSET - 1)) So it's not always 8M, bigger than 8M possible. I set it to ((unsigned long)high_memory + VMALLOC_OFFSET) 4. the VMALLOC_RESERVE is an unused macro, so remove it here. Signed-off-by: Dave Young Cc: akpm@linux-foundation.org Cc: hidave.darkstar@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton --- arch/x86/mm/pgtable_32.c | 3 ++- include/asm-x86/page_32.h | 3 --- include/asm-x86/pgtable_32.h | 5 +++-- 3 files changed, 5 insertions(+), 6 deletions(-) diff --git a/arch/x86/mm/pgtable_32.c b/arch/x86/mm/pgtable_32.c index cab0abbd1eb..0951db9ee51 100644 --- a/arch/x86/mm/pgtable_32.c +++ b/arch/x86/mm/pgtable_32.c @@ -123,7 +123,8 @@ static int __init parse_vmalloc(char *arg) if (!arg) return -EINVAL; - __VMALLOC_RESERVE = memparse(arg, &arg); + /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/ + __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET; return 0; } early_param("vmalloc", parse_vmalloc); diff --git a/include/asm-x86/page_32.h b/include/asm-x86/page_32.h index ab8528793f0..632feb156cc 100644 --- a/include/asm-x86/page_32.h +++ b/include/asm-x86/page_32.h @@ -89,9 +89,6 @@ extern int nx_enabled; extern unsigned int __VMALLOC_RESERVE; extern int sysctl_legacy_va_layout; -#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE) -#define MAXMEM (-__PAGE_OFFSET - __VMALLOC_RESERVE) - extern void find_low_pfn_range(void); extern unsigned long init_memory_mapping(unsigned long start, unsigned long end); diff --git a/include/asm-x86/pgtable_32.h b/include/asm-x86/pgtable_32.h index 5c3b26567a9..9bb5269475c 100644 --- a/include/asm-x86/pgtable_32.h +++ b/include/asm-x86/pgtable_32.h @@ -56,8 +56,7 @@ void paging_init(void); * area for the same reason. ;) */ #define VMALLOC_OFFSET (8 * 1024 * 1024) -#define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \ - & ~(VMALLOC_OFFSET - 1)) +#define VMALLOC_START ((unsigned long)high_memory + VMALLOC_OFFSET) #ifdef CONFIG_X86_PAE #define LAST_PKMAP 512 #else @@ -73,6 +72,8 @@ void paging_init(void); # define VMALLOC_END (FIXADDR_START - 2 * PAGE_SIZE) #endif +#define MAXMEM (VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE) + /* * Define this if things work differently on an i386 and an i486: * it will (on an i486) warn about kernel memory accesses that are -- 2.41.1