Messages in this thread Patch in this message | | | Date | Mon, 11 Jun 2012 16:44:34 +0800 | From | Wen Congyang <> | Subject | [PATCH 1/2 v2] x86: add max_addr boot option |
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Currently, the boot option max_addr is only supported on ia64 platform. We also need it on x86 platform. For example: There are two nodes: NODE#0 address range 0x00000000 00000000 - 0x00010000 00000000 NODE#1 address range 0x00010000 00000000 - 0x00020000 00000000 If we only want to use node0, we can specify the max_addr. The boot option "mem=" can do the same thing now. But the boot option "mem=" means the total memory used by the system. If we tell the user that the boot option "mem=" can do this, it will confuse the user. So we need an new boot option "max_addr" on x86 platform.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com> --- Documentation/kernel-parameters.txt | 2 +- arch/x86/kernel/e820.c | 36 +++++++++++++++++++++++++++++++++++ 2 files changed, 37 insertions(+), 1 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a92c5eb..034609d 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1441,7 +1441,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. yeeloong laptop. Example: machtype=lemote-yeeloong-2f-7inch - max_addr=nn[KMG] [KNL,BOOT,ia64] All physical memory greater + max_addr=nn[KMG] [KNL,BOOT,ia64,X86] All physical memory greater than or equal to this physical address is ignored. maxcpus= [SMP] Maximum number of processors that an SMP kernel diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c index 4185797..cd07226 100644 --- a/arch/x86/kernel/e820.c +++ b/arch/x86/kernel/e820.c @@ -47,6 +47,7 @@ unsigned long pci_mem_start = 0xaeedbabe; #ifdef CONFIG_PCI EXPORT_SYMBOL(pci_mem_start); #endif +static u64 max_addr = ~0ULL; /* * This function checks if any part of the range <start,end> is mapped @@ -119,6 +120,20 @@ static void __init __e820_add_region(struct e820map *e820x, u64 start, u64 size, return; } + if (start >= max_addr) { + printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n", + (unsigned long long)start, + (unsigned long long)(start + size - 1)); + return; + } + + if (max_addr - start < size) { + printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n", + (unsigned long long)max_addr, + (unsigned long long)(start + size - 1)); + size = max_addr - start; + } + e820x->map[x].addr = start; e820x->map[x].size = size; e820x->map[x].type = type; @@ -835,6 +850,22 @@ static int __init parse_memopt(char *p) } early_param("mem", parse_memopt); +static int __init parse_memmax_opt(char *p) +{ + char *oldp; + + if (!p) + return -EINVAL; + + oldp = p; + max_addr = memparse(p, &p); + if (p == oldp) + return -EINVAL; + + return 0; +} +early_param("max_addr", parse_memmax_opt); + static int __init parse_memmap_opt(char *p) { char *oldp; @@ -881,6 +912,11 @@ early_param("memmap", parse_memmap_opt); void __init finish_e820_parsing(void) { + if (max_addr != ~0ULL) { + userdef = 1; + e820_remove_range(max_addr, ULLONG_MAX - max_addr, E820_RAM, 1); + } + if (userdef) { u32 nr = e820.nr_map; -- 1.7.1
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