* [RESEND PATCH v2 2/2] x86: reimplement mem boot option
2012-10-11 10:38 [RESEND PATCH v2 1/2] update mem= option's spec wency
@ 2012-10-11 10:38 ` wency
2012-10-11 10:39 ` [RESEND PATCH v2 1/2] update mem= option's spec Wen Congyang
1 sibling, 0 replies; 3+ messages in thread
From: wency @ 2012-10-11 10:38 UTC (permalink / raw)
To: x86, linux-kernel; +Cc: rob, tglx, mingo, bhelgaas, hpa, Wen Congyang
From: Wen Congyang <wency@cn.fujitsu.com>
Current mem boot option only can work for non efi environment. If the user
specifies add_efi_memmap, it cannot work for efi environment. In
the efi environment, we call e820_add_region() to add the memory map. So
we can modify __e820_add_region() and the mem boot option can work for
efi environment.
Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
---
arch/x86/kernel/e820.c | 29 +++++++++++++++++++++++++----
1 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c
index 4185797..20bc467 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 mem_limit = ~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 >= mem_limit) {
+ printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
+ (unsigned long long)start,
+ (unsigned long long)(start + size - 1));
+ return;
+ }
+
+ if (mem_limit - start < size) {
+ printk(KERN_ERR "e820: ignoring [mem %#010llx-%#010llx]\n",
+ (unsigned long long)mem_limit,
+ (unsigned long long)(start + size - 1));
+ size = mem_limit - start;
+ }
+
e820x->map[x].addr = start;
e820x->map[x].size = size;
e820x->map[x].type = type;
@@ -809,7 +824,7 @@ static int userdef __initdata;
/* "mem=nopentium" disables the 4MB page tables. */
static int __init parse_memopt(char *p)
{
- u64 mem_size;
+ char *oldp;
if (!p)
return -EINVAL;
@@ -825,11 +840,11 @@ static int __init parse_memopt(char *p)
}
userdef = 1;
- mem_size = memparse(p, &p);
+ oldp = p;
+ mem_limit = memparse(p, &p);
/* don't remove all of memory when handling "mem={invalid}" param */
- if (mem_size == 0)
+ if (mem_limit == 0 || p == oldp)
return -EINVAL;
- e820_remove_range(mem_size, ULLONG_MAX - mem_size, E820_RAM, 1);
return 0;
}
@@ -881,6 +896,12 @@ early_param("memmap", parse_memmap_opt);
void __init finish_e820_parsing(void)
{
+ if (mem_limit != ~0ULL) {
+ userdef = 1;
+ e820_remove_range(mem_limit, ULLONG_MAX - mem_limit,
+ E820_RAM, 1);
+ }
+
if (userdef) {
u32 nr = e820.nr_map;
--
1.7.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [RESEND PATCH v2 1/2] update mem= option's spec
2012-10-11 10:38 [RESEND PATCH v2 1/2] update mem= option's spec wency
2012-10-11 10:38 ` [RESEND PATCH v2 2/2] x86: reimplement mem boot option wency
@ 2012-10-11 10:39 ` Wen Congyang
1 sibling, 0 replies; 3+ messages in thread
From: Wen Congyang @ 2012-10-11 10:39 UTC (permalink / raw)
To: hpa; +Cc: x86, linux-kernel, rob, tglx, mingo, bhelgaas
Hi, HPA
When do you have time to review this patchset?
Thanks
Wen Congyang
At 10/11/2012 06:38 PM, wency@cn.fujitsu.com Wrote:
> From: Wen Congyang <wency@cn.fujitsu.com>
>
> Current mem= implementation seems buggy because specification and
> implementation doesn't match. Current mem= has been working
> for many years and it's not buggy, it works as expected. So
> we should update the specification.
>
> Signed-off-by: Wen Congyang <wency@cn.fujitsu.com>
> Sort-of-tentatively-acked-by: Rob Landley <rob@landley.net>
>
> ---
> Documentation/kernel-parameters.txt | 7 ++++---
> 1 files changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index a92c5eb..924b1a4 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1471,9 +1471,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> mem=nn[KMG] [KNL,BOOT] Force usage of a specific amount of memory
> Amount of memory to be used when the kernel is not able
> to see the whole system memory or for test.
> - [X86-32] Use together with memmap= to avoid physical
> - address space collisions. Without memmap= PCI devices
> - could be placed at addresses belonging to unused RAM.
> + [X86-32] Work as limiting max address. Use together
> + with memmap= to avoid physical address space collisions.
> + Without memmap= PCI devices could be placed at addresses
> + belonging to unused RAM.
>
> mem=nopentium [BUGS=X86-32] Disable usage of 4MB pages for kernel
> memory.
^ permalink raw reply [flat|nested] 3+ messages in thread