Messages in this thread | | | Date | Fri, 4 Aug 2017 07:49:01 +0800 | From | Baoquan He <> | Subject | Re: [PATCH] x86/boot/KASLR: Extend movable_node option for KASLR |
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On 08/03/17 at 08:24pm, Chao Fan wrote: > It's almost another "mem=".
Then why not using 'mem=' directly?
> > On Thu, Aug 03, 2017 at 08:17:21PM +0800, Dou Liyang wrote: > >movable_node is a boot-time switch to make hot-pluggable memory > >NUMA nodes to be movable. This option is based on an assumption > >that any node which the kernel resides in is defined as > >un-hotpluggable. Linux can allocates memory near the kernel image > >to try the best to keep the kernel away from hotpluggable memory > >in the same NUMA node. So other nodes can be movable. > > > >But, KASLR doesn't know which node is un-hotpluggable, the all > >hotpluggable memory ranges is recorded in ACPI SRAT table, SRAT > >is not parsed. So, KASLR may randomize the kernel in a movable > >node which will be immovable. > > > >Extend movable_node option to restrict kernel to be randomized in > >immovable nodes by adding a parameter. this parameter sets up > >the boundaries between the movable nodes and immovable nodes. > > > >Reported-by: Chao Fan <fanc.fnst@cn.fujitsu.com> > >Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com> > >--- > > Documentation/admin-guide/kernel-parameters.txt | 11 +++++++++-- > > arch/x86/boot/compressed/kaslr.c | 19 ++++++++++++++++--- > > 2 files changed, 25 insertions(+), 5 deletions(-) > > > >diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > >index d9c171c..44c7e33 100644 > >--- a/Documentation/admin-guide/kernel-parameters.txt > >+++ b/Documentation/admin-guide/kernel-parameters.txt > >@@ -2305,7 +2305,8 @@ > > mousedev.yres= [MOUSE] Vertical screen resolution, used for devices > > reporting absolute coordinates, such as tablets > > > >- movablecore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter > >+ movablecore=nn[KMG] > >+ [KNL,X86,IA-64,PPC] This parameter > > is similar to kernelcore except it specifies the > > amount of memory used for migratable allocations. > > If both kernelcore and movablecore is specified, > >@@ -2315,12 +2316,18 @@ > > that the amount of memory usable for all allocations > > is not too small. > > > >- movable_node [KNL] Boot-time switch to make hotplugable memory > >+ movable_node [KNL] Boot-time switch to make hot-pluggable memory > > NUMA nodes to be movable. This means that the memory > > of such nodes will be usable only for movable > > allocations which rules out almost all kernel > > allocations. Use with caution! > > > >+ movable_node=nn[KMG] > >+ [KNL] Extend movable_node to work well with KASLR. This > >+ parameter is the boundaries between the movable nodes > >+ and immovable nodes, the memory which exceeds it will > >+ be regarded as hot-pluggable. > >+ > > MTD_Partition= [MTD] > > Format: <name>,<region-number>,<size>,<offset> > > > >diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c > >index 91f27ab..7e2351b 100644 > >--- a/arch/x86/boot/compressed/kaslr.c > >+++ b/arch/x86/boot/compressed/kaslr.c > >@@ -89,7 +89,10 @@ struct mem_vector { > > static bool memmap_too_large; > > > > > >-/* Store memory limit specified by "mem=nn[KMG]" or "memmap=nn[KMG]" */ > >+/* > >+ * Store memory limit specified by the following situations: > >+ * "mem=nn[KMG]" or "memmap=nn[KMG]" or "movable_node=nn[KMG]" > >+ */ > > unsigned long long mem_limit = ULLONG_MAX; > > > > > >@@ -212,7 +215,8 @@ static int handle_mem_memmap(void) > > char *param, *val; > > u64 mem_size; > > > >- if (!strstr(args, "memmap=") && !strstr(args, "mem=")) > >+ if (!strstr(args, "memmap=") && !strstr(args, "mem=") && > >+ !strstr(args, "movable_node=")) > > return 0; > > > > tmp_cmdline = malloc(len + 1); > >@@ -247,7 +251,16 @@ static int handle_mem_memmap(void) > > free(tmp_cmdline); > > return -EINVAL; > > } > >- mem_limit = mem_size; > >+ mem_limit = mem_limit > mem_size ? mem_size : mem_limit; > >+ } else if (!strcmp(param, "movable_node")) { > >+ char *p = val; > >+ > >+ mem_size = memparse(p, &p); > >+ if (mem_size == 0) { > >+ free(tmp_cmdline); > >+ return -EINVAL; > >+ } > >+ mem_limit = mem_limit > mem_size ? mem_size : mem_limit; > > } > > } > > > >-- > >2.5.5 > > > >
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