It's almost another "mem=". Thanks, Chao Fan
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 <[email protected]> >Signed-off-by: Dou Liyang <[email protected]> >--- > 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 >
