| Kconfig (bd072111e7319d90a7b8127f91c2806b9a6f279e) | Kconfig (a2551df7ec568d87793d2eea4ca744e86318f205) |
|---|---|
| 1config SELECT_MEMORY_MODEL 2 def_bool y 3 depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL 4 5choice 6 prompt "Memory model" 7 depends on SELECT_MEMORY_MODEL 8 default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT --- 211 unchanged lines hidden (view full) --- 220 help 221 This is the portion of low virtual memory which should be protected 222 from userspace allocation. Keeping a user from writing to low pages 223 can help reduce the impact of kernel NULL pointer bugs. 224 225 For most ia64, ppc64 and x86 users with lots of address space 226 a value of 65536 is reasonable and should cause no problems. 227 On arm and other archs it should not be higher than 32768. | 1config SELECT_MEMORY_MODEL 2 def_bool y 3 depends on EXPERIMENTAL || ARCH_SELECT_MEMORY_MODEL 4 5choice 6 prompt "Memory model" 7 depends on SELECT_MEMORY_MODEL 8 default DISCONTIGMEM_MANUAL if ARCH_DISCONTIGMEM_DEFAULT --- 211 unchanged lines hidden (view full) --- 220 help 221 This is the portion of low virtual memory which should be protected 222 from userspace allocation. Keeping a user from writing to low pages 223 can help reduce the impact of kernel NULL pointer bugs. 224 225 For most ia64, ppc64 and x86 users with lots of address space 226 a value of 65536 is reasonable and should cause no problems. 227 On arm and other archs it should not be higher than 32768. |
| 228 Programs which use vm86 functionality would either need additional 229 permissions from either the LSM or the capabilities module or have 230 this protection disabled. | 228 Programs which use vm86 functionality or have some need to map 229 this low address space will need CAP_SYS_RAWIO or disable this 230 protection by setting the value to 0. |
| 231 232 This value can be changed after boot using the 233 /proc/sys/vm/mmap_min_addr tunable. 234 235 236config NOMMU_INITIAL_TRIM_EXCESS 237 int "Turn on mmap() excess space trimming before booting" 238 depends on !MMU --- 24 unchanged lines hidden --- | 231 232 This value can be changed after boot using the 233 /proc/sys/vm/mmap_min_addr tunable. 234 235 236config NOMMU_INITIAL_TRIM_EXCESS 237 int "Turn on mmap() excess space trimming before booting" 238 depends on !MMU --- 24 unchanged lines hidden --- |