diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 44 | ||||
| -rw-r--r-- | arch/powerpc/mm/mmap.c | 11 |
2 files changed, 50 insertions, 5 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 9ff731f50a29..276a624ec355 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -22,6 +22,48 @@ config MMU bool default y +config ARCH_MMAP_RND_BITS_MAX + # On Book3S 64, the default virtual address space for 64-bit processes + # is 2^47 (128TB). As a maximum, allow randomisation to consume up to + # 32T of address space (2^45), which should ensure a reasonable gap + # between bottom-up and top-down allocations for applications that + # consume "normal" amounts of address space. Book3S 64 only supports 64K + # and 4K page sizes. + default 29 if PPC_BOOK3S_64 && PPC_64K_PAGES # 29 = 45 (32T) - 16 (64K) + default 33 if PPC_BOOK3S_64 # 33 = 45 (32T) - 12 (4K) + # + # On all other 64-bit platforms (currently only Book3E), the virtual + # address space is 2^46 (64TB). Allow randomisation to consume up to 16T + # of address space (2^44). Only 4K page sizes are supported. + default 32 if 64BIT # 32 = 44 (16T) - 12 (4K) + # + # For 32-bit, use the compat values, as they're the same. + default ARCH_MMAP_RND_COMPAT_BITS_MAX + +config ARCH_MMAP_RND_BITS_MIN + # Allow randomisation to consume up to 1GB of address space (2^30). + default 14 if 64BIT && PPC_64K_PAGES # 14 = 30 (1GB) - 16 (64K) + default 18 if 64BIT # 18 = 30 (1GB) - 12 (4K) + # + # For 32-bit, use the compat values, as they're the same. + default ARCH_MMAP_RND_COMPAT_BITS_MIN + +config ARCH_MMAP_RND_COMPAT_BITS_MAX + # Total virtual address space for 32-bit processes is 2^31 (2GB). + # Allow randomisation to consume up to 512MB of address space (2^29). + default 11 if PPC_256K_PAGES # 11 = 29 (512MB) - 18 (256K) + default 13 if PPC_64K_PAGES # 13 = 29 (512MB) - 16 (64K) + default 15 if PPC_16K_PAGES # 15 = 29 (512MB) - 14 (16K) + default 17 # 17 = 29 (512MB) - 12 (4K) + +config ARCH_MMAP_RND_COMPAT_BITS_MIN + # Total virtual address space for 32-bit processes is 2^31 (2GB). + # Allow randomisation to consume up to 8MB of address space (2^23). + default 5 if PPC_256K_PAGES # 5 = 23 (8MB) - 18 (256K) + default 7 if PPC_64K_PAGES # 7 = 23 (8MB) - 16 (64K) + default 9 if PPC_16K_PAGES # 9 = 23 (8MB) - 14 (16K) + default 11 # 11 = 23 (8MB) - 12 (4K) + config HAVE_SETUP_PER_CPU_AREA def_bool PPC64 @@ -120,6 +162,8 @@ config PPC select HAVE_ARCH_HARDENED_USERCOPY select HAVE_ARCH_JUMP_LABEL select HAVE_ARCH_KGDB + select HAVE_ARCH_MMAP_RND_BITS + select HAVE_ARCH_MMAP_RND_COMPAT_BITS if COMPAT select HAVE_ARCH_SECCOMP_FILTER select HAVE_ARCH_TRACEHOOK select HAVE_CBPF_JIT if !PPC64 diff --git a/arch/powerpc/mm/mmap.c b/arch/powerpc/mm/mmap.c index 82fc5762f971..005aa8a44915 100644 --- a/arch/powerpc/mm/mmap.c +++ b/arch/powerpc/mm/mmap.c @@ -59,13 +59,14 @@ static inline int mmap_is_legacy(void) unsigned long arch_mmap_rnd(void) { - unsigned long rnd; + unsigned long shift, rnd; - /* 8MB for 32bit, 1GB for 64bit */ + shift = mmap_rnd_bits; +#ifdef CONFIG_COMPAT if (is_32bit_task()) - rnd = get_random_long() % (1<<(23-PAGE_SHIFT)); - else - rnd = get_random_long() % (1UL<<(30-PAGE_SHIFT)); + shift = mmap_rnd_compat_bits; +#endif + rnd = get_random_long() % (1 << shift); return rnd << PAGE_SHIFT; } |