I need those arch_{native,compat}_rnd() to compute separately
random factor for mmap() in compat syscalls for 64-bit binaries
and vice-versa for native syscall in 32-bit compat binaries.
They will be used in the following patches.Signed-off-by: Dmitry Safonov <[email protected]> --- arch/x86/include/asm/elf.h | 5 +++++ arch/x86/mm/mmap.c | 25 ++++++++++++++++--------- 2 files changed, 21 insertions(+), 9 deletions(-) diff --git a/arch/x86/include/asm/elf.h b/arch/x86/include/asm/elf.h index e7f155c3045e..ee1a87782b2c 100644 --- a/arch/x86/include/asm/elf.h +++ b/arch/x86/include/asm/elf.h @@ -349,6 +349,11 @@ static inline int mmap_is_ia32(void) test_thread_flag(TIF_ADDR32)); } +#ifdef CONFIG_COMPAT +extern unsigned long arch_compat_rnd(void); +#endif +extern unsigned long arch_native_rnd(void); + /* Do not change the values. See get_align_mask() */ enum align_flags { ALIGN_VA_32 = BIT(0), diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c index d2dc0438d654..0b2007b08194 100644 --- a/arch/x86/mm/mmap.c +++ b/arch/x86/mm/mmap.c @@ -65,20 +65,27 @@ static int mmap_is_legacy(void) return sysctl_legacy_va_layout; } -unsigned long arch_mmap_rnd(void) +#ifdef CONFIG_COMPAT +unsigned long arch_compat_rnd(void) { - unsigned long rnd; + return (get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1)) + << PAGE_SHIFT; +} +#endif - if (mmap_is_ia32()) +unsigned long arch_native_rnd(void) +{ + return (get_random_long() & ((1UL << mmap_rnd_bits) - 1)) << PAGE_SHIFT; +} + +unsigned long arch_mmap_rnd(void) +{ #ifdef CONFIG_COMPAT - rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); -#else - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); + if (mmap_is_ia32()) + return arch_compat_rnd(); #endif - else - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); - return rnd << PAGE_SHIFT; + return arch_native_rnd(); } static unsigned long mmap_base(unsigned long rnd) -- 2.11.0
