Hi Kees, On 22 June 2017 at 18:06, Kees Cook <keescook@xxxxxxxxxxxx> wrote: > Now that explicitly executed loaders are loaded in the mmap region, > position PIE binaries lower in the address space to avoid possible > collisions with mmap or stack regions. For 64-bit, align to 4GB to > allow runtimes to use the entire 32-bit address space for 32-bit > pointers. > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > --- > arch/arm64/include/asm/elf.h | 13 ++++++------- > 1 file changed, 6 insertions(+), 7 deletions(-) > > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h > index 5d1700425efe..f742af8f7c42 100644 > --- a/arch/arm64/include/asm/elf.h > +++ b/arch/arm64/include/asm/elf.h > @@ -113,12 +113,13 @@ > #define ELF_EXEC_PAGESIZE PAGE_SIZE > > /* > - * This is the location that an ET_DYN program is loaded if exec'ed. Typical > - * use of this is to invoke "./ld.so someprog" to test out a new version of > - * the loader. We need to make sure that it is out of the way of the program > - * that it will "exec", and that there is sufficient room for the brk. > + * This is the base location for PIE (ET_DYN with INTERP) loads. On > + * 64-bit, this is raised to 4GB to leave the entire 32-bit address > + * space open for things that want to use the area for 32-bit pointers. > */ > -#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) > +#define ELF_ET_DYN_BASE (test_thread_flag(TIF_32BIT) ? \ > + 0x000400000UL : \ > + 0x100000000UL) > Why are you merging this with the COMPAT definition? > #ifndef __ASSEMBLY__ > > @@ -173,8 +174,6 @@ extern int arch_setup_additional_pages(struct linux_binprm *bprm, > > #ifdef CONFIG_COMPAT > > -#define COMPAT_ELF_ET_DYN_BASE (2 * TASK_SIZE_32 / 3) > - > /* AArch32 registers. */ > #define COMPAT_ELF_NGREG 18 > typedef unsigned int compat_elf_greg_t; > -- > 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
