From 214f0e804358cdd13b5cbe4445189f23e30618b4 Mon Sep 17 00:00:00 2001 From: Gabriel Krisman Bertazi Date: Sat, 3 Oct 2020 23:25:28 -0400 Subject: x86/compat: Simplify compat syscall userspace allocation When allocating user memory space for a compat system call, don't consider whether the originating code is IA32 or X32, just allocate from a safe region for both, beyond the redzone. This should be safe for IA32, and has the benefit of avoiding TIF_IA32, which is about to be removed. Suggested-by: Andy Lutomirski Signed-off-by: Gabriel Krisman Bertazi Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201004032536.1229030-3-krisman@collabora.com --- arch/x86/include/asm/compat.h | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h index 0e327a01f50f..f145e3326c6d 100644 --- a/arch/x86/include/asm/compat.h +++ b/arch/x86/include/asm/compat.h @@ -177,14 +177,13 @@ typedef struct user_regs_struct compat_elf_gregset_t; static inline void __user *arch_compat_alloc_user_space(long len) { - compat_uptr_t sp; - - if (test_thread_flag(TIF_IA32)) { - sp = task_pt_regs(current)->sp; - } else { - /* -128 for the x32 ABI redzone */ - sp = task_pt_regs(current)->sp - 128; - } + compat_uptr_t sp = task_pt_regs(current)->sp; + + /* + * -128 for the x32 ABI redzone. For IA32, it is not strictly + * necessary, but not harmful. + */ + sp -= 128; return (void __user *)round_down(sp - len, 16); } -- cgit v1.2.3