The following commit has been merged into the x86/cleanups branch of tip: Commit-ID: 214f0e804358cdd13b5cbe4445189f23e30618b4 Gitweb: https://git.kernel.org/tip/214f0e804358cdd13b5cbe4445189f23e30618b4 Author: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> AuthorDate: Sat, 03 Oct 2020 23:25:28 -04:00 Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx> CommitterDate: Mon, 26 Oct 2020 13:46:46 +01:00 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 <luto@xxxxxxxxxx> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxxxxxxxx> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20201004032536.1229030-3-krisman@xxxxxxxxxxxxx --- arch/x86/include/asm/compat.h | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/compat.h b/arch/x86/include/asm/compat.h index 0e327a0..f145e33 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); }
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