From 50ba0232fd5312410f1b65247e774244f89a628e Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 18 May 2024 20:50:36 +0200 Subject: Merging upstream version 6.8.9. Signed-off-by: Daniel Baumann --- arch/x86/um/syscalls_64.c | 62 ++++++++++------------------------------------- 1 file changed, 13 insertions(+), 49 deletions(-) (limited to 'arch/x86/um/syscalls_64.c') diff --git a/arch/x86/um/syscalls_64.c b/arch/x86/um/syscalls_64.c index 27b29ae6c4..6a00a28c9c 100644 --- a/arch/x86/um/syscalls_64.c +++ b/arch/x86/um/syscalls_64.c @@ -16,60 +16,24 @@ long arch_prctl(struct task_struct *task, int option, unsigned long __user *arg2) { - unsigned long *ptr = arg2, tmp; - long ret; - int pid = task->mm->context.id.u.pid; - - /* - * With ARCH_SET_FS (and ARCH_SET_GS is treated similarly to - * be safe), we need to call arch_prctl on the host because - * setting %fs may result in something else happening (like a - * GDT or thread.fs being set instead). So, we let the host - * fiddle the registers and thread struct and restore the - * registers afterwards. - * - * So, the saved registers are stored to the process (this - * needed because a stub may have been the last thing to run), - * arch_prctl is run on the host, then the registers are read - * back. - */ - switch (option) { - case ARCH_SET_FS: - case ARCH_SET_GS: - ret = restore_pid_registers(pid, ¤t->thread.regs.regs); - if (ret) - return ret; - break; - case ARCH_GET_FS: - case ARCH_GET_GS: - /* - * With these two, we read to a local pointer and - * put_user it to the userspace pointer that we were - * given. If addr isn't valid (because it hasn't been - * faulted in or is just bogus), we want put_user to - * fault it in (or return -EFAULT) instead of having - * the host return -EFAULT. - */ - ptr = &tmp; - } - - ret = os_arch_prctl(pid, option, ptr); - if (ret) - return ret; + long ret = -EINVAL; switch (option) { case ARCH_SET_FS: - current->thread.arch.fs = (unsigned long) ptr; - ret = save_registers(pid, ¤t->thread.regs.regs); + current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)] = + (unsigned long) arg2; + ret = 0; break; case ARCH_SET_GS: - ret = save_registers(pid, ¤t->thread.regs.regs); + current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)] = + (unsigned long) arg2; + ret = 0; break; case ARCH_GET_FS: - ret = put_user(tmp, arg2); + ret = put_user(current->thread.regs.regs.gp[FS_BASE / sizeof(unsigned long)], arg2); break; case ARCH_GET_GS: - ret = put_user(tmp, arg2); + ret = put_user(current->thread.regs.regs.gp[GS_BASE / sizeof(unsigned long)], arg2); break; } @@ -83,10 +47,10 @@ SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2) void arch_switch_to(struct task_struct *to) { - if ((to->thread.arch.fs == 0) || (to->mm == NULL)) - return; - - arch_prctl(to, ARCH_SET_FS, (void __user *) to->thread.arch.fs); + /* + * Nothing needs to be done on x86_64. + * The FS_BASE/GS_BASE registers are saved in the ptrace register set. + */ } SYSCALL_DEFINE6(mmap, unsigned long, addr, unsigned long, len, -- cgit v1.2.3