x86/um: Drop gate area handling

With the removal of the vDSO passthrough from the host,
FIXADDR_USER_START is always 0 and the gate area setup code is dead.

Remove it.

Signed-off-by: Thomas Weißschuh <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Johannes Berg <[e-mail]>

arch/um/include/asm/page.h

···
 
 #endif	/* __ASSEMBLER__ */
 
-#ifdef CONFIG_X86_32
-#define __HAVE_ARCH_GATE_AREA 1
-#endif
-
 #endif	/* __UM_PAGE_H */

arch/x86/um/Makefile

···
 	ptrace.o ptrace_$(BITS).o ptrace_user.o setjmp_$(BITS).o signal.o \
 	stub_segv.o \
 	sys_call_table_$(BITS).o sysrq_$(BITS).o tls_$(BITS).o \
-	mem_$(BITS).o subarch.o os-Linux/
+	subarch.o os-Linux/
 
 ifeq ($(CONFIG_X86_32),y)
 
···
 
 else
 
-obj-y += syscalls_64.o vdso/
+obj-y += mem_64.o syscalls_64.o vdso/
 
 subarch-y = ../lib/csum-partial_64.o ../lib/memcpy_64.o \
 	../lib/memmove_64.o ../lib/memset_64.o

arch/x86/um/mem_32.c

···
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- * Copyright (C) 2011 Richard Weinberger <[e-mail]>
- */
-
-#include <linux/mm.h>
-#include <asm/elf.h>
-
-static struct vm_area_struct gate_vma;
-
-static int __init gate_vma_init(void)
-{
-	if (!FIXADDR_USER_START)
-		return 0;
-
-	vma_init(&gate_vma, NULL);
-	gate_vma.vm_start = FIXADDR_USER_START;
-	gate_vma.vm_end = FIXADDR_USER_END;
-	vm_flags_init(&gate_vma, VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC);
-	gate_vma.vm_page_prot = PAGE_READONLY;
-
-	return 0;
-}
-__initcall(gate_vma_init);
-
-struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
-{
-	return FIXADDR_USER_START ? &gate_vma : NULL;
-}
-
-int in_gate_area_no_mm(unsigned long addr)
-{
-	if (!FIXADDR_USER_START)
-		return 0;
-
-	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
-		return 1;
-
-	return 0;
-}
-
-int in_gate_area(struct mm_struct *mm, unsigned long addr)
-{
-	struct vm_area_struct *vma = get_gate_vma(mm);
-
-	if (!vma)
-		return 0;
-
-	return (addr >= vma->vm_start) && (addr < vma->vm_end);
-}