s390: Remove 2k vs 4k page table leftovers

Since commit d08d4e7 ("s390/mm: use full 4KB page for 2KB PTE") always
4k page tables are allocated, however there is still some (now) obsolete
code left which deals with switching from 2k to 4k page tables for qemu/kvm
processes.

Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Remove the not needed code.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

Author: hcahca

arch/s390/Kconfig

@@ -73,7 +73,6 @@ config S390
 	imply IMA_SECURE_AND_OR_TRUSTED_BOOT
 	select ALTERNATE_USER_ADDRESS_SPACE
 	select ARCH_32BIT_USTAT_F_TINODE
-	select ARCH_BINFMT_ELF_STATE
 	select ARCH_CORRECT_STACKTRACE_ON_KRETPROBE
 	select ARCH_ENABLE_MEMORY_HOTPLUG if SPARSEMEM
 	select ARCH_ENABLE_MEMORY_HOTREMOVE

arch/s390/include/asm/elf.h

@@ -158,9 +158,6 @@ enum {
 #define ELF_DATA	ELFDATA2MSB
 #define ELF_ARCH	EM_S390
 
-/* s390 specific phdr types */
-#define PT_S390_PGSTE	0x70000000
-
 /*
  * ELF register definitions..
  */
@@ -191,35 +188,6 @@ typedef s390_compat_regs compat_elf_gregset_t;
 	 && (x)->e_ident[EI_CLASS] == ELF_CLASS)
 #define compat_start_thread	start_thread31
 
-struct arch_elf_state {
-	int rc;
-};
-
-#define INIT_ARCH_ELF_STATE { .rc = 0 }
-
-#define arch_check_elf(ehdr, interp, interp_ehdr, state) (0)
-#ifdef CONFIG_PGSTE
-#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state)	\
-({								\
-	struct arch_elf_state *_state = state;			\
-	if ((phdr)->p_type == PT_S390_PGSTE &&			\
-	    !page_table_allocate_pgste &&			\
-	    !test_thread_flag(TIF_PGSTE) &&			\
-	    !current->mm->context.alloc_pgste) {		\
-		set_thread_flag(TIF_PGSTE);			\
-		set_pt_regs_flag(task_pt_regs(current),		\
-				 PIF_EXECVE_PGSTE_RESTART);	\
-		_state->rc = -EAGAIN;				\
-	}							\
-	_state->rc;						\
-})
-#else
-#define arch_elf_pt_proc(ehdr, phdr, elf, interp, state)	\
-({								\
-	(state)->rc;						\
-})
-#endif
-
 /* For SVR4/S390 the function pointer to be registered with `atexit` is
    passed in R14. */
 #define ELF_PLAT_INIT(_r, load_addr) \

arch/s390/include/asm/mmu.h

@@ -22,10 +22,7 @@ typedef struct {
 	 * The following bitfields need a down_write on the mm
 	 * semaphore when they are written to. As they are only
 	 * written once, they can be read without a lock.
-	 *
-	 * The mmu context allocates 4K page tables.
 	 */
-	unsigned int alloc_pgste:1;
 	/* The mmu context uses extended page tables. */
 	unsigned int has_pgste:1;
 	/* The mmu context uses storage keys. */

arch/s390/include/asm/mmu_context.h

@@ -29,9 +29,6 @@ static inline int init_new_context(struct task_struct *tsk,
 	mm->context.gmap_asce = 0;
 	mm->context.flush_mm = 0;
 #ifdef CONFIG_PGSTE
-	mm->context.alloc_pgste = page_table_allocate_pgste ||
-		test_thread_flag(TIF_PGSTE) ||
-		(current->mm && current->mm->context.alloc_pgste);
 	mm->context.has_pgste = 0;
 	mm->context.uses_skeys = 0;
 	mm->context.uses_cmm = 0;

arch/s390/include/asm/pgtable.h

@@ -584,15 +584,6 @@ static inline int mm_is_protected(struct mm_struct *mm)
 	return 0;
 }
 
-static inline int mm_alloc_pgste(struct mm_struct *mm)
-{
-#ifdef CONFIG_PGSTE
-	if (unlikely(mm->context.alloc_pgste))
-		return 1;
-#endif
-	return 0;
-}
-
 static inline pgste_t clear_pgste_bit(pgste_t pgste, unsigned long mask)
 {
 	return __pgste(pgste_val(pgste) & ~mask);

arch/s390/include/asm/ptrace.h

@@ -12,13 +12,11 @@
 #include <asm/tpi.h>
 
 #define PIF_SYSCALL			0	/* inside a system call */
-#define PIF_EXECVE_PGSTE_RESTART	1	/* restart execve for PGSTE binaries */
 #define PIF_SYSCALL_RET_SET		2	/* return value was set via ptrace */
 #define PIF_GUEST_FAULT			3	/* indicates program check in sie64a */
 #define PIF_FTRACE_FULL_REGS		4	/* all register contents valid (ftrace) */
 
 #define _PIF_SYSCALL			BIT(PIF_SYSCALL)
-#define _PIF_EXECVE_PGSTE_RESTART	BIT(PIF_EXECVE_PGSTE_RESTART)
 #define _PIF_SYSCALL_RET_SET		BIT(PIF_SYSCALL_RET_SET)
 #define _PIF_GUEST_FAULT		BIT(PIF_GUEST_FAULT)
 #define _PIF_FTRACE_FULL_REGS		BIT(PIF_FTRACE_FULL_REGS)

arch/s390/include/asm/thread_info.h

@@ -67,7 +67,6 @@ void arch_setup_new_exec(void);
 #define TIF_NEED_RESCHED_LAZY	3	/* lazy rescheduling needed */
 #define TIF_UPROBE		4	/* breakpointed or single-stepping */
 #define TIF_PATCH_PENDING	5	/* pending live patching update */
-#define TIF_PGSTE		6	/* New mm's will use 4K page tables */
 #define TIF_NOTIFY_SIGNAL	7	/* signal notifications exist */
 #define TIF_GUARDED_STORAGE	8	/* load guarded storage control block */
 #define TIF_ISOLATE_BP_GUEST	9	/* Run KVM guests with isolated BP */
@@ -89,7 +88,6 @@ void arch_setup_new_exec(void);
 #define _TIF_NEED_RESCHED_LAZY	BIT(TIF_NEED_RESCHED_LAZY)
 #define _TIF_UPROBE		BIT(TIF_UPROBE)
 #define _TIF_PATCH_PENDING	BIT(TIF_PATCH_PENDING)
-#define _TIF_PGSTE		BIT(TIF_PGSTE)
 #define _TIF_NOTIFY_SIGNAL	BIT(TIF_NOTIFY_SIGNAL)
 #define _TIF_GUARDED_STORAGE	BIT(TIF_GUARDED_STORAGE)
 #define _TIF_ISOLATE_BP_GUEST	BIT(TIF_ISOLATE_BP_GUEST)

arch/s390/kernel/syscall.c

@@ -121,11 +121,8 @@ void noinstr __do_syscall(struct pt_regs *regs, int per_trap)
 	if (unlikely(test_and_clear_pt_regs_flag(regs, PIF_SYSCALL_RET_SET)))
 		goto out;
 	regs->gprs[2] = -ENOSYS;
-	if (unlikely(nr >= NR_syscalls))
-		goto out;
-	do {
+	if (likely(nr < NR_syscalls))
 		regs->gprs[2] = current->thread.sys_call_table[nr](regs);
-	} while (test_and_clear_pt_regs_flag(regs, PIF_EXECVE_PGSTE_RESTART));
 out:
 	syscall_exit_to_user_mode(regs);
 }

arch/s390/mm/gmap.c

@@ -2260,9 +2260,6 @@ int s390_enable_sie(void)
 	/* Do we have pgstes? if yes, we are done */
 	if (mm_has_pgste(mm))
 		return 0;
-	/* Fail if the page tables are 2K */
-	if (!mm_alloc_pgste(mm))
-		return -EINVAL;
 	mmap_write_lock(mm);
 	mm->context.has_pgste = 1;
 	/* split thp mappings and disable thp for future mappings */