s390/uaccess: always run the kernel in home space

Simplify the uaccess code by removing the user_mode=home option.
The kernel will now always run in the home space mode.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

10 files changed, 33 insertions, 75 deletions

diff --git a/arch/s390/kernel/compat_signal.c b/arch/s390/kernel/compat_signal.c
index adaa9e9478d8..ee820079c06d 100644
--- a/arch/s390/kernel/compat_signal.c
+++ b/arch/s390/kernel/compat_signal.c
@@ -188,8 +188,8 @@ static int restore_sigregs32(struct pt_regs *regs,_sigregs32 __user *sregs)
 		(__u64)(regs32.psw.mask & PSW32_MASK_USER) << 32 |
 		(__u64)(regs32.psw.addr & PSW32_ADDR_AMODE);
 	/* Check for invalid user address space control. */
-	if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
-		regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
+	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
+		regs->psw.mask = PSW_ASC_PRIMARY |
 			(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__u64)(regs32.psw.addr & PSW32_ADDR_INSN);
 	for (i = 0; i < NUM_GPRS; i++)
@@ -348,7 +348,7 @@ static int setup_frame32(int sig, struct k_sigaction *ka,
 	regs->gprs[15] = (__force __u64) frame;
 	/* Force 31 bit amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_BA |
-		(psw_user_bits & PSW_MASK_ASC) |
+		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__force __u64) ka->sa.sa_handler;
 
@@ -415,7 +415,7 @@ static int setup_rt_frame32(int sig, struct k_sigaction *ka, siginfo_t *info,
 	regs->gprs[15] = (__force __u64) frame;
 	/* Force 31 bit amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_BA |
-		(psw_user_bits & PSW_MASK_ASC) |
+		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (__u64 __force) ka->sa.sa_handler;
 
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index feb719d3c851..633ca7504536 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -2051,12 +2051,12 @@ void s390_reset_system(void (*func)(void *), void *data)
 	__ctl_clear_bit(0,28);
 
 	/* Set new machine check handler */
-	S390_lowcore.mcck_new_psw.mask = psw_kernel_bits | PSW_MASK_DAT;
+	S390_lowcore.mcck_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT;
 	S390_lowcore.mcck_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) s390_base_mcck_handler;
 
 	/* Set new program check handler */
-	S390_lowcore.program_new_psw.mask = psw_kernel_bits | PSW_MASK_DAT;
+	S390_lowcore.program_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT;
 	S390_lowcore.program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler;
 
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index c5dbb335716d..e1cdd31acabb 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -139,7 +139,7 @@ int copy_thread(unsigned long clone_flags, unsigned long new_stackp,
 	if (unlikely(p->flags & PF_KTHREAD)) {
 		/* kernel thread */
 		memset(&frame->childregs, 0, sizeof(struct pt_regs));
-		frame->childregs.psw.mask = psw_kernel_bits | PSW_MASK_DAT |
+		frame->childregs.psw.mask = PSW_KERNEL_BITS | PSW_MASK_DAT |
 				PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 		frame->childregs.psw.addr = PSW_ADDR_AMODE |
 				(unsigned long) kernel_thread_starter;
diff --git a/arch/s390/kernel/ptrace.c b/arch/s390/kernel/ptrace.c
index 9556905bd3ce..e6abd5bd31b0 100644
--- a/arch/s390/kernel/ptrace.c
+++ b/arch/s390/kernel/ptrace.c
@@ -200,7 +200,7 @@ static unsigned long __peek_user(struct task_struct *child, addr_t addr)
 		tmp = *(addr_t *)((addr_t) &task_pt_regs(child)->psw + addr);
 		if (addr == (addr_t) &dummy->regs.psw.mask)
 			/* Return a clean psw mask. */
-			tmp = psw_user_bits | (tmp & PSW_MASK_USER);
+			tmp = PSW_USER_BITS | (tmp & PSW_MASK_USER);
 
 	} else if (addr < (addr_t) &dummy->regs.orig_gpr2) {
 		/*
@@ -322,7 +322,7 @@ static int __poke_user(struct task_struct *child, addr_t addr, addr_t data)
 		 * psw and gprs are stored on the stack
 		 */
 		if (addr == (addr_t) &dummy->regs.psw.mask &&
-		    ((data & ~PSW_MASK_USER) != psw_user_bits ||
+		    ((data & ~PSW_MASK_USER) != PSW_USER_BITS ||
 		     ((data & PSW_MASK_EA) && !(data & PSW_MASK_BA))))
 			/* Invalid psw mask. */
 			return -EINVAL;
diff --git a/arch/s390/kernel/runtime_instr.c b/arch/s390/kernel/runtime_instr.c
index e1c9d1c292fa..d817cce7e72d 100644
--- a/arch/s390/kernel/runtime_instr.c
+++ b/arch/s390/kernel/runtime_instr.c
@@ -40,8 +40,6 @@ static void disable_runtime_instr(void)
 static void init_runtime_instr_cb(struct runtime_instr_cb *cb)
 {
 	cb->buf_limit = 0xfff;
-	if (s390_user_mode == HOME_SPACE_MODE)
-		cb->home_space = 1;
 	cb->int_requested = 1;
 	cb->pstate = 1;
 	cb->pstate_set_buf = 1;
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index aeed8a61fa0d..ffe1c53264a7 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -64,12 +64,6 @@
 #include <asm/sclp.h>
 #include "entry.h"
 
-long psw_kernel_bits	= PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_ASC_PRIMARY |
-			  PSW_MASK_EA | PSW_MASK_BA;
-long psw_user_bits	= PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT |
-			  PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_MCHECK |
-			  PSW_MASK_PSTATE | PSW_ASC_HOME;
-
 /*
  * User copy operations.
  */
@@ -300,43 +294,14 @@ static int __init parse_vmalloc(char *arg)
 }
 early_param("vmalloc", parse_vmalloc);
 
-unsigned int s390_user_mode = PRIMARY_SPACE_MODE;
-EXPORT_SYMBOL_GPL(s390_user_mode);
-
-static void __init set_user_mode_primary(void)
-{
-	psw_kernel_bits = (psw_kernel_bits & ~PSW_MASK_ASC) | PSW_ASC_HOME;
-	psw_user_bits = (psw_user_bits & ~PSW_MASK_ASC) | PSW_ASC_PRIMARY;
-#ifdef CONFIG_COMPAT
-	psw32_user_bits =
-		(psw32_user_bits & ~PSW32_MASK_ASC) | PSW32_ASC_PRIMARY;
-#endif
-	uaccess = MACHINE_HAS_MVCOS ? uaccess_mvcos_switch : uaccess_pt;
-}
-
 static int __init early_parse_user_mode(char *p)
 {
-	if (p && strcmp(p, "primary") == 0)
-		s390_user_mode = PRIMARY_SPACE_MODE;
-	else if (!p || strcmp(p, "home") == 0)
-		s390_user_mode = HOME_SPACE_MODE;
-	else
-		return 1;
-	return 0;
+	if (!p || strcmp(p, "primary") == 0)
+		return 0;
+	return 1;
 }
 early_param("user_mode", early_parse_user_mode);
 
-static void __init setup_addressing_mode(void)
-{
-	if (s390_user_mode != PRIMARY_SPACE_MODE)
-		return;
-	set_user_mode_primary();
-	if (MACHINE_HAS_MVCOS)
-		pr_info("Address spaces switched, mvcos available\n");
-	else
-		pr_info("Address spaces switched, mvcos not available\n");
-}
-
 void *restart_stack __attribute__((__section__(".data")));
 
 static void __init setup_lowcore(void)
@@ -348,24 +313,24 @@ static void __init setup_lowcore(void)
 	 */
 	BUILD_BUG_ON(sizeof(struct _lowcore) != LC_PAGES * 4096);
 	lc = __alloc_bootmem_low(LC_PAGES * PAGE_SIZE, LC_PAGES * PAGE_SIZE, 0);
-	lc->restart_psw.mask = psw_kernel_bits;
+	lc->restart_psw.mask = PSW_KERNEL_BITS;
 	lc->restart_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
-	lc->external_new_psw.mask = psw_kernel_bits |
+	lc->external_new_psw.mask = PSW_KERNEL_BITS |
 		PSW_MASK_DAT | PSW_MASK_MCHECK;
 	lc->external_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
-	lc->svc_new_psw.mask = psw_kernel_bits |
+	lc->svc_new_psw.mask = PSW_KERNEL_BITS |
 		PSW_MASK_DAT | PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 	lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
-	lc->program_new_psw.mask = psw_kernel_bits |
+	lc->program_new_psw.mask = PSW_KERNEL_BITS |
 		PSW_MASK_DAT | PSW_MASK_MCHECK;
 	lc->program_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) pgm_check_handler;
-	lc->mcck_new_psw.mask = psw_kernel_bits;
+	lc->mcck_new_psw.mask = PSW_KERNEL_BITS;
 	lc->mcck_new_psw.addr =
 		PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
-	lc->io_new_psw.mask = psw_kernel_bits |
+	lc->io_new_psw.mask = PSW_KERNEL_BITS |
 		PSW_MASK_DAT | PSW_MASK_MCHECK;
 	lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
 	lc->clock_comparator = -1ULL;
@@ -1043,10 +1008,7 @@ void __init setup_arch(char **cmdline_p)
 	init_mm.end_data = (unsigned long) &_edata;
 	init_mm.brk = (unsigned long) &_end;
 
-	if (MACHINE_HAS_MVCOS)
-		memcpy(&uaccess, &uaccess_mvcos, sizeof(uaccess));
-	else
-		memcpy(&uaccess, &uaccess_std, sizeof(uaccess));
+	uaccess = MACHINE_HAS_MVCOS ? uaccess_mvcos : uaccess_pt;
 
 	parse_early_param();
 	detect_memory_layout(memory_chunk, memory_end);
@@ -1054,7 +1016,6 @@ void __init setup_arch(char **cmdline_p)
 	setup_ipl();
 	reserve_oldmem();
 	setup_memory_end();
-	setup_addressing_mode();
 	reserve_crashkernel();
 	setup_memory();
 	setup_resources();
diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c
index c45becf82e01..b4fa7c0223e5 100644
--- a/arch/s390/kernel/signal.c
+++ b/arch/s390/kernel/signal.c
@@ -57,7 +57,7 @@ static int save_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 
 	/* Copy a 'clean' PSW mask to the user to avoid leaking
 	   information about whether PER is currently on.  */
-	user_sregs.regs.psw.mask = psw_user_bits |
+	user_sregs.regs.psw.mask = PSW_USER_BITS |
 		(regs->psw.mask & PSW_MASK_USER);
 	user_sregs.regs.psw.addr = regs->psw.addr;
 	memcpy(&user_sregs.regs.gprs, &regs->gprs, sizeof(sregs->regs.gprs));
@@ -85,12 +85,12 @@ static int restore_sigregs(struct pt_regs *regs, _sigregs __user *sregs)
 	err = __copy_from_user(&user_sregs, sregs, sizeof(_sigregs));
 	if (err)
 		return err;
-	/* Use regs->psw.mask instead of psw_user_bits to preserve PER bit. */
+	/* Use regs->psw.mask instead of PSW_USER_BITS to preserve PER bit. */
 	regs->psw.mask = (regs->psw.mask & ~PSW_MASK_USER) |
 		(user_sregs.regs.psw.mask & PSW_MASK_USER);
 	/* Check for invalid user address space control. */
-	if ((regs->psw.mask & PSW_MASK_ASC) >= (psw_kernel_bits & PSW_MASK_ASC))
-		regs->psw.mask = (psw_user_bits & PSW_MASK_ASC) |
+	if ((regs->psw.mask & PSW_MASK_ASC) == PSW_ASC_HOME)
+		regs->psw.mask = PSW_ASC_PRIMARY |
 			(regs->psw.mask & ~PSW_MASK_ASC);
 	/* Check for invalid amode */
 	if (regs->psw.mask & PSW_MASK_EA)
@@ -224,7 +224,7 @@ static int setup_frame(int sig, struct k_sigaction *ka,
 	regs->gprs[15] = (unsigned long) frame;
 	/* Force default amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
-		(psw_user_bits & PSW_MASK_ASC) |
+		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
 
@@ -295,7 +295,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
 	regs->gprs[15] = (unsigned long) frame;
 	/* Force default amode and default user address space control. */
 	regs->psw.mask = PSW_MASK_EA | PSW_MASK_BA |
-		(psw_user_bits & PSW_MASK_ASC) |
+		(PSW_USER_BITS & PSW_MASK_ASC) |
 		(regs->psw.mask & ~PSW_MASK_ASC);
 	regs->psw.addr = (unsigned long) ka->sa.sa_handler | PSW_ADDR_AMODE;
 
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 1a4313a1b60f..cca6cf6abacc 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -283,7 +283,7 @@ static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
 	struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
 	unsigned long source_cpu = stap();
 
-	__load_psw_mask(psw_kernel_bits);
+	__load_psw_mask(PSW_KERNEL_BITS);
 	if (pcpu->address == source_cpu)
 		func(data);	/* should not return */
 	/* Stop target cpu (if func returns this stops the current cpu). */
@@ -395,7 +395,7 @@ void smp_send_stop(void)
 	int cpu;
 
 	/* Disable all interrupts/machine checks */
-	__load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
+	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 	trace_hardirqs_off();
 
 	debug_set_critical();
@@ -693,7 +693,7 @@ static void smp_start_secondary(void *cpuvoid)
 	S390_lowcore.restart_source = -1UL;
 	restore_access_regs(S390_lowcore.access_regs_save_area);
 	__ctl_load(S390_lowcore.cregs_save_area, 0, 15);
-	__load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
+	__load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
 	cpu_init();
 	preempt_disable();
 	init_cpu_timer();
diff --git a/arch/s390/kernel/vdso.c b/arch/s390/kernel/vdso.c
index 05d75c413137..a84476f2a9bb 100644
--- a/arch/s390/kernel/vdso.c
+++ b/arch/s390/kernel/vdso.c
@@ -84,8 +84,7 @@ struct vdso_data *vdso_data = &vdso_data_store.data;
  */
 static void vdso_init_data(struct vdso_data *vd)
 {
-	vd->ectg_available =
-		s390_user_mode != HOME_SPACE_MODE && test_facility(31);
+	vd->ectg_available = test_facility(31);
 }
 
 #ifdef CONFIG_64BIT
@@ -102,7 +101,7 @@ int vdso_alloc_per_cpu(struct _lowcore *lowcore)
 
 	lowcore->vdso_per_cpu_data = __LC_PASTE;
 
-	if (s390_user_mode == HOME_SPACE_MODE || !vdso_enabled)
+	if (!vdso_enabled)
 		return 0;
 
 	segment_table = __get_free_pages(GFP_KERNEL, SEGMENT_ORDER);
@@ -147,7 +146,7 @@ void vdso_free_per_cpu(struct _lowcore *lowcore)
 	unsigned long segment_table, page_table, page_frame;
 	u32 *psal, *aste;
 
-	if (s390_user_mode == HOME_SPACE_MODE || !vdso_enabled)
+	if (!vdso_enabled)
 		return;
 
 	psal = (u32 *)(addr_t) lowcore->paste[4];
@@ -165,7 +164,7 @@ static void vdso_init_cr5(void)
 {
 	unsigned long cr5;
 
-	if (s390_user_mode == HOME_SPACE_MODE || !vdso_enabled)
+	if (!vdso_enabled)
 		return;
 	cr5 = offsetof(struct _lowcore, paste);
 	__ctl_load(cr5, 5, 5);
diff --git a/arch/s390/kernel/vtime.c b/arch/s390/kernel/vtime.c
index abcfab55f99b..e312c48a1c40 100644
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -161,7 +161,7 @@ void __kprobes vtime_stop_cpu(void)
 	trace_hardirqs_on();
 
 	/* Wait for external, I/O or machine check interrupt. */
-	psw_mask = psw_kernel_bits | PSW_MASK_WAIT | PSW_MASK_DAT |
+	psw_mask = PSW_KERNEL_BITS | PSW_MASK_WAIT | PSW_MASK_DAT |
 		PSW_MASK_IO | PSW_MASK_EXT | PSW_MASK_MCHECK;
 	idle->nohz_delay = 0;