Merge branch 'fixes' into features

This helps to avoid several merge conflicts later.

* fixes:
  s390/extable: fix exception table sorting
  s390/ftrace: fix arch_ftrace_get_regs implementation
  s390/ftrace: fix ftrace_caller/ftrace_regs_caller generation
  s390/setup: preserve memory at OLDMEM_BASE and OLDMEM_SIZE
  s390/cio: verify the driver availability for path_event call
  s390/module: fix building test_modules_helpers.o with clang
  MAINTAINERS: downgrade myself to Reviewer for s390
  MAINTAINERS: add Alexander Gordeev as maintainer for s390
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

MAINTAINERS

@@ -16817,8 +16817,8 @@ F:	drivers/video/fbdev/savage/
 S390
 M:	Heiko Carstens <hca@linux.ibm.com>
 M:	Vasily Gorbik <gor@linux.ibm.com>
-M:	Christian Borntraeger <borntraeger@linux.ibm.com>
-R:	Alexander Gordeev <agordeev@linux.ibm.com>
+M:	Alexander Gordeev <agordeev@linux.ibm.com>
+R:	Christian Borntraeger <borntraeger@linux.ibm.com>
 R:	Sven Schnelle <svens@linux.ibm.com>
 L:	linux-s390@vger.kernel.org
 S:	Supported

arch/s390/include/asm/extable.h

@@ -69,8 +69,13 @@ static inline void swap_ex_entry_fixup(struct exception_table_entry *a,
 {
 	a->fixup = b->fixup + delta;
 	b->fixup = tmp.fixup - delta;
-	a->handler = b->handler + delta;
-	b->handler = tmp.handler - delta;
+	a->handler = b->handler;
+	if (a->handler)
+		a->handler += delta;
+	b->handler = tmp.handler;
+	if (b->handler)
+		b->handler -= delta;
 }
+#define swap_ex_entry_fixup swap_ex_entry_fixup
 
 #endif

arch/s390/include/asm/ftrace.h

@@ -47,15 +47,17 @@ struct ftrace_regs {
 
 static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs *fregs)
 {
-	return &fregs->regs;
+	struct pt_regs *regs = &fregs->regs;
+
+	if (test_pt_regs_flag(regs, PIF_FTRACE_FULL_REGS))
+		return regs;
+	return NULL;
 }
 
 static __always_inline void ftrace_instruction_pointer_set(struct ftrace_regs *fregs,
 							   unsigned long ip)
 {
-	struct pt_regs *regs = arch_ftrace_get_regs(fregs);
-
-	regs->psw.addr = ip;
+	fregs->regs.psw.addr = ip;
 }
 
 /*

arch/s390/include/asm/ptrace.h

@@ -15,11 +15,13 @@
 #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)
 
 #ifndef __ASSEMBLY__
 

arch/s390/kernel/ftrace.c

@@ -158,9 +158,38 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec)
 	return 0;
 }
 
+static struct ftrace_hotpatch_trampoline *ftrace_get_trampoline(struct dyn_ftrace *rec)
+{
+	struct ftrace_hotpatch_trampoline *trampoline;
+	struct ftrace_insn insn;
+	s64 disp;
+	u16 opc;
+
+	if (copy_from_kernel_nofault(&insn, (void *)rec->ip, sizeof(insn)))
+		return ERR_PTR(-EFAULT);
+	disp = (s64)insn.disp * 2;
+	trampoline = (void *)(rec->ip + disp);
+	if (get_kernel_nofault(opc, &trampoline->brasl_opc))
+		return ERR_PTR(-EFAULT);
+	if (opc != 0xc015)
+		return ERR_PTR(-EINVAL);
+	return trampoline;
+}
+
 int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 		       unsigned long addr)
 {
+	struct ftrace_hotpatch_trampoline *trampoline;
+	u64 old;
+
+	trampoline = ftrace_get_trampoline(rec);
+	if (IS_ERR(trampoline))
+		return PTR_ERR(trampoline);
+	if (get_kernel_nofault(old, &trampoline->interceptor))
+		return -EFAULT;
+	if (old != old_addr)
+		return -EINVAL;
+	s390_kernel_write(&trampoline->interceptor, &addr, sizeof(addr));
 	return 0;
 }
 
@@ -188,6 +217,12 @@ int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
 
 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 {
+	struct ftrace_hotpatch_trampoline *trampoline;
+
+	trampoline = ftrace_get_trampoline(rec);
+	if (IS_ERR(trampoline))
+		return PTR_ERR(trampoline);
+	s390_kernel_write(&trampoline->interceptor, &addr, sizeof(addr));
 	/* Expect brcl 0x0,... */
 	return ftrace_patch_branch_mask((void *)rec->ip, 0xc004, true);
 }
@@ -301,7 +336,7 @@ void kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip,
 
 	regs = ftrace_get_regs(fregs);
 	p = get_kprobe((kprobe_opcode_t *)ip);
-	if (unlikely(!p) || kprobe_disabled(p))
+	if (!regs || unlikely(!p) || kprobe_disabled(p))
 		goto out;
 
 	if (kprobe_running()) {

arch/s390/kernel/mcount.S

@@ -25,6 +25,7 @@ ENDPROC(ftrace_stub)
 #define STACK_PTREGS_GPRS	(STACK_PTREGS + __PT_GPRS)
 #define STACK_PTREGS_PSW	(STACK_PTREGS + __PT_PSW)
 #define STACK_PTREGS_ORIG_GPR2	(STACK_PTREGS + __PT_ORIG_GPR2)
+#define STACK_PTREGS_FLAGS	(STACK_PTREGS + __PT_FLAGS)
 #ifdef __PACK_STACK
 /* allocate just enough for r14, r15 and backchain */
 #define TRACED_FUNC_FRAME_SIZE	24
@@ -55,6 +56,14 @@ ENDPROC(ftrace_stub)
 	.if \allregs == 1
 	stg	%r14,(STACK_PTREGS_PSW)(%r15)
 	stosm	(STACK_PTREGS_PSW)(%r15),0
+#ifdef CONFIG_HAVE_MARCH_Z10_FEATURES
+	mvghi	STACK_PTREGS_FLAGS(%r15),_PIF_FTRACE_FULL_REGS
+#else
+	lghi	%r14,_PIF_FTRACE_FULL_REGS
+	stg	%r14,STACK_PTREGS_FLAGS(%r15)
+#endif
+	.else
+	xc	STACK_PTREGS_FLAGS(8,%r15),STACK_PTREGS_FLAGS(%r15)
 	.endif
 
 	lg	%r14,(__SF_GPRS+8*8)(%r1)	# restore original return address

arch/s390/kernel/setup.c

@@ -800,6 +800,8 @@ static void __init check_initrd(void)
 static void __init reserve_kernel(void)
 {
 	memblock_reserve(0, STARTUP_NORMAL_OFFSET);
+	memblock_reserve(OLDMEM_BASE, sizeof(unsigned long));
+	memblock_reserve(OLDMEM_SIZE, sizeof(unsigned long));
 	memblock_reserve(__amode31_base, __eamode31 - __samode31);
 	memblock_reserve(__pa(sclp_early_sccb), EXT_SCCB_READ_SCP);
 	memblock_reserve(__pa(_stext), _end - _stext);

arch/s390/lib/test_modules.c

@@ -5,9 +5,6 @@
 
 #include "test_modules.h"
 
-#define DECLARE_RETURN(i) int test_modules_return_ ## i(void)
-REPEAT_10000(DECLARE_RETURN);
-
 /*
  * Test that modules with many relocations are loaded properly.
  */

arch/s390/lib/test_modules.h

@@ -47,4 +47,7 @@
 	__REPEAT_10000_1(f, 8); \
 	__REPEAT_10000_1(f, 9)
 
+#define DECLARE_RETURN(i) int test_modules_return_ ## i(void)
+REPEAT_10000(DECLARE_RETURN);
+
 #endif

drivers/s390/cio/device.c

@@ -1180,7 +1180,7 @@ static int io_subchannel_chp_event(struct subchannel *sch,
 			else
 				path_event[chpid] = PE_NONE;
 		}
-		if (cdev)
+		if (cdev && cdev->drv && cdev->drv->path_event)
 			cdev->drv->path_event(cdev, path_event);
 		break;
 	}