Merge tag 's390-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 fixes from Vasily Gorbik:

 - Fix HAVE_DYNAMIC_FTRACE_WITH_ARGS implementation by providing correct
   switching between ftrace_caller/ftrace_regs_caller and supplying
   pt_regs only when ftrace_regs_caller is activated.

 - Fix exception table sorting.

 - Fix breakage of kdump tooling by preserving metadata it cannot
   function without.

* tag 's390-5.17-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  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

6 files changed, 62 insertions, 7 deletions

diff --git a/arch/s390/include/asm/extable.h b/arch/s390/include/asm/extable.h
index 16dc57dd90b3..8511f0e59290 100644
--- a/arch/s390/include/asm/extable.h
+++ b/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
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 267f70f4393f..6f80ec9c04be 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/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;
 }
 
 /*
diff --git a/arch/s390/include/asm/ptrace.h b/arch/s390/include/asm/ptrace.h
index 4ffa8e7f0ed3..ddb70fb13fbc 100644
--- a/arch/s390/include/asm/ptrace.h
+++ b/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__
 
diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 21d62d8b6b9a..89c0870d5679 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -159,9 +159,38 @@ 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 @@ static void brcl_enable(void *brcl)
 
 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));
 	brcl_enable((void *)rec->ip);
 	return 0;
 }
@@ -291,7 +326,7 @@ 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()) {
diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 39bcc0e39a10..a24177dcd12a 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -27,6 +27,7 @@ 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
@@ -57,6 +58,14 @@ 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
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index f2c25d113e7b..05327be3a982 100644
--- a/arch/s390/kernel/setup.c
+++ b/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);