Merge tag 's390-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux

Pull s390 updates from Vasily Gorbik:

 - Raise minimum supported machine generation to z10, which comes with
   various cleanups and code simplifications (usercopy/spectre
   mitigation/etc).

 - Rework extables and get rid of anonymous out-of-line fixups.

 - Page table helpers cleanup. Add set_pXd()/set_pte() helper functions.
   Covert pte_val()/pXd_val() macros to functions.

 - Optimize kretprobe handling by avoiding extra kprobe on
   __kretprobe_trampoline.

 - Add support for CEX8 crypto cards.

 - Allow to trigger AP bus rescan via writing to /sys/bus/ap/scans.

 - Add CONFIG_EXPOLINE_EXTERN option to build the kernel without COMDAT
   group sections which simplifies kpatch support.

 - Always use the packed stack layout and extend kernel unwinder tests.

 - Add sanity checks for ftrace code patching.

 - Add s390dbf debug log for the vfio_ap device driver.

 - Various virtual vs physical address confusion fixes.

 - Various small fixes and improvements all over the code.

* tag 's390-5.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: (69 commits)
  s390/test_unwind: add kretprobe tests
  s390/kprobes: Avoid additional kprobe in kretprobe handling
  s390: convert ".insn" encoding to instruction names
  s390: assume stckf is always present
  s390/nospec: move to single register thunks
  s390: raise minimum supported machine generation to z10
  s390/uaccess: Add copy_from/to_user_key functions
  s390/nospec: align and size extern thunks
  s390/nospec: add an option to use thunk-extern
  s390/nospec: generate single register thunks if possible
  s390/pci: make zpci_set_irq()/zpci_clear_irq() static
  s390: remove unused expoline to BC instructions
  s390/irq: use assignment instead of cast
  s390/traps: get rid of magic cast for per code
  s390/traps: get rid of magic cast for program interruption code
  s390/signal: fix typo in comments
  s390/asm-offsets: remove unused defines
  s390/test_unwind: avoid build warning with W=1
  s390: remove .fixup section
  s390/bpf: encode register within extable entry
  ...

1 files changed, 31 insertions, 34 deletions

diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c
index 89c0870d5679..1852d46babb1 100644
--- a/arch/s390/kernel/ftrace.c
+++ b/arch/s390/kernel/ftrace.c
@@ -4,8 +4,7 @@
  *
  * Copyright IBM Corp. 2009,2014
  *
- *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
- *		Martin Schwidefsky <schwidefsky@de.ibm.com>
+ *   Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
  */
 
 #include <linux/moduleloader.h>
@@ -61,18 +60,9 @@ asm(
 #ifdef CONFIG_EXPOLINE
 asm(
 	"	.align 16\n"
-	"ftrace_shared_hotpatch_trampoline_ex:\n"
-	"	lmg	%r0,%r1,2(%r1)\n"
-	"	ex	%r0," __stringify(__LC_BR_R1) "(%r0)\n"
-	"	j	.\n"
-	"ftrace_shared_hotpatch_trampoline_ex_end:\n"
-);
-
-asm(
-	"	.align 16\n"
 	"ftrace_shared_hotpatch_trampoline_exrl:\n"
 	"	lmg	%r0,%r1,2(%r1)\n"
-	"	.insn	ril,0xc60000000000,%r0,0f\n" /* exrl */
+	"	exrl	%r0,0f\n"
 	"	j	.\n"
 	"0:	br	%r1\n"
 	"ftrace_shared_hotpatch_trampoline_exrl_end:\n"
@@ -91,12 +81,8 @@ static const char *ftrace_shared_hotpatch_trampoline(const char **end)
 	tend = ftrace_shared_hotpatch_trampoline_br_end;
 #ifdef CONFIG_EXPOLINE
 	if (!nospec_disable) {
-		tstart = ftrace_shared_hotpatch_trampoline_ex;
-		tend = ftrace_shared_hotpatch_trampoline_ex_end;
-		if (test_facility(35)) { /* exrl */
-			tstart = ftrace_shared_hotpatch_trampoline_exrl;
-			tend = ftrace_shared_hotpatch_trampoline_exrl_end;
-		}
+		tstart = ftrace_shared_hotpatch_trampoline_exrl;
+		tend = ftrace_shared_hotpatch_trampoline_exrl_end;
 	}
 #endif /* CONFIG_EXPOLINE */
 	if (end)
@@ -194,25 +180,26 @@ int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr,
 	return 0;
 }
 
-static void brcl_disable(void *brcl)
+static int ftrace_patch_branch_mask(void *addr, u16 expected, bool enable)
 {
-	u8 op = 0x04; /* set mask field to zero */
+	u16 old;
+	u8 op;
 
-	s390_kernel_write((char *)brcl + 1, &op, sizeof(op));
+	if (get_kernel_nofault(old, addr))
+		return -EFAULT;
+	if (old != expected)
+		return -EINVAL;
+	/* set mask field to all ones or zeroes */
+	op = enable ? 0xf4 : 0x04;
+	s390_kernel_write((char *)addr + 1, &op, sizeof(op));
+	return 0;
 }
 
 int ftrace_make_nop(struct module *mod, struct dyn_ftrace *rec,
 		    unsigned long addr)
 {
-	brcl_disable((void *)rec->ip);
-	return 0;
-}
-
-static void brcl_enable(void *brcl)
-{
-	u8 op = 0xf4; /* set mask field to all ones */
-
-	s390_kernel_write((char *)brcl + 1, &op, sizeof(op));
+	/* Expect brcl 0xf,... */
+	return ftrace_patch_branch_mask((void *)rec->ip, 0xc0f4, false);
 }
 
 int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
@@ -223,8 +210,8 @@ int ftrace_make_call(struct dyn_ftrace *rec, unsigned long addr)
 	if (IS_ERR(trampoline))
 		return PTR_ERR(trampoline);
 	s390_kernel_write(&trampoline->interceptor, &addr, sizeof(addr));
-	brcl_enable((void *)rec->ip);
-	return 0;
+	/* Expect brcl 0x0,... */
+	return ftrace_patch_branch_mask((void *)rec->ip, 0xc004, true);
 }
 
 int ftrace_update_ftrace_func(ftrace_func_t func)
@@ -297,14 +284,24 @@ NOKPROBE_SYMBOL(prepare_ftrace_return);
  */
 int ftrace_enable_ftrace_graph_caller(void)
 {
-	brcl_disable(ftrace_graph_caller);
+	int rc;
+
+	/* Expect brc 0xf,... */
+	rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa7f4, false);
+	if (rc)
+		return rc;
 	text_poke_sync_lock();
 	return 0;
 }
 
 int ftrace_disable_ftrace_graph_caller(void)
 {
-	brcl_enable(ftrace_graph_caller);
+	int rc;
+
+	/* Expect brc 0x0,... */
+	rc = ftrace_patch_branch_mask(ftrace_graph_caller, 0xa704, true);
+	if (rc)
+		return rc;
 	text_poke_sync_lock();
 	return 0;
 }