s390/cmma: move parsing of cmma kernel parameter to early boot code

The "cmma=" kernel command line parameter needs to be parsed early for
upcoming changes. Therefore move the parsing code.

Note that EX_TABLE handling of cmma_test_essa() needs to be open-coded,
since the early boot code doesn't have infrastructure for handling expected
exceptions.

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

7 files changed, 58 insertions, 42 deletions

diff --git a/arch/s390/boot/ipl_parm.c b/arch/s390/boot/ipl_parm.c
index 7b7521762633..2ab4872fbee1 100644
--- a/arch/s390/boot/ipl_parm.c
+++ b/arch/s390/boot/ipl_parm.c
@@ -3,6 +3,7 @@
 #include <linux/init.h>
 #include <linux/ctype.h>
 #include <linux/pgtable.h>
+#include <asm/page-states.h>
 #include <asm/ebcdic.h>
 #include <asm/sclp.h>
 #include <asm/sections.h>
@@ -24,6 +25,7 @@ unsigned int __bootdata_preserved(zlib_dfltcc_support) = ZLIB_DFLTCC_FULL;
 struct ipl_parameter_block __bootdata_preserved(ipl_block);
 int __bootdata_preserved(ipl_block_valid);
 int __bootdata_preserved(__kaslr_enabled);
+int __bootdata_preserved(cmma_flag) = 1;
 
 unsigned long vmalloc_size = VMALLOC_DEFAULT_SIZE;
 unsigned long memory_limit;
@@ -295,6 +297,12 @@ void parse_boot_command_line(void)
 		if (!strcmp(param, "nokaslr"))
 			__kaslr_enabled = 0;
 
+		if (!strcmp(param, "cmma")) {
+			rc = kstrtobool(val, &enabled);
+			if (!rc && !enabled)
+				cmma_flag = 0;
+		}
+
 #if IS_ENABLED(CONFIG_KVM)
 		if (!strcmp(param, "prot_virt")) {
 			rc = kstrtobool(val, &enabled);
diff --git a/arch/s390/boot/startup.c b/arch/s390/boot/startup.c
index 8826c4f18645..8104e0e3d188 100644
--- a/arch/s390/boot/startup.c
+++ b/arch/s390/boot/startup.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/string.h>
 #include <linux/elf.h>
+#include <asm/page-states.h>
 #include <asm/boot_data.h>
 #include <asm/sections.h>
 #include <asm/maccess.h>
@@ -57,6 +58,48 @@ static void detect_facilities(void)
 		machine.has_nx = 1;
 }
 
+static int cmma_test_essa(void)
+{
+	unsigned long reg1, reg2, tmp = 0;
+	int rc = 1;
+	psw_t old;
+
+	/* Test ESSA_GET_STATE */
+	asm volatile(
+		"	mvc	0(16,%[psw_old]),0(%[psw_pgm])\n"
+		"	epsw	%[reg1],%[reg2]\n"
+		"	st	%[reg1],0(%[psw_pgm])\n"
+		"	st	%[reg2],4(%[psw_pgm])\n"
+		"	larl	%[reg1],1f\n"
+		"	stg	%[reg1],8(%[psw_pgm])\n"
+		"	.insn	rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
+		"	la	%[rc],0\n"
+		"1:	mvc	0(16,%[psw_pgm]),0(%[psw_old])\n"
+		: [reg1] "=&d" (reg1),
+		  [reg2] "=&a" (reg2),
+		  [rc] "+&d" (rc),
+		  [tmp] "=&d" (tmp),
+		  "+Q" (S390_lowcore.program_new_psw),
+		  "=Q" (old)
+		: [psw_old] "a" (&old),
+		  [psw_pgm] "a" (&S390_lowcore.program_new_psw),
+		  [cmd] "i" (ESSA_GET_STATE)
+		: "cc", "memory");
+	return rc;
+}
+
+static void cmma_init(void)
+{
+	if (!cmma_flag)
+		return;
+	if (cmma_test_essa()) {
+		cmma_flag = 0;
+		return;
+	}
+	if (test_facility(147))
+		cmma_flag = 2;
+}
+
 static void setup_lpp(void)
 {
 	S390_lowcore.current_pid = 0;
@@ -306,6 +349,7 @@ void startup_kernel(void)
 	setup_boot_command_line();
 	parse_boot_command_line();
 	detect_facilities();
+	cmma_init();
 	sanitize_prot_virt_host();
 	max_physmem_end = detect_max_physmem_end();
 	setup_ident_map_size(max_physmem_end);
diff --git a/arch/s390/include/asm/page-states.h b/arch/s390/include/asm/page-states.h
index c33c4deb545f..659e3c963ce6 100644
--- a/arch/s390/include/asm/page-states.h
+++ b/arch/s390/include/asm/page-states.h
@@ -7,6 +7,8 @@
 #ifndef PAGE_STATES_H
 #define PAGE_STATES_H
 
+#include <asm/sections.h>
+
 #define ESSA_GET_STATE			0
 #define ESSA_SET_STABLE			1
 #define ESSA_SET_UNUSED			2
@@ -18,4 +20,6 @@
 
 #define ESSA_MAX	ESSA_SET_STABLE_NODAT
 
+extern int __bootdata_preserved(cmma_flag);
+
 #endif
diff --git a/arch/s390/include/asm/setup.h b/arch/s390/include/asm/setup.h
index 25cadc2b9cff..ad6641245658 100644
--- a/arch/s390/include/asm/setup.h
+++ b/arch/s390/include/asm/setup.h
@@ -125,7 +125,6 @@ static inline void vmcp_cma_reserve(void) { }
 
 void report_user_fault(struct pt_regs *regs, long signr, int is_mm_fault);
 
-void cmma_init(void);
 void cmma_init_nodat(void);
 
 extern void (*_machine_restart)(char *command);
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index ff1f02b54771..eb43e5922a25 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -46,6 +46,7 @@ decompressor_handled_param(vmalloc);
 decompressor_handled_param(dfltcc);
 decompressor_handled_param(facilities);
 decompressor_handled_param(nokaslr);
+decompressor_handled_param(cmma);
 #if IS_ENABLED(CONFIG_KVM)
 decompressor_handled_param(prot_virt);
 #endif
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 7eca10c32caa..c322d09624bc 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -164,8 +164,6 @@ void __init mem_init(void)
 
 	pv_init();
 	kfence_split_mapping();
-	/* Setup guest page hinting */
-	cmma_init();
 
 	/* this will put all low memory onto the freelists */
 	memblock_free_all();
diff --git a/arch/s390/mm/page-states.c b/arch/s390/mm/page-states.c
index 202dacdf17db..b68fef3d1230 100644
--- a/arch/s390/mm/page-states.c
+++ b/arch/s390/mm/page-states.c
@@ -18,45 +18,7 @@
 #include <asm/facility.h>
 #include <asm/page-states.h>
 
-static int cmma_flag = 1;
-
-static int __init cmma(char *str)
-{
-	bool enabled;
-
-	if (!kstrtobool(str, &enabled))
-		cmma_flag = enabled;
-	return 1;
-}
-__setup("cmma=", cmma);
-
-static inline int cmma_test_essa(void)
-{
-	unsigned long tmp = 0;
-	int rc = -EOPNOTSUPP;
-
-	/* test ESSA_GET_STATE */
-	asm volatile(
-		"	.insn	rrf,0xb9ab0000,%[tmp],%[tmp],%[cmd],0\n"
-		"0:     la      %[rc],0\n"
-		"1:\n"
-		EX_TABLE(0b, 1b)
-		: [rc] "+&d" (rc), [tmp] "+&d" (tmp)
-		: [cmd] "i" (ESSA_GET_STATE));
-	return rc;
-}
-
-void __init cmma_init(void)
-{
-	if (!cmma_flag)
-		return;
-	if (cmma_test_essa()) {
-		cmma_flag = 0;
-		return;
-	}
-	if (test_facility(147))
-		cmma_flag = 2;
-}
+int __bootdata_preserved(cmma_flag);
 
 static __always_inline void essa(unsigned long paddr, unsigned char cmd)
 {