[S390] Convert machine feature detection code to C.

From: Heiko Carstens <heiko.carstens@de.ibm.com>
From: Carsten Otte <cotte@de.ibm.com>

This lets us use defines for the magic bits in machine flags instead
of using plain numbers all over the place.
In addition on newer machines features/facilities are indicated by the
result of the stfl instruction. So we use these bits instead of trying
to execute new instructions and check wether we get an exception or
not.
Also the mvpg instruction is always available when in zArch mode,
whereas the idte instruction is only available in zArch mode. This
results in some minor optimizations.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

4 files changed, 107 insertions, 127 deletions

diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 68ec4083bf7..bd188f6bd0e 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -139,15 +139,15 @@ static noinline __init void detect_machine_type(void)
 
 	/* Running under z/VM ? */
 	if (cpuinfo->cpu_id.version == 0xff)
-		machine_flags |= 1;
+		machine_flags |= MACHINE_FLAG_VM;
 
 	/* Running on a P/390 ? */
 	if (cpuinfo->cpu_id.machine == 0x7490)
-		machine_flags |= 4;
+		machine_flags |= MACHINE_FLAG_P390;
 
 	/* Running under KVM ? */
 	if (cpuinfo->cpu_id.version == 0xfe)
-		machine_flags |= 64;
+		machine_flags |= MACHINE_FLAG_KVM;
 }
 
 #ifdef CONFIG_64BIT
@@ -268,6 +268,103 @@ static noinline __init void setup_lowcore_early(void)
 	s390_base_pgm_handler_fn = early_pgm_check_handler;
 }
 
+static __init void detect_mvpg(void)
+{
+#ifndef CONFIG_64BIT
+	int rc;
+
+	asm volatile(
+		"	la	0,0\n"
+		"	mvpg	%2,%2\n"
+		"0:	la	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=d" (rc) : "0" (-EOPNOTSUPP), "a" (0) : "memory", "cc", "0");
+	if (!rc)
+		machine_flags |= MACHINE_FLAG_MVPG;
+#endif
+}
+
+static __init void detect_ieee(void)
+{
+#ifndef CONFIG_64BIT
+	int rc, tmp;
+
+	asm volatile(
+		"	efpc	%1,0\n"
+		"0:	la	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=d" (rc), "=d" (tmp): "0" (-EOPNOTSUPP) : "cc");
+	if (!rc)
+		machine_flags |= MACHINE_FLAG_IEEE;
+#endif
+}
+
+static __init void detect_csp(void)
+{
+#ifndef CONFIG_64BIT
+	int rc;
+
+	asm volatile(
+		"	la	0,0\n"
+		"	la	1,0\n"
+		"	la	2,4\n"
+		"	csp	0,2\n"
+		"0:	la	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=d" (rc) : "0" (-EOPNOTSUPP) : "cc", "0", "1", "2");
+	if (!rc)
+		machine_flags |= MACHINE_FLAG_CSP;
+#endif
+}
+
+static __init void detect_diag9c(void)
+{
+	unsigned int cpu_address;
+	int rc;
+
+	cpu_address = stap();
+	asm volatile(
+		"	diag	%2,0,0x9c\n"
+		"0:	la	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=d" (rc) : "0" (-EOPNOTSUPP), "d" (cpu_address) : "cc");
+	if (!rc)
+		machine_flags |= MACHINE_FLAG_DIAG9C;
+}
+
+static __init void detect_diag44(void)
+{
+#ifdef CONFIG_64BIT
+	int rc;
+
+	asm volatile(
+		"	diag	0,0,0x44\n"
+		"0:	la	%0,0\n"
+		"1:\n"
+		EX_TABLE(0b,1b)
+		: "=d" (rc) : "0" (-EOPNOTSUPP) : "cc");
+	if (!rc)
+		machine_flags |= MACHINE_FLAG_DIAG44;
+#endif
+}
+
+static __init void detect_machine_facilities(void)
+{
+#ifdef CONFIG_64BIT
+	unsigned int facilities;
+
+	facilities = stfl();
+	if (facilities & (1 << 28))
+		machine_flags |= MACHINE_FLAG_IDTE;
+	if (facilities & (1 << 4))
+		machine_flags |= MACHINE_FLAG_MVCOS;
+#endif
+}
+
 /*
  * Save ipl parameters, clear bss memory, initialize storage keys
  * and create a kernel NSS at startup if the SAVESYS= parm is defined
@@ -285,6 +382,12 @@ void __init startup_init(void)
 	create_kernel_nss();
 	sort_main_extable();
 	setup_lowcore_early();
+	detect_mvpg();
+	detect_ieee();
+	detect_csp();
+	detect_diag9c();
+	detect_diag44();
+	detect_machine_facilities();
 	sclp_read_info_early();
 	sclp_facilities_detect();
 	memsize = sclp_memory_detect();
diff --git a/arch/s390/kernel/head31.S b/arch/s390/kernel/head31.S
index dc364c1419a..a816e2de32b 100644
--- a/arch/s390/kernel/head31.S
+++ b/arch/s390/kernel/head31.S
@@ -57,61 +57,6 @@ startup_continue:
 #
 	l	%r14,.Lstartup_init-.LPG1(%r13)
 	basr	%r14,%r14
-
-	l	%r12,.Lmflags-.LPG1(%r13) # get address of machine_flags
-#
-# find out if we have an IEEE fpu
-#
-	mvc	__LC_PGM_NEW_PSW(8),.Lpcfpu-.LPG1(%r13)
-	efpc	%r0,0			# test IEEE extract fpc instruction
-	oi	3(%r12),2		# set IEEE fpu flag
-.Lchkfpu:
-
-#
-# find out if we have the CSP instruction
-#
-       mvc	 __LC_PGM_NEW_PSW(8),.Lpccsp-.LPG1(%r13)
-       la	 %r0,0
-       lr	%r1,%r0
-       la	%r2,4
-       csp	%r0,%r2			# Test CSP instruction
-       oi	3(%r12),8		# set CSP flag
-.Lchkcsp:
-
-#
-# find out if we have the MVPG instruction
-#
-       mvc	__LC_PGM_NEW_PSW(8),.Lpcmvpg-.LPG1(%r13)
-       sr	%r0,%r0
-       la	%r1,0
-       la	%r2,0
-       mvpg	%r1,%r2			# Test CSP instruction
-       oi	3(%r12),16		# set MVPG flag
-.Lchkmvpg:
-
-#
-# find out if we have the IDTE instruction
-#
-	mvc	__LC_PGM_NEW_PSW(8),.Lpcidte-.LPG1(%r13)
-	.long	0xb2b10000		# store facility list
-	tm	0xc8,0x08		# check bit for clearing-by-ASCE
-	bno	.Lchkidte-.LPG1(%r13)
-	lhi	%r1,2094
-	lhi	%r2,0
-	.long	0xb98e2001
-	oi	3(%r12),0x80		# set IDTE flag
-.Lchkidte:
-
-#
-# find out if the diag 0x9c is available
-#
-	mvc	__LC_PGM_NEW_PSW(8),.Lpcdiag9c-.LPG1(%r13)
-	stap	__LC_CPUID+4		# store cpu address
-	lh	%r1,__LC_CPUID+4
-	diag	%r1,0,0x9c		# test diag 0x9c
-	oi	2(%r12),1		# set diag9c flag
-.Lchkdiag9c:
-
 	lpsw  .Lentry-.LPG1(13)		# jump to _stext in primary-space,
 					# virtual and never return ...
 	.align	8
@@ -132,13 +77,7 @@ startup_continue:
 	.long	0			# cr13: home space segment table
 	.long	0xc0000000		# cr14: machine check handling off
 	.long	0			# cr15: linkage stack operations
-.Lpcfpu:.long	0x00080000,0x80000000 + .Lchkfpu
-.Lpccsp:.long	0x00080000,0x80000000 + .Lchkcsp
-.Lpcmvpg:.long	0x00080000,0x80000000 + .Lchkmvpg
-.Lpcidte:.long	0x00080000,0x80000000 + .Lchkidte
-.Lpcdiag9c:.long 0x00080000,0x80000000 + .Lchkdiag9c
 .Lmchunk:.long	memory_chunk
-.Lmflags:.long	machine_flags
 .Lbss_bgn:  .long __bss_start
 .Lbss_end:  .long _end
 .Lparmaddr: .long PARMAREA
diff --git a/arch/s390/kernel/head64.S b/arch/s390/kernel/head64.S
index 79dccd206a6..9c2c6f7d37e 100644
--- a/arch/s390/kernel/head64.S
+++ b/arch/s390/kernel/head64.S
@@ -125,68 +125,6 @@ startup_continue:
 # and create a kernel NSS if the SAVESYS= parm is defined
 #
 	brasl	%r14,startup_init
-					# set program check new psw mask
-	mvc	__LC_PGM_NEW_PSW(8),.Lpcmsk-.LPG1(%r13)
-	larl	%r12,machine_flags
-#
-# find out if we have the MVPG instruction
-#
-	la	%r1,0f-.LPG1(%r13)	# set program check address
-	stg	%r1,__LC_PGM_NEW_PSW+8
-	sgr	%r0,%r0
-	lghi	%r1,0
-	lghi	%r2,0
-	mvpg	%r1,%r2 		# test MVPG instruction
-	oi	7(%r12),16		# set MVPG flag
-0:
-
-#
-# find out if the diag 0x44 works in 64 bit mode
-#
-	la	%r1,0f-.LPG1(%r13)	# set program check address
-	stg	%r1,__LC_PGM_NEW_PSW+8
-	diag	0,0,0x44		# test diag 0x44
-	oi	7(%r12),32		# set diag44 flag
-0:
-
-#
-# find out if we have the IDTE instruction
-#
-	la	%r1,0f-.LPG1(%r13)	# set program check address
-	stg	%r1,__LC_PGM_NEW_PSW+8
-	.long	0xb2b10000		# store facility list
-	tm	0xc8,0x08		# check bit for clearing-by-ASCE
-	bno	0f-.LPG1(%r13)
-	lhi	%r1,2048
-	lhi	%r2,0
-	.long	0xb98e2001
-	oi	7(%r12),0x80		# set IDTE flag
-0:
-
-#
-# find out if the diag 0x9c is available
-#
-	la	%r1,0f-.LPG1(%r13)	# set program check address
-	stg	%r1,__LC_PGM_NEW_PSW+8
-	stap	__LC_CPUID+4		# store cpu address
-	lh	%r1,__LC_CPUID+4
-	diag	%r1,0,0x9c		# test diag 0x9c
-	oi	6(%r12),1		# set diag9c flag
-0:
-
-#
-# find out if we have the MVCOS instruction
-#
-	la	%r1,0f-.LPG1(%r13)	# set program check address
-	stg	%r1,__LC_PGM_NEW_PSW+8
-	.short	0xc800			# mvcos 0(%r0),0(%r0),%r0
-	.short	0x0000
-	.short	0x0000
-0:	tm	0x8f,0x13		# special-operation exception?
-	bno	1f-.LPG1(%r13)		# if yes, MVCOS is present
-	oi	6(%r12),2		# set MVCOS flag
-1:
-
 	lpswe	.Lentry-.LPG1(13)	# jump to _stext in primary-space,
 					# virtual and never return ...
 	.align	16
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 024180e25e8..694c6546ce6 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -73,7 +73,7 @@ EXPORT_SYMBOL(uaccess);
 unsigned int console_mode = 0;
 unsigned int console_devno = -1;
 unsigned int console_irq = -1;
-unsigned long machine_flags = 0;
+unsigned long machine_flags;
 unsigned long elf_hwcap = 0;
 char elf_platform[ELF_PLATFORM_SIZE];