Commit be2412c2 authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/als: convert architecture level set code to C 



There is no reason to have this code in assembly language. Therefore
convert it to C.

Note that this code needs special treatment: it is called very early
and one of the side effects is that e.g. the bss section is not
cleared. Therefore the preferred way for static variables is to put
them on the stack which has a size of 16KB.

There is no functional change with this patch.

Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarSascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent cf9fdfea

arch/s390/boot/compressed/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ KBUILD_CFLAGS += $(call cc-option,-ffreestanding) 


GCOV_PROFILE := n



OBJECTS := $(addprefix $(objtree)/arch/s390/kernel/, head.o sclp.o ebcdic.o)

OBJECTS := $(addprefix $(objtree)/arch/s390/kernel/, head.o sclp.o ebcdic.o als.o)

OBJECTS += $(obj)/head.o $(obj)/misc.o $(obj)/piggy.o



LDFLAGS_vmlinux := --oformat $(LD_BFD) -e startup -T

arch/s390/kernel/Makefile

+7 −3
Original line number Diff line number Diff line
@@ -4,6 +4,7 @@ 


KCOV_INSTRUMENT_early.o := n

KCOV_INSTRUMENT_sclp.o := n

KCOV_INSTRUMENT_als.o := n



ifdef CONFIG_FUNCTION_TRACER

# Don't trace early setup code and tracing code
@@ -32,13 +33,16 @@ CFLAGS_ptrace.o += -DUTS_MACHINE='"$(UTS_MACHINE)"' 
CFLAGS_sysinfo.o += -w



#

# Use -march=z900 for sclp.c to be able to print an error message if

# the kernel is started on a machine which is too old

# Use -march=z900 for sclp.c and als.c to be able to print an error

# message if the kernel is started on a machine which is too old

#

CFLAGS_REMOVE_sclp.o = $(CC_FLAGS_FTRACE)

CFLAGS_REMOVE_als.o = $(CC_FLAGS_FTRACE)

ifneq ($(CC_FLAGS_MARCH),-march=z900)

CFLAGS_REMOVE_sclp.o	+= $(CC_FLAGS_MARCH)

CFLAGS_sclp.o		+= -march=z900

CFLAGS_REMOVE_als.o	+= $(CC_FLAGS_MARCH)

CFLAGS_als.o		+= -march=z900

AFLAGS_REMOVE_head.o	+= $(CC_FLAGS_MARCH)

AFLAGS_head.o		+= -march=z900

endif
@@ -46,7 +50,7 @@ GCOV_PROFILE_sclp.o := n 


obj-y	:= traps.o time.o process.o base.o early.o setup.o idle.o vtime.o

obj-y	+= processor.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o nmi.o

obj-y	+= debug.o irq.o ipl.o dis.o diag.o sclp.o vdso.o

obj-y	+= debug.o irq.o ipl.o dis.o diag.o sclp.o vdso.o als.o

obj-y	+= sysinfo.o jump_label.o lgr.o os_info.o machine_kexec.o pgm_check.o

obj-y	+= runtime_instr.o cache.o fpu.o dumpstack.o

obj-y	+= entry.o reipl.o relocate_kernel.o

arch/s390/kernel/als.c

0 → 100644
+46 −0
Original line number Diff line number Diff line 
/*

 *    Copyright IBM Corp. 2016

 */

#include <linux/kernel.h>

#include <linux/init.h>

#include <asm/processor.h>

#include <asm/facility.h>

#include <asm/lowcore.h>

#include <asm/sclp.h>

#include "entry.h"



/*

 * The code within this file will be called very early. It may _not_

 * access anything within the bss section, since that is not cleared

 * yet and may contain data (e.g. initrd) that must be saved by other

 * code.

 * For temporary objects the stack (16k) should be used.

 */



static unsigned long als[] __initdata = { FACILITIES_ALS };



void __init verify_facilities(void)

{

	int i;



	for (i = 0; i < ARRAY_SIZE(S390_lowcore.stfle_fac_list); i++)

		S390_lowcore.stfle_fac_list[i] = 0;

	asm volatile(

		"	stfl	0(0)\n"

		: "=m" (S390_lowcore.stfl_fac_list));

	S390_lowcore.stfle_fac_list[0] = (u64)S390_lowcore.stfl_fac_list << 32;

	if (S390_lowcore.stfl_fac_list & 0x01000000) {

		register unsigned long reg0 asm("0") = ARRAY_SIZE(als) - 1;



		asm volatile(".insn s,0xb2b00000,0(%1)" /* stfle */

			     : "+d" (reg0)

			     : "a" (&S390_lowcore.stfle_fac_list)

			     : "memory", "cc");

	}

	for (i = 0; i < ARRAY_SIZE(als); i++) {

		if ((S390_lowcore.stfle_fac_list[i] & als[i]) == als[i])

			continue;

		_sclp_print_early("The Linux kernel requires more recent processor hardware");

		disabled_wait(0x8badcccc);

	}

}

arch/s390/kernel/entry.h

+2 −0
Original line number Diff line number Diff line
@@ -79,4 +79,6 @@ long sys_s390_pci_mmio_read(unsigned long, void __user *, size_t); 


DECLARE_PER_CPU(u64, mt_cycles[8]);



void verify_facilities(void);



#endif /* _ENTRY_H */

arch/s390/kernel/head.S

+4 −39
Original line number Diff line number Diff line
@@ -306,49 +306,14 @@ ENTRY(startup_kdump) 
	stck	__LC_LAST_UPDATE_CLOCK

	spt	6f-.LPG0(%r13)

	mvc	__LC_LAST_UPDATE_TIMER(8),6f-.LPG0(%r13)

	stfl	0(%r0)			# store facilities @ __LC_STFL_FAC_LIST

	mvc	__LC_STFLE_FAC_LIST(4),__LC_STFL_FAC_LIST

	tm	__LC_STFLE_FAC_LIST,0x01	# stfle available ?

	jz	0f

	lghi	%r0,FACILITIES_ALS_DWORDS-1

	.insn	s,0xb2b00000,__LC_STFLE_FAC_LIST # store facility list extended

	# verify if all required facilities are supported by the machine

0:	la	%r1,__LC_STFLE_FAC_LIST

	la	%r2,3f+8-.LPG0(%r13)

	lhi	%r3,FACILITIES_ALS_DWORDS

1:	lg	%r0,0(%r1)

	ng	%r0,0(%r2)

	clg	%r0,0(%r2)

	jne	2f

	la	%r1,8(%r1)

	la	%r2,8(%r2)

	ahi	%r3,-1

	jnz	1b

	j	4f

2:	l	%r15,.Lstack-.LPG0(%r13)

	l	%r15,.Lstack-.LPG0(%r13)

	ahi	%r15,-STACK_FRAME_OVERHEAD

	la	%r2,.Lals_string-.LPG0(%r13)

	l	%r3,.Lsclp_print-.LPG0(%r13)

	basr	%r14,%r3

	lpsw	3f-.LPG0(%r13)		# machine type not good enough, crash

.Lals_string:

	.asciz	"The Linux kernel requires more recent processor hardware"

.Lsclp_print:

	.long	_sclp_print_early

.Lstack:

	.long	0x8000 + (1<<(PAGE_SHIFT+THREAD_ORDER))

	.align 16

3:	.long	0x000a0000,0x8badcccc



# List of facilities that are required. If not all facilities are present

# the kernel will crash.



	.quad FACILITIES_ALS



4:

	brasl	%r14,verify_facilities

	/* Continue with startup code in head64.S */

	jg	startup_continue



.Lstack:

	.long	0x8000 + (1<<(PAGE_SHIFT+THREAD_ORDER))

	.align	8

6:	.long	0x7fffffff,0xffffffff

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