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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: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Sascha Silbe <silbe@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
hifive-unleashed-5.1
Heiko Carstens 2016-06-27 15:52:38 +02:00 committed by Martin Schwidefsky
parent cf9fdfea5f
commit be2412c247
5 changed files with 60 additions and 43 deletions
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2
arch/s390/boot/compressed/Makefile
View File

@ -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

10
arch/s390/kernel/Makefile
View File

@ -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

46
arch/s390/kernel/als.c 100644
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@ -0,0 +1,46 @@
/*
* 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);
}
}

2
arch/s390/kernel/entry.h
View File

@ -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 */

43
arch/s390/kernel/head.S
View File

@ -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