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s390/dump: rework CPU register dump code 

To collect the CPU registers of the crashed system allocated a single
page with memblock_alloc_base and use it as a copy buffer. Replace the
stop-and-store-status sigp with a store-status-at-address sigp in
smp_save_dump_cpus() and smp_store_status(). In both cases the target
CPU is already stopped and store-status-at-address avoids the detour
via the absolute zero page.

For kexec simplify s390_reset_system and call store_status() before
the prefix register of the boot CPU has been set to zero. Use STPX
to store the prefix register and remove dump_prefix_page.

Acked-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2015-10-29 10:28:26 +01:00
parent f08b841463
commit 1a36a39e22
12 changed files with 158 additions and 145 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/s390/include/asm/fpu/internal.h
View File

@ -12,21 +12,13 @@
#include <asm/ctl_reg.h>
#include <asm/fpu/types.h>
static inline void save_vx_regs_safe(__vector128 *vxrs)
static inline void save_vx_regs(__vector128 *vxrs)
{
unsigned long cr0, flags;
flags = arch_local_irq_save();
__ctl_store(cr0, 0, 0);
__ctl_set_bit(0, 17);
__ctl_set_bit(0, 18);
asm volatile(
" la 1,%0\n"
" .word 0xe70f,0x1000,0x003e\n" /* vstm 0,15,0(1) */
" .word 0xe70f,0x1100,0x0c3e\n" /* vstm 16,31,256(1) */
: "=Q" (*(struct vx_array *) vxrs) : : "1");
__ctl_load(cr0, 0, 0);
arch_local_irq_restore(flags);
}
static inline void convert_vx_to_fp(freg_t *fprs, __vector128 *vxrs)

3
arch/s390/include/asm/ipl.h
View File

@ -87,7 +87,6 @@ struct ipl_parameter_block {
* IPL validity flags
*/
extern u32 ipl_flags;
extern u32 dump_prefix_page;
struct dump_save_areas {
struct save_area_ext **areas;
@ -176,7 +175,7 @@ enum diag308_rc {
extern int diag308(unsigned long subcode, void *addr);
extern void diag308_reset(void);
extern void store_status(void);
extern void store_status(void (*fn)(void *), void *data);
extern void lgr_info_log(void);
#endif /* _ASM_S390_IPL_H */

3
arch/s390/include/asm/reset.h
View File

@ -15,6 +15,5 @@ struct reset_call {
extern void register_reset_call(struct reset_call *reset);
extern void unregister_reset_call(struct reset_call *reset);
extern void s390_reset_system(void (*fn_pre)(void),
void (*fn_post)(void *), void *data);
extern void s390_reset_system(void);
#endif /* _ASM_S390_RESET_H */

2
arch/s390/include/asm/smp.h
View File

@ -18,6 +18,7 @@
extern struct mutex smp_cpu_state_mutex;
extern unsigned int smp_cpu_mt_shift;
extern unsigned int smp_cpu_mtid;
extern __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
extern int __cpu_up(unsigned int cpu, struct task_struct *tidle);
@ -55,7 +56,6 @@ static inline int smp_store_status(int cpu) { return 0; }
static inline int smp_vcpu_scheduled(int cpu) { return 1; }
static inline void smp_yield_cpu(int cpu) { }
static inline void smp_fill_possible_mask(void) { }
static inline void smp_save_dump_cpus(void) { }
#endif /* CONFIG_SMP */

9
arch/s390/kernel/early.c
View File

@ -335,6 +335,14 @@ static __init void detect_machine_facilities(void)
}
}
static inline void save_vector_registers(void)
{
#ifdef CONFIG_CRASH_DUMP
if (test_facility(129))
save_vx_regs(boot_cpu_vector_save_area);
#endif
}
static int __init disable_vector_extension(char *str)
{
S390_lowcore.machine_flags &= ~MACHINE_FLAG_VX;
@ -451,6 +459,7 @@ void __init startup_init(void)
detect_diag9c();
detect_diag44();
detect_machine_facilities();
save_vector_registers();
setup_topology();
sclp_early_detect();
lockdep_on();

17
arch/s390/kernel/ipl.c
View File

@ -2039,10 +2039,7 @@ static void do_reset_calls(void)
reset->fn();
}
u32 dump_prefix_page;
void s390_reset_system(void (*fn_pre)(void),
void (*fn_post)(void *), void *data)
void s390_reset_system(void)
{
struct _lowcore *lc;
@ -2051,9 +2048,6 @@ void s390_reset_system(void (*fn_pre)(void),
/* Stack for interrupt/machine check handler */
lc->panic_stack = S390_lowcore.panic_stack;
/* Save prefix page address for dump case */
dump_prefix_page = (u32)(unsigned long) lc;
/* Disable prefixing */
set_prefix(0);
@ -2077,14 +2071,5 @@ void s390_reset_system(void (*fn_pre)(void),
S390_lowcore.subchannel_id = 0;
S390_lowcore.subchannel_nr = 0;
/* Store status at absolute zero */
store_status();
/* Call function before reset */
if (fn_pre)
fn_pre();
do_reset_calls();
/* Call function after reset */
if (fn_post)
fn_post(data);
}

104
arch/s390/kernel/machine_kexec.c
View File

@ -34,40 +34,6 @@ extern const unsigned long long relocate_kernel_len;
#ifdef CONFIG_CRASH_DUMP
/*
* Initialize CPU ELF notes
*/
static void setup_regs(void)
{
struct save_area *sa, *sa_0;
unsigned long prefix;
int cpu, this_cpu;
/* setup_regs is called with the prefix register = 0 */
sa_0 = (struct save_area *) __LC_FPREGS_SAVE_AREA;
/* Get status of this CPU out of absolute zero */
prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
sa = (struct save_area *)(prefix + __LC_FPREGS_SAVE_AREA);
memcpy(sa, sa_0, sizeof(struct save_area));
if (MACHINE_HAS_VX) {
struct _lowcore *lc = (struct _lowcore *) prefix;
save_vx_regs_safe((void *) lc->vector_save_area_addr);
}
/* Get status of the other CPUs */
this_cpu = smp_find_processor_id(stap());
for_each_online_cpu(cpu) {
if (cpu == this_cpu)
continue;
if (smp_store_status(cpu))
continue;
prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
sa = (struct save_area *)(prefix + __LC_FPREGS_SAVE_AREA);
memcpy(sa, sa_0, sizeof(struct save_area));
}
}
/*
* PM notifier callback for kdump
*/
@ -99,14 +65,66 @@ static int __init machine_kdump_pm_init(void)
arch_initcall(machine_kdump_pm_init);
/*
* Start kdump: We expect here that a store status has been done on our CPU
* Reset the system, copy boot CPU registers to absolute zero,
* and jump to the kdump image
*/
static void __do_machine_kdump(void *image)
{
int (*start_kdump)(int) = (void *)((struct kimage *) image)->start;
int (*start_kdump)(int);
unsigned long prefix;
/* store_status() saved the prefix register to lowcore */
prefix = (unsigned long) S390_lowcore.prefixreg_save_area;
/* Now do the reset */
s390_reset_system();
/*
* Copy dump CPU store status info to absolute zero.
* This need to be done *after* s390_reset_system set the
* prefix register of this CPU to zero
*/
memcpy((void *) __LC_FPREGS_SAVE_AREA,
(void *)(prefix + __LC_FPREGS_SAVE_AREA), 512);
__load_psw_mask(PSW_MASK_BASE | PSW_DEFAULT_KEY | PSW_MASK_EA | PSW_MASK_BA);
start_kdump = (void *)((struct kimage *) image)->start;
start_kdump(1);
/* Die if start_kdump returns */
disabled_wait((unsigned long) __builtin_return_address(0));
}
/*
* Start kdump: create a LGR log entry, store status of all CPUs and
* branch to __do_machine_kdump.
*/
static noinline void __machine_kdump(void *image)
{
int this_cpu, cpu;
lgr_info_log();
/* Get status of the other CPUs */
this_cpu = smp_find_processor_id(stap());
for_each_online_cpu(cpu) {
if (cpu == this_cpu)
continue;
if (smp_store_status(cpu))
continue;
}
/* Store status of the boot CPU */
if (MACHINE_HAS_VX)
save_vx_regs((void *) &S390_lowcore.vector_save_area);
/*
* To create a good backchain for this CPU in the dump store_status
* is passed the address of a function. The address is saved into
* the PSW save area of the boot CPU and the function is invoked as
* a tail call of store_status. The backchain in the dump will look
* like this:
* restart_int_handler -> __machine_kexec -> __do_machine_kdump
* The call to store_status() will not return.
*/
store_status(__do_machine_kdump, image);
}
#endif
@ -229,10 +247,14 @@ static void __do_machine_kexec(void *data)
relocate_kernel_t data_mover;
struct kimage *image = data;
s390_reset_system();
data_mover = (relocate_kernel_t) page_to_phys(image->control_code_page);
/* Call the moving routine */
(*data_mover)(&image->head, image->start);
/* Die if kexec returns */
disabled_wait((unsigned long) __builtin_return_address(0));
}
/*
@ -245,14 +267,10 @@ static void __machine_kexec(void *data)
tracing_off();
debug_locks_off();
#ifdef CONFIG_CRASH_DUMP
if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH) {
lgr_info_log();
s390_reset_system(setup_regs, __do_machine_kdump, data);
} else
if (((struct kimage *) data)->type == KEXEC_TYPE_CRASH)
__machine_kdump(data);
#endif
s390_reset_system(NULL, __do_machine_kexec, data);
disabled_wait((unsigned long) __builtin_return_address(0));
__do_machine_kexec(data);
}
/*

37
arch/s390/kernel/reipl.S
View File

@ -9,12 +9,11 @@
#include <asm/sigp.h>
#
# store_status
# Issue "store status" for the current CPU to its prefix page
# and call passed function afterwards
#
# Prerequisites to run this function:
# - Prefix register is set to zero
# - Original prefix register is stored in "dump_prefix_page"
# - Lowcore protection is off
# r2 = Function to be called after store status
# r3 = Parameter for function
#
ENTRY(store_status)
/* Save register one and load save area base */
@ -53,23 +52,23 @@ ENTRY(store_status)
/* CPU timer */
lghi %r1,__LC_CPU_TIMER_SAVE_AREA
stpt 0(%r1)
/* Saved prefix register */
/* Store prefix register */
lghi %r1,__LC_PREFIX_SAVE_AREA
larl %r2,dump_prefix_page
mvc 0(4,%r1),0(%r2)
stpx 0(%r1)
/* Clock comparator - seven bytes */
lghi %r1,__LC_CLOCK_COMP_SAVE_AREA
larl %r2,.Lclkcmp
stckc 0(%r2)
mvc 1(7,%r1),1(%r2)
larl %r4,.Lclkcmp
stckc 0(%r4)
mvc 1(7,%r1),1(%r4)
/* Program status word */
lghi %r1,__LC_PSW_SAVE_AREA
epsw %r2,%r3
st %r2,0(%r1)
st %r3,4(%r1)
larl %r2,store_status
epsw %r4,%r5
st %r4,0(%r1)
st %r5,4(%r1)
stg %r2,8(%r1)
br %r14
lgr %r1,%r2
lgr %r2,%r3
br %r1
.section .bss
.align 8
@ -84,9 +83,11 @@ ENTRY(store_status)
ENTRY(do_reipl_asm)
basr %r13,0
.Lpg0: lpswe .Lnewpsw-.Lpg0(%r13)
.Lpg1: brasl %r14,store_status
.Lpg1: lgr %r3,%r2
larl %r2,.Lstatus
brasl %r14,store_status
lctlg %c6,%c6,.Lall-.Lpg0(%r13)
.Lstatus: lctlg %c6,%c6,.Lall-.Lpg0(%r13)
lgr %r1,%r2
mvc __LC_PGM_NEW_PSW(16),.Lpcnew-.Lpg0(%r13)
stsch .Lschib-.Lpg0(%r13)

2
arch/s390/kernel/setup.c
View File

@ -865,11 +865,13 @@ void __init setup_arch(char **cmdline_p)
check_initrd();
reserve_crashkernel();
#ifdef CONFIG_CRASH_DUMP
/*
* Be aware that smp_save_dump_cpus() triggers a system reset.
* Therefore CPU and device initialization should be done afterwards.
*/
smp_save_dump_cpus();
#endif
setup_resources();
setup_vmcoreinfo();

112
arch/s390/kernel/smp.c
View File

@ -80,6 +80,10 @@ EXPORT_SYMBOL(smp_cpu_mt_shift);
unsigned int smp_cpu_mtid;
EXPORT_SYMBOL(smp_cpu_mtid);
#ifdef CONFIG_CRASH_DUMP
__vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
#endif
static unsigned int smp_max_threads __initdata = -1U;
static int __init early_nosmt(char *s)
@ -105,8 +109,7 @@ DEFINE_MUTEX(smp_cpu_state_mutex);
/*
* Signal processor helper functions.
*/
static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm,
u32 *status)
static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
{
int cc;
@ -538,53 +541,24 @@ EXPORT_SYMBOL(smp_ctl_clear_bit);
#ifdef CONFIG_CRASH_DUMP
static void __init __smp_store_cpu_state(struct save_area_ext *sa_ext,
u16 address, int is_boot_cpu)
{
void *lc = (void *)(unsigned long) store_prefix();
unsigned long vx_sa;
if (is_boot_cpu) {
/* Copy the registers of the boot CPU. */
copy_oldmem_kernel(&sa_ext->sa, (void *) __LC_FPREGS_SAVE_AREA,
sizeof(sa_ext->sa));
if (MACHINE_HAS_VX)
save_vx_regs_safe(sa_ext->vx_regs);
return;
}
/* Get the registers of a non-boot cpu. */
__pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
memcpy_real(&sa_ext->sa, lc + __LC_FPREGS_SAVE_AREA, sizeof(sa_ext->sa));
if (!MACHINE_HAS_VX)
return;
/* Get the VX registers */
vx_sa = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
if (!vx_sa)
panic("could not allocate memory for VX save area\n");
__pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
memblock_free(vx_sa, PAGE_SIZE);
}
int smp_store_status(int cpu)
{
unsigned long vx_sa;
struct pcpu *pcpu;
struct pcpu *pcpu = pcpu_devices + cpu;
unsigned long pa;
pcpu = pcpu_devices + cpu;
if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
pa = __pa(&pcpu->lowcore->floating_pt_save_area);
if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
return -EIO;
if (!MACHINE_HAS_VX)
return 0;
vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
vx_sa, NULL);
pa = __pa(pcpu->lowcore->vector_save_area_addr);
if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
return -EIO;
return 0;
}
#endif /* CONFIG_CRASH_DUMP */
/*
* Collect CPU state of the previous, crashed system.
* There are four cases:
@ -593,7 +567,7 @@ int smp_store_status(int cpu)
* The state for all CPUs except the boot CPU needs to be collected
* with sigp stop-and-store-status. The boot CPU state is located in
* the absolute lowcore of the memory stored in the HSA. The zcore code
* will allocate the save area and copy the boot CPU state from the HSA.
* will copy the boot CPU state from the HSA.
* 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
* condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
* The state for all CPUs except the boot CPU needs to be collected
@ -611,21 +585,49 @@ int smp_store_status(int cpu)
* This case does not exist for s390 anymore, setup_arch explicitly
* deactivates the elfcorehdr= kernel parameter
*/
static __init void smp_save_cpu_vxrs(struct save_area_ext *sa_ext, u16 addr,
bool is_boot_cpu, unsigned long page)
{
__vector128 *vxrs = (__vector128 *) page;
if (is_boot_cpu)
vxrs = boot_cpu_vector_save_area;
else
__pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
memcpy(&sa_ext->vx_regs, vxrs, sizeof(sa_ext->vx_regs));
}
static __init void smp_save_cpu_regs(struct save_area_ext *sa_ext, u16 addr,
bool is_boot_cpu, unsigned long page)
{
void *regs = (void *) page;
if (is_boot_cpu)
copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
else
__pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
memcpy(&sa_ext->sa, regs, sizeof(sa_ext->sa));
}
void __init smp_save_dump_cpus(void)
{
#ifdef CONFIG_CRASH_DUMP
int addr, cpu, boot_cpu_addr, max_cpu_addr;
struct save_area_ext *sa_ext;
unsigned long page;
bool is_boot_cpu;
if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
/* No previous system present, normal boot. */
return;
/* Allocate a page as dumping area for the store status sigps */
page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
if (!page)
panic("could not allocate memory for save area\n");
/* Set multi-threading state to the previous system. */
pcpu_set_smt(sclp.mtid_prev);
max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
SIGP_CC_NOT_OPERATIONAL)
continue;
cpu += 1;
@ -634,7 +636,7 @@ void __init smp_save_dump_cpus(void)
dump_save_areas.count = cpu;
boot_cpu_addr = stap();
for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
SIGP_CC_NOT_OPERATIONAL)
continue;
sa_ext = (void *) memblock_alloc(sizeof(*sa_ext), 8);
@ -643,16 +645,24 @@ void __init smp_save_dump_cpus(void)
panic("could not allocate memory for save area\n");
is_boot_cpu = (addr == boot_cpu_addr);
cpu += 1;
if (is_boot_cpu && !OLDMEM_BASE)
/* Skip boot CPU for standard zfcp dump. */
continue;
/* Get state for this CPU. */
__smp_store_cpu_state(sa_ext, addr, is_boot_cpu);
if (MACHINE_HAS_VX)
/* Get the vector registers */
smp_save_cpu_vxrs(sa_ext, addr, is_boot_cpu, page);
/*
* For a zfcp dump OLDMEM_BASE == NULL and the registers
* of the boot CPU are stored in the HSA. To retrieve
* these registers an SCLP request is required which is
* done by drivers/s390/char/zcore.c:init_cpu_info()
*/
if (!is_boot_cpu || OLDMEM_BASE)
/* Get the CPU registers */
smp_save_cpu_regs(sa_ext, addr, is_boot_cpu, page);
}
memblock_free(page, PAGE_SIZE);
diag308_reset();
pcpu_set_smt(0);
#endif /* CONFIG_CRASH_DUMP */
}
#endif /* CONFIG_CRASH_DUMP */
void smp_cpu_set_polarization(int cpu, int val)
{
@ -676,7 +686,7 @@ static struct sclp_core_info *smp_get_core_info(void)
for (address = 0;
address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
address += (1U << smp_cpu_mt_shift)) {
if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
SIGP_CC_NOT_OPERATIONAL)
continue;
info->core[info->configured].core_id =

2
drivers/s390/char/zcore.c
View File

@ -129,8 +129,6 @@ static int __init init_cpu_info(void)
TRACE("could not copy from HSA\n");
return -EIO;
}
if (MACHINE_HAS_VX)
save_vx_regs_safe(sa_ext->vx_regs);
return 0;
}

2
drivers/s390/cio/cio.c
View File

@ -917,7 +917,7 @@ void reipl_ccw_dev(struct ccw_dev_id *devid)
{
struct subchannel_id uninitialized_var(schid);
s390_reset_system(NULL, NULL, NULL);
s390_reset_system();
if (reipl_find_schid(devid, &schid) != 0)
panic("IPL Device not found\n");
do_reipl_asm(*((__u32*)&schid));