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s390/dump: rework CPU register dump code

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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
Download Patch File Download Diff File Expand all files Collapse all files

112
arch/s390/kernel/smp.c
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@@ -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 =