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s390/dump: cleanup CPU save area handling
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Introduce save_area_alloc(), save_area_boot_cpu(), save_area_add_regs()
and save_area_add_vxrs to deal with storing the CPU state in case of a
system dump. Remove struct save_area and save_area_ext, and create a new
struct save_area as a local definition to arch/s390/kernel/crash_dump.c.
Copy each individual field from the hardware status area to the save area,
storing the minimum of required data.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Martin Schwidefsky committed Nov 27, 2015
1 parent 1a36a39 commit 1a2c584
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Showing 5 changed files with 145 additions and 198 deletions.
11 changes: 5 additions & 6 deletions arch/s390/include/asm/ipl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -88,12 +88,11 @@ struct ipl_parameter_block {
*/
extern u32 ipl_flags;

struct dump_save_areas {
struct save_area_ext **areas;
int count;
};

extern struct dump_save_areas dump_save_areas;
struct save_area;
struct save_area * __init save_area_alloc(bool is_boot_cpu);
struct save_area * __init save_area_boot_cpu(void);
void __init save_area_add_regs(struct save_area *, void *regs);
void __init save_area_add_vxrs(struct save_area *, __vector128 *vxrs);

extern void do_reipl(void);
extern void do_halt(void);
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21 changes: 0 additions & 21 deletions arch/s390/include/asm/lowcore.h
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Original file line number Diff line number Diff line change
Expand Up @@ -16,27 +16,6 @@
#define LC_ORDER 1
#define LC_PAGES 2

struct save_area {
u64 fp_regs[16];
u64 gp_regs[16];
u8 psw[16];
u8 pad1[8];
u32 pref_reg;
u32 fp_ctrl_reg;
u8 pad2[4];
u32 tod_reg;
u64 timer;
u64 clk_cmp;
u8 pad3[8];
u32 acc_regs[16];
u64 ctrl_regs[16];
} __packed;

struct save_area_ext {
struct save_area sa;
__vector128 vx_regs[32];
};

struct _lowcore {
__u8 pad_0x0000[0x0014-0x0000]; /* 0x0000 */
__u32 ipl_parmblock_ptr; /* 0x0014 */
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263 changes: 121 additions & 142 deletions arch/s390/kernel/crash_dump.c
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@
#include <linux/slab.h>
#include <linux/bootmem.h>
#include <linux/elf.h>
#include <asm/asm-offsets.h>
#include <linux/memblock.h>
#include <asm/os_info.h>
#include <asm/elf.h>
Expand All @@ -32,7 +33,84 @@ static struct memblock_type oldmem_type = {
.regions = &oldmem_region,
};

struct dump_save_areas dump_save_areas;
struct save_area {
struct list_head list;
u64 psw[2];
u64 ctrs[16];
u64 gprs[16];
u32 acrs[16];
u64 fprs[16];
u32 fpc;
u32 prefix;
u64 todpreg;
u64 timer;
u64 todcmp;
u64 vxrs_low[16];
__vector128 vxrs_high[16];
};

static LIST_HEAD(dump_save_areas);

/*
* Allocate a save area
*/
struct save_area * __init save_area_alloc(bool is_boot_cpu)
{
struct save_area *sa;

sa = (void *) memblock_alloc(sizeof(*sa), 8);
if (!sa)
return NULL;
if (is_boot_cpu)
list_add(&sa->list, &dump_save_areas);
else
list_add_tail(&sa->list, &dump_save_areas);
return sa;
}

/*
* Return the address of the save area for the boot CPU
*/
struct save_area * __init save_area_boot_cpu(void)
{
if (list_empty(&dump_save_areas))
return NULL;
return list_first_entry(&dump_save_areas, struct save_area, list);
}

/*
* Copy CPU registers into the save area
*/
void __init save_area_add_regs(struct save_area *sa, void *regs)
{
struct _lowcore *lc;

lc = (struct _lowcore *)(regs - __LC_FPREGS_SAVE_AREA);
memcpy(&sa->psw, &lc->psw_save_area, sizeof(sa->psw));
memcpy(&sa->ctrs, &lc->cregs_save_area, sizeof(sa->ctrs));
memcpy(&sa->gprs, &lc->gpregs_save_area, sizeof(sa->gprs));
memcpy(&sa->acrs, &lc->access_regs_save_area, sizeof(sa->acrs));
memcpy(&sa->fprs, &lc->floating_pt_save_area, sizeof(sa->fprs));
memcpy(&sa->fpc, &lc->fpt_creg_save_area, sizeof(sa->fpc));
memcpy(&sa->prefix, &lc->prefixreg_save_area, sizeof(sa->prefix));
memcpy(&sa->todpreg, &lc->tod_progreg_save_area, sizeof(sa->todpreg));
memcpy(&sa->timer, &lc->cpu_timer_save_area, sizeof(sa->timer));
memcpy(&sa->todcmp, &lc->clock_comp_save_area, sizeof(sa->todcmp));
}

/*
* Copy vector registers into the save area
*/
void __init save_area_add_vxrs(struct save_area *sa, __vector128 *vxrs)
{
int i;

/* Copy lower halves of vector registers 0-15 */
for (i = 0; i < 16; i++)
memcpy(&sa->vxrs_low[i], &vxrs[i].u[2], 8);
/* Copy vector registers 16-31 */
memcpy(sa->vxrs_high, vxrs + 16, 16 * sizeof(__vector128));
}

/*
* Return physical address for virtual address
Expand Down Expand Up @@ -232,8 +310,8 @@ static void *kzalloc_panic(int len)
/*
* Initialize ELF note
*/
static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
const char *name)
static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
const char *name)
{
Elf64_Nhdr *note;
u64 len;
Expand All @@ -253,137 +331,42 @@ static void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len,
return PTR_ADD(buf, len);
}

/*
* Initialize prstatus note
*/
static void *nt_prstatus(void *ptr, struct save_area *sa)
static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
{
struct elf_prstatus nt_prstatus;
static int cpu_nr = 1;

memset(&nt_prstatus, 0, sizeof(nt_prstatus));
memcpy(&nt_prstatus.pr_reg.gprs, sa->gp_regs, sizeof(sa->gp_regs));
memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
memcpy(&nt_prstatus.pr_reg.acrs, sa->acc_regs, sizeof(sa->acc_regs));
nt_prstatus.pr_pid = cpu_nr;
cpu_nr++;

return nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus),
"CORE");
return nt_init_name(buf, type, desc, d_len, KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize fpregset (floating point) note
* Fill ELF notes for one CPU with save area registers
*/
static void *nt_fpregset(void *ptr, struct save_area *sa)
static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
{
struct elf_prstatus nt_prstatus;
elf_fpregset_t nt_fpregset;

/* Prepare prstatus note */
memset(&nt_prstatus, 0, sizeof(nt_prstatus));
memcpy(&nt_prstatus.pr_reg.gprs, sa->gprs, sizeof(sa->gprs));
memcpy(&nt_prstatus.pr_reg.psw, sa->psw, sizeof(sa->psw));
memcpy(&nt_prstatus.pr_reg.acrs, sa->acrs, sizeof(sa->acrs));
nt_prstatus.pr_pid = cpu;
/* Prepare fpregset (floating point) note */
memset(&nt_fpregset, 0, sizeof(nt_fpregset));
memcpy(&nt_fpregset.fpc, &sa->fp_ctrl_reg, sizeof(sa->fp_ctrl_reg));
memcpy(&nt_fpregset.fprs, &sa->fp_regs, sizeof(sa->fp_regs));

return nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset),
"CORE");
}

/*
* Initialize timer note
*/
static void *nt_s390_timer(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer),
KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize TOD clock comparator note
*/
static void *nt_s390_tod_cmp(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TODCMP, &sa->clk_cmp,
sizeof(sa->clk_cmp), KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize TOD programmable register note
*/
static void *nt_s390_tod_preg(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_TODPREG, &sa->tod_reg,
sizeof(sa->tod_reg), KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize control register note
*/
static void *nt_s390_ctrs(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_CTRS, &sa->ctrl_regs,
sizeof(sa->ctrl_regs), KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize prefix register note
*/
static void *nt_s390_prefix(void *ptr, struct save_area *sa)
{
return nt_init(ptr, NT_S390_PREFIX, &sa->pref_reg,
sizeof(sa->pref_reg), KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize vxrs high note (full 128 bit VX registers 16-31)
*/
static void *nt_s390_vx_high(void *ptr, __vector128 *vx_regs)
{
return nt_init(ptr, NT_S390_VXRS_HIGH, &vx_regs[16],
16 * sizeof(__vector128), KEXEC_CORE_NOTE_NAME);
}

/*
* Initialize vxrs low note (lower halves of VX registers 0-15)
*/
static void *nt_s390_vx_low(void *ptr, __vector128 *vx_regs)
{
Elf64_Nhdr *note;
u64 len;
int i;

note = (Elf64_Nhdr *)ptr;
note->n_namesz = strlen(KEXEC_CORE_NOTE_NAME) + 1;
note->n_descsz = 16 * 8;
note->n_type = NT_S390_VXRS_LOW;
len = sizeof(Elf64_Nhdr);

memcpy(ptr + len, KEXEC_CORE_NOTE_NAME, note->n_namesz);
len = roundup(len + note->n_namesz, 4);

ptr += len;
/* Copy lower halves of SIMD registers 0-15 */
for (i = 0; i < 16; i++) {
memcpy(ptr, &vx_regs[i].u[2], 8);
ptr += 8;
}
return ptr;
}

/*
* Fill ELF notes for one CPU with save area registers
*/
static void *fill_cpu_elf_notes(void *ptr, struct save_area *sa,
__vector128 *vx_regs)
{
ptr = nt_prstatus(ptr, sa);
ptr = nt_fpregset(ptr, sa);
ptr = nt_s390_timer(ptr, sa);
ptr = nt_s390_tod_cmp(ptr, sa);
ptr = nt_s390_tod_preg(ptr, sa);
ptr = nt_s390_ctrs(ptr, sa);
ptr = nt_s390_prefix(ptr, sa);
if (MACHINE_HAS_VX && vx_regs) {
ptr = nt_s390_vx_low(ptr, vx_regs);
ptr = nt_s390_vx_high(ptr, vx_regs);
memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
/* Create ELF notes for the CPU */
ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
if (MACHINE_HAS_VX) {
ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
&sa->vxrs_high, sizeof(sa->vxrs_high));
ptr = nt_init(ptr, NT_S390_VXRS_LOW,
&sa->vxrs_low, sizeof(sa->vxrs_low));
}
return ptr;
}
Expand All @@ -398,8 +381,7 @@ static void *nt_prpsinfo(void *ptr)
memset(&prpsinfo, 0, sizeof(prpsinfo));
prpsinfo.pr_sname = 'R';
strcpy(prpsinfo.pr_fname, "vmlinux");
return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo),
KEXEC_CORE_NOTE_NAME);
return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
}

/*
Expand Down Expand Up @@ -441,7 +423,7 @@ static void *nt_vmcoreinfo(void *ptr)
vmcoreinfo = get_vmcoreinfo_old(&size);
if (!vmcoreinfo)
return ptr;
return nt_init(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
return nt_init_name(ptr, 0, vmcoreinfo, size, "VMCOREINFO");
}

/*
Expand Down Expand Up @@ -470,13 +452,12 @@ static void *ehdr_init(Elf64_Ehdr *ehdr, int mem_chunk_cnt)
*/
static int get_cpu_cnt(void)
{
int i, cpus = 0;
struct save_area *sa;
int cpus = 0;

for (i = 0; i < dump_save_areas.count; i++) {
if (dump_save_areas.areas[i]->sa.pref_reg == 0)
continue;
cpus++;
}
list_for_each_entry(sa, &dump_save_areas, list)
if (sa->prefix != 0)
cpus++;
return cpus;
}

Expand Down Expand Up @@ -521,18 +502,16 @@ static void loads_init(Elf64_Phdr *phdr, u64 loads_offset)
*/
static void *notes_init(Elf64_Phdr *phdr, void *ptr, u64 notes_offset)
{
struct save_area_ext *sa_ext;
struct save_area *sa;
void *ptr_start = ptr;
int i;
int cpu;

ptr = nt_prpsinfo(ptr);

for (i = 0; i < dump_save_areas.count; i++) {
sa_ext = dump_save_areas.areas[i];
if (sa_ext->sa.pref_reg == 0)
continue;
ptr = fill_cpu_elf_notes(ptr, &sa_ext->sa, sa_ext->vx_regs);
}
cpu = 1;
list_for_each_entry(sa, &dump_save_areas, list)
if (sa->prefix != 0)
ptr = fill_cpu_elf_notes(ptr, cpu++, sa);
ptr = nt_vmcoreinfo(ptr);
memset(phdr, 0, sizeof(*phdr));
phdr->p_type = PT_NOTE;
Expand Down
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