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s390/sclp: do not use static sccbs
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The sccbs for init/read/sdias/early have to be located below 2 GB, and
they are currently defined as a static buffer.

With a relocatable kernel that could reside at any place in memory, this
will no longer guarantee the location below 2 GB, so use a dynamic
GFP_DMA allocation instead.

The sclp_early_sccb buffer needs special handling, as it can be used
very early, and by both the decompressor and also the decompressed
kernel. Therefore, a fixed 4 KB buffer is introduced at 0x11000, the
former PARMAREA_END. The new PARMAREA_END is now 0x12000, and it is
renamed to HEAD_END, as it is rather the end of head.S and not the end
of the parmarea.

Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: Philipp Rudo <prudo@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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Gerald Schaefer authored and Martin Schwidefsky committed Apr 29, 2019
1 parent fd3d274 commit 087c4d7
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Showing 9 changed files with 71 additions and 57 deletions.
5 changes: 4 additions & 1 deletion arch/s390/boot/head.S
Original file line number Diff line number Diff line change
Expand Up @@ -336,4 +336,7 @@ ENTRY(startup_kdump)
.byte "root=/dev/ram0 ro"
.byte 0

.org 0x11000
.org EARLY_SCCB_OFFSET
.fill 4096

.org HEAD_END
5 changes: 4 additions & 1 deletion arch/s390/include/asm/setup.h
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,10 @@
#define EP_OFFSET 0x10008
#define EP_STRING "S390EP"
#define PARMAREA 0x10400
#define PARMAREA_END 0x11000
#define EARLY_SCCB_OFFSET 0x11000
#define HEAD_END 0x12000

#define EARLY_SCCB_SIZE PAGE_SIZE

/*
* Machine features detected in early.c
Expand Down
4 changes: 1 addition & 3 deletions arch/s390/kernel/machine_kexec_file.c
Original file line number Diff line number Diff line change
Expand Up @@ -337,10 +337,8 @@ int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,
* load memory in head.S will be accessed, e.g. to register the next
* command line. If the next kernel were smaller the current kernel
* will panic at load.
*
* 0x11000 = sizeof(head.S)
*/
if (buf_len < 0x11000)
if (buf_len < HEAD_END)
return -ENOEXEC;

return kexec_image_probe_default(image, buf, buf_len);
Expand Down
2 changes: 1 addition & 1 deletion arch/s390/kernel/setup.c
Original file line number Diff line number Diff line change
Expand Up @@ -829,7 +829,7 @@ static void __init reserve_kernel(void)
{
unsigned long start_pfn = PFN_UP(__pa(_end));

memblock_reserve(0, PARMAREA_END);
memblock_reserve(0, HEAD_END);
memblock_reserve((unsigned long)_stext, PFN_PHYS(start_pfn)
- (unsigned long)_stext);
}
Expand Down
14 changes: 9 additions & 5 deletions drivers/s390/char/sclp.c
Original file line number Diff line number Diff line change
Expand Up @@ -45,8 +45,8 @@ static struct list_head sclp_req_queue;
/* Data for read and and init requests. */
static struct sclp_req sclp_read_req;
static struct sclp_req sclp_init_req;
static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE)));
static void *sclp_read_sccb;
static struct init_sccb *sclp_init_sccb;

/* Suspend request */
static DECLARE_COMPLETION(sclp_request_queue_flushed);
Expand Down Expand Up @@ -753,9 +753,8 @@ EXPORT_SYMBOL(sclp_remove_processed);
static inline void
__sclp_make_init_req(sccb_mask_t receive_mask, sccb_mask_t send_mask)
{
struct init_sccb *sccb;
struct init_sccb *sccb = sclp_init_sccb;

sccb = (struct init_sccb *) sclp_init_sccb;
clear_page(sccb);
memset(&sclp_init_req, 0, sizeof(struct sclp_req));
sclp_init_req.command = SCLP_CMDW_WRITE_EVENT_MASK;
Expand All @@ -782,7 +781,7 @@ static int
sclp_init_mask(int calculate)
{
unsigned long flags;
struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
struct init_sccb *sccb = sclp_init_sccb;
sccb_mask_t receive_mask;
sccb_mask_t send_mask;
int retry;
Expand Down Expand Up @@ -1175,6 +1174,9 @@ sclp_init(void)
if (sclp_init_state != sclp_init_state_uninitialized)
goto fail_unlock;
sclp_init_state = sclp_init_state_initializing;
sclp_read_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
sclp_init_sccb = (void *) __get_free_page(GFP_ATOMIC | GFP_DMA);
BUG_ON(!sclp_read_sccb || !sclp_init_sccb);
/* Set up variables */
INIT_LIST_HEAD(&sclp_req_queue);
INIT_LIST_HEAD(&sclp_reg_list);
Expand Down Expand Up @@ -1207,6 +1209,8 @@ sclp_init(void)
unregister_reboot_notifier(&sclp_reboot_notifier);
fail_init_state_uninitialized:
sclp_init_state = sclp_init_state_uninitialized;
free_page((unsigned long) sclp_read_sccb);
free_page((unsigned long) sclp_init_sccb);
fail_unlock:
spin_unlock_irqrestore(&sclp_lock, flags);
return rc;
Expand Down
2 changes: 1 addition & 1 deletion drivers/s390/char/sclp.h
Original file line number Diff line number Diff line change
Expand Up @@ -321,7 +321,7 @@ extern int sclp_console_drop;
extern unsigned long sclp_console_full;
extern bool sclp_mask_compat_mode;

extern char sclp_early_sccb[PAGE_SIZE];
extern char *sclp_early_sccb;

void sclp_early_wait_irq(void);
int sclp_early_cmd(sclp_cmdw_t cmd, void *sccb);
Expand Down
2 changes: 1 addition & 1 deletion drivers/s390/char/sclp_early.c
Original file line number Diff line number Diff line change
Expand Up @@ -147,7 +147,7 @@ static void __init sclp_early_console_detect(struct init_sccb *sccb)

void __init sclp_early_detect(void)
{
void *sccb = &sclp_early_sccb;
void *sccb = sclp_early_sccb;

sclp_early_facilities_detect(sccb);
sclp_early_init_core_info(sccb);
Expand Down
20 changes: 10 additions & 10 deletions drivers/s390/char/sclp_early_core.c
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@

static struct read_info_sccb __bootdata(sclp_info_sccb);
static int __bootdata(sclp_info_sccb_valid);
char sclp_early_sccb[PAGE_SIZE] __aligned(PAGE_SIZE) __section(.data);
char *sclp_early_sccb = (char *) EARLY_SCCB_OFFSET;
int sclp_init_state __section(.data) = sclp_init_state_uninitialized;
/*
* Used to keep track of the size of the event masks. Qemu until version 2.11
Expand Down Expand Up @@ -91,8 +91,8 @@ static void sclp_early_print_lm(const char *str, unsigned int len)
struct mto *mto;
struct go *go;

sccb = (struct write_sccb *) &sclp_early_sccb;
end = (unsigned char *) sccb + sizeof(sclp_early_sccb) - 1;
sccb = (struct write_sccb *) sclp_early_sccb;
end = (unsigned char *) sccb + EARLY_SCCB_SIZE - 1;
memset(sccb, 0, sizeof(*sccb));
ptr = (unsigned char *) &sccb->msg.mdb.mto;
offset = 0;
Expand Down Expand Up @@ -139,9 +139,9 @@ static void sclp_early_print_vt220(const char *str, unsigned int len)
{
struct vt220_sccb *sccb;

sccb = (struct vt220_sccb *) &sclp_early_sccb;
if (sizeof(*sccb) + len >= sizeof(sclp_early_sccb))
len = sizeof(sclp_early_sccb) - sizeof(*sccb);
sccb = (struct vt220_sccb *) sclp_early_sccb;
if (sizeof(*sccb) + len >= EARLY_SCCB_SIZE)
len = EARLY_SCCB_SIZE - sizeof(*sccb);
memset(sccb, 0, sizeof(*sccb));
memcpy(&sccb->msg.data, str, len);
sccb->header.length = sizeof(*sccb) + len;
Expand Down Expand Up @@ -199,7 +199,7 @@ static int sclp_early_setup(int disable, int *have_linemode, int *have_vt220)
BUILD_BUG_ON(sizeof(struct init_sccb) > PAGE_SIZE);

*have_linemode = *have_vt220 = 0;
sccb = (struct init_sccb *) &sclp_early_sccb;
sccb = (struct init_sccb *) sclp_early_sccb;
receive_mask = disable ? 0 : EVTYP_OPCMD_MASK;
send_mask = disable ? 0 : EVTYP_VT220MSG_MASK | EVTYP_MSG_MASK;
rc = sclp_early_set_event_mask(sccb, receive_mask, send_mask);
Expand Down Expand Up @@ -304,7 +304,7 @@ int __init sclp_early_get_hsa_size(unsigned long *hsa_size)
void __weak __init add_mem_detect_block(u64 start, u64 end) {}
int __init sclp_early_read_storage_info(void)
{
struct read_storage_sccb *sccb = (struct read_storage_sccb *)&sclp_early_sccb;
struct read_storage_sccb *sccb = (struct read_storage_sccb *)sclp_early_sccb;
int rc, id, max_id = 0;
unsigned long rn, rzm;
sclp_cmdw_t command;
Expand All @@ -320,8 +320,8 @@ int __init sclp_early_read_storage_info(void)
rzm <<= 20;

for (id = 0; id <= max_id; id++) {
memset(sclp_early_sccb, 0, sizeof(sclp_early_sccb));
sccb->header.length = sizeof(sclp_early_sccb);
memset(sclp_early_sccb, 0, EARLY_SCCB_SIZE);
sccb->header.length = EARLY_SCCB_SIZE;
command = SCLP_CMDW_READ_STORAGE_INFO | (id << 8);
rc = sclp_early_cmd(command, sccb);
if (rc)
Expand Down
74 changes: 40 additions & 34 deletions drivers/s390/char/sclp_sdias.c
Original file line number Diff line number Diff line change
Expand Up @@ -29,7 +29,7 @@ static struct sclp_register sclp_sdias_register = {
.send_mask = EVTYP_SDIAS_MASK,
};

static struct sdias_sccb sccb __attribute__((aligned(4096)));
static struct sdias_sccb *sclp_sdias_sccb;
static struct sdias_evbuf sdias_evbuf;

static DECLARE_COMPLETION(evbuf_accepted);
Expand Down Expand Up @@ -58,6 +58,7 @@ static void sdias_callback(struct sclp_req *request, void *data)

static int sdias_sclp_send(struct sclp_req *req)
{
struct sdias_sccb *sccb = sclp_sdias_sccb;
int retries;
int rc;

Expand All @@ -78,16 +79,16 @@ static int sdias_sclp_send(struct sclp_req *req)
continue;
}
/* if not accepted, retry */
if (!(sccb.evbuf.hdr.flags & 0x80)) {
if (!(sccb->evbuf.hdr.flags & 0x80)) {
TRACE("sclp request failed: flags=%x\n",
sccb.evbuf.hdr.flags);
sccb->evbuf.hdr.flags);
continue;
}
/*
* for the sync interface the response is in the initial sccb
*/
if (!sclp_sdias_register.receiver_fn) {
memcpy(&sdias_evbuf, &sccb.evbuf, sizeof(sdias_evbuf));
memcpy(&sdias_evbuf, &sccb->evbuf, sizeof(sdias_evbuf));
TRACE("sync request done\n");
return 0;
}
Expand All @@ -104,23 +105,24 @@ static int sdias_sclp_send(struct sclp_req *req)
*/
int sclp_sdias_blk_count(void)
{
struct sdias_sccb *sccb = sclp_sdias_sccb;
struct sclp_req request;
int rc;

mutex_lock(&sdias_mutex);

memset(&sccb, 0, sizeof(sccb));
memset(sccb, 0, sizeof(*sccb));
memset(&request, 0, sizeof(request));

sccb.hdr.length = sizeof(sccb);
sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
sccb.evbuf.hdr.type = EVTYP_SDIAS;
sccb.evbuf.event_qual = SDIAS_EQ_SIZE;
sccb.evbuf.data_id = SDIAS_DI_FCP_DUMP;
sccb.evbuf.event_id = 4712;
sccb.evbuf.dbs = 1;
sccb->hdr.length = sizeof(*sccb);
sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
sccb->evbuf.hdr.type = EVTYP_SDIAS;
sccb->evbuf.event_qual = SDIAS_EQ_SIZE;
sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
sccb->evbuf.event_id = 4712;
sccb->evbuf.dbs = 1;

request.sccb = &sccb;
request.sccb = sccb;
request.command = SCLP_CMDW_WRITE_EVENT_DATA;
request.status = SCLP_REQ_FILLED;
request.callback = sdias_callback;
Expand All @@ -130,8 +132,8 @@ int sclp_sdias_blk_count(void)
pr_err("sclp_send failed for get_nr_blocks\n");
goto out;
}
if (sccb.hdr.response_code != 0x0020) {
TRACE("send failed: %x\n", sccb.hdr.response_code);
if (sccb->hdr.response_code != 0x0020) {
TRACE("send failed: %x\n", sccb->hdr.response_code);
rc = -EIO;
goto out;
}
Expand Down Expand Up @@ -163,30 +165,31 @@ int sclp_sdias_blk_count(void)
*/
int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
{
struct sdias_sccb *sccb = sclp_sdias_sccb;
struct sclp_req request;
int rc;

mutex_lock(&sdias_mutex);

memset(&sccb, 0, sizeof(sccb));
memset(sccb, 0, sizeof(*sccb));
memset(&request, 0, sizeof(request));

sccb.hdr.length = sizeof(sccb);
sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
sccb.evbuf.hdr.type = EVTYP_SDIAS;
sccb.evbuf.hdr.flags = 0;
sccb.evbuf.event_qual = SDIAS_EQ_STORE_DATA;
sccb.evbuf.data_id = SDIAS_DI_FCP_DUMP;
sccb.evbuf.event_id = 4712;
sccb.evbuf.asa_size = SDIAS_ASA_SIZE_64;
sccb.evbuf.event_status = 0;
sccb.evbuf.blk_cnt = nr_blks;
sccb.evbuf.asa = (unsigned long)dest;
sccb.evbuf.fbn = start_blk;
sccb.evbuf.lbn = 0;
sccb.evbuf.dbs = 1;

request.sccb = &sccb;
sccb->hdr.length = sizeof(*sccb);
sccb->evbuf.hdr.length = sizeof(struct sdias_evbuf);
sccb->evbuf.hdr.type = EVTYP_SDIAS;
sccb->evbuf.hdr.flags = 0;
sccb->evbuf.event_qual = SDIAS_EQ_STORE_DATA;
sccb->evbuf.data_id = SDIAS_DI_FCP_DUMP;
sccb->evbuf.event_id = 4712;
sccb->evbuf.asa_size = SDIAS_ASA_SIZE_64;
sccb->evbuf.event_status = 0;
sccb->evbuf.blk_cnt = nr_blks;
sccb->evbuf.asa = (unsigned long)dest;
sccb->evbuf.fbn = start_blk;
sccb->evbuf.lbn = 0;
sccb->evbuf.dbs = 1;

request.sccb = sccb;
request.command = SCLP_CMDW_WRITE_EVENT_DATA;
request.status = SCLP_REQ_FILLED;
request.callback = sdias_callback;
Expand All @@ -196,8 +199,8 @@ int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
pr_err("sclp_send failed: %x\n", rc);
goto out;
}
if (sccb.hdr.response_code != 0x0020) {
TRACE("copy failed: %x\n", sccb.hdr.response_code);
if (sccb->hdr.response_code != 0x0020) {
TRACE("copy failed: %x\n", sccb->hdr.response_code);
rc = -EIO;
goto out;
}
Expand Down Expand Up @@ -256,6 +259,8 @@ int __init sclp_sdias_init(void)
{
if (ipl_info.type != IPL_TYPE_FCP_DUMP)
return 0;
sclp_sdias_sccb = (void *) __get_free_page(GFP_KERNEL | GFP_DMA);
BUG_ON(!sclp_sdias_sccb);
sdias_dbf = debug_register("dump_sdias", 4, 1, 4 * sizeof(long));
debug_register_view(sdias_dbf, &debug_sprintf_view);
debug_set_level(sdias_dbf, 6);
Expand All @@ -264,6 +269,7 @@ int __init sclp_sdias_init(void)
if (sclp_sdias_init_async() == 0)
goto out;
TRACE("init failed\n");
free_page((unsigned long) sclp_sdias_sccb);
return -ENODEV;
out:
TRACE("init done\n");
Expand Down

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