Commit 087c4d74 authored by Gerald Schaefer's avatar Gerald Schaefer Committed by Martin Schwidefsky
Browse files

s390/sclp: do not use static sccbs 



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: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: default avatarPhilipp Rudo <prudo@linux.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent fd3d2742

arch/s390/boot/head.S

+4 −1
Original line number Diff line number Diff line
@@ -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

arch/s390/include/asm/setup.h

+4 −1
Original line number Diff line number Diff line
@@ -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

arch/s390/kernel/machine_kexec_file.c

+1 −3
Original line number Diff line number Diff line
@@ -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);

arch/s390/kernel/setup.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

}

drivers/s390/char/sclp.c

+9 −5
Original line number Diff line number Diff line
@@ -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);
@@ -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;
@@ -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;
@@ -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);
@@ -1207,6 +1209,8 @@ fail_unregister_reboot_notifier: 
	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;

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