arch/s390/kernel/ipl_vmparm.c

Source file repositories/reference/linux-study-clean/arch/s390/kernel/ipl_vmparm.c

File Facts

System
Linux kernel
Corpus path
arch/s390/kernel/ipl_vmparm.c
Extension
.c
Size
968 bytes
Lines
39
Domain
Architecture Layer
Bucket
arch/s390
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0
#include <linux/minmax.h>
#include <linux/string.h>
#include <asm/ebcdic.h>
#include <asm/ipl.h>

/* VM IPL PARM routines */
size_t ipl_block_get_ascii_vmparm(char *dest, size_t size,
				  const struct ipl_parameter_block *ipb)
{
	int i;
	size_t len;
	char has_lowercase = 0;

	len = 0;
	if ((ipb->ccw.vm_flags & IPL_PB0_CCW_VM_FLAG_VP) &&
	    (ipb->ccw.vm_parm_len > 0)) {

		len = min_t(size_t, size - 1, ipb->ccw.vm_parm_len);
		memcpy(dest, ipb->ccw.vm_parm, len);
		/* If at least one character is lowercase, we assume mixed
		 * case; otherwise we convert everything to lowercase.
		 */
		for (i = 0; i < len; i++)
			if ((dest[i] > 0x80 && dest[i] < 0x8a) || /* a-i */
			    (dest[i] > 0x90 && dest[i] < 0x9a) || /* j-r */
			    (dest[i] > 0xa1 && dest[i] < 0xaa)) { /* s-z */
				has_lowercase = 1;
				break;
			}
		if (!has_lowercase)
			EBC_TOLOWER(dest, len);
		EBCASC(dest, len);
	}
	dest[len] = 0;

	return len;
}

Annotation

Implementation Notes