[PATCH v3 1/2] s390/ebcdic: Add character classes for the invariant subset of EBCDIC
From: Ilya Leoshkevich
Date: Fri Aug 28 2026 - 10:06:42 EST
Add _ctypes-like array for the invariant subset of EBCDIC, which
consists of characters that should have the same assignments on all
EBCDIC code pages that use the Latin alphabet [1].
[1] https://en.wikipedia.org/wiki/EBCDIC#Code_page_layout
Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
arch/s390/include/asm/ebcdic.h | 5 +++++
arch/s390/kernel/ebcdic.c | 40 +++++++++++++++++++++++++++++++++-
2 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/arch/s390/include/asm/ebcdic.h b/arch/s390/include/asm/ebcdic.h
index 7164cb6584355..9b7e3a58ca738 100644
--- a/arch/s390/include/asm/ebcdic.h
+++ b/arch/s390/include/asm/ebcdic.h
@@ -10,6 +10,7 @@
#ifndef _EBCDIC_H
#define _EBCDIC_H
+#include <linux/ctype.h>
#include <linux/types.h>
extern __u8 _ascebc_500[256]; /* ASCII -> EBCDIC 500 conversion table */
@@ -18,6 +19,10 @@ extern __u8 _ascebc[256]; /* ASCII -> EBCDIC conversion table */
extern __u8 _ebcasc[256]; /* EBCDIC -> ASCII conversion table */
extern __u8 _ebc_tolower[256]; /* EBCDIC -> lowercase */
extern __u8 _ebc_toupper[256]; /* EBCDIC -> uppercase */
+extern const __u8 _ebctype_inv[256]; /* EBCDIC -> character classes */
+
+#define __ismask_ebc_inv(x) (_ebctype_inv[(int)(unsigned char)(x)])
+#define isprint_ebc_inv(c) ((__ismask_ebc_inv(c)&(_P|_U|_L|_D|_SP)) != 0)
static inline void
codepage_convert(const __u8 *codepage, volatile char *addr, unsigned long nr)
diff --git a/arch/s390/kernel/ebcdic.c b/arch/s390/kernel/ebcdic.c
index 0e51fa537262b..15cbb0b42aa6e 100644
--- a/arch/s390/kernel/ebcdic.c
+++ b/arch/s390/kernel/ebcdic.c
@@ -392,10 +392,48 @@ __u8 _ebc_toupper[256] =
0xF8, 0xF9, 0xFA, 0xFB, 0xFC, 0xFD, 0xFE, 0xFF
};
+/*
+ * EBCDIC -> character classes
+ */
+const __u8 _ebctype_inv[256] = {
+ _C, _C, _C, _C, _C, _C|_S, _C, _C, /* 0x00-0x07 */
+ _C, _C, _C, _C|_S, _C|_S, _C|_S, _C, _C, /* 0x08-0x0f */
+ _C, _C, _C, _C, _C, _C|_S, _C, _C, /* 0x10-0x17 */
+ _C, _C, _C, _C, _C, _C, _C, _C, /* 0x18-0x1f */
+ _C, _C, _C, _C, _C, _C|_S, _C, _C, /* 0x20-0x27 */
+ _C, _C, _C, _C, _C, _C, _C, _C, /* 0x28-0x2f */
+ 0, 0, _C, _C, _C, _C, _C, _C, /* 0x30-0x37 */
+ _C, _C, _C, _C, _C, _C, 0, _C, /* 0x38-0x3f */
+ _S|_SP, 0, 0, 0, 0, 0, 0, 0, /* 0x40-0x47 */
+ 0, 0, _P, _P, _P, _P, _P, _P, /* 0x48-0x4f */
+ _P, 0, 0, 0, 0, 0, 0, 0, /* 0x50-0x57 */
+ 0, 0, _P, _P, _P, _P, _P, _P, /* 0x58-0x5f */
+ _P, _P, 0, 0, 0, 0, 0, 0, /* 0x60-0x67 */
+ 0, 0, _P, _P, _P, _P, _P, _P, /* 0x68-0x6f */
+ 0, 0, 0, 0, 0, 0, 0, 0, /* 0x70-0x77 */
+ 0, _P, _P, _P, _P, _P, _P, _P, /* 0x78-0x7f */
+ 0, _L|_X, _L|_X, _L|_X, _L|_X, _L|_X, _L|_X, _L, /* 0x80-0x87 */
+ _L, _L, 0, 0, 0, 0, 0, _P, /* 0x88-0x8f */
+ 0, _L, _L, _L, _L, _L, _L, _L, /* 0x90-0x97 */
+ _L, _L, 0, 0, 0, 0, 0, 0, /* 0x98-0x9f */
+ 0, _P, _L, _L, _L, _L, _L, _L, /* 0xa0-0xa7 */
+ _L, _L, 0, 0, 0, 0, 0, 0, /* 0xa8-0xaf */
+ _P, 0, 0, 0, 0, 0, 0, 0, /* 0xb0-0xb7 */
+ 0, 0, _P, _P, 0, 0, 0, 0, /* 0xb8-0xbf */
+ _P, _U|_X, _U|_X, _U|_X, _U|_X, _U|_X, _U|_X, _U, /* 0xc0-0xc7 */
+ _U, _U, 0, 0, 0, 0, 0, 0, /* 0xc8-0xcf */
+ _P, _U, _U, _U, _U, _U, _U, _U, /* 0xd0-0xd7 */
+ _U, _U, 0, 0, 0, 0, 0, 0, /* 0xd8-0xdf */
+ _P, 0, _U, _U, _U, _U, _U, _U, /* 0xe0-0xe7 */
+ _U, _U, 0, 0, 0, 0, 0, 0, /* 0xe8-0xef */
+ _D, _D, _D, _D, _D, _D, _D, _D, /* 0xf0-0xf7 */
+ _D, _D, 0, 0, 0, 0, 0, _C, /* 0xf8-0xff */
+};
+
EXPORT_SYMBOL(_ascebc_500);
EXPORT_SYMBOL(_ebcasc_500);
EXPORT_SYMBOL(_ascebc);
EXPORT_SYMBOL(_ebcasc);
EXPORT_SYMBOL(_ebc_tolower);
EXPORT_SYMBOL(_ebc_toupper);
-
+EXPORT_SYMBOL(_ebctype_inv);
--
2.55.0