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From: Ilya Leoshkevich <iii@linux.ibm.com>
To: Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>
Cc: David Laight <david.laight.linux@gmail.com>,
	linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
	Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH v3 1/2] s390/ebcdic: Add character classes for the invariant subset of EBCDIC
Date: Fri, 28 Aug 2026 15:59:34 +0200	[thread overview]
Message-ID: <20260828140057.1728173-2-iii@linux.ibm.com> (raw)
In-Reply-To: <20260828140057.1728173-1-iii@linux.ibm.com>

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@linux.ibm.com>
---
 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


  reply	other threads:[~2026-08-28 14:01 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-28 13:59 [PATCH v3 0/2] s390: Warn if kernel command line contains non-printable EBCDIC Ilya Leoshkevich
2026-08-28 13:59 ` Ilya Leoshkevich [this message]
2026-08-28 13:59 ` [PATCH v3 2/2] s390: Warn if kernel command line contains non-printable EBCDIC characters Ilya Leoshkevich

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