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Date: Thu, 16 Nov 2017 20:06:39 -0500 (EST)
From: Nicolas Pitre <nicolas.pitre@...aro.org>
To: Masahiro Yamada <yamada.masahiro@...ionext.com>,
Michal Marek <michal.lkml@...kovi.net>,
Jan Beulich <JBeulich@...e.com>
cc: Arnd Bergmann <arnd@...db.de>, linux-kbuild@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [PATCH] kconfig: fix relational operators for bool and tristate
symbols
Since commit 31847b67bec0 ("kconfig: allow use of relations other than
(in)equality") it is possible to use relational operators in Kconfig
statements. However, those operators give unexpected results when
applied to bool/tristate values:
(n < y) = y (correct)
(m < y) = y (correct)
(n < m) = n (wrong)
This happens because relational operators process bool and tristate
symbols as strings and m sorts before n. It makes little sense to do a
lexicographical compare on bool and tristate values though.
Documentation/kbuild/kconfig-language.txt states that expression can have
a value of 'n', 'm' or 'y' (or 0, 1, 2 respectively for calculations).
Let's make it so for relational comparisons with bool/tristate
expressions as well and document them. If at least one symbol is an
actual string then the lexicographical compare works just as before.
Signed-off-by: Nicolas Pitre <nico@...aro.org>
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index 262722d886..c4a293a03c 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -200,10 +200,14 @@ module state. Dependency expressions have the following syntax:
<expr> ::= <symbol> (1)
<symbol> '=' <symbol> (2)
<symbol> '!=' <symbol> (3)
- '(' <expr> ')' (4)
- '!' <expr> (5)
- <expr> '&&' <expr> (6)
- <expr> '||' <expr> (7)
+ <symbol1> '<' <symbol2> (4)
+ <symbol1> '>' <symbol2> (4)
+ <symbol1> '<=' <symbol2> (4)
+ <symbol1> '>=' <symbol2> (4)
+ '(' <expr> ')' (5)
+ '!' <expr> (6)
+ <expr> '&&' <expr> (7)
+ <expr> '||' <expr> (8)
Expressions are listed in decreasing order of precedence.
@@ -214,10 +218,13 @@ Expressions are listed in decreasing order of precedence.
otherwise 'n'.
(3) If the values of both symbols are equal, it returns 'n',
otherwise 'y'.
-(4) Returns the value of the expression. Used to override precedence.
-(5) Returns the result of (2-/expr/).
-(6) Returns the result of min(/expr/, /expr/).
-(7) Returns the result of max(/expr/, /expr/).
+(4) If value of <symbol1> is respectively lower, greater, lower-or-equal,
+ or greater-or-equal than value of <symbol2>, it returns 'y',
+ otherwise 'n'.
+(5) Returns the value of the expression. Used to override precedence.
+(6) Returns the result of (2-/expr/).
+(7) Returns the result of min(/expr/, /expr/).
+(8) Returns the result of max(/expr/, /expr/).
An expression can have a value of 'n', 'm' or 'y' (or 0, 1, 2
respectively for calculations). A menu entry becomes visible when its
diff --git a/scripts/kconfig/expr.c b/scripts/kconfig/expr.c
index cbf4996dd9..8cee597d33 100644
--- a/scripts/kconfig/expr.c
+++ b/scripts/kconfig/expr.c
@@ -893,7 +893,10 @@ static enum string_value_kind expr_parse_string(const char *str,
switch (type) {
case S_BOOLEAN:
case S_TRISTATE:
- return k_string;
+ val->s = !strcmp(str, "n") ? 0 :
+ !strcmp(str, "m") ? 1 :
+ !strcmp(str, "y") ? 2 : -1;
+ return k_signed;
case S_INT:
val->s = strtoll(str, &tail, 10);
kind = k_signed;
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