kconfig: fix comparison to constant symbols, 'm', 'n'
Currently, comparisons to 'm' or 'n' result in incorrect output.
[Test Code]
config MODULES
def_bool y
modules
config A
def_tristate m
config B
def_bool A > n
CONFIG_B is unset, while CONFIG_B=y is expected.
The reason for the issue is because Kconfig compares the tristate values
as strings.
Currently, the .type fields in the constant symbol definitions,
symbol_{yes,mod,no} are unspecified, i.e., S_UNKNOWN.
When expr_calc_value() evaluates 'A > n', it checks the types of 'A' and
'n' to determine how to compare them.
The left-hand side, 'A', is a tristate symbol with a value of 'm', which
corresponds to a numeric value of 1. (Internally, 'y', 'm', and 'n' are
represented as 2, 1, and 0, respectively.)
The right-hand side, 'n', has an unknown type, so it is treated as the
string "n" during the comparison.
expr_calc_value() compares two values numerically only when both can
have numeric values. Otherwise, they are compared as strings.
symbol numeric value ASCII code
-------------------------------------
y 2 0x79
m 1 0x6d
n 0 0x6e
'm' is greater than 'n' if compared numerically (since 1 is greater
than 0), but smaller than 'n' if compared as strings (since the ASCII
code 0x6d is smaller than 0x6e).
Specifying .type=S_TRISTATE for symbol_{yes,mod,no} fixes the above
test code.
Doing so, however, would cause a regression to the following test code.
[Test Code 2]
config MODULES
def_bool n
modules
config A
def_tristate n
config B
def_bool A = m
You would get CONFIG_B=y, while CONFIG_B should not be set.
The reason is because sym_get_string_value() turns 'm' into 'n' when the
module feature is disabled. Consequently, expr_calc_value() evaluates
'A = n' instead of 'A = m'. This oddity has been hidden because the type
of 'm' was previously S_UNKNOWN instead of S_TRISTATE.
sym_get_string_value() should not tweak the string because the tristate
value has already been correctly calculated. There is no reason to
return the string "n" where its tristate value is mod.
Fixes: 31847b67be
("kconfig: allow use of relations other than (in)equality")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
This commit is contained in:
parent
a607468b52
commit
aabdc960a2
@ -14,6 +14,7 @@
|
||||
|
||||
struct symbol symbol_yes = {
|
||||
.name = "y",
|
||||
.type = S_TRISTATE,
|
||||
.curr = { "y", yes },
|
||||
.menus = LIST_HEAD_INIT(symbol_yes.menus),
|
||||
.flags = SYMBOL_CONST|SYMBOL_VALID,
|
||||
@ -21,6 +22,7 @@ struct symbol symbol_yes = {
|
||||
|
||||
struct symbol symbol_mod = {
|
||||
.name = "m",
|
||||
.type = S_TRISTATE,
|
||||
.curr = { "m", mod },
|
||||
.menus = LIST_HEAD_INIT(symbol_mod.menus),
|
||||
.flags = SYMBOL_CONST|SYMBOL_VALID,
|
||||
@ -28,6 +30,7 @@ struct symbol symbol_mod = {
|
||||
|
||||
struct symbol symbol_no = {
|
||||
.name = "n",
|
||||
.type = S_TRISTATE,
|
||||
.curr = { "n", no },
|
||||
.menus = LIST_HEAD_INIT(symbol_no.menus),
|
||||
.flags = SYMBOL_CONST|SYMBOL_VALID,
|
||||
@ -820,8 +823,7 @@ const char *sym_get_string_value(struct symbol *sym)
|
||||
case no:
|
||||
return "n";
|
||||
case mod:
|
||||
sym_calc_value(modules_sym);
|
||||
return (modules_sym->curr.tri == no) ? "n" : "m";
|
||||
return "m";
|
||||
case yes:
|
||||
return "y";
|
||||
}
|
||||
|
Loading…
Reference in New Issue
Block a user