The following commit has been merged into the x86/misc branch of tip:
Commit-ID: 62e724494db7954c47b4417769f1225cf98f4d77
Gitweb: https://git.kernel.org/tip/62e724494db7954c47b4417769f1225cf98f4d77
Author: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 08 Nov 2024 17:30:10 +02:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Fri, 08 Nov 2024 09:08:48 -08:00
x86/cpu: Make sure flag_is_changeable_p() is always being used
When flag_is_changeable_p() is unused, it prevents kernel builds
with clang, `make W=1` and CONFIG_WERROR=y:
arch/x86/kernel/cpu/common.c:351:19: error: unused function 'flag_is_changeable_p' [-Werror,-Wunused-function]
351 | static inline int flag_is_changeable_p(u32 flag)
| ^~~~~~~~~~~~~~~~~~~~
Fix this by moving core around to make sure flag_is_changeable_p() is
always being used.
See also commit 6863f5643dd7 ("kbuild: allow Clang to find unused static
inline functions for W=1 build").
While at it, fix the argument type to be unsigned long along with
the local variables, although it currently only runs in 32-bit cases.
Besides that, makes it return boolean instead of int. This induces
the change of the returning type of have_cpuid_p() to be boolean
as well.
Suggested-by: Dave Hansen <dave.hansen@xxxxxxxxx>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx>
Link: https://lore.kernel.org/all/20241108153105.1578186-1-andriy.shevchenko%40linux.intel.com
---
arch/x86/include/asm/cpuid.h | 8 ++++---
arch/x86/kernel/cpu/common.c | 39 ++++++++++++++++-------------------
2 files changed, 23 insertions(+), 24 deletions(-)
diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h
index ca42433..239b9ba 100644
--- a/arch/x86/include/asm/cpuid.h
+++ b/arch/x86/include/asm/cpuid.h
@@ -6,6 +6,8 @@
#ifndef _ASM_X86_CPUID_H
#define _ASM_X86_CPUID_H
+#include <linux/types.h>
+
#include <asm/string.h>
struct cpuid_regs {
@@ -20,11 +22,11 @@ enum cpuid_regs_idx {
};
#ifdef CONFIG_X86_32
-extern int have_cpuid_p(void);
+bool have_cpuid_p(void);
#else
-static inline int have_cpuid_p(void)
+static inline bool have_cpuid_p(void)
{
- return 1;
+ return true;
}
#endif
static inline void native_cpuid(unsigned int *eax, unsigned int *ebx,
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 07a34d7..e09ffde 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -275,21 +275,13 @@ static int __init x86_noinvpcid_setup(char *s)
}
early_param("noinvpcid", x86_noinvpcid_setup);
-#ifdef CONFIG_X86_32
-static int cachesize_override = -1;
-static int disable_x86_serial_nr = 1;
-
-static int __init cachesize_setup(char *str)
-{
- get_option(&str, &cachesize_override);
- return 1;
-}
-__setup("cachesize=", cachesize_setup);
-
/* Standard macro to see if a specific flag is changeable */
-static inline int flag_is_changeable_p(u32 flag)
+static inline bool flag_is_changeable_p(unsigned long flag)
{
- u32 f1, f2;
+ unsigned long f1, f2;
+
+ if (!IS_ENABLED(CONFIG_X86_32))
+ return true;
/*
* Cyrix and IDT cpus allow disabling of CPUID
@@ -312,11 +304,22 @@ static inline int flag_is_changeable_p(u32 flag)
: "=&r" (f1), "=&r" (f2)
: "ir" (flag));
- return ((f1^f2) & flag) != 0;
+ return (f1 ^ f2) & flag;
}
+#ifdef CONFIG_X86_32
+static int cachesize_override = -1;
+static int disable_x86_serial_nr = 1;
+
+static int __init cachesize_setup(char *str)
+{
+ get_option(&str, &cachesize_override);
+ return 1;
+}
+__setup("cachesize=", cachesize_setup);
+
/* Probe for the CPUID instruction */
-int have_cpuid_p(void)
+bool have_cpuid_p(void)
{
return flag_is_changeable_p(X86_EFLAGS_ID);
}
@@ -348,10 +351,6 @@ static int __init x86_serial_nr_setup(char *s)
}
__setup("serialnumber", x86_serial_nr_setup);
#else
-static inline int flag_is_changeable_p(u32 flag)
-{
- return 1;
-}
static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c)
{
}
@@ -1087,7 +1086,6 @@ void get_cpu_address_sizes(struct cpuinfo_x86 *c)
static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
{
-#ifdef CONFIG_X86_32
int i;
/*
@@ -1108,7 +1106,6 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c)
break;
}
}
-#endif
}
#define NO_SPECULATION BIT(0)
|