LoongArch: Adjust VDSO/VSYSCALL for 32BIT/64BIT

Adjust VDSO/VSYSCALL because read_cpu_id() for 32BIT/64BIT are
different, and LoongArch32 doesn't support GENERIC_GETTIMEOFDAY now
(will be supported in future).

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

arch/loongarch/include/asm/vdso/gettimeofday.h

@@ -12,6 +12,8 @@
 #include <asm/unistd.h>
 #include <asm/vdso/vdso.h>
 
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+
 #define VDSO_HAS_CLOCK_GETRES		1
 
 static __always_inline long gettimeofday_fallback(
@@ -89,6 +91,8 @@ static inline bool loongarch_vdso_hres_capable(void)
 }
 #define __arch_vdso_hres_capable loongarch_vdso_hres_capable
 
+#endif /* CONFIG_GENERIC_GETTIMEOFDAY */
+
 #endif /* !__ASSEMBLER__ */
 
 #endif /* __ASM_VDSO_GETTIMEOFDAY_H */

arch/loongarch/kernel/time.c

@@ -212,7 +212,9 @@ static struct clocksource clocksource_const = {
 	.read = read_const_counter,
 	.mask = CLOCKSOURCE_MASK(64),
 	.flags = CLOCK_SOURCE_IS_CONTINUOUS,
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
 	.vdso_clock_mode = VDSO_CLOCKMODE_CPU,
+#endif
 };
 
 int __init constant_clocksource_init(void)

arch/loongarch/vdso/Makefile

@@ -4,8 +4,9 @@
 # Include the generic Makefile to check the built vdso.
 include $(srctree)/lib/vdso/Makefile.include
 
-obj-vdso-y := elf.o vgetcpu.o vgettimeofday.o vgetrandom.o \
+obj-vdso-y := elf.o vgetcpu.o vgetrandom.o \
               vgetrandom-chacha.o sigreturn.o
+obj-vdso-$(CONFIG_GENERIC_GETTIMEOFDAY) += vgettimeofday.o
 
 # Common compiler flags between ABIs.
 ccflags-vdso := \
@@ -16,6 +17,10 @@ ccflags-vdso := \
 	$(CLANG_FLAGS) \
 	-D__VDSO__
 
+ifdef CONFIG_32BIT
+ccflags-vdso += -DBUILD_VDSO32
+endif
+
 cflags-vdso := $(ccflags-vdso) \
 	-isystem $(shell $(CC) -print-file-name=include) \
 	$(filter -W%,$(filter-out -Wa$(comma)%,$(KBUILD_CFLAGS))) \

arch/loongarch/vdso/vdso.lds.S

@@ -7,8 +7,6 @@
 #include <generated/asm-offsets.h>
 #include <vdso/datapage.h>
 
-OUTPUT_FORMAT("elf64-loongarch", "elf64-loongarch", "elf64-loongarch")
-
 OUTPUT_ARCH(loongarch)
 
 SECTIONS
@@ -63,9 +61,11 @@ VERSION
 	LINUX_5.10 {
 	global:
 		__vdso_getcpu;
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
 		__vdso_clock_getres;
 		__vdso_clock_gettime;
 		__vdso_gettimeofday;
+#endif
 		__vdso_getrandom;
 		__vdso_rt_sigreturn;
 	local: *;

arch/loongarch/vdso/vgetcpu.c

@@ -10,11 +10,19 @@ static __always_inline int read_cpu_id(void)
 {
 	int cpu_id;
 
+#ifdef CONFIG_64BIT
 	__asm__ __volatile__(
 	"	rdtime.d $zero, %0\n"
 	: "=r" (cpu_id)
 	:
 	: "memory");
+#else
+	__asm__ __volatile__(
+	"	rdtimel.w $zero, %0\n"
+	: "=r" (cpu_id)
+	:
+	: "memory");
+#endif
 
 	return cpu_id;
 }