diff --git a/grub-core/efiemu/runtime/efiemu.c b/grub-core/efiemu/runtime/efiemu.c
index d923e409f..5db1f347b 100644
--- a/grub-core/efiemu/runtime/efiemu.c
+++ b/grub-core/efiemu/runtime/efiemu.c
@@ -174,17 +174,17 @@ efiemu_memset (grub_uint8_t *a, grub_uint8_t b, grub_size_t n)
 static inline void
 write_cmos (grub_uint8_t addr, grub_uint8_t val)
 {
-  __asm__ __volatile__ ("outb %%al,$0x70\n"
-			"mov %%cl, %%al\n"
-			"outb %%al,$0x71": :"a" (addr), "c" (val));
+  asm volatile ("outb %%al,$0x70\n"
+		"mov %%cl, %%al\n"
+		"outb %%al,$0x71": :"a" (addr), "c" (val));
 }
 
 static inline grub_uint8_t
 read_cmos (grub_uint8_t addr)
 {
   grub_uint8_t ret;
-  __asm__ __volatile__ ("outb %%al, $0x70\n"
-			"inb $0x71, %%al": "=a"(ret) :"a" (addr));
+  asm volatile ("outb %%al, $0x70\n"
+		"inb $0x71, %%al": "=a"(ret) :"a" (addr));
   return ret;
 }
 
diff --git a/grub-core/lib/i386/halt.c b/grub-core/lib/i386/halt.c
index 9f8405494..2364fe4d7 100644
--- a/grub-core/lib/i386/halt.c
+++ b/grub-core/lib/i386/halt.c
@@ -66,7 +66,7 @@ grub_halt (void)
 #endif
 
   /* Disable interrupts.  */
-  __asm__ __volatile__ ("cli");
+  asm volatile ("cli");
 
   /* Bochs, QEMU, etc. Removed in newer QEMU releases.  */
   for (i = 0; i < sizeof (bochs_shutdown) - 1; i++)
diff --git a/include/grub/arm/time.h b/include/grub/arm/time.h
index 4128506cb..c5a685225 100644
--- a/include/grub/arm/time.h
+++ b/include/grub/arm/time.h
@@ -23,7 +23,7 @@ static __inline void
 grub_cpu_idle (void)
 {
   /* FIXME: this can't work until we handle interrupts.  */
-/*  __asm__ __volatile__ ("wfi"); */
+/*  asm volatile ("wfi"); */
 }
 
 #endif /* ! KERNEL_CPU_TIME_HEADER */
diff --git a/include/grub/arm64/time.h b/include/grub/arm64/time.h
index 4128506cb..c5a685225 100644
--- a/include/grub/arm64/time.h
+++ b/include/grub/arm64/time.h
@@ -23,7 +23,7 @@ static __inline void
 grub_cpu_idle (void)
 {
   /* FIXME: this can't work until we handle interrupts.  */
-/*  __asm__ __volatile__ ("wfi"); */
+/*  asm volatile ("wfi"); */
 }
 
 #endif /* ! KERNEL_CPU_TIME_HEADER */
diff --git a/include/grub/i386/io.h b/include/grub/i386/io.h
index ae12a3e3d..e9cd80957 100644
--- a/include/grub/i386/io.h
+++ b/include/grub/i386/io.h
@@ -28,7 +28,7 @@ grub_inb (unsigned short int port)
 {
   unsigned char _v;
 
-  __asm__ __volatile__ ("inb %w1,%0":"=a" (_v):"Nd" (port));
+  asm volatile ("inb %w1,%0":"=a" (_v):"Nd" (port));
   return _v;
 }
 
@@ -37,7 +37,7 @@ grub_inw (unsigned short int port)
 {
   unsigned short _v;
 
-  __asm__ __volatile__ ("inw %w1,%0":"=a" (_v):"Nd" (port));
+  asm volatile ("inw %w1,%0":"=a" (_v):"Nd" (port));
   return _v;
 }
 
@@ -46,27 +46,27 @@ grub_inl (unsigned short int port)
 {
   unsigned int _v;
 
-  __asm__ __volatile__ ("inl %w1,%0":"=a" (_v):"Nd" (port));
+  asm volatile ("inl %w1,%0":"=a" (_v):"Nd" (port));
   return _v;
 }
 
 static __inline void
 grub_outb (unsigned char value, unsigned short int port)
 {
-  __asm__ __volatile__ ("outb %b0,%w1": :"a" (value), "Nd" (port));
+  asm volatile ("outb %b0,%w1": :"a" (value), "Nd" (port));
 }
 
 static __inline void
 grub_outw (unsigned short int value, unsigned short int port)
 {
-  __asm__ __volatile__ ("outw %w0,%w1": :"a" (value), "Nd" (port));
+  asm volatile ("outw %w0,%w1": :"a" (value), "Nd" (port));
 
 }
 
 static __inline void
 grub_outl (unsigned int value, unsigned short int port)
 {
-  __asm__ __volatile__ ("outl %0,%w1": :"a" (value), "Nd" (port));
+  asm volatile ("outl %0,%w1": :"a" (value), "Nd" (port));
 }
 
 #endif /* _SYS_IO_H */
diff --git a/include/grub/i386/time.h b/include/grub/i386/time.h
index 842882cf2..4da5ae93c 100644
--- a/include/grub/i386/time.h
+++ b/include/grub/i386/time.h
@@ -23,7 +23,7 @@ static __inline void
 grub_cpu_idle (void)
 {
   /* FIXME: this can't work until we handle interrupts.  */
-/*  __asm__ __volatile__ ("hlt"); */
+/*  asm volatile ("hlt"); */
 }
 
 #endif /* ! KERNEL_CPU_TIME_HEADER */
diff --git a/include/grub/i386/tsc.h b/include/grub/i386/tsc.h
index 324174ded..947e62fa1 100644
--- a/include/grub/i386/tsc.h
+++ b/include/grub/i386/tsc.h
@@ -46,7 +46,7 @@ grub_get_tsc (void)
   grub_cpuid (0,a,b,c,d);
   /* Read TSC value.  We cannot use "=A", since this would use
      %rax on x86_64. */
-  __asm__ __volatile__ ("rdtsc":"=a" (lo), "=d" (hi));
+  asm volatile ("rdtsc":"=a" (lo), "=d" (hi));
 
   return (((grub_uint64_t) hi) << 32) | lo;
 }
diff --git a/include/grub/x86_64/time.h b/include/grub/x86_64/time.h
index 842882cf2..4da5ae93c 100644
--- a/include/grub/x86_64/time.h
+++ b/include/grub/x86_64/time.h
@@ -23,7 +23,7 @@ static __inline void
 grub_cpu_idle (void)
 {
   /* FIXME: this can't work until we handle interrupts.  */
-/*  __asm__ __volatile__ ("hlt"); */
+/*  asm volatile ("hlt"); */
 }
 
 #endif /* ! KERNEL_CPU_TIME_HEADER */