[PATCH] 64-bit jiffies, a better solution

Ok, here it is.  The following arch are not covered:
Mips, Mips64 in 32-bit mode, parisc in __LP64__ mode.

In addition, x86_64 mentions jiffies in the existing script.
This may be a problem.

arch/alpha/vmlinux.lds.in

@@ -3,6 +3,7 @@
 OUTPUT_FORMAT("elf64-alpha")
 ENTRY(__start)
 PHDRS { kernel PT_LOAD ; }
+jiffies = jiffies_64;
 SECTIONS
 {
 #ifdef CONFIG_ALPHA_LEGACY_START_ADDRESS

arch/arm/vmlinux-armo.lds.in

@@ -4,6 +4,7 @@
  */
 OUTPUT_ARCH(arm)
 ENTRY(stext)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
 	. = TEXTADDR;

arch/arm/vmlinux-armv.lds.in

@@ -4,6 +4,7 @@
  */
 OUTPUT_ARCH(arm)
 ENTRY(stext)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
 	. = TEXTADDR;

arch/cris/cris.ld

@@ -8,6 +8,7 @@
  * the kernel has booted. 
  */	
 
+jiffies = jiffies_64;
 SECTIONS
 {
 	. = @CONFIG_ETRAX_DRAM_VIRTUAL_BASE@;

arch/i386/vmlinux.lds

@@ -4,6 +4,7 @@
 OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386")
 OUTPUT_ARCH(i386)
 ENTRY(_start)
+jiffies = jiffies_64;
 SECTIONS
 {
   . = 0xC0000000 + 0x100000;

arch/ia64/vmlinux.lds.S

@@ -7,6 +7,7 @@
 OUTPUT_FORMAT("elf64-ia64-little")
 OUTPUT_ARCH(ia64)
 ENTRY(phys_start)
+jiffies = jiffies_64; 
 SECTIONS
 {
   /* Sections to be discarded */

arch/m68k/vmlinux-sun3.lds

@@ -2,6 +2,7 @@
 OUTPUT_FORMAT("elf32-m68k", "elf32-m68k", "elf32-m68k")
 OUTPUT_ARCH(m68k)
 ENTRY(_start)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   . = 0xE004000;

arch/m68k/vmlinux.lds

@@ -2,6 +2,7 @@
 OUTPUT_FORMAT("elf32-m68k", "elf32-m68k", "elf32-m68k")
 OUTPUT_ARCH(m68k)
 ENTRY(_start)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   . = 0x1000;

arch/mips64/ld.script.elf64

 OUTPUT_ARCH(mips)
 ENTRY(kernel_entry)
+jiffies = jiffies_64;
 SECTIONS
 {
   /* Read-only sections, merged into text segment: */

arch/parisc/vmlinux.lds

@@ -2,6 +2,7 @@
 OUTPUT_FORMAT("elf32-hppa")
 OUTPUT_ARCH(hppa)
 ENTRY(_stext)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
 

arch/ppc/vmlinux.lds

@@ -2,6 +2,7 @@ OUTPUT_ARCH(powerpc)
 SEARCH_DIR(/lib); SEARCH_DIR(/usr/lib); SEARCH_DIR(/usr/local/lib); SEARCH_DIR(/usr/local/powerpc-any-elf/lib);
 /* Do we need any of these for elf?
    __DYNAMIC = 0;    */
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   /* Read-only sections, merged into text segment: */

arch/ppc64/vmlinux.lds

@@ -2,6 +2,7 @@ OUTPUT_ARCH(powerpc)
 SEARCH_DIR(/lib); SEARCH_DIR(/usr/lib); SEARCH_DIR(/usr/local/lib); SEARCH_DIR(/usr/local/powerpc-any-elf/lib);
 /* Do we need any of these for elf?
    __DYNAMIC = 0;    */
+jiffies = jiffies_64;
 SECTIONS
 {
   /* Read-only sections, merged into text segment: */

arch/s390/vmlinux-shared.lds

@@ -4,6 +4,7 @@
 OUTPUT_FORMAT("elf32-s390", "elf32-s390", "elf32-s390")
 OUTPUT_ARCH(s390)
 ENTRY(_start)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   . = 0x00000000;

arch/s390/vmlinux.lds

@@ -4,6 +4,7 @@
 OUTPUT_FORMAT("elf32-s390", "elf32-s390", "elf32-s390")
 OUTPUT_ARCH(s390)
 ENTRY(_start)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   . = 0x00000000;

arch/s390x/vmlinux-shared.lds

@@ -4,6 +4,7 @@
 OUTPUT_FORMAT("elf64-s390", "elf64-s390", "elf64-s390")
 OUTPUT_ARCH(s390)
 ENTRY(_start)
+jiffies = jiffies_64;
 SECTIONS
 {
   . = 0x00000000;

arch/s390x/vmlinux.lds

@@ -4,6 +4,7 @@
 OUTPUT_FORMAT("elf64-s390", "elf64-s390", "elf64-s390")
 OUTPUT_ARCH(s390)
 ENTRY(_start)
+jiffies = jiffies_64;
 SECTIONS
 {
   . = 0x00000000;

arch/sh/vmlinux.lds.S

@@ -5,8 +5,10 @@
 #include <linux/config.h>
 #ifdef CONFIG_CPU_LITTLE_ENDIAN
 OUTPUT_FORMAT("elf32-sh-linux", "elf32-sh-linux", "elf32-sh-linux")
+jiffies = jiffies_64;        
 #else
 OUTPUT_FORMAT("elf32-shbig-linux", "elf32-shbig-linux", "elf32-shbig-linux")
+jiffies = jiffies_64 + 4;
 #endif
 OUTPUT_ARCH(sh)
 ENTRY(_start)

arch/sparc/vmlinux.lds

@@ -2,6 +2,7 @@
 OUTPUT_FORMAT("elf32-sparc", "elf32-sparc", "elf32-sparc")
 OUTPUT_ARCH(sparc)
 ENTRY(_start)
+jiffies = jiffies_64 + 4;
 SECTIONS
 {
   . = 0x10000 + SIZEOF_HEADERS;

arch/sparc64/vmlinux.lds

@@ -3,6 +3,7 @@ OUTPUT_FORMAT("elf64-sparc", "elf64-sparc", "elf64-sparc")
 OUTPUT_ARCH(sparc:v9a)
 ENTRY(_start)
 
+jiffies = jiffies_64;
 SECTIONS
 {
   swapper_pmd_dir = 0x0000000000402000;

arch/x86_64/vmlinux.lds

@@ -3,6 +3,7 @@
  */
 OUTPUT_FORMAT("elf64-x86-64", "elf64-x86-64", "elf64-x86-64")
 OUTPUT_ARCH(i386:x86-64)
+jiffies = jiffies_64;
 ENTRY(_start)
 SECTIONS
 {

include/linux/sched.h

@@ -459,6 +459,11 @@ extern void free_uid(struct user_struct *);
 
 #include <asm/current.h>
 
+/*
+ * The 64-bit value is not volatile - you MUST NOT read it
+ * without holding read_lock_irq(&xtime_lock)
+ */
+extern u64 jiffies_64;
 extern unsigned long volatile jiffies;
 extern unsigned long itimer_ticks;
 extern unsigned long itimer_next;

kernel/ksyms.c

@@ -471,6 +471,7 @@ EXPORT_SYMBOL_GPL(idle_cpu);
 EXPORT_SYMBOL_GPL(set_cpus_allowed);
 #endif
 EXPORT_SYMBOL(jiffies);
+EXPORT_SYMBOL(jiffies_64);
 EXPORT_SYMBOL(xtime);
 EXPORT_SYMBOL(do_gettimeofday);
 EXPORT_SYMBOL(do_settimeofday);

kernel/timer.c

@@ -67,7 +67,12 @@ unsigned long event;
 
 extern int do_setitimer(int, struct itimerval *, struct itimerval *);
 
-unsigned long volatile jiffies;
+/*
+ * The 64-bit value is not volatile - you MUST NOT read it
+ * without holding read_lock_irq(&xtime_lock).
+ * jiffies is defined in the linker script...
+ */
+u64 jiffies_64;
 
 unsigned int * prof_buffer;
 unsigned long prof_len;
@@ -664,7 +669,7 @@ void timer_bh(void)
 
 void do_timer(struct pt_regs *regs)
 {
-	(*(unsigned long *)&jiffies)++;
+	jiffies_64++;
 #ifndef CONFIG_SMP
 	/* SMP process accounting uses the local APIC timer */