From: luyu <luyu@redhat.com>
Subject: Re: [RHEL 5.1 PATCH] BZ 233046 getcpu system call
Date: Sat, 28 Apr 2007 10:06:33 +0800
Bugzilla: 233046
Message-Id: <4632AC29.3070109@redhat.com>
Changelog: [misc] getcpu system call
BZ 233046
Recently Fenghua implemented getcpu system call for IPF that is a clean
interface to get the CPU and node number a process is running on.
There is /proc/<pid>/stat, but that is not a well documented API that
can be used in production systems. Andi added a system call in x86-64
that does this.
The implementation includes both sys_getcpu and fsys_getcpu.
sys_getcpu patch can be found at:
[PATCH] Hook up getcpu system call for IA64
http://www.gelato.unsw.edu.au/archives/linux-ia64/0702/19940.html
fsys_getcpu patch can be found at:
[PATCH] fsys_getcpu for IA64
http://www.gelato.unsw.edu.au/archives/linux-ia64/0702/19994.html
Fenghua's patch has been in upstream kernel and his patches are on top
of Andi Kleen's getcpu patch:
Thanks,
Luming
diff -BruN linux-2.6.18.ia64/arch/i386/kernel/syscall_table.S linux-2.6.18.ia64-patched/arch/i386/kernel/syscall_table.S
--- linux-2.6.18.ia64/arch/i386/kernel/syscall_table.S 2007-03-20 18:40:15.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/i386/kernel/syscall_table.S 2007-03-20 21:53:11.000000000 -0400
@@ -325,3 +325,4 @@
.long sys_tee /* 315 */
.long sys_vmsplice
.long sys_move_pages
+ .long sys_getcpu
diff -BruN linux-2.6.18.ia64/arch/ia64/kernel/asm-offsets.c linux-2.6.18.ia64-patched/arch/ia64/kernel/asm-offsets.c
--- linux-2.6.18.ia64/arch/ia64/kernel/asm-offsets.c 2007-03-20 18:40:15.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/ia64/kernel/asm-offsets.c 2007-03-20 19:13:04.000000000 -0400
@@ -35,6 +35,7 @@
BLANK();
DEFINE(TI_FLAGS, offsetof(struct thread_info, flags));
+ DEFINE(TI_CPU, offsetof(struct thread_info, cpu));
DEFINE(TI_PRE_COUNT, offsetof(struct thread_info, preempt_count));
BLANK();
diff -BruN linux-2.6.18.ia64/arch/ia64/kernel/entry.S linux-2.6.18.ia64-patched/arch/ia64/kernel/entry.S
--- linux-2.6.18.ia64/arch/ia64/kernel/entry.S 2007-03-20 18:40:20.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/ia64/kernel/entry.S 2007-03-20 19:12:57.000000000 -0400
@@ -1624,5 +1624,7 @@
data8 sys_sync_file_range // 1300
data8 sys_tee
data8 sys_vmsplice
+ data8 sys_ni_syscall // reserved for move_pages
+ data8 sys_getcpu
.org sys_call_table + 8*NR_syscalls // guard against failures to increase NR_syscalls
diff -BruN linux-2.6.18.ia64/arch/ia64/kernel/fsys.S linux-2.6.18.ia64-patched/arch/ia64/kernel/fsys.S
--- linux-2.6.18.ia64/arch/ia64/kernel/fsys.S 2007-03-20 18:40:14.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/ia64/kernel/fsys.S 2007-03-20 19:13:04.000000000 -0400
@@ -10,6 +10,8 @@
* probably broke it along the way... ;-)
* 13-Jul-04 clameter Implement fsys_clock_gettime and revise fsys_gettimeofday to make
* it capable of using memory based clocks without falling back to C code.
+ * 08-Feb-07 Fenghua Yu Implement fsys_getcpu.
+ *
*/
#include <asm/asmmacro.h>
@@ -505,6 +507,59 @@
#endif
END(fsys_rt_sigprocmask)
+/*
+ * fsys_getcpu doesn't use the third parameter in this implementation. It reads
+ * current_thread_info()->cpu and corresponding node in cpu_to_node_map.
+ */
+ENTRY(fsys_getcpu)
+ .prologue
+ .altrp b6
+ .body
+ ;;
+ add r2=TI_FLAGS+IA64_TASK_SIZE,r16
+ tnat.nz p6,p0 = r32 // guard against NaT argument
+ add r3=TI_CPU+IA64_TASK_SIZE,r16
+ ;;
+ ld4 r3=[r3] // M r3 = thread_info->cpu
+ ld4 r2=[r2] // M r2 = thread_info->flags
+(p6) br.cond.spnt.few .fail_einval // B
+ ;;
+ tnat.nz p7,p0 = r33 // I guard against NaT argument
+(p7) br.cond.spnt.few .fail_einval // B
+#ifdef CONFIG_NUMA
+ movl r17=cpu_to_node_map
+ ;;
+EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles
+EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles
+ shladd r18=r3,1,r17
+ ;;
+ ld2 r20=[r18] // r20 = cpu_to_node_map[cpu]
+ and r2 = TIF_ALLWORK_MASK,r2
+ ;;
+ cmp.ne p8,p0=0,r2
+(p8) br.spnt.many fsys_fallback_syscall
+ ;;
+ ;;
+EX(.fail_efault, st4 [r32] = r3)
+EX(.fail_efault, st2 [r33] = r20)
+ mov r8=0
+ ;;
+#else
+EX(.fail_efault, probe.w.fault r32, 3) // M This takes 5 cycles
+EX(.fail_efault, probe.w.fault r33, 3) // M This takes 5 cycles
+ and r2 = TIF_ALLWORK_MASK,r2
+ ;;
+ cmp.ne p8,p0=0,r2
+(p8) br.spnt.many fsys_fallback_syscall
+ ;;
+EX(.fail_efault, st4 [r32] = r3)
+EX(.fail_efault, st2 [r33] = r0)
+ mov r8=0
+ ;;
+#endif
+ FSYS_RETURN
+END(fsys_getcpu)
+
ENTRY(fsys_fallback_syscall)
.prologue
.altrp b6
@@ -878,6 +933,56 @@
data8 0 // timer_delete
data8 0 // clock_settime
data8 fsys_clock_gettime // clock_gettime
+ data8 0 // clock_getres // 1255
+ data8 0 // clock_nanosleep
+ data8 0 // fstatfs64
+ data8 0 // statfs64
+ data8 0 // mbind
+ data8 0 // get_mempolicy // 1260
+ data8 0 // set_mempolicy
+ data8 0 // mq_open
+ data8 0 // mq_unlink
+ data8 0 // mq_timedsend
+ data8 0 // mq_timedreceive // 1265
+ data8 0 // mq_notify
+ data8 0 // mq_getsetattr
+ data8 0 // kexec_load
+ data8 0 // vserver
+ data8 0 // waitid // 1270
+ data8 0 // add_key
+ data8 0 // request_key
+ data8 0 // keyctl
+ data8 0 // ioprio_set
+ data8 0 // ioprio_get // 1275
+ data8 0 // move_pages
+ data8 0 // inotify_init
+ data8 0 // inotify_add_watch
+ data8 0 // inotify_rm_watch
+ data8 0 // migrate_pages // 1280
+ data8 0 // openat
+ data8 0 // mkdirat
+ data8 0 // mknodat
+ data8 0 // fchownat
+ data8 0 // futimesat // 1285
+ data8 0 // newfstatat
+ data8 0 // unlinkat
+ data8 0 // renameat
+ data8 0 // linkat
+ data8 0 // symlinkat // 1290
+ data8 0 // readlinkat
+ data8 0 // fchmodat
+ data8 0 // faccessat
+ data8 0
+ data8 0 // 1295
+ data8 0 // unshare
+ data8 0 // splice
+ data8 0 // set_robust_list
+ data8 0 // get_robust_list
+ data8 0 // sync_file_range // 1300
+ data8 0 // tee
+ data8 0 // vmsplice
+ data8 0
+ data8 fsys_getcpu // getcpu // 1304
// fill in zeros for the remaining entries
.zero:
diff -BruN linux-2.6.18.ia64/arch/x86_64/ia32/ia32entry.S linux-2.6.18.ia64-patched/arch/x86_64/ia32/ia32entry.S
--- linux-2.6.18.ia64/arch/x86_64/ia32/ia32entry.S 2007-03-20 18:40:15.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/x86_64/ia32/ia32entry.S 2007-03-20 21:53:11.000000000 -0400
@@ -721,4 +721,5 @@
.quad sys_tee
.quad compat_sys_vmsplice
.quad compat_sys_move_pages
+ .quad sys_getcpu
ia32_syscall_end:
diff -BruN linux-2.6.18.ia64/arch/x86_64/kernel/head.S linux-2.6.18.ia64-patched/arch/x86_64/kernel/head.S
--- linux-2.6.18.ia64/arch/x86_64/kernel/head.S 2007-03-20 18:40:20.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/x86_64/kernel/head.S 2007-04-03 19:54:20.000000000 -0400
@@ -371,7 +371,7 @@
.quad 0,0 /* TSS */
.quad 0,0 /* LDT */
.quad 0,0,0 /* three TLS descriptors */
- .quad 0 /* unused */
+ .quad 0x0000f40000000000 /* node/CPU stored in limit */
gdt_end:
/* asm/segment.h:GDT_ENTRIES must match this */
/* This should be a multiple of the cache line size */
diff -BruN linux-2.6.18.ia64/arch/x86_64/kernel/time.c linux-2.6.18.ia64-patched/arch/x86_64/kernel/time.c
--- linux-2.6.18.ia64/arch/x86_64/kernel/time.c 2007-03-20 18:40:14.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/x86_64/kernel/time.c 2007-04-03 19:56:37.000000000 -0400
@@ -899,13 +899,8 @@
time_cpu_notifier(struct notifier_block *nb, unsigned long action, void *hcpu)
{
unsigned cpu = (unsigned long) hcpu;
-
- if (action == CPU_ONLINE && cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP)) {
- unsigned p;
- p = smp_processor_id() | (cpu_to_node(smp_processor_id())<<12);
- write_rdtscp_aux(p);
- }
-
+ if (action == CPU_ONLINE)
+ vsyscall_set_cpu(cpu);
return NOTIFY_DONE;
}
@@ -999,6 +994,11 @@
if (unsynchronized_tsc())
notsc = 1;
+ if (cpu_has(&boot_cpu_data, X86_FEATURE_RDTSCP))
+ vgetcpu_mode = VGETCPU_RDTSCP;
+ else
+ vgetcpu_mode = VGETCPU_LSL;
+
if (vxtime.hpet_address && notsc) {
timetype = hpet_use_timer ? "HPET" : "PIT/HPET";
if (hpet_use_timer)
diff -BruN linux-2.6.18.ia64/arch/x86_64/kernel/vmlinux.lds.S linux-2.6.18.ia64-patched/arch/x86_64/kernel/vmlinux.lds.S
--- linux-2.6.18.ia64/arch/x86_64/kernel/vmlinux.lds.S 2007-03-20 18:40:21.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/x86_64/kernel/vmlinux.lds.S 2007-03-20 22:16:00.000000000 -0400
@@ -103,6 +103,9 @@
.vxtime : AT(VLOAD(.vxtime)) { *(.vxtime) }
vxtime = VVIRT(.vxtime);
+ .vgetcpu_mode : AT(VLOAD(.vgetcpu_mode)) { *(.vgetcpu_mode) }
+ vgetcpu_mode = VVIRT(.vgetcpu_mode);
+
.wall_jiffies : AT(VLOAD(.wall_jiffies)) { *(.wall_jiffies) }
wall_jiffies = VVIRT(.wall_jiffies);
diff -BruN linux-2.6.18.ia64/arch/x86_64/kernel/vsyscall.c linux-2.6.18.ia64-patched/arch/x86_64/kernel/vsyscall.c
--- linux-2.6.18.ia64/arch/x86_64/kernel/vsyscall.c 2007-03-20 18:40:20.000000000 -0400
+++ linux-2.6.18.ia64-patched/arch/x86_64/kernel/vsyscall.c 2007-03-20 22:16:30.000000000 -0400
@@ -26,6 +26,7 @@
#include <linux/seqlock.h>
#include <linux/jiffies.h>
#include <linux/sysctl.h>
+#include <linux/getcpu.h>
#include <asm/vsyscall.h>
#include <asm/pgtable.h>
@@ -33,11 +34,15 @@
#include <asm/fixmap.h>
#include <asm/errno.h>
#include <asm/io.h>
+#include <asm/segment.h>
+#include <asm/desc.h>
+#include <asm/topology.h>
#define __vsyscall(nr) __attribute__ ((unused,__section__(".vsyscall_" #nr)))
int __sysctl_vsyscall __section_sysctl_vsyscall = 1;
seqlock_t __xtime_lock __section_xtime_lock = SEQLOCK_UNLOCKED;
+int __vgetcpu_mode __section_vgetcpu_mode;
#include <asm/unistd.h>
@@ -133,9 +138,46 @@
return __xtime.tv_sec;
}
-long __vsyscall(2) venosys_0(void)
-{
- return -ENOSYS;
+/* Fast way to get current CPU and node.
+ This helps to do per node and per CPU caches in user space.
+ The result is not guaranteed without CPU affinity, but usually
+ works out because the scheduler tries to keep a thread on the same
+ CPU.
+
+ tcache must point to a two element sized long array.
+ All arguments can be NULL. */
+long __vsyscall(2)
+vgetcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *tcache)
+{
+ unsigned int dummy, p;
+ unsigned long j = 0;
+
+ /* Fast cache - only recompute value once per jiffies and avoid
+ relatively costly rdtscp/cpuid otherwise.
+ This works because the scheduler usually keeps the process
+ on the same CPU and this syscall doesn't guarantee its
+ results anyways.
+ We do this here because otherwise user space would do it on
+ its own in a likely inferior way (no access to jiffies).
+ If you don't like it pass NULL. */
+ if (tcache && tcache->blob[0] == (j = __jiffies)) {
+ p = tcache->blob[1];
+ } else if (__vgetcpu_mode == VGETCPU_RDTSCP) {
+ /* Load per CPU data from RDTSCP */
+ rdtscp(dummy, dummy, p);
+ } else {
+ /* Load per CPU data from GDT */
+ asm("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
+ }
+ if (tcache) {
+ tcache->blob[0] = j;
+ tcache->blob[1] = p;
+ }
+ if (cpu)
+ *cpu = p & 0xfff;
+ if (node)
+ *node = p >> 12;
+ return 0;
}
long __vsyscall(3) venosys_1(void)
@@ -206,6 +248,43 @@
#endif
+static void __cpuinit write_rdtscp_cb(void *info)
+{
+ write_rdtscp_aux((unsigned long)info);
+}
+
+void __cpuinit vsyscall_set_cpu(int cpu)
+{
+ unsigned long *d;
+ unsigned long node = 0;
+#ifdef CONFIG_NUMA
+ node = cpu_to_node[cpu];
+#endif
+ if (cpu_has(&cpu_data[cpu], X86_FEATURE_RDTSCP)) {
+ void *info = (void *)((node << 12) | cpu);
+ /* Can happen on preemptive kernel */
+ if (get_cpu() == cpu)
+ write_rdtscp_cb(info);
+#ifdef CONFIG_SMP
+ else {
+ /* the notifier is unfortunately not executed on the
+ target CPU */
+ smp_call_function_single(cpu,write_rdtscp_cb,info,0,1);
+ }
+#endif
+ put_cpu();
+ }
+
+ /* Store cpu number in limit so that it can be loaded quickly
+ in user space in vgetcpu.
+ 12 bits for the CPU and 8 bits for the node. */
+ d = (unsigned long *)(cpu_gdt(cpu) + GDT_ENTRY_PER_CPU);
+ *d = 0x0f40000000000ULL;
+ *d |= cpu;
+ *d |= (node & 0xf) << 12;
+ *d |= (node >> 4) << 48;
+}
+
static void __init map_vsyscall(void)
{
extern char __vsyscall_0;
@@ -220,6 +299,7 @@
VSYSCALL_ADDR(__NR_vgettimeofday)));
BUG_ON((unsigned long) &vtime != VSYSCALL_ADDR(__NR_vtime));
BUG_ON((VSYSCALL_ADDR(0) != __fix_to_virt(VSYSCALL_FIRST_PAGE)));
+ BUG_ON((unsigned long) &vgetcpu != VSYSCALL_ADDR(__NR_vgetcpu));
map_vsyscall();
#ifdef CONFIG_SYSCTL
register_sysctl_table(kernel_root_table2, 0);
diff -BruN linux-2.6.18.ia64/include/asm-i386/unistd.h linux-2.6.18.ia64-patched/include/asm-i386/unistd.h
--- linux-2.6.18.ia64/include/asm-i386/unistd.h 2007-03-20 18:40:15.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/asm-i386/unistd.h 2007-03-20 21:53:11.000000000 -0400
@@ -323,10 +323,11 @@
#define __NR_tee 315
#define __NR_vmsplice 316
#define __NR_move_pages 317
+#define __NR_getcpu 318
#ifdef __KERNEL__
-#define NR_syscalls 318
+#define NR_syscalls 319
#ifndef __KERNEL_SYSCALLS_NO_ERRNO__
/*
diff -BruN linux-2.6.18.ia64/include/asm-ia64/unistd.h linux-2.6.18.ia64-patched/include/asm-ia64/unistd.h
--- linux-2.6.18.ia64/include/asm-ia64/unistd.h 2007-03-20 18:40:15.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/asm-ia64/unistd.h 2007-03-20 19:12:57.000000000 -0400
@@ -291,11 +291,13 @@
#define __NR_sync_file_range 1300
#define __NR_tee 1301
#define __NR_vmsplice 1302
+/* 1303 reserved for move_pages */
+#define __NR_getcpu 1304
#ifdef __KERNEL__
-#define NR_syscalls 279 /* length of syscall table */
+#define NR_syscalls 281 /* length of syscall table */
#define __ARCH_WANT_SYS_RT_SIGACTION
diff -BruN linux-2.6.18.ia64/include/asm-x86_64/segment.h linux-2.6.18.ia64-patched/include/asm-x86_64/segment.h
--- linux-2.6.18.ia64/include/asm-x86_64/segment.h 2007-03-20 18:40:20.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/asm-x86_64/segment.h 2007-04-03 19:52:47.000000000 -0400
@@ -25,10 +25,12 @@
#define GDT_ENTRY_LDT 10 /* needs two entries */
#define GDT_ENTRY_TLS_MIN 12
#define GDT_ENTRY_TLS_MAX 14
-/* 15 free */
#define GDT_ENTRY_TLS_ENTRIES 3
+#define GDT_ENTRY_PER_CPU 15 /* Abused to load per CPU data from limit */
+#define __PER_CPU_SEG (GDT_ENTRY_PER_CPU * 8 + 3)
+
/* TLS indexes for 64bit - hardcoded in arch_prctl */
#define FS_TLS 0
#define GS_TLS 1
diff -BruN linux-2.6.18.ia64/include/asm-x86_64/smp.h linux-2.6.18.ia64-patched/include/asm-x86_64/smp.h
--- linux-2.6.18.ia64/include/asm-x86_64/smp.h 2007-03-20 18:40:21.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/asm-x86_64/smp.h 2007-03-20 22:16:00.000000000 -0400
@@ -131,13 +131,19 @@
/* we don't want to mark this access volatile - bad code generation */
return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR));
}
-#endif
#ifdef CONFIG_SMP
#define cpu_physical_id(cpu) x86_cpu_to_apicid[cpu]
#else
#define cpu_physical_id(cpu) boot_cpu_id
-#endif
-
+static inline int smp_call_function_single(int cpuid, void (*func) (void *info),
+ void *info, int retry, int wait)
+{
+ /* Disable interrupts here? */
+ func(info);
+ return 0;
+}
+#endif /* !CONFIG_SMP */
+#endif /* !__ASSEMBLY */
#endif
diff -BruN linux-2.6.18.ia64/include/asm-x86_64/vsyscall.h linux-2.6.18.ia64-patched/include/asm-x86_64/vsyscall.h
--- linux-2.6.18.ia64/include/asm-x86_64/vsyscall.h 2006-09-19 23:42:06.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/asm-x86_64/vsyscall.h 2007-03-20 22:16:00.000000000 -0400
@@ -4,6 +4,7 @@
enum vsyscall_num {
__NR_vgettimeofday,
__NR_vtime,
+ __NR_vgetcpu,
};
#define VSYSCALL_START (-10UL << 20)
@@ -15,6 +16,7 @@
#include <linux/seqlock.h>
#define __section_vxtime __attribute__ ((unused, __section__ (".vxtime"), aligned(16)))
+#define __section_vgetcpu_mode __attribute__ ((unused, __section__ (".vgetcpu_mode"), aligned(16)))
#define __section_wall_jiffies __attribute__ ((unused, __section__ (".wall_jiffies"), aligned(16)))
#define __section_jiffies __attribute__ ((unused, __section__ (".jiffies"), aligned(16)))
#define __section_sys_tz __attribute__ ((unused, __section__ (".sys_tz"), aligned(16)))
@@ -26,6 +28,9 @@
#define VXTIME_HPET 2
#define VXTIME_PMTMR 3
+#define VGETCPU_RDTSCP 1
+#define VGETCPU_LSL 2
+
struct vxtime_data {
long hpet_address; /* HPET base address */
int last;
@@ -40,6 +45,7 @@
/* vsyscall space (readonly) */
extern struct vxtime_data __vxtime;
+extern int __vgetcpu_mode;
extern struct timespec __xtime;
extern volatile unsigned long __jiffies;
extern unsigned long __wall_jiffies;
@@ -48,6 +54,7 @@
/* kernel space (writeable) */
extern struct vxtime_data vxtime;
+extern int vgetcpu_mode;
extern unsigned long wall_jiffies;
extern struct timezone sys_tz;
extern int sysctl_vsyscall;
@@ -55,6 +62,8 @@
extern int sysctl_vsyscall;
+extern void vsyscall_set_cpu(int cpu);
+
#define ARCH_HAVE_XTIME_LOCK 1
#endif /* __KERNEL__ */
diff -BruN linux-2.6.18.ia64/include/linux/getcpu.h linux-2.6.18.ia64-patched/include/linux/getcpu.h
--- linux-2.6.18.ia64/include/linux/getcpu.h 1969-12-31 19:00:00.000000000 -0500
+++ linux-2.6.18.ia64-patched/include/linux/getcpu.h 2007-03-20 22:16:30.000000000 -0400
@@ -0,0 +1,18 @@
+#ifndef _LINUX_GETCPU_H
+#define _LINUX_GETCPU_H 1
+
+/* Cache for getcpu() to speed it up. Results might be a short time
+ out of date, but will be faster.
+
+ User programs should not refer to the contents of this structure.
+ I repeat they should not refer to it. If they do they will break
+ in future kernels.
+
+ It is only a private cache for vgetcpu(). It will change in future kernels.
+ The user program must store this information per thread (__thread)
+ If you want 100% accurate information pass NULL instead. */
+struct getcpu_cache {
+ unsigned long blob[128 / sizeof(long)];
+};
+
+#endif
diff -BruN linux-2.6.18.ia64/include/linux/syscalls.h linux-2.6.18.ia64-patched/include/linux/syscalls.h
--- linux-2.6.18.ia64/include/linux/syscalls.h 2006-09-19 23:42:06.000000000 -0400
+++ linux-2.6.18.ia64-patched/include/linux/syscalls.h 2007-03-20 21:53:11.000000000 -0400
@@ -53,6 +53,7 @@
struct compat_stat;
struct compat_timeval;
struct robust_list_head;
+struct getcpu_cache;
#include <linux/types.h>
#include <linux/aio_abi.h>
@@ -596,5 +597,6 @@
size_t __user *len_ptr);
asmlinkage long sys_set_robust_list(struct robust_list_head __user *head,
size_t len);
+asmlinkage long sys_getcpu(unsigned *cpu, unsigned *node, struct getcpu_cache *cache);
#endif
diff -BruN linux-2.6.18.ia64/kernel/sys.c linux-2.6.18.ia64-patched/kernel/sys.c
--- linux-2.6.18.ia64/kernel/sys.c 2007-03-20 18:40:14.000000000 -0400
+++ linux-2.6.18.ia64-patched/kernel/sys.c 2007-03-20 22:16:30.000000000 -0400
@@ -28,6 +28,7 @@
#include <linux/tty.h>
#include <linux/signal.h>
#include <linux/cn_proc.h>
+#include <linux/getcpu.h>
#include <linux/compat.h>
#include <linux/syscalls.h>
@@ -2062,3 +2063,33 @@
}
return error;
}
+
+asmlinkage long sys_getcpu(unsigned __user *cpup, unsigned __user *nodep,
+ struct getcpu_cache __user *cache)
+{
+ int err = 0;
+ int cpu = raw_smp_processor_id();
+ if (cpup)
+ err |= put_user(cpu, cpup);
+ if (nodep)
+ err |= put_user(cpu_to_node(cpu), nodep);
+ if (cache) {
+ /*
+ * The cache is not needed for this implementation,
+ * but make sure user programs pass something
+ * valid. vsyscall implementations can instead make
+ * good use of the cache. Only use t0 and t1 because
+ * these are available in both 32bit and 64bit ABI (no
+ * need for a compat_getcpu). 32bit has enough
+ * padding
+ */
+ unsigned long t0, t1;
+ get_user(t0, &cache->blob[0]);
+ get_user(t1, &cache->blob[1]);
+ t0++;
+ t1++;
+ put_user(t0, &cache->blob[0]);
+ put_user(t1, &cache->blob[1]);
+ }
+ return err ? -EFAULT : 0;
+}
distrib
>
Scientific%20Linux
>
5x
>
x86_64
>
by-pkgid
>
27922b4260f65d317aabda37e42bbbff
>
files
>
1940
