Pin ar.kr2 of each CPU, so that smp_processor_id can use it.
This will save some memory foot-print when smp_procerror_id()
is called.
This is also useful for implement sys_getcpu in fast path.
I have simply tested the patch by boot on a 16p system then try
offline and online some CPUs through /sys/.
Signed-off-by: Zou Nan hai <nanhai.zou@xxxxxxxxx>
diff -Nraup linux-2.6.20/arch/ia64/kernel/setup.c b/arch/ia64/kernel/setup.c
--- linux-2.6.20/arch/ia64/kernel/setup.c 2007-02-04 13:44:54.000000000 -0500
+++ b/arch/ia64/kernel/setup.c 2007-02-07 23:30:03.000000000 -0500
@@ -458,6 +458,9 @@ early_param("elfcorehdr", parse_elfcoreh
void __init
setup_arch (char **cmdline_p)
{
+ /* setup SMP processor id */
+ ia64_set_kr(IA64_KR_CPU_ID, (current_thread_info()->cpu));
+
unw_init();
ia64_patch_vtop((u64) __start___vtop_patchlist, (u64) __end___vtop_patchlist);
diff -Nraup linux-2.6.20/arch/ia64/kernel/smpboot.c b/arch/ia64/kernel/smpboot.c
--- linux-2.6.20/arch/ia64/kernel/smpboot.c 2007-02-04 13:44:54.000000000 -0500
+++ b/arch/ia64/kernel/smpboot.c 2007-02-07 23:29:44.000000000 -0500
@@ -445,8 +445,12 @@ smp_callin (void)
int __devinit
start_secondary (void *unused)
{
+ /* setup SMP processor id */
+ ia64_set_kr(IA64_KR_CPU_ID, (current_thread_info()->cpu));
+
/* Early console may use I/O ports */
ia64_set_kr(IA64_KR_IO_BASE, __pa(ia64_iobase));
+
Dprintk("start_secondary: starting CPU 0x%x\n", hard_smp_processor_id());
efi_map_pal_code();
cpu_init();
diff -Nraup linux-2.6.20/include/asm-ia64/kregs.h b/include/asm-ia64/kregs.h
--- linux-2.6.20/include/asm-ia64/kregs.h 2007-02-04 13:44:54.000000000 -0500
+++ b/include/asm-ia64/kregs.h 2007-02-07 23:28:21.000000000 -0500
@@ -14,6 +14,7 @@
*/
#define IA64_KR_IO_BASE 0 /* ar.k0: legacy I/O base address */
#define IA64_KR_TSSD 1 /* ar.k1: IVE uses this as the TSSD */
+#define IA64_KR_CPU_ID 2 /* ar.k2: Processor ID */
#define IA64_KR_PER_CPU_DATA 3 /* ar.k3: physical per-CPU base */
#define IA64_KR_CURRENT_STACK 4 /* ar.k4: what's mapped in IA64_TR_CURRENT_STACK */
#define IA64_KR_FPU_OWNER 5 /* ar.k5: fpu-owner (UP only, at the moment) */
diff -Nraup linux-2.6.20/include/asm-ia64/smp.h b/include/asm-ia64/smp.h
--- linux-2.6.20/include/asm-ia64/smp.h 2007-02-04 13:44:54.000000000 -0500
+++ b/include/asm-ia64/smp.h 2007-02-08 00:53:58.000000000 -0500
@@ -45,7 +45,7 @@ ia64_get_lid (void)
#define SMP_IRQ_REDIRECTION (1 << 0)
#define SMP_IPI_REDIRECTION (1 << 1)
-#define raw_smp_processor_id() (current_thread_info()->cpu)
+#define raw_smp_processor_id() (ia64_get_kr(IA64_KR_CPU_ID))
extern struct smp_boot_data {
int cpu_count;
-
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