[PATCH] powerpc: Remove some unneeded fields from the paca

This patch removes several unnecessary fields from the paca:

- next_jiffy_update_tb was simply unused.  Remove trivially.

- The exdsi exception save area was not used.  There were plans to use
  it, but they never seem to have gone anywhere.  If they ever do, we
  can put it back.  Remove from the paca, and from asm-offsets.c

- The default_decr field was used from asm, but was only ever assigned
  the value of tb_ticks_per_jiffy.  Just access tb_ticks_per_jiffy from
  asm directly instead.

Built and booted on POWER5 LPAR and iSeries RS64.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>

arch/powerpc/kernel/asm-offsets.c

@@ -131,11 +131,9 @@ int main(void)
 	DEFINE(PACALOWHTLBAREAS, offsetof(struct paca_struct, context.low_htlb_areas));
 	DEFINE(PACAHIGHHTLBAREAS, offsetof(struct paca_struct, context.high_htlb_areas));
 #endif /* CONFIG_HUGETLB_PAGE */
-	DEFINE(PACADEFAULTDECR, offsetof(struct paca_struct, default_decr));
 	DEFINE(PACA_EXGEN, offsetof(struct paca_struct, exgen));
 	DEFINE(PACA_EXMC, offsetof(struct paca_struct, exmc));
 	DEFINE(PACA_EXSLB, offsetof(struct paca_struct, exslb));
-	DEFINE(PACA_EXDSI, offsetof(struct paca_struct, exdsi));
 	DEFINE(PACAEMERGSP, offsetof(struct paca_struct, emergency_sp));
 	DEFINE(PACALPPACA, offsetof(struct paca_struct, lppaca));
 	DEFINE(PACAHWCPUID, offsetof(struct paca_struct, hw_cpu_id));

arch/powerpc/kernel/head_64.S

@@ -726,7 +726,8 @@ iSeries_secondary_smp_loop:
 decrementer_iSeries_masked:
 	li	r11,1
 	stb	r11,PACALPPACA+LPPACADECRINT(r13)
-	lwz	r12,PACADEFAULTDECR(r13)
+	LOADBASE(r12,tb_ticks_per_jiffy)
+	lwz	r12,OFF(tb_ticks_per_jiffy)(r13)
 	mtspr	SPRN_DEC,r12
 	/* fall through */
 

arch/powerpc/kernel/paca.c

@@ -37,7 +37,6 @@ extern unsigned long __toc_start;
 #define PACA_INIT_COMMON(number, start, asrr, asrv)			    \
 	.lock_token = 0x8000,						    \
 	.paca_index = (number),		/* Paca Index */		    \
-	.default_decr = 0x00ff0000,	/* Initial Decr */		    \
 	.kernel_toc = (unsigned long)(&__toc_start) + 0x8000UL,		    \
 	.stab_real = (asrr), 		/* Real pointer to segment table */ \
 	.stab_addr = (asrv),		/* Virt pointer to segment table */ \

arch/powerpc/kernel/smp.c

@@ -452,10 +452,6 @@ int __devinit __cpu_up(unsigned int cpu)
 	if (smp_ops->cpu_bootable && !smp_ops->cpu_bootable(cpu))
 		return -EINVAL;
 
-#ifdef CONFIG_PPC64
-	paca[cpu].default_decr = tb_ticks_per_jiffy;
-#endif
-
 	/* Make sure callin-map entry is 0 (can be leftover a CPU
 	 * hotplug
 	 */

arch/powerpc/kernel/time.c

@@ -699,10 +699,6 @@ void __init time_init(void)
 	div128_by_32(1024*1024, 0, tb_ticks_per_sec, &res);
 	tb_to_xs = res.result_low;
 
-#ifdef CONFIG_PPC64
-	get_paca()->default_decr = tb_ticks_per_jiffy;
-#endif
-
 	/*
 	 * Compute scale factor for sched_clock.
 	 * The calibrate_decr() function has set tb_ticks_per_sec,

include/asm-powerpc/paca.h

@@ -60,7 +60,6 @@ struct paca_struct {
 	u16 lock_token;			/* Constant 0x8000, used in locks */
 	u16 paca_index;			/* Logical processor number */
 
-	u32 default_decr;		/* Default decrementer value */
 	u64 kernel_toc;			/* Kernel TOC address */
 	u64 stab_real;			/* Absolute address of segment table */
 	u64 stab_addr;			/* Virtual address of segment table */
@@ -91,14 +90,10 @@ struct paca_struct {
 	struct task_struct *__current;	/* Pointer to current */
 	u64 kstack;			/* Saved Kernel stack addr */
 	u64 stab_rr;			/* stab/slb round-robin counter */
-	u64 next_jiffy_update_tb;	/* TB value for next jiffy update */
 	u64 saved_r1;			/* r1 save for RTAS calls */
 	u64 saved_msr;			/* MSR saved here by enter_rtas */
 	u8 proc_enabled;		/* irq soft-enable flag */
 
-	/* not yet used */
-	u64 exdsi[8];		/* used for linear mapping hash table misses */
-
 	/*
 	 * iSeries structure which the hypervisor knows about -
 	 * this structure should not cross a page boundary.