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authorPaul Mackerras <paulus@samba.org>2008-10-27 19:56:03 -0400
committerPaul Mackerras <paulus@samba.org>2008-11-05 17:49:22 -0500
commit597bc5c00b666fe123abb0af64f6e86f7ab72a90 (patch)
treef6be6e6f07fb1caff3b670a7ac3df74a621ae364 /arch
parentc73049f6aa58ac1d1a9ca8cb2b415ef97240b2d3 (diff)
powerpc: Improve resolution of VDSO clock_gettime
Currently the clock_gettime implementation in the VDSO produces a result with microsecond resolution for the cases that are handled without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC. The nanoseconds field of the result is obtained by computing a microseconds value and multiplying by 1000. This changes the code in the VDSO to do the computation for clock_gettime with nanosecond resolution. That means that the resolution of the result will ultimately depend on the timebase frequency. Because the timestamp in the VDSO datapage (stamp_xsec, the real time corresponding to the timebase count in tb_orig_stamp) is in units of 2^-20 seconds, it doesn't have sufficient resolution for computing a result with nanosecond resolution. Therefore this adds a copy of xtime to the VDSO datapage and updates it in update_gtod() along with the other time-related fields. Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/vdso_datapage.h3
-rw-r--r--arch/powerpc/kernel/asm-offsets.c1
-rw-r--r--arch/powerpc/kernel/time.c1
-rw-r--r--arch/powerpc/kernel/vdso32/gettimeofday.S208
-rw-r--r--arch/powerpc/kernel/vdso64/gettimeofday.S141
5 files changed, 206 insertions, 148 deletions
diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index f01393224b52..13c2c283e178 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -39,6 +39,7 @@
39#ifndef __ASSEMBLY__ 39#ifndef __ASSEMBLY__
40 40
41#include <linux/unistd.h> 41#include <linux/unistd.h>
42#include <linux/time.h>
42 43
43#define SYSCALL_MAP_SIZE ((__NR_syscalls + 31) / 32) 44#define SYSCALL_MAP_SIZE ((__NR_syscalls + 31) / 32)
44 45
@@ -83,6 +84,7 @@ struct vdso_data {
83 __u32 icache_log_block_size; /* L1 i-cache log block size */ 84 __u32 icache_log_block_size; /* L1 i-cache log block size */
84 __s32 wtom_clock_sec; /* Wall to monotonic clock */ 85 __s32 wtom_clock_sec; /* Wall to monotonic clock */
85 __s32 wtom_clock_nsec; 86 __s32 wtom_clock_nsec;
87 struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
86 __u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */ 88 __u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls */
87 __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */ 89 __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
88}; 90};
@@ -102,6 +104,7 @@ struct vdso_data {
102 __u32 tz_dsttime; /* Type of dst correction 0x5C */ 104 __u32 tz_dsttime; /* Type of dst correction 0x5C */
103 __s32 wtom_clock_sec; /* Wall to monotonic clock */ 105 __s32 wtom_clock_sec; /* Wall to monotonic clock */
104 __s32 wtom_clock_nsec; 106 __s32 wtom_clock_nsec;
107 struct timespec stamp_xtime; /* xtime as at tb_orig_stamp */
105 __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */ 108 __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
106 __u32 dcache_block_size; /* L1 d-cache block size */ 109 __u32 dcache_block_size; /* L1 d-cache block size */
107 __u32 icache_block_size; /* L1 i-cache block size */ 110 __u32 icache_block_size; /* L1 i-cache block size */
diff --git a/arch/powerpc/kernel/asm-offsets.c b/arch/powerpc/kernel/asm-offsets.c
index 75c5dd0138fd..050abfd5c17c 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -306,6 +306,7 @@ int main(void)
306 DEFINE(CFG_SYSCALL_MAP32, offsetof(struct vdso_data, syscall_map_32)); 306 DEFINE(CFG_SYSCALL_MAP32, offsetof(struct vdso_data, syscall_map_32));
307 DEFINE(WTOM_CLOCK_SEC, offsetof(struct vdso_data, wtom_clock_sec)); 307 DEFINE(WTOM_CLOCK_SEC, offsetof(struct vdso_data, wtom_clock_sec));
308 DEFINE(WTOM_CLOCK_NSEC, offsetof(struct vdso_data, wtom_clock_nsec)); 308 DEFINE(WTOM_CLOCK_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));
309 DEFINE(STAMP_XTIME, offsetof(struct vdso_data, stamp_xtime));
309 DEFINE(CFG_ICACHE_BLOCKSZ, offsetof(struct vdso_data, icache_block_size)); 310 DEFINE(CFG_ICACHE_BLOCKSZ, offsetof(struct vdso_data, icache_block_size));
310 DEFINE(CFG_DCACHE_BLOCKSZ, offsetof(struct vdso_data, dcache_block_size)); 311 DEFINE(CFG_DCACHE_BLOCKSZ, offsetof(struct vdso_data, dcache_block_size));
311 DEFINE(CFG_ICACHE_LOGBLOCKSZ, offsetof(struct vdso_data, icache_log_block_size)); 312 DEFINE(CFG_ICACHE_LOGBLOCKSZ, offsetof(struct vdso_data, icache_log_block_size));
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index e2ee66b5831d..8389c5be149c 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -456,6 +456,7 @@ static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
456 vdso_data->tb_to_xs = new_tb_to_xs; 456 vdso_data->tb_to_xs = new_tb_to_xs;
457 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; 457 vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
458 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; 458 vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
459 vdso_data->stamp_xtime = xtime;
459 smp_wmb(); 460 smp_wmb();
460 ++(vdso_data->tb_update_count); 461 ++(vdso_data->tb_update_count);
461} 462}
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index 72ca26df457e..ee038d4bf252 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -16,6 +16,13 @@
16#include <asm/asm-offsets.h> 16#include <asm/asm-offsets.h>
17#include <asm/unistd.h> 17#include <asm/unistd.h>
18 18
19/* Offset for the low 32-bit part of a field of long type */
20#ifdef CONFIG_PPC64
21#define LOPART 4
22#else
23#define LOPART 0
24#endif
25
19 .text 26 .text
20/* 27/*
21 * Exact prototype of gettimeofday 28 * Exact prototype of gettimeofday
@@ -90,101 +97,53 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
90 97
91 mflr r12 /* r12 saves lr */ 98 mflr r12 /* r12 saves lr */
92 .cfi_register lr,r12 99 .cfi_register lr,r12
93 mr r10,r3 /* r10 saves id */
94 mr r11,r4 /* r11 saves tp */ 100 mr r11,r4 /* r11 saves tp */
95 bl __get_datapage@local /* get data page */ 101 bl __get_datapage@local /* get data page */
96 mr r9,r3 /* datapage ptr in r9 */ 102 mr r9,r3 /* datapage ptr in r9 */
97 beq cr1,50f /* if monotonic -> jump there */
98
99 /*
100 * CLOCK_REALTIME
101 */
102
103 bl __do_get_xsec@local /* get xsec from tb & kernel */
104 bne- 98f /* out of line -> do syscall */
105
106 /* seconds are xsec >> 20 */
107 rlwinm r5,r4,12,20,31
108 rlwimi r5,r3,12,0,19
109 stw r5,TSPC32_TV_SEC(r11)
110 103
111 /* get remaining xsec and convert to nsec. we scale 10450: bl __do_get_tspec@local /* get sec/nsec from tb & kernel */
112 * up remaining xsec by 12 bits and get the top 32 bits 105 bne cr1,80f /* not monotonic -> all done */
113 * of the multiplication, then we multiply by 1000
114 */
115 rlwinm r5,r4,12,0,19
116 lis r6,1000000@h
117 ori r6,r6,1000000@l
118 mulhwu r5,r5,r6
119 mulli r5,r5,1000
120 stw r5,TSPC32_TV_NSEC(r11)
121 mtlr r12
122 crclr cr0*4+so
123 li r3,0
124 blr
125 106
126 /* 107 /*
127 * CLOCK_MONOTONIC 108 * CLOCK_MONOTONIC
128 */ 109 */
129 110
13050: bl __do_get_xsec@local /* get xsec from tb & kernel */
131 bne- 98f /* out of line -> do syscall */
132
133 /* seconds are xsec >> 20 */
134 rlwinm r6,r4,12,20,31
135 rlwimi r6,r3,12,0,19
136
137 /* get remaining xsec and convert to nsec. we scale
138 * up remaining xsec by 12 bits and get the top 32 bits
139 * of the multiplication, then we multiply by 1000
140 */
141 rlwinm r7,r4,12,0,19
142 lis r5,1000000@h
143 ori r5,r5,1000000@l
144 mulhwu r7,r7,r5
145 mulli r7,r7,1000
146
147 /* now we must fixup using wall to monotonic. We need to snapshot 111 /* now we must fixup using wall to monotonic. We need to snapshot
148 * that value and do the counter trick again. Fortunately, we still 112 * that value and do the counter trick again. Fortunately, we still
149 * have the counter value in r8 that was returned by __do_get_xsec. 113 * have the counter value in r8 that was returned by __do_get_xsec.
150 * At this point, r6,r7 contain our sec/nsec values, r3,r4 and r5 114 * At this point, r3,r4 contain our sec/nsec values, r5 and r6
151 * can be used 115 * can be used, r7 contains NSEC_PER_SEC.
152 */ 116 */
153 117
154 lwz r3,WTOM_CLOCK_SEC(r9) 118 lwz r5,WTOM_CLOCK_SEC(r9)
155 lwz r4,WTOM_CLOCK_NSEC(r9) 119 lwz r6,WTOM_CLOCK_NSEC(r9)
156 120
157 /* We now have our result in r3,r4. We create a fake dependency 121 /* We now have our offset in r5,r6. We create a fake dependency
158 * on that result and re-check the counter 122 * on that value and re-check the counter
159 */ 123 */
160 or r5,r4,r3 124 or r0,r6,r5
161 xor r0,r5,r5 125 xor r0,r0,r0
162 add r9,r9,r0 126 add r9,r9,r0
163#ifdef CONFIG_PPC64 127 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
164 lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
165#else
166 lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
167#endif
168 cmpl cr0,r8,r0 /* check if updated */ 128 cmpl cr0,r8,r0 /* check if updated */
169 bne- 50b 129 bne- 50b
170 130
171 /* Calculate and store result. Note that this mimmics the C code, 131 /* Calculate and store result. Note that this mimics the C code,
172 * which may cause funny results if nsec goes negative... is that 132 * which may cause funny results if nsec goes negative... is that
173 * possible at all ? 133 * possible at all ?
174 */ 134 */
175 add r3,r3,r6 135 add r3,r3,r5
176 add r4,r4,r7 136 add r4,r4,r6
177 lis r5,NSEC_PER_SEC@h 137 cmpw cr0,r4,r7
178 ori r5,r5,NSEC_PER_SEC@l 138 cmpwi cr1,r4,0
179 cmpl cr0,r4,r5
180 cmpli cr1,r4,0
181 blt 1f 139 blt 1f
182 subf r4,r5,r4 140 subf r4,r7,r4
183 addi r3,r3,1 141 addi r3,r3,1
1841: bge cr1,1f 1421: bge cr1,80f
185 addi r3,r3,-1 143 addi r3,r3,-1
186 add r4,r4,r5 144 add r4,r4,r7
1871: stw r3,TSPC32_TV_SEC(r11) 145
14680: stw r3,TSPC32_TV_SEC(r11)
188 stw r4,TSPC32_TV_NSEC(r11) 147 stw r4,TSPC32_TV_NSEC(r11)
189 148
190 mtlr r12 149 mtlr r12
@@ -195,10 +154,6 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
195 /* 154 /*
196 * syscall fallback 155 * syscall fallback
197 */ 156 */
19898:
199 mtlr r12
200 mr r3,r10
201 mr r4,r11
20299: 15799:
203 li r0,__NR_clock_gettime 158 li r0,__NR_clock_gettime
204 sc 159 sc
@@ -254,11 +209,7 @@ __do_get_xsec:
254 /* Check for update count & load values. We use the low 209 /* Check for update count & load values. We use the low
255 * order 32 bits of the update count 210 * order 32 bits of the update count
256 */ 211 */
257#ifdef CONFIG_PPC64 2121: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
2581: lwz r8,(CFG_TB_UPDATE_COUNT+4)(r9)
259#else
2601: lwz r8,(CFG_TB_UPDATE_COUNT)(r9)
261#endif
262 andi. r0,r8,1 /* pending update ? loop */ 213 andi. r0,r8,1 /* pending update ? loop */
263 bne- 1b 214 bne- 1b
264 xor r0,r8,r8 /* create dependency */ 215 xor r0,r8,r8 /* create dependency */
@@ -305,11 +256,7 @@ __do_get_xsec:
305 or r6,r4,r3 256 or r6,r4,r3
306 xor r0,r6,r6 257 xor r0,r6,r6
307 add r9,r9,r0 258 add r9,r9,r0
308#ifdef CONFIG_PPC64 259 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
309 lwz r0,(CFG_TB_UPDATE_COUNT+4)(r9)
310#else
311 lwz r0,(CFG_TB_UPDATE_COUNT)(r9)
312#endif
313 cmpl cr0,r8,r0 /* check if updated */ 260 cmpl cr0,r8,r0 /* check if updated */
314 bne- 1b 261 bne- 1b
315 262
@@ -322,3 +269,98 @@ __do_get_xsec:
322 */ 269 */
3233: blr 2703: blr
324 .cfi_endproc 271 .cfi_endproc
272
273/*
274 * This is the core of clock_gettime(), it returns the current
275 * time in seconds and nanoseconds in r3 and r4.
276 * It expects the datapage ptr in r9 and doesn't clobber it.
277 * It clobbers r0, r5, r6, r10 and returns NSEC_PER_SEC in r7.
278 * On return, r8 contains the counter value that can be reused.
279 * This clobbers cr0 but not any other cr field.
280 */
281__do_get_tspec:
282 .cfi_startproc
283 /* Check for update count & load values. We use the low
284 * order 32 bits of the update count
285 */
2861: lwz r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
287 andi. r0,r8,1 /* pending update ? loop */
288 bne- 1b
289 xor r0,r8,r8 /* create dependency */
290 add r9,r9,r0
291
292 /* Load orig stamp (offset to TB) */
293 lwz r5,CFG_TB_ORIG_STAMP(r9)
294 lwz r6,(CFG_TB_ORIG_STAMP+4)(r9)
295
296 /* Get a stable TB value */
2972: mftbu r3
298 mftbl r4
299 mftbu r0
300 cmpl cr0,r3,r0
301 bne- 2b
302
303 /* Subtract tb orig stamp and shift left 12 bits.
304 */
305 subfc r7,r6,r4
306 subfe r0,r5,r3
307 slwi r0,r0,12
308 rlwimi. r0,r7,12,20,31
309 slwi r7,r7,12
310
311 /* Load scale factor & do multiplication */
312 lwz r5,CFG_TB_TO_XS(r9) /* load values */
313 lwz r6,(CFG_TB_TO_XS+4)(r9)
314 mulhwu r3,r7,r6
315 mullw r10,r7,r5
316 mulhwu r4,r7,r5
317 addc r10,r3,r10
318 li r3,0
319
320 beq+ 4f /* skip high part computation if 0 */
321 mulhwu r3,r0,r5
322 mullw r7,r0,r5
323 mulhwu r5,r0,r6
324 mullw r6,r0,r6
325 adde r4,r4,r7
326 addze r3,r3
327 addc r4,r4,r5
328 addze r3,r3
329 addc r10,r10,r6
330
3314: addze r4,r4 /* add in carry */
332 lis r7,NSEC_PER_SEC@h
333 ori r7,r7,NSEC_PER_SEC@l
334 mulhwu r4,r4,r7 /* convert to nanoseconds */
335
336 /* At this point, we have seconds & nanoseconds since the xtime
337 * stamp in r3+CA and r4. Load & add the xtime stamp.
338 */
339#ifdef CONFIG_PPC64
340 lwz r5,STAMP_XTIME+TSPC64_TV_SEC+LOPART(r9)
341 lwz r6,STAMP_XTIME+TSPC64_TV_NSEC+LOPART(r9)
342#else
343 lwz r5,STAMP_XTIME+TSPC32_TV_SEC(r9)
344 lwz r6,STAMP_XTIME+TSPC32_TV_NSEC(r9)
345#endif
346 add r4,r4,r6
347 adde r3,r3,r5
348
349 /* We now have our result in r3,r4. We create a fake dependency
350 * on that result and re-check the counter
351 */
352 or r6,r4,r3
353 xor r0,r6,r6
354 add r9,r9,r0
355 lwz r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
356 cmpl cr0,r8,r0 /* check if updated */
357 bne- 1b
358
359 /* check for nanosecond overflow and adjust if necessary */
360 cmpw r4,r7
361 bltlr /* all done if no overflow */
362 subf r4,r7,r4 /* adjust if overflow */
363 addi r3,r3,1
364
365 blr
366 .cfi_endproc
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
index c6401f9e37f1..262cd5857a56 100644
--- a/arch/powerpc/kernel/vdso64/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
@@ -75,90 +75,49 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
75 75
76 mflr r12 /* r12 saves lr */ 76 mflr r12 /* r12 saves lr */
77 .cfi_register lr,r12 77 .cfi_register lr,r12
78 mr r10,r3 /* r10 saves id */
79 mr r11,r4 /* r11 saves tp */ 78 mr r11,r4 /* r11 saves tp */
80 bl V_LOCAL_FUNC(__get_datapage) /* get data page */ 79 bl V_LOCAL_FUNC(__get_datapage) /* get data page */
81 beq cr1,50f /* if monotonic -> jump there */ 8050: bl V_LOCAL_FUNC(__do_get_tspec) /* get time from tb & kernel */
82 81 bne cr1,80f /* if not monotonic, all done */
83 /*
84 * CLOCK_REALTIME
85 */
86
87 bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
88
89 lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */
90 ori r7,r7,16960
91 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
92 rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
93 std r5,TSPC64_TV_SEC(r11) /* store sec in tv */
94 subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
95 mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) /
96 * XSEC_PER_SEC
97 */
98 rldicl r0,r0,44,20
99 mulli r0,r0,1000 /* nsec = usec * 1000 */
100 std r0,TSPC64_TV_NSEC(r11) /* store nsec in tp */
101
102 mtlr r12
103 crclr cr0*4+so
104 li r3,0
105 blr
106 82
107 /* 83 /*
108 * CLOCK_MONOTONIC 84 * CLOCK_MONOTONIC
109 */ 85 */
110 86
11150: bl V_LOCAL_FUNC(__do_get_xsec) /* get xsec from tb & kernel */
112
113 lis r7,15 /* r7 = 1000000 = USEC_PER_SEC */
114 ori r7,r7,16960
115 rldicl r5,r4,44,20 /* r5 = sec = xsec / XSEC_PER_SEC */
116 rldicr r6,r5,20,43 /* r6 = sec * XSEC_PER_SEC */
117 subf r0,r6,r4 /* r0 = xsec = (xsec - r6) */
118 mulld r0,r0,r7 /* usec = (xsec * USEC_PER_SEC) /
119 * XSEC_PER_SEC
120 */
121 rldicl r6,r0,44,20
122 mulli r6,r6,1000 /* nsec = usec * 1000 */
123
124 /* now we must fixup using wall to monotonic. We need to snapshot 87 /* now we must fixup using wall to monotonic. We need to snapshot
125 * that value and do the counter trick again. Fortunately, we still 88 * that value and do the counter trick again. Fortunately, we still
126 * have the counter value in r8 that was returned by __do_get_xsec. 89 * have the counter value in r8 that was returned by __do_get_tspec.
127 * At this point, r5,r6 contain our sec/nsec values. 90 * At this point, r4,r5 contain our sec/nsec values.
128 * can be used
129 */ 91 */
130 92
131 lwa r4,WTOM_CLOCK_SEC(r3) 93 lwa r6,WTOM_CLOCK_SEC(r3)
132 lwa r7,WTOM_CLOCK_NSEC(r3) 94 lwa r9,WTOM_CLOCK_NSEC(r3)
133 95
134 /* We now have our result in r4,r7. We create a fake dependency 96 /* We now have our result in r6,r9. We create a fake dependency
135 * on that result and re-check the counter 97 * on that result and re-check the counter
136 */ 98 */
137 or r9,r4,r7 99 or r0,r6,r9
138 xor r0,r9,r9 100 xor r0,r0,r0
139 add r3,r3,r0 101 add r3,r3,r0
140 ld r0,CFG_TB_UPDATE_COUNT(r3) 102 ld r0,CFG_TB_UPDATE_COUNT(r3)
141 cmpld cr0,r0,r8 /* check if updated */ 103 cmpld cr0,r0,r8 /* check if updated */
142 bne- 50b 104 bne- 50b
143 105
144 /* Calculate and store result. Note that this mimmics the C code, 106 /* Add wall->monotonic offset and check for overflow or underflow.
145 * which may cause funny results if nsec goes negative... is that
146 * possible at all ?
147 */ 107 */
148 add r4,r4,r5 108 add r4,r4,r6
149 add r7,r7,r6 109 add r5,r5,r9
150 lis r9,NSEC_PER_SEC@h 110 cmpd cr0,r5,r7
151 ori r9,r9,NSEC_PER_SEC@l 111 cmpdi cr1,r5,0
152 cmpl cr0,r7,r9
153 cmpli cr1,r7,0
154 blt 1f 112 blt 1f
155 subf r7,r9,r7 113 subf r5,r7,r5
156 addi r4,r4,1 114 addi r4,r4,1
1571: bge cr1,1f 1151: bge cr1,80f
158 addi r4,r4,-1 116 addi r4,r4,-1
159 add r7,r7,r9 117 add r5,r5,r7
1601: std r4,TSPC64_TV_SEC(r11) 118
161 std r7,TSPC64_TV_NSEC(r11) 11980: std r4,TSPC64_TV_SEC(r11)
120 std r5,TSPC64_TV_NSEC(r11)
162 121
163 mtlr r12 122 mtlr r12
164 crclr cr0*4+so 123 crclr cr0*4+so
@@ -168,10 +127,6 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
168 /* 127 /*
169 * syscall fallback 128 * syscall fallback
170 */ 129 */
17198:
172 mtlr r12
173 mr r3,r10
174 mr r4,r11
17599: 13099:
176 li r0,__NR_clock_gettime 131 li r0,__NR_clock_gettime
177 sc 132 sc
@@ -253,3 +208,59 @@ V_FUNCTION_BEGIN(__do_get_xsec)
253 blr 208 blr
254 .cfi_endproc 209 .cfi_endproc
255V_FUNCTION_END(__do_get_xsec) 210V_FUNCTION_END(__do_get_xsec)
211
212/*
213 * This is the core of clock_gettime(), it returns the current
214 * time in seconds and nanoseconds in r4 and r5.
215 * It expects the datapage ptr in r3 and doesn't clobber it.
216 * It clobbers r0 and r6 and returns NSEC_PER_SEC in r7.
217 * On return, r8 contains the counter value that can be reused.
218 * This clobbers cr0 but not any other cr field.
219 */
220V_FUNCTION_BEGIN(__do_get_tspec)
221 .cfi_startproc
222 /* check for update count & load values */
2231: ld r8,CFG_TB_UPDATE_COUNT(r3)
224 andi. r0,r8,1 /* pending update ? loop */
225 bne- 1b
226 xor r0,r8,r8 /* create dependency */
227 add r3,r3,r0
228
229 /* Get TB & offset it. We use the MFTB macro which will generate
230 * workaround code for Cell.
231 */
232 MFTB(r7)
233 ld r9,CFG_TB_ORIG_STAMP(r3)
234 subf r7,r9,r7
235
236 /* Scale result */
237 ld r5,CFG_TB_TO_XS(r3)
238 sldi r7,r7,12 /* compute time since stamp_xtime */
239 mulhdu r6,r7,r5 /* in units of 2^-32 seconds */
240
241 /* Add stamp since epoch */
242 ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
243 ld r5,STAMP_XTIME+TSPC64_TV_NSEC(r3)
244 or r0,r4,r5
245 or r0,r0,r6
246 xor r0,r0,r0
247 add r3,r3,r0
248 ld r0,CFG_TB_UPDATE_COUNT(r3)
249 cmpld r0,r8 /* check if updated */
250 bne- 1b /* reload if so */
251
252 /* convert to seconds & nanoseconds and add to stamp */
253 lis r7,NSEC_PER_SEC@h
254 ori r7,r7,NSEC_PER_SEC@l
255 mulhwu r0,r6,r7 /* compute nanoseconds and */
256 srdi r6,r6,32 /* seconds since stamp_xtime */
257 clrldi r0,r0,32
258 add r5,r5,r0 /* add nanoseconds together */
259 cmpd r5,r7 /* overflow? */
260 add r4,r4,r6
261 bltlr /* all done if no overflow */
262 subf r5,r7,r5 /* if overflow, adjust */
263 addi r4,r4,1
264 blr
265 .cfi_endproc
266V_FUNCTION_END(__do_get_tspec)