5 files changed, 99 insertions, 237 deletions

diff --git a/arch/powerpc/include/asm/vdso_datapage.h b/arch/powerpc/include/asm/vdso_datapage.h
index 13c2c283e178..08679c5319b8 100644
--- a/arch/powerpc/include/asm/vdso_datapage.h
+++ b/arch/powerpc/include/asm/vdso_datapage.h
@@ -85,6 +85,7 @@ struct vdso_data {
         __s32 wtom_clock_sec;                   /* Wall to monotonic clock */
         __s32 wtom_clock_nsec;
         struct timespec stamp_xtime;    /* xtime as at tb_orig_stamp */
+        __u32 stamp_sec_fraction;       /* fractional seconds of stamp_xtime */
         __u32 syscall_map_64[SYSCALL_MAP_SIZE]; /* map of syscalls  */
         __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
 };
@@ -105,6 +106,7 @@ struct vdso_data {
         __s32 wtom_clock_sec;                   /* Wall to monotonic clock */
         __s32 wtom_clock_nsec;
         struct timespec stamp_xtime;    /* xtime as at tb_orig_stamp */
+        __u32 stamp_sec_fraction;       /* fractional seconds of stamp_xtime */
         __u32 syscall_map_32[SYSCALL_MAP_SIZE]; /* map of syscalls */
         __u32 dcache_block_size;        /* L1 d-cache block size     */
         __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 496cc5b3984f..acbbac6aaa22 100644
--- a/arch/powerpc/kernel/asm-offsets.c
+++ b/arch/powerpc/kernel/asm-offsets.c
@@ -342,6 +342,7 @@ int main(void)
         DEFINE(WTOM_CLOCK_SEC, offsetof(struct vdso_data, wtom_clock_sec));
         DEFINE(WTOM_CLOCK_NSEC, offsetof(struct vdso_data, wtom_clock_nsec));
         DEFINE(STAMP_XTIME, offsetof(struct vdso_data, stamp_xtime));
+        DEFINE(STAMP_SEC_FRAC, offsetof(struct vdso_data, stamp_sec_fraction));
         DEFINE(CFG_ICACHE_BLOCKSZ, offsetof(struct vdso_data, icache_block_size));
         DEFINE(CFG_DCACHE_BLOCKSZ, offsetof(struct vdso_data, dcache_block_size));
         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 0441bbdadbd1..5adebaf47f13 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -423,30 +423,6 @@ void udelay(unsigned long usecs)
 }
 EXPORT_SYMBOL(udelay);
 
-static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
-                               u64 new_tb_to_xs)
-{
-        /*
-         * tb_update_count is used to allow the userspace gettimeofday code
-         * to assure itself that it sees a consistent view of the tb_to_xs and
-         * stamp_xsec variables.  It reads the tb_update_count, then reads
-         * tb_to_xs and stamp_xsec and then reads tb_update_count again.  If
-         * the two values of tb_update_count match and are even then the
-         * tb_to_xs and stamp_xsec values are consistent.  If not, then it
-         * loops back and reads them again until this criteria is met.
-         * We expect the caller to have done the first increment of
-         * vdso_data->tb_update_count already.
-         */
-        vdso_data->tb_orig_stamp = new_tb_stamp;
-        vdso_data->stamp_xsec = new_stamp_xsec;
-        vdso_data->tb_to_xs = new_tb_to_xs;
-        vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
-        vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
-        vdso_data->stamp_xtime = xtime;
-        smp_wmb();
-        ++(vdso_data->tb_update_count);
-}
-
 #ifdef CONFIG_SMP
 unsigned long profile_pc(struct pt_regs *regs)
 {
@@ -873,10 +849,37 @@ static cycle_t timebase_read(struct clocksource *cs)
         return (cycle_t)get_tb();
 }
 
+static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
+                               u64 new_tb_to_xs, struct timespec *now,
+                               u32 frac_sec)
+{
+        /*
+         * tb_update_count is used to allow the userspace gettimeofday code
+         * to assure itself that it sees a consistent view of the tb_to_xs and
+         * stamp_xsec variables.  It reads the tb_update_count, then reads
+         * tb_to_xs and stamp_xsec and then reads tb_update_count again.  If
+         * the two values of tb_update_count match and are even then the
+         * tb_to_xs and stamp_xsec values are consistent.  If not, then it
+         * loops back and reads them again until this criteria is met.
+         * We expect the caller to have done the first increment of
+         * vdso_data->tb_update_count already.
+         */
+        vdso_data->tb_orig_stamp = new_tb_stamp;
+        vdso_data->stamp_xsec = new_stamp_xsec;
+        vdso_data->tb_to_xs = new_tb_to_xs;
+        vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec;
+        vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec;
+        vdso_data->stamp_xtime = *now;
+        vdso_data->stamp_sec_fraction = frac_sec;
+        smp_wmb();
+        ++(vdso_data->tb_update_count);
+}
+
 void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
                      u32 mult)
 {
         u64 t2x, stamp_xsec;
+        u32 frac_sec;
 
         if (clock != &clocksource_timebase)
                 return;
@@ -888,10 +891,14 @@ void update_vsyscall(struct timespec *wall_time, struct clocksource *clock,
         /* XXX this assumes clock->shift == 22 */
         /* 4611686018 ~= 2^(20+64-22) / 1e9 */
         t2x = (u64) mult * 4611686018ULL;
-        stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+        stamp_xsec = (u64) wall_time->tv_nsec * XSEC_PER_SEC;
         do_div(stamp_xsec, 1000000000);
-        stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
-        update_gtod(clock->cycle_last, stamp_xsec, t2x);
+        stamp_xsec += (u64) wall_time->tv_sec * XSEC_PER_SEC;
+
+        BUG_ON(wall_time->tv_nsec >= NSEC_PER_SEC);
+        /* this is tv_nsec / 1e9 as a 0.32 fraction */
+        frac_sec = ((u64) wall_time->tv_nsec * 18446744073ULL) >> 32;
+        update_gtod(clock->cycle_last, stamp_xsec, t2x, wall_time, frac_sec);
 }
 
 void update_vsyscall_tz(void)
diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S
index ee038d4bf252..4ee09ee2e836 100644
--- a/arch/powerpc/kernel/vdso32/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso32/gettimeofday.S
@@ -19,8 +19,10 @@
 /* Offset for the low 32-bit part of a field of long type */
 #ifdef CONFIG_PPC64
 #define LOPART  4
+#define TSPEC_TV_SEC    TSPC64_TV_SEC+LOPART
 #else
 #define LOPART  0
+#define TSPEC_TV_SEC    TSPC32_TV_SEC
 #endif
 
         .text
@@ -41,23 +43,11 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
         mr      r9, r3                  /* datapage ptr in r9 */
         cmplwi  r10,0                   /* check if tv is NULL */
         beq     3f
-        bl      __do_get_xsec@local     /* get xsec from tb & kernel */
-        bne-    2f                      /* out of line -> do syscall */
-
-        /* seconds are xsec >> 20 */
-        rlwinm  r5,r4,12,20,31
-        rlwimi  r5,r3,12,0,19
-        stw     r5,TVAL32_TV_SEC(r10)
-
-        /* get remaining xsec and convert to usec. we scale
-         * up remaining xsec by 12 bits and get the top 32 bits
-         * of the multiplication
-         */
-        rlwinm  r5,r4,12,0,19
-        lis     r6,1000000@h
-        ori     r6,r6,1000000@l
-        mulhwu  r5,r5,r6
-        stw     r5,TVAL32_TV_USEC(r10)
+        lis     r7,1000000@ha           /* load up USEC_PER_SEC */
+        addi    r7,r7,1000000@l         /* so we get microseconds in r4 */
+        bl      __do_get_tspec@local    /* get sec/usec from tb & kernel */
+        stw     r3,TVAL32_TV_SEC(r10)
+        stw     r4,TVAL32_TV_USEC(r10)
 
 3:      cmplwi  r11,0                   /* check if tz is NULL */
         beq     1f
@@ -70,14 +60,6 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
         crclr   cr0*4+so
         li      r3,0
         blr
-
-2:
-        mtlr    r12
-        mr      r3,r10
-        mr      r4,r11
-        li      r0,__NR_gettimeofday
-        sc
-        blr
   .cfi_endproc
 V_FUNCTION_END(__kernel_gettimeofday)
 
@@ -100,7 +82,8 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
         mr      r11,r4                  /* r11 saves tp */
         bl      __get_datapage@local    /* get data page */
         mr      r9,r3                   /* datapage ptr in r9 */
-
+        lis     r7,NSEC_PER_SEC@h       /* want nanoseconds */
+        ori     r7,r7,NSEC_PER_SEC@l
 50:     bl      __do_get_tspec@local    /* get sec/nsec from tb & kernel */
         bne     cr1,80f                 /* not monotonic -> all done */
 
@@ -198,83 +181,12 @@ V_FUNCTION_END(__kernel_clock_getres)
 
 
 /*
- * This is the core of gettimeofday() & friends, it returns the xsec
- * value in r3 & r4 and expects the datapage ptr (non clobbered)
- * in r9. clobbers r0,r4,r5,r6,r7,r8.
- * When returning, r8 contains the counter value that can be reused
- * by the monotonic clock implementation
- */
-__do_get_xsec:
-  .cfi_startproc
-        /* Check for update count & load values. We use the low
-         * order 32 bits of the update count
-         */
-1:      lwz     r8,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-        andi.   r0,r8,1                 /* pending update ? loop */
-        bne-    1b
-        xor     r0,r8,r8                /* create dependency */
-        add     r9,r9,r0
-
-        /* Load orig stamp (offset to TB) */
-        lwz     r5,CFG_TB_ORIG_STAMP(r9)
-        lwz     r6,(CFG_TB_ORIG_STAMP+4)(r9)
-
-        /* Get a stable TB value */
-2:      mftbu   r3
-        mftbl   r4
-        mftbu   r0
-        cmpl    cr0,r3,r0
-        bne-    2b
-
-        /* Substract tb orig stamp. If the high part is non-zero, we jump to
-         * the slow path which call the syscall.
-         * If it's ok, then we have our 32 bits tb_ticks value in r7
-         */
-        subfc   r7,r6,r4
-        subfe.  r0,r5,r3
-        bne-    3f
-
-        /* Load scale factor & do multiplication */
-        lwz     r5,CFG_TB_TO_XS(r9)     /* load values */
-        lwz     r6,(CFG_TB_TO_XS+4)(r9)
-        mulhwu  r4,r7,r5
-        mulhwu  r6,r7,r6
-        mullw   r0,r7,r5
-        addc    r6,r6,r0
-
-        /* At this point, we have the scaled xsec value in r4 + XER:CA
-         * we load & add the stamp since epoch
-         */
-        lwz     r5,CFG_STAMP_XSEC(r9)
-        lwz     r6,(CFG_STAMP_XSEC+4)(r9)
-        adde    r4,r4,r6
-        addze   r3,r5
-
-        /* We now have our result in r3,r4. We create a fake dependency
-         * on that result and re-check the counter
-         */
-        or      r6,r4,r3
-        xor     r0,r6,r6
-        add     r9,r9,r0
-        lwz     r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-        cmpl    cr0,r8,r0               /* check if updated */
-        bne-    1b
-
-        /* Warning ! The caller expects CR:EQ to be set to indicate a
-         * successful calculation (so it won't fallback to the syscall
-         * method). We have overriden that CR bit in the counter check,
-         * but fortunately, the loop exit condition _is_ CR:EQ set, so
-         * we can exit safely here. If you change this code, be careful
-         * of that side effect.
-         */
-3:      blr
-  .cfi_endproc
-
-/*
- * This is the core of clock_gettime(), it returns the current
- * time in seconds and nanoseconds in r3 and r4.
+ * This is the core of clock_gettime() and gettimeofday(),
+ * it returns the current time in r3 (seconds) and r4.
+ * On entry, r7 gives the resolution of r4, either USEC_PER_SEC
+ * or NSEC_PER_SEC, giving r4 in microseconds or nanoseconds.
  * It expects the datapage ptr in r9 and doesn't clobber it.
- * It clobbers r0, r5, r6, r10 and returns NSEC_PER_SEC in r7.
+ * It clobbers r0, r5 and r6.
  * On return, r8 contains the counter value that can be reused.
  * This clobbers cr0 but not any other cr field.
  */
@@ -297,70 +209,58 @@ __do_get_tspec:
 2:      mftbu   r3
         mftbl   r4
         mftbu   r0
-        cmpl    cr0,r3,r0
+        cmplw   cr0,r3,r0
         bne-    2b
 
         /* Subtract tb orig stamp and shift left 12 bits.
          */
-        subfc   r7,r6,r4
+        subfc   r4,r6,r4
         subfe   r0,r5,r3
         slwi    r0,r0,12
-        rlwimi. r0,r7,12,20,31
-        slwi    r7,r7,12
+        rlwimi. r0,r4,12,20,31
+        slwi    r4,r4,12
 
-        /* Load scale factor & do multiplication */
+        /*
+         * Load scale factor & do multiplication.
+         * We only use the high 32 bits of the tb_to_xs value.
+         * Even with a 1GHz timebase clock, the high 32 bits of
+         * tb_to_xs will be at least 4 million, so the error from
+         * ignoring the low 32 bits will be no more than 0.25ppm.
+         * The error will just make the clock run very very slightly
+         * slow until the next time the kernel updates the VDSO data,
+         * at which point the clock will catch up to the kernel's value,
+         * so there is no long-term error accumulation.
+         */
         lwz     r5,CFG_TB_TO_XS(r9)     /* load values */
-        lwz     r6,(CFG_TB_TO_XS+4)(r9)
-        mulhwu  r3,r7,r6
-        mullw   r10,r7,r5
-        mulhwu  r4,r7,r5
-        addc    r10,r3,r10
+        mulhwu  r4,r4,r5
         li      r3,0
 
         beq+    4f                      /* skip high part computation if 0 */
         mulhwu  r3,r0,r5
-        mullw   r7,r0,r5
-        mulhwu  r5,r0,r6
-        mullw   r6,r0,r6
-        adde    r4,r4,r7
-        addze   r3,r3
+        mullw   r5,r0,r5
         addc    r4,r4,r5
         addze   r3,r3
-        addc    r10,r10,r6
-
-4:      addze   r4,r4                   /* add in carry */
-        lis     r7,NSEC_PER_SEC@h
-        ori     r7,r7,NSEC_PER_SEC@l
-        mulhwu  r4,r4,r7                /* convert to nanoseconds */
-
-        /* At this point, we have seconds & nanoseconds since the xtime
-         * stamp in r3+CA and r4.  Load & add the xtime stamp.
+4:
+        /* At this point, we have seconds since the xtime stamp
+         * as a 32.32 fixed-point number in r3 and r4.
+         * Load & add the xtime stamp.
          */
-#ifdef CONFIG_PPC64
-        lwz     r5,STAMP_XTIME+TSPC64_TV_SEC+LOPART(r9)
-        lwz     r6,STAMP_XTIME+TSPC64_TV_NSEC+LOPART(r9)
-#else
-        lwz     r5,STAMP_XTIME+TSPC32_TV_SEC(r9)
-        lwz     r6,STAMP_XTIME+TSPC32_TV_NSEC(r9)
-#endif
-        add     r4,r4,r6
+        lwz     r5,STAMP_XTIME+TSPEC_TV_SEC(r9)
+        lwz     r6,STAMP_SEC_FRAC(r9)
+        addc    r4,r4,r6
         adde    r3,r3,r5
 
-        /* We now have our result in r3,r4. We create a fake dependency
-         * on that result and re-check the counter
+        /* We create a fake dependency on the result in r3/r4
+         * and re-check the counter
          */
         or      r6,r4,r3
         xor     r0,r6,r6
         add     r9,r9,r0
         lwz     r0,(CFG_TB_UPDATE_COUNT+LOPART)(r9)
-        cmpl    cr0,r8,r0               /* check if updated */
+        cmplw   cr0,r8,r0               /* check if updated */
         bne-    1b
 
-        /* check for nanosecond overflow and adjust if necessary */
-        cmpw    r4,r7
-        bltlr                           /* all done if no overflow */
-        subf    r4,r7,r4                /* adjust if overflow */
-        addi    r3,r3,1
+        mulhwu  r4,r4,r7                /* convert to micro or nanoseconds */
 
         blr
   .cfi_endproc
diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S
index 262cd5857a56..e97a9a0dc4ac 100644
--- a/arch/powerpc/kernel/vdso64/gettimeofday.S
+++ b/arch/powerpc/kernel/vdso64/gettimeofday.S
@@ -33,18 +33,11 @@ V_FUNCTION_BEGIN(__kernel_gettimeofday)
         bl      V_LOCAL_FUNC(__get_datapage)    /* get data page */
         cmpldi  r11,0                   /* check if tv is NULL */
         beq     2f
-        bl      V_LOCAL_FUNC(__do_get_xsec)     /* get xsec from tb & kernel */
-        lis     r7,15                   /* r7 = 1000000 = USEC_PER_SEC */
-        ori     r7,r7,16960
-        rldicl  r5,r4,44,20             /* r5 = sec = xsec / XSEC_PER_SEC */
-        rldicr  r6,r5,20,43             /* r6 = sec * XSEC_PER_SEC */
-        std     r5,TVAL64_TV_SEC(r11)   /* store sec in tv */
-        subf    r0,r6,r4                /* r0 = xsec = (xsec - r6) */
-        mulld   r0,r0,r7                /* usec = (xsec * USEC_PER_SEC) /
-                                         * XSEC_PER_SEC
-                                         */
-        rldicl  r0,r0,44,20
-        std     r0,TVAL64_TV_USEC(r11)  /* store usec in tv */
+        lis     r7,1000000@ha           /* load up USEC_PER_SEC */
+        addi    r7,r7,1000000@l
+        bl      V_LOCAL_FUNC(__do_get_tspec) /* get sec/us from tb & kernel */
+        std     r4,TVAL64_TV_SEC(r11)   /* store sec in tv */
+        std     r5,TVAL64_TV_USEC(r11)  /* store usec in tv */
 2:      cmpldi  r10,0                   /* check if tz is NULL */
         beq     1f
         lwz     r4,CFG_TZ_MINUTEWEST(r3)/* fill tz */
@@ -77,6 +70,8 @@ V_FUNCTION_BEGIN(__kernel_clock_gettime)
   .cfi_register lr,r12
         mr      r11,r4                  /* r11 saves tp */
         bl      V_LOCAL_FUNC(__get_datapage)    /* get data page */
+        lis     r7,NSEC_PER_SEC@h       /* want nanoseconds */
+        ori     r7,r7,NSEC_PER_SEC@l
 50:     bl      V_LOCAL_FUNC(__do_get_tspec)    /* get time from tb & kernel */
         bne     cr1,80f                 /* if not monotonic, all done */
 
@@ -171,49 +166,12 @@ V_FUNCTION_END(__kernel_clock_getres)
 
 
 /*
- * This is the core of gettimeofday(), it returns the xsec
- * value in r4 and expects the datapage ptr (non clobbered)
- * in r3. clobbers r0,r4,r5,r6,r7,r8
- * When returning, r8 contains the counter value that can be reused
- */
-V_FUNCTION_BEGIN(__do_get_xsec)
-  .cfi_startproc
-        /* check for update count & load values */
-1:      ld      r8,CFG_TB_UPDATE_COUNT(r3)
-        andi.   r0,r8,1                 /* pending update ? loop */
-        bne-    1b
-        xor     r0,r8,r8                /* create dependency */
-        add     r3,r3,r0
-
-        /* Get TB & offset it. We use the MFTB macro which will generate
-         * workaround code for Cell.
-         */
-        MFTB(r7)
-        ld      r9,CFG_TB_ORIG_STAMP(r3)
-        subf    r7,r9,r7
-
-        /* Scale result */
-        ld      r5,CFG_TB_TO_XS(r3)
-        mulhdu  r7,r7,r5
-
-        /* Add stamp since epoch */
-        ld      r6,CFG_STAMP_XSEC(r3)
-        add     r4,r6,r7
-
-        xor     r0,r4,r4
-        add     r3,r3,r0
-        ld      r0,CFG_TB_UPDATE_COUNT(r3)
-        cmpld   cr0,r0,r8               /* check if updated */
-        bne-    1b
-        blr
-  .cfi_endproc
-V_FUNCTION_END(__do_get_xsec)
-
-/*
- * This is the core of clock_gettime(), it returns the current
- * time in seconds and nanoseconds in r4 and r5.
+ * This is the core of clock_gettime() and gettimeofday(),
+ * it returns the current time in r4 (seconds) and r5.
+ * On entry, r7 gives the resolution of r5, either USEC_PER_SEC
+ * or NSEC_PER_SEC, giving r5 in microseconds or nanoseconds.
  * It expects the datapage ptr in r3 and doesn't clobber it.
- * It clobbers r0 and r6 and returns NSEC_PER_SEC in r7.
+ * It clobbers r0, r6 and r9.
  * On return, r8 contains the counter value that can be reused.
  * This clobbers cr0 but not any other cr field.
  */
@@ -229,18 +187,18 @@ V_FUNCTION_BEGIN(__do_get_tspec)
         /* Get TB & offset it. We use the MFTB macro which will generate
          * workaround code for Cell.
          */
-        MFTB(r7)
+        MFTB(r6)
         ld      r9,CFG_TB_ORIG_STAMP(r3)
-        subf    r7,r9,r7
+        subf    r6,r9,r6
 
         /* Scale result */
         ld      r5,CFG_TB_TO_XS(r3)
-        sldi    r7,r7,12                /* compute time since stamp_xtime */
-        mulhdu  r6,r7,r5                /* in units of 2^-32 seconds */
+        sldi    r6,r6,12                /* compute time since stamp_xtime */
+        mulhdu  r6,r6,r5                /* in units of 2^-32 seconds */
 
         /* Add stamp since epoch */
         ld      r4,STAMP_XTIME+TSPC64_TV_SEC(r3)
-        ld      r5,STAMP_XTIME+TSPC64_TV_NSEC(r3)
+        lwz     r5,STAMP_SEC_FRAC(r3)
         or      r0,r4,r5
         or      r0,r0,r6
         xor     r0,r0,r0
@@ -250,17 +208,11 @@ V_FUNCTION_BEGIN(__do_get_tspec)
         bne-    1b                      /* reload if so */
 
         /* convert to seconds & nanoseconds and add to stamp */
-        lis     r7,NSEC_PER_SEC@h
-        ori     r7,r7,NSEC_PER_SEC@l
-        mulhwu  r0,r6,r7                /* compute nanoseconds and */
+        add     r6,r6,r5                /* add on fractional seconds of xtime */
+        mulhwu  r5,r6,r7                /* compute micro or nanoseconds and */
         srdi    r6,r6,32                /* seconds since stamp_xtime */
-        clrldi  r0,r0,32
-        add     r5,r5,r0                /* add nanoseconds together */
-        cmpd    r5,r7                   /* overflow? */
+        clrldi  r5,r5,32
         add     r4,r4,r6
-        bltlr                           /* all done if no overflow */
-        subf    r5,r7,r5                /* if overflow, adjust */
-        addi    r4,r4,1
         blr
   .cfi_endproc
 V_FUNCTION_END(__do_get_tspec)