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-rw-r--r--arch/x86/lib/copy_user_64.S25
-rw-r--r--arch/x86/lib/copy_user_nocache_64.S25
-rw-r--r--arch/x86/lib/delay_32.c56
-rw-r--r--arch/x86/lib/delay_64.c30
4 files changed, 91 insertions, 45 deletions
diff --git a/arch/x86/lib/copy_user_64.S b/arch/x86/lib/copy_user_64.S
index 70bebd3..ee1c3f6 100644
--- a/arch/x86/lib/copy_user_64.S
+++ b/arch/x86/lib/copy_user_64.S
@@ -217,19 +217,19 @@ ENTRY(copy_user_generic_unrolled)
/* table sorted by exception address */
.section __ex_table,"a"
.align 8
- .quad .Ls1,.Ls1e
- .quad .Ls2,.Ls2e
- .quad .Ls3,.Ls3e
- .quad .Ls4,.Ls4e
- .quad .Ld1,.Ls1e
+ .quad .Ls1,.Ls1e /* Ls1-Ls4 have copied zero bytes */
+ .quad .Ls2,.Ls1e
+ .quad .Ls3,.Ls1e
+ .quad .Ls4,.Ls1e
+ .quad .Ld1,.Ls1e /* Ld1-Ld4 have copied 0-24 bytes */
.quad .Ld2,.Ls2e
.quad .Ld3,.Ls3e
.quad .Ld4,.Ls4e
- .quad .Ls5,.Ls5e
- .quad .Ls6,.Ls6e
- .quad .Ls7,.Ls7e
- .quad .Ls8,.Ls8e
- .quad .Ld5,.Ls5e
+ .quad .Ls5,.Ls5e /* Ls5-Ls8 have copied 32 bytes */
+ .quad .Ls6,.Ls5e
+ .quad .Ls7,.Ls5e
+ .quad .Ls8,.Ls5e
+ .quad .Ld5,.Ls5e /* Ld5-Ld8 have copied 32-56 bytes */
.quad .Ld6,.Ls6e
.quad .Ld7,.Ls7e
.quad .Ld8,.Ls8e
@@ -244,11 +244,8 @@ ENTRY(copy_user_generic_unrolled)
.quad .Le5,.Le_zero
.previous
- /* compute 64-offset for main loop. 8 bytes accuracy with error on the
- pessimistic side. this is gross. it would be better to fix the
- interface. */
/* eax: zero, ebx: 64 */
-.Ls1e: addl $8,%eax
+.Ls1e: addl $8,%eax /* eax is bytes left uncopied within the loop (Ls1e: 64 .. Ls8e: 8) */
.Ls2e: addl $8,%eax
.Ls3e: addl $8,%eax
.Ls4e: addl $8,%eax
diff --git a/arch/x86/lib/copy_user_nocache_64.S b/arch/x86/lib/copy_user_nocache_64.S
index 5196762..9d3d1ab 100644
--- a/arch/x86/lib/copy_user_nocache_64.S
+++ b/arch/x86/lib/copy_user_nocache_64.S
@@ -145,19 +145,19 @@ ENTRY(__copy_user_nocache)
/* table sorted by exception address */
.section __ex_table,"a"
.align 8
- .quad .Ls1,.Ls1e
- .quad .Ls2,.Ls2e
- .quad .Ls3,.Ls3e
- .quad .Ls4,.Ls4e
- .quad .Ld1,.Ls1e
+ .quad .Ls1,.Ls1e /* .Ls[1-4] - 0 bytes copied */
+ .quad .Ls2,.Ls1e
+ .quad .Ls3,.Ls1e
+ .quad .Ls4,.Ls1e
+ .quad .Ld1,.Ls1e /* .Ld[1-4] - 0..24 bytes coped */
.quad .Ld2,.Ls2e
.quad .Ld3,.Ls3e
.quad .Ld4,.Ls4e
- .quad .Ls5,.Ls5e
- .quad .Ls6,.Ls6e
- .quad .Ls7,.Ls7e
- .quad .Ls8,.Ls8e
- .quad .Ld5,.Ls5e
+ .quad .Ls5,.Ls5e /* .Ls[5-8] - 32 bytes copied */
+ .quad .Ls6,.Ls5e
+ .quad .Ls7,.Ls5e
+ .quad .Ls8,.Ls5e
+ .quad .Ld5,.Ls5e /* .Ld[5-8] - 32..56 bytes copied */
.quad .Ld6,.Ls6e
.quad .Ld7,.Ls7e
.quad .Ld8,.Ls8e
@@ -172,11 +172,8 @@ ENTRY(__copy_user_nocache)
.quad .Le5,.Le_zero
.previous
- /* compute 64-offset for main loop. 8 bytes accuracy with error on the
- pessimistic side. this is gross. it would be better to fix the
- interface. */
/* eax: zero, ebx: 64 */
-.Ls1e: addl $8,%eax
+.Ls1e: addl $8,%eax /* eax: bytes left uncopied: Ls1e: 64 .. Ls8e: 8 */
.Ls2e: addl $8,%eax
.Ls3e: addl $8,%eax
.Ls4e: addl $8,%eax
diff --git a/arch/x86/lib/delay_32.c b/arch/x86/lib/delay_32.c
index 4535e6d..ef69131 100644
--- a/arch/x86/lib/delay_32.c
+++ b/arch/x86/lib/delay_32.c
@@ -3,6 +3,7 @@
*
* Copyright (C) 1993 Linus Torvalds
* Copyright (C) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
+ * Copyright (C) 2008 Jiri Hladky <hladky _dot_ jiri _at_ gmail _dot_ com>
*
* The __delay function must _NOT_ be inlined as its execution time
* depends wildly on alignment on many x86 processors. The additional
@@ -28,29 +29,58 @@
/* simple loop based delay: */
static void delay_loop(unsigned long loops)
{
- int d0;
-
__asm__ __volatile__(
- "\tjmp 1f\n"
- ".align 16\n"
- "1:\tjmp 2f\n"
- ".align 16\n"
- "2:\tdecl %0\n\tjns 2b"
- :"=&a" (d0)
- :"0" (loops));
+ " test %0,%0 \n"
+ " jz 3f \n"
+ " jmp 1f \n"
+
+ ".align 16 \n"
+ "1: jmp 2f \n"
+
+ ".align 16 \n"
+ "2: decl %0 \n"
+ " jnz 2b \n"
+ "3: decl %0 \n"
+
+ : /* we don't need output */
+ :"a" (loops)
+ );
}
/* TSC based delay: */
static void delay_tsc(unsigned long loops)
{
unsigned long bclock, now;
+ int cpu;
- preempt_disable(); /* TSC's are per-cpu */
+ preempt_disable();
+ cpu = smp_processor_id();
rdtscl(bclock);
- do {
- rep_nop();
+ for (;;) {
rdtscl(now);
- } while ((now-bclock) < loops);
+ if ((now - bclock) >= loops)
+ break;
+
+ /* Allow RT tasks to run */
+ preempt_enable();
+ rep_nop();
+ preempt_disable();
+
+ /*
+ * It is possible that we moved to another CPU, and
+ * since TSC's are per-cpu we need to calculate
+ * that. The delay must guarantee that we wait "at
+ * least" the amount of time. Being moved to another
+ * CPU could make the wait longer but we just need to
+ * make sure we waited long enough. Rebalance the
+ * counter for this CPU.
+ */
+ if (unlikely(cpu != smp_processor_id())) {
+ loops -= (now - bclock);
+ cpu = smp_processor_id();
+ rdtscl(bclock);
+ }
+ }
preempt_enable();
}
diff --git a/arch/x86/lib/delay_64.c b/arch/x86/lib/delay_64.c
index bbc6105..4c441be 100644
--- a/arch/x86/lib/delay_64.c
+++ b/arch/x86/lib/delay_64.c
@@ -31,14 +31,36 @@ int __devinit read_current_timer(unsigned long *timer_value)
void __delay(unsigned long loops)
{
unsigned bclock, now;
+ int cpu;
- preempt_disable(); /* TSC's are pre-cpu */
+ preempt_disable();
+ cpu = smp_processor_id();
rdtscl(bclock);
- do {
- rep_nop();
+ for (;;) {
rdtscl(now);
+ if ((now - bclock) >= loops)
+ break;
+
+ /* Allow RT tasks to run */
+ preempt_enable();
+ rep_nop();
+ preempt_disable();
+
+ /*
+ * It is possible that we moved to another CPU, and
+ * since TSC's are per-cpu we need to calculate
+ * that. The delay must guarantee that we wait "at
+ * least" the amount of time. Being moved to another
+ * CPU could make the wait longer but we just need to
+ * make sure we waited long enough. Rebalance the
+ * counter for this CPU.
+ */
+ if (unlikely(cpu != smp_processor_id())) {
+ loops -= (now - bclock);
+ cpu = smp_processor_id();
+ rdtscl(bclock);
+ }
}
- while ((now-bclock) < loops);
preempt_enable();
}
EXPORT_SYMBOL(__delay);
generated by cgit v1.1 at 2025-08-18 08:55:45 +0000