[profile] Standardise return type of profile_timestamp()

All consumers of profile_timestamp() currently treat the value as an
unsigned long.  Only the elapsed number of ticks is ever relevant: the
absolute value of the timestamp is not used.  Profiling is used to
measure short durations that are generally fewer than a million CPU
cycles, for which an unsigned long is easily large enough.

Standardise the return type of profile_timestamp() as unsigned long
across all CPU architectures.  This allows 32-bit architectures such
as i386 and riscv32 to omit all logic associated with retrieving the
upper 32 bits of the 64-bit hardware counter, which simplifies the
code and allows riscv32 and riscv64 to share the same implementation.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

7 files changed, 9 insertions, 45 deletions

diff --git a/src/arch/arm32/include/bits/profile.h b/src/arch/arm32/include/bits/profile.h
index 2b15d1604..4e4bf48a3 100644
--- a/src/arch/arm32/include/bits/profile.h
+++ b/src/arch/arm32/include/bits/profile.h
@@ -16,7 +16,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
 	uint32_t cycles;
 
diff --git a/src/arch/arm64/include/bits/profile.h b/src/arch/arm64/include/bits/profile.h
index 62ffa3772..4a5b3f7a1 100644
--- a/src/arch/arm64/include/bits/profile.h
+++ b/src/arch/arm64/include/bits/profile.h
@@ -16,7 +16,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
 	uint64_t cycles;
 
diff --git a/src/arch/i386/include/bits/profile.h b/src/arch/i386/include/bits/profile.h
index e184d7b51..21c216a81 100644
--- a/src/arch/i386/include/bits/profile.h
+++ b/src/arch/i386/include/bits/profile.h
@@ -16,12 +16,12 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
-	uint64_t tsc;
+	uint32_t tsc;
 
 	/* Read timestamp counter */
-	__asm__ __volatile__ ( "rdtsc" : "=A" ( tsc ) );
+	__asm__ __volatile__ ( "rdtsc" : "=a" ( tsc ) : : "edx" );
 	return tsc;
 }
 
diff --git a/src/arch/loong64/include/bits/profile.h b/src/arch/loong64/include/bits/profile.h
index 9f597ce2d..02f8d4b7c 100644
--- a/src/arch/loong64/include/bits/profile.h
+++ b/src/arch/loong64/include/bits/profile.h
@@ -16,7 +16,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
 	uint64_t cycles;
 
diff --git a/src/arch/riscv64/include/bits/profile.h b/src/arch/riscv/include/bits/profile.h
index 2c8e29a22..e9e003dab 100644
--- a/src/arch/riscv64/include/bits/profile.h
+++ b/src/arch/riscv/include/bits/profile.h
@@ -16,9 +16,9 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
-	uint64_t cycles;
+	unsigned long cycles;
 
 	/* Read timestamp counter */
 	__asm__ __volatile__ ( "rdcycle %0" : "=r" ( cycles ) );
diff --git a/src/arch/riscv32/include/bits/profile.h b/src/arch/riscv32/include/bits/profile.h
deleted file mode 100644
index cb969077d..000000000
--- a/src/arch/riscv32/include/bits/profile.h
+++ /dev/null
@@ -1,36 +0,0 @@
-#ifndef _BITS_PROFILE_H
-#define _BITS_PROFILE_H
-
-/** @file
- *
- * Profiling
- *
- */
-
-FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
-
-#include <stdint.h>
-
-/**
- * Get profiling timestamp
- *
- * @ret timestamp	Timestamp
- */
-static inline __attribute__ (( always_inline )) uint64_t
-profile_timestamp ( void ) {
-	uint32_t cycles_lo;
-	uint32_t cycles_hi;
-	uint32_t tmp;
-
-	/* Read timestamp counter */
-	__asm__ __volatile__ ( "\n1:\n\t"
-			       "rdcycleh %1\n\t"
-			       "rdcycle %0\n\t"
-			       "rdcycleh %2\n\t"
-			       "bne %1, %2, 1b\n\t"
-			       : "=r" ( cycles_lo ), "=r" ( cycles_hi ),
-				 "=r" ( tmp ) );
-	return ( ( ( ( uint64_t ) cycles_hi ) << 32 ) | cycles_lo );
-}
-
-#endif /* _BITS_PROFILE_H */
diff --git a/src/arch/x86_64/include/bits/profile.h b/src/arch/x86_64/include/bits/profile.h
index b7c74fbe7..c85b6fe5c 100644
--- a/src/arch/x86_64/include/bits/profile.h
+++ b/src/arch/x86_64/include/bits/profile.h
@@ -16,7 +16,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  *
  * @ret timestamp	Timestamp
  */
-static inline __attribute__ (( always_inline )) uint64_t
+static inline __attribute__ (( always_inline )) unsigned long
 profile_timestamp ( void ) {
 	uint32_t eax;
 	uint32_t edx;