[PATCH v2 3/4] posix_fadvise: handle 2 variants for SYSCALL_ALIGN_64BIT

arm/powerpc/xtensa pass @advice as 2nd arg to syscall (vs. canonical 4th)

Current code however does this for UCLIBC_SYSCALL_ALIGN_64BIT which
powerpc/xtensa also happen to define.

This is not true for ARCv2 ISA and possibly other arch of future with
64-bit even register requirement, which uses the standard syscall
handler in kernel.

Fix that by providing 2 variants of SYSCALL_ALIGN_64BIT

Signed-off-by: Vineet Gupta <[email protected]>
Cc: Baruch Siach <[email protected]>
Cc: Max Filippov <[email protected]>
---
 libc/sysdeps/linux/common/posix_fadvise.c   | 10 +++++++++-
 libc/sysdeps/linux/common/posix_fadvise64.c | 11 ++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/libc/sysdeps/linux/common/posix_fadvise.c b/libc/sysdeps/linux/common/posix_fadvise.c
index 14bbeeea13bc..74d8409c01c5 100644
--- a/libc/sysdeps/linux/common/posix_fadvise.c
+++ b/libc/sysdeps/linux/common/posix_fadvise.c
@@ -41,9 +41,17 @@ int posix_fadvise(int fd, off_t offset, off_t len, int advice)
 #  if __WORDSIZE == 64
 	ret = INTERNAL_SYSCALL(fadvise64_64, err, 4, fd, offset, len, advice);
 #  else
-#   if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) || defined(__arm__)
+#   if defined (__arm__) || \
+      (defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) && (defined(__powerpc__) || defined(__xtensa__)))
+	/* arch with 64-bit data in even reg alignment #1: [powerpc/xtensa]
+	 * custom syscall handler (rearranges @advice to avoid register hole punch) */
 	ret = INTERNAL_SYSCALL(fadvise64_64, err, 6, fd, advice,
 			OFF_HI_LO (offset), OFF_HI_LO (len));
+#   elif defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
+	/* arch with 64-bit data in even reg alignment #2: [arcv2/others-in-future]
+	 * stock syscall handler in kernel (reg hole punched) */
+	ret = INTERNAL_SYSCALL(fadvise64_64, err, 7, fd, 0,
+			OFF_HI_LO (offset), OFF_HI_LO (len), advice);
 #   else
 	ret = INTERNAL_SYSCALL(fadvise64_64, err, 6, fd,
 			OFF_HI_LO (offset), OFF_HI_LO (len), advice);
diff --git a/libc/sysdeps/linux/common/posix_fadvise64.c b/libc/sysdeps/linux/common/posix_fadvise64.c
index 5d8989121871..37fb269ca8dc 100644
--- a/libc/sysdeps/linux/common/posix_fadvise64.c
+++ b/libc/sysdeps/linux/common/posix_fadvise64.c
@@ -24,9 +24,18 @@ int posix_fadvise64(int fd, off64_t offset, off64_t len, int advice)
 {
 	INTERNAL_SYSCALL_DECL (err);
 	/* ARM has always been funky. */
-# if defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) || defined(__arm__)
+#if defined (__arm__) || \
+    (defined(__UCLIBC_SYSCALL_ALIGN_64BIT__) && (defined(__powerpc__) || defined(__xtensa__)))
+	/* arch with 64-bit data in even reg alignment #1: [powerpc/xtensa]
+	 * custom syscall handler (rearranges @advice to avoid register hole punch) */
 	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 6, fd, advice,
 			OFF64_HI_LO (offset), OFF64_HI_LO (len));
+#elif defined(__UCLIBC_SYSCALL_ALIGN_64BIT__)
+	/* arch with 64-bit data in even reg alignment #2: [arcv2/others-in-future]
+	 * stock syscall handler in kernel (reg hole punched) */
+	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 7, fd, 0,
+			OFF64_HI_LO (offset), OFF64_HI_LO (len),
+			advice);
 # else
 	int ret = INTERNAL_SYSCALL (fadvise64_64, err, 6, fd,
 			OFF64_HI_LO (offset), OFF64_HI_LO (len),
-- 
1.9.1