mariadb: fix runtime failure on riscv

Starting with Linux 6.6, RDCYCLE is a privileged instruction on RISC-V
and can't be used directly from userland. This causes 'systemctl start
mysqld.service' failed with error:
[ 1456.918172] mariadbd[12115]: unhandled signal 4 code 0x1 at 0x000055558689d134 in mariadbd[555585bfa000+14a7000]
[ 1456.921772] CPU: 1 PID: 12115 Comm: mariadbd Not tainted 6.6.43-yocto-standard #1
[ 1456.922327] Hardware name: riscv-virtio,qemu (DT)
[ 1456.923045] epc : 000055558689d134 ra : 000055558620ea48 sp : 00007fffdc487770
[ 1456.923525]  gp : 00005555872ec400 tp : 00007fff89560780 t0 : 0000555587be32e8
[ 1456.923951]  t1 : 0000555586886042 t2 : 000000002d6a89f0 s0 : 00007fffdc4877b0

Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

2 files changed, 67 insertions, 0 deletions

diff --git a/meta-oe/recipes-dbs/mysql/mariadb.inc b/meta-oe/recipes-dbs/mysql/mariadb.inc
index 33da32fb28..124a49ff96 100644
--- a/meta-oe/recipes-dbs/mysql/mariadb.inc
+++ b/meta-oe/recipes-dbs/mysql/mariadb.inc
@@ -25,6 +25,7 @@ SRC_URI = "https://archive.mariadb.org/${BP}/source/${BP}.tar.gz \
            file://0001-Add-missing-includes-cstdint-and-cstdio.patch \
            file://0001-Remove-the-compile_time_assert-lines.patch \
            file://0001-MDEV-33439-Fix-build-with-libxml2-2.12.patch \
+           file://0001-RISC-V-use-RDTIME-instead-of-RDCYCLE.patch \
           "
 SRC_URI:append:libc-musl = " file://ppc-remove-glibc-dep.patch"
 SRC_URI[sha256sum] = "5239a245ed90517e96396605cd01ccd8f73cd7442d1b3076b6ffe258110e5157"
diff --git a/meta-oe/recipes-dbs/mysql/mariadb/0001-RISC-V-use-RDTIME-instead-of-RDCYCLE.patch b/meta-oe/recipes-dbs/mysql/mariadb/0001-RISC-V-use-RDTIME-instead-of-RDCYCLE.patch
new file mode 100644
index 0000000000..25a2c399cc
--- /dev/null
+++ b/meta-oe/recipes-dbs/mysql/mariadb/0001-RISC-V-use-RDTIME-instead-of-RDCYCLE.patch
@@ -0,0 +1,66 @@
+From 342f0dd9b4f9fc49dcb589cd98933ea330de55d8 Mon Sep 17 00:00:00 2001
+From: Aurelien Jarno <aurelien@aurel32.net>
+Date: Thu, 4 Jan 2024 11:30:34 +0100
+Subject: [PATCH] RISC-V: use RDTIME instead of RDCYCLE
+
+Starting with Linux 6.6 [1], RDCYCLE is a privileged instruction on
+RISC-V and can't be used directly from userland. There is a sysctl
+option to change that as a transition period, but it will eventually
+disappear.
+
+Use RDTIME instead, which while less accurate has the advantage of being
+synchronized between CPU (and thus monotonic) and of constant frequency.
+
+[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cc4c07c89aada16229084eeb93895c95b7eabaa3
+
+Upstream-Status: Backport [https://github.com/MariaDB/server/commit/656f8867720efc1b4dd0969319f35a3e1a2a005e]
+Signed-off-by: Changqing Li <changqing.li@windriver.com>
+---
+ include/my_rdtsc.h | 12 ++++++------
+ 1 file changed, 6 insertions(+), 6 deletions(-)
+
+diff --git a/include/my_rdtsc.h b/include/my_rdtsc.h
+index 8b9b0046bc0..21e44847d9a 100644
+--- a/include/my_rdtsc.h
++++ b/include/my_rdtsc.h
+@@ -111,7 +111,7 @@ C_MODE_START
+   On AARCH64, we use the generic timer base register. We override clang
+   implementation for aarch64 as it access a PMU register which is not
+   guaranteed to be active.
+-  On RISC-V, we use the rdcycle instruction to read from mcycle register.
++  On RISC-V, we use the rdtime instruction to read from mtime register.
+ 
+   Sadly, we have nothing for the Digital Alpha, MIPS, Motorola m68k,
+   HP PA-RISC or other non-mainstream (or obsolete) processors.
+@@ -211,15 +211,15 @@ static inline ulonglong my_timer_cycles(void)
+   }
+ #elif defined(__riscv)
+   #define MY_TIMER_ROUTINE_CYCLES MY_TIMER_ROUTINE_RISCV
+-  /* Use RDCYCLE (and RDCYCLEH on riscv32) */
++  /* Use RDTIME (and RDTIMEH on riscv32) */
+   {
+ # if __riscv_xlen == 32
+     ulong result_lo, result_hi0, result_hi1;
+     /* Implemented in assembly because Clang insisted on branching. */
+     __asm __volatile__(
+-        "rdcycleh %0\n"
+-        "rdcycle %1\n"
+-        "rdcycleh %2\n"
++        "rdtimeh %0\n"
++        "rdtime %1\n"
++        "rdtimeh %2\n"
+         "sub %0, %0, %2\n"
+         "seqz %0, %0\n"
+         "sub %0, zero, %0\n"
+@@ -228,7 +228,7 @@ static inline ulonglong my_timer_cycles(void)
+     return (static_cast<ulonglong>(result_hi1) << 32) | result_lo;
+ # else
+     ulonglong result;
+-    __asm __volatile__("rdcycle %0" : "=r"(result));
++    __asm __volatile__("rdtime %0" : "=r"(result));
+     return result;
+   }
+ # endif
+-- 
+2.25.1
+