Merge remote-tracking branch 'remotes/alistair/tags/pull-riscv-to-apply-20210901-2' into staging

First RISC-V PR for QEMU 6.2

 - Add a config for Shakti UART
 - Fixup virt flash node
 - Don't override users supplied ISA version
 - Fixup some CSR accesses
 - Use g_strjoinv() for virt machine PLIC string config
 - Fix an overflow in the SiFive CLINT
 - Add 64-bit register access helpers
 - Replace tcg_const_* with direct constant usage

# gpg: Signature made Wed 01 Sep 2021 03:08:48 BST
# gpg:                using RSA key F6C4AC46D4934868D3B8CE8F21E10D29DF977054
# gpg: Good signature from "Alistair Francis <alistair@alistair23.me>" [full]
# Primary key fingerprint: F6C4 AC46 D493 4868 D3B8  CE8F 21E1 0D29 DF97 7054

* remotes/alistair/tags/pull-riscv-to-apply-20210901-2: (33 commits)
  target/riscv: Use {get,dest}_gpr for RVV
  target/riscv: Tidy trans_rvh.c.inc
  target/riscv: Use {get,dest}_gpr for RVD
  target/riscv: Use {get,dest}_gpr for RVF
  target/riscv: Use gen_shift_imm_fn for slli_uw
  target/riscv: Use {get,dest}_gpr for RVA
  target/riscv: Reorg csr instructions
  target/riscv: Fix hgeie, hgeip
  target/riscv: Fix rmw_sip, rmw_vsip, rmw_hsip vs write-only operation
  target/riscv: Use {get, dest}_gpr for integer load/store
  target/riscv: Use get_gpr in branches
  target/riscv: Use extracts for sraiw and srliw
  target/riscv: Use DisasExtend in shift operations
  target/riscv: Add DisasExtend to gen_unary
  target/riscv: Move gen_* helpers for RVB
  target/riscv: Move gen_* helpers for RVM
  target/riscv: Use gen_arith for mulh and mulhu
  target/riscv: Remove gen_arith_div*
  target/riscv: Add DisasExtend to gen_arith*
  target/riscv: Introduce DisasExtend and new helpers
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 23 insertions, 2 deletions

diff --git a/hw/intc/sifive_clint.c b/hw/intc/sifive_clint.c
index 0f41e5ea1c..99c870ced2 100644
--- a/hw/intc/sifive_clint.c
+++ b/hw/intc/sifive_clint.c
@@ -59,8 +59,29 @@ static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value,
     riscv_cpu_update_mip(cpu, MIP_MTIP, BOOL_TO_MASK(0));
     diff = cpu->env.timecmp - rtc_r;
     /* back to ns (note args switched in muldiv64) */
-    next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-        muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
+    uint64_t ns_diff = muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
+
+    /*
+     * check if ns_diff overflowed and check if the addition would potentially
+     * overflow
+     */
+    if ((NANOSECONDS_PER_SECOND > timebase_freq && ns_diff < diff) ||
+        ns_diff > INT64_MAX) {
+        next = INT64_MAX;
+    } else {
+        /*
+         * as it is very unlikely qemu_clock_get_ns will return a value
+         * greater than INT64_MAX, no additional check is needed for an
+         * unsigned integer overflow.
+         */
+        next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + ns_diff;
+        /*
+         * if ns_diff is INT64_MAX next may still be outside the range
+         * of a signed integer.
+         */
+        next = MIN(next, INT64_MAX);
+    }
+
     timer_mod(cpu->env.timer, next);
 }