RISC-V Patches for the 5.0 Soft Freeze, Part 1

This patch set contains a handful of collected fixes that I'd like to target
 for the 5.0 soft freeze (I know that's a long way away, I just don't know what
 else to call these):
 
 * A fix for a memory leak initializing the sifive_u board.
 * Fixes to privilege mode emulation related to interrupts and fstatus.
 
 Notably absent is the H extension implementation.  That's pretty much reviewed,
 but not quite ready to go yet and I didn't want to hold back these important
 fixes.  This boots 32-bit and 64-bit Linux (buildroot this time, just for fun)
 and passes "make check".
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Merge remote-tracking branch 'remotes/palmer/tags/riscv-for-master-5.0-sf1' into staging

RISC-V Patches for the 5.0 Soft Freeze, Part 1

This patch set contains a handful of collected fixes that I'd like to target
for the 5.0 soft freeze (I know that's a long way away, I just don't know what
else to call these):

* A fix for a memory leak initializing the sifive_u board.
* Fixes to privilege mode emulation related to interrupts and fstatus.

Notably absent is the H extension implementation.  That's pretty much reviewed,
but not quite ready to go yet and I didn't want to hold back these important
fixes.  This boots 32-bit and 64-bit Linux (buildroot this time, just for fun)
and passes "make check".

# gpg: Signature made Tue 21 Jan 2020 22:55:28 GMT
# gpg:                using RSA key 2B3C3747446843B24A943A7A2E1319F35FBB1889
# gpg:                issuer "palmer@dabbelt.com"
# gpg: Good signature from "Palmer Dabbelt <palmer@dabbelt.com>" [unknown]
# gpg:                 aka "Palmer Dabbelt <palmer@sifive.com>" [unknown]
# gpg:                 aka "Palmer Dabbelt <palmerdabbelt@google.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 00CE 76D1 8349 60DF CE88  6DF8 EF4C A150 2CCB AB41
#      Subkey fingerprint: 2B3C 3747 4468 43B2 4A94  3A7A 2E13 19F3 5FBB 1889

* remotes/palmer/tags/riscv-for-master-5.0-sf1:
  target/riscv: update mstatus.SD when FS is set dirty
  target/riscv: fsd/fsw doesn't dirty FP state
  target/riscv: Fix tb->flags FS status
  riscv: Set xPIE to 1 after xRET
  riscv/sifive_u: fix a memory leak in soc_realize()

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

hw/riscv/sifive_u.c

@@ -542,6 +542,7 @@ static void riscv_sifive_u_soc_realize(DeviceState *dev, Error **errp)
         SIFIVE_U_PLIC_CONTEXT_BASE,
         SIFIVE_U_PLIC_CONTEXT_STRIDE,
         memmap[SIFIVE_U_PLIC].size);
+    g_free(plic_hart_config);
     sifive_uart_create(system_memory, memmap[SIFIVE_U_UART0].base,
         serial_hd(0), qdev_get_gpio_in(DEVICE(s->plic), SIFIVE_U_UART0_IRQ));
     sifive_uart_create(system_memory, memmap[SIFIVE_U_UART1].base,

target/riscv/cpu.h

@@ -293,10 +293,7 @@ static inline void cpu_get_tb_cpu_state(CPURISCVState *env, target_ulong *pc,
 #ifdef CONFIG_USER_ONLY
     *flags = TB_FLAGS_MSTATUS_FS;
 #else
-    *flags = cpu_mmu_index(env, 0);
-    if (riscv_cpu_fp_enabled(env)) {
-        *flags |= TB_FLAGS_MSTATUS_FS;
-    }
+    *flags = cpu_mmu_index(env, 0) | (env->mstatus & MSTATUS_FS);
 #endif
 }
 

target/riscv/csr.c

@@ -341,8 +341,7 @@ static int write_mstatus(CPURISCVState *env, int csrno, target_ulong val)
 
     mstatus = (mstatus & ~mask) | (val & mask);
 
-    dirty = (riscv_cpu_fp_enabled(env) &&
-             ((mstatus & MSTATUS_FS) == MSTATUS_FS)) |
+    dirty = ((mstatus & MSTATUS_FS) == MSTATUS_FS) |
             ((mstatus & MSTATUS_XS) == MSTATUS_XS);
     mstatus = set_field(mstatus, MSTATUS_SD, dirty);
     env->mstatus = mstatus;

target/riscv/insn_trans/trans_rvd.inc.c

@@ -43,7 +43,6 @@ static bool trans_fsd(DisasContext *ctx, arg_fsd *a)
 
     tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEQ);
 
-    mark_fs_dirty(ctx);
     tcg_temp_free(t0);
     return true;
 }

target/riscv/insn_trans/trans_rvf.inc.c

@@ -52,7 +52,6 @@ static bool trans_fsw(DisasContext *ctx, arg_fsw *a)
     tcg_gen_qemu_st_i64(cpu_fpr[a->rs2], t0, ctx->mem_idx, MO_TEUL);
 
     tcg_temp_free(t0);
-    mark_fs_dirty(ctx);
     return true;
 }
 

target/riscv/op_helper.c

@@ -93,7 +93,7 @@ target_ulong helper_sret(CPURISCVState *env, target_ulong cpu_pc_deb)
         env->priv_ver >= PRIV_VERSION_1_10_0 ?
         MSTATUS_SIE : MSTATUS_UIE << prev_priv,
         get_field(mstatus, MSTATUS_SPIE));
-    mstatus = set_field(mstatus, MSTATUS_SPIE, 0);
+    mstatus = set_field(mstatus, MSTATUS_SPIE, 1);
     mstatus = set_field(mstatus, MSTATUS_SPP, PRV_U);
     riscv_cpu_set_mode(env, prev_priv);
     env->mstatus = mstatus;
@@ -118,7 +118,7 @@ target_ulong helper_mret(CPURISCVState *env, target_ulong cpu_pc_deb)
         env->priv_ver >= PRIV_VERSION_1_10_0 ?
         MSTATUS_MIE : MSTATUS_UIE << prev_priv,
         get_field(mstatus, MSTATUS_MPIE));
-    mstatus = set_field(mstatus, MSTATUS_MPIE, 0);
+    mstatus = set_field(mstatus, MSTATUS_MPIE, 1);
     mstatus = set_field(mstatus, MSTATUS_MPP, PRV_U);
     riscv_cpu_set_mode(env, prev_priv);
     env->mstatus = mstatus;

target/riscv/translate.c

@@ -394,7 +394,7 @@ static void mark_fs_dirty(DisasContext *ctx)
 
     tmp = tcg_temp_new();
     tcg_gen_ld_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
-    tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS);
+    tcg_gen_ori_tl(tmp, tmp, MSTATUS_FS | MSTATUS_SD);
     tcg_gen_st_tl(tmp, cpu_env, offsetof(CPURISCVState, mstatus));
     tcg_temp_free(tmp);
 }