[Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports

Paolo Bonzini posted 1 patch 7 years, 3 months ago
Patches applied successfully (tree, apply log)
git fetch https://github.com/patchew-project/qemu tags/patchew/20180801151417.23655-1-pbonzini@redhat.com
Test checkpatch passed
Test docker-mingw@fedora passed
Test docker-clang@ubuntu passed
Test docker-quick@centos7 passed
disas/m68k.c            | 1 +
hw/arm/pxa2xx.c         | 2 +-
hw/audio/cs4231a.c      | 1 +
hw/audio/gusemu_hal.c   | 1 +
hw/audio/sb16.c         | 4 +---
hw/display/cg3.c        | 1 +
hw/display/cirrus_vga.c | 3 ++-
hw/timer/sh_timer.c     | 1 +
target/arm/helper.c     | 1 +
target/i386/translate.c | 2 ++
target/mips/translate.c | 2 ++
11 files changed, 14 insertions(+), 5 deletions(-)
[Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports
Posted by Paolo Bonzini 7 years, 3 months ago
Many of these are marked as "intentional/fix required" because they
just need adding a fall through comment.  This is exactly what this
patch does, except for target/mips/translate.c where it is easier to
duplicate the code, and hw/audio/sb16.c where I consulted the DOSBox
sources and decide to just remove the LOG_UNIMP before the fallthrough.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 disas/m68k.c            | 1 +
 hw/arm/pxa2xx.c         | 2 +-
 hw/audio/cs4231a.c      | 1 +
 hw/audio/gusemu_hal.c   | 1 +
 hw/audio/sb16.c         | 4 +---
 hw/display/cg3.c        | 1 +
 hw/display/cirrus_vga.c | 3 ++-
 hw/timer/sh_timer.c     | 1 +
 target/arm/helper.c     | 1 +
 target/i386/translate.c | 2 ++
 target/mips/translate.c | 2 ++
 11 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/disas/m68k.c b/disas/m68k.c
index a687df437c..0dc8aa1a3c 100644
--- a/disas/m68k.c
+++ b/disas/m68k.c
@@ -1623,6 +1623,7 @@ print_insn_arg (const char *d,
 
     case 'X':
       place = '8';
+      /* fall through */
     case 'Y':
     case 'Z':
     case 'W':
diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
index b67b0cefb6..f598a1c053 100644
--- a/hw/arm/pxa2xx.c
+++ b/hw/arm/pxa2xx.c
@@ -409,7 +409,7 @@ static uint64_t pxa2xx_mm_read(void *opaque, hwaddr addr,
     case MDCNFG ... SA1110:
         if ((addr & 3) == 0)
             return s->mm_regs[addr >> 2];
-
+        /* fall through */
     default:
         printf("%s: Bad register " REG_FMT "\n", __func__, addr);
         break;
diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
index aaebec1839..9089dcb47e 100644
--- a/hw/audio/cs4231a.c
+++ b/hw/audio/cs4231a.c
@@ -305,6 +305,7 @@ static void cs_reset_voices (CSState *s, uint32_t val)
 
     case 6:
         as.endianness = 1;
+        /* fall through */
     case 2:
         as.fmt = AUD_FMT_S16;
         s->shift = as.nchannels;
diff --git a/hw/audio/gusemu_hal.c b/hw/audio/gusemu_hal.c
index 1150fc4426..ae40ca341c 100644
--- a/hw/audio/gusemu_hal.c
+++ b/hw/audio/gusemu_hal.c
@@ -261,6 +261,7 @@ void gus_write(GUSEmuState * state, int port, int size, unsigned int data)
             GUSregb(IRQStatReg2x6) = 0x10;
             GUS_irqrequest(state, state->gusirq, 1);
         }
+        /* fall through */
     case 0x20D:                /* SB2xCd no IRQ */
         GUSregb(SB2xCd) = (uint8_t) data;
         break;
diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
index 5a4d32364e..665a7e75c5 100644
--- a/hw/audio/sb16.c
+++ b/hw/audio/sb16.c
@@ -741,10 +741,8 @@ static void complete (SB16State *s)
             ldebug ("set time const %d\n", s->time_const);
             break;
 
-        case 0x42:              /* FT2 sets output freq with this, go figure */
-            qemu_log_mask(LOG_UNIMP, "cmd 0x42 might not do what it think it"
-                          " should\n");
         case 0x41:
+        case 0x42:              /* FT2 sets output freq with this, go figure */
             s->freq = dsp_get_hilo (s);
             ldebug ("set freq %d\n", s->freq);
             break;
diff --git a/hw/display/cg3.c b/hw/display/cg3.c
index 6fff4852c5..1c199ab369 100644
--- a/hw/display/cg3.c
+++ b/hw/display/cg3.c
@@ -232,6 +232,7 @@ static void cg3_reg_write(void *opaque, hwaddr addr, uint64_t val,
                 s->b[s->dac_index] = regval;
                 /* Index autoincrement */
                 s->dac_index = (s->dac_index + 1) & 0xff;
+                /* fall through */
             default:
                 s->dac_state = 0;
                 break;
diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
index 7583b18c29..04c87c8e8d 100644
--- a/hw/display/cirrus_vga.c
+++ b/hw/display/cirrus_vga.c
@@ -1426,7 +1426,8 @@ static void cirrus_vga_write_sr(CirrusVGAState * s, uint32_t val)
         s->vga.hw_cursor_y = (val << 3) | (s->vga.sr_index >> 5);
 	break;
     case 0x07:			// Extended Sequencer Mode
-    cirrus_update_memory_access(s);
+        cirrus_update_memory_access(s);
+        /* fall through */
     case 0x08:			// EEPROM Control
     case 0x09:			// Scratch Register 0
     case 0x0a:			// Scratch Register 1
diff --git a/hw/timer/sh_timer.c b/hw/timer/sh_timer.c
index 5f8736cf10..91b18ba312 100644
--- a/hw/timer/sh_timer.c
+++ b/hw/timer/sh_timer.c
@@ -74,6 +74,7 @@ static uint32_t sh_timer_read(void *opaque, hwaddr offset)
     case OFFSET_TCPR:
         if (s->feat & TIMER_FEAT_CAPT)
             return s->tcpr;
+        /* fall through */
     default:
         hw_error("sh_timer_read: Bad offset %x\n", (int)offset);
         return 0;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 66afb08ee0..12735ff089 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -12277,6 +12277,7 @@ int arm_rmode_to_sf(int rmode)
         /* FIXME: add support for TIEAWAY and ODD */
         qemu_log_mask(LOG_UNIMP, "arm: unimplemented rounding mode: %d\n",
                       rmode);
+        /* fall through for now */
     case FPROUNDING_TIEEVEN:
     default:
         rmode = float_round_nearest_even;
diff --git a/target/i386/translate.c b/target/i386/translate.c
index 07d185e7b6..1f9d1d9b24 100644
--- a/target/i386/translate.c
+++ b/target/i386/translate.c
@@ -4689,6 +4689,7 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
     case 0x82:
         if (CODE64(s))
             goto illegal_op;
+        /* fall through */
     case 0x80: /* GRP1 */
     case 0x81:
     case 0x83:
@@ -8292,6 +8293,7 @@ static target_ulong disas_insn(DisasContext *s, CPUState *cpu)
     case 0x10e ... 0x10f:
         /* 3DNow! instructions, ignore prefixes */
         s->prefix &= ~(PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA);
+        /* fall through */
     case 0x110 ... 0x117:
     case 0x128 ... 0x12f:
     case 0x138 ... 0x13a:
diff --git a/target/mips/translate.c b/target/mips/translate.c
index 20b43c0337..60408dcda3 100644
--- a/target/mips/translate.c
+++ b/target/mips/translate.c
@@ -19874,6 +19874,8 @@ static void decode_opc(CPUMIPSState *env, DisasContext *ctx)
         case OPC_MTHC1:
             check_cp1_enabled(ctx);
             check_insn(ctx, ISA_MIPS32R2);
+            gen_cp1(ctx, op1, rt, rd);
+            break;
         case OPC_MFC1:
         case OPC_CFC1:
         case OPC_MTC1:
-- 
2.17.1


Re: [Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports
Posted by Philippe Mathieu-Daudé 7 years, 3 months ago
Le mer. 1 août 2018 12:15, Paolo Bonzini <pbonzini@redhat.com> a écrit :

> Many of these are marked as "intentional/fix required" because they
> just need adding a fall through comment.  This is exactly what this
> patch does, except for target/mips/translate.c where it is easier to
> duplicate the code, and hw/audio/sb16.c where I consulted the DOSBox
> sources and decide to just remove the LOG_UNIMP before the fallthrough.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
>  disas/m68k.c            | 1 +
>  hw/arm/pxa2xx.c         | 2 +-
>  hw/audio/cs4231a.c      | 1 +
>  hw/audio/gusemu_hal.c   | 1 +
>  hw/audio/sb16.c         | 4 +---
>  hw/display/cg3.c        | 1 +
>  hw/display/cirrus_vga.c | 3 ++-
>  hw/timer/sh_timer.c     | 1 +
>  target/arm/helper.c     | 1 +
>  target/i386/translate.c | 2 ++
>  target/mips/translate.c | 2 ++
>  11 files changed, 14 insertions(+), 5 deletions(-)
>
> diff --git a/disas/m68k.c b/disas/m68k.c
> index a687df437c..0dc8aa1a3c 100644
> --- a/disas/m68k.c
> +++ b/disas/m68k.c
> @@ -1623,6 +1623,7 @@ print_insn_arg (const char *d,
>
>      case 'X':
>        place = '8';
> +      /* fall through */
>      case 'Y':
>      case 'Z':
>      case 'W':
> diff --git a/hw/arm/pxa2xx.c b/hw/arm/pxa2xx.c
> index b67b0cefb6..f598a1c053 100644
> --- a/hw/arm/pxa2xx.c
> +++ b/hw/arm/pxa2xx.c
> @@ -409,7 +409,7 @@ static uint64_t pxa2xx_mm_read(void *opaque, hwaddr
> addr,
>      case MDCNFG ... SA1110:
>          if ((addr & 3) == 0)
>              return s->mm_regs[addr >> 2];
> -
> +        /* fall through */
>      default:
>          printf("%s: Bad register " REG_FMT "\n", __func__, addr);
>          break;
> diff --git a/hw/audio/cs4231a.c b/hw/audio/cs4231a.c
> index aaebec1839..9089dcb47e 100644
> --- a/hw/audio/cs4231a.c
> +++ b/hw/audio/cs4231a.c
> @@ -305,6 +305,7 @@ static void cs_reset_voices (CSState *s, uint32_t val)
>
>      case 6:
>          as.endianness = 1;
> +        /* fall through */
>      case 2:
>          as.fmt = AUD_FMT_S16;
>          s->shift = as.nchannels;
> diff --git a/hw/audio/gusemu_hal.c b/hw/audio/gusemu_hal.c
> index 1150fc4426..ae40ca341c 100644
> --- a/hw/audio/gusemu_hal.c
> +++ b/hw/audio/gusemu_hal.c
> @@ -261,6 +261,7 @@ void gus_write(GUSEmuState * state, int port, int
> size, unsigned int data)
>              GUSregb(IRQStatReg2x6) = 0x10;
>              GUS_irqrequest(state, state->gusirq, 1);
>          }
> +        /* fall through */
>      case 0x20D:                /* SB2xCd no IRQ */
>          GUSregb(SB2xCd) = (uint8_t) data;
>          break;
> diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
> index 5a4d32364e..665a7e75c5 100644
> --- a/hw/audio/sb16.c
> +++ b/hw/audio/sb16.c
> @@ -741,10 +741,8 @@ static void complete (SB16State *s)
>              ldebug ("set time const %d\n", s->time_const);
>              break;
>
> -        case 0x42:              /* FT2 sets output freq with this, go
> figure */
> -            qemu_log_mask(LOG_UNIMP, "cmd 0x42 might not do what it think
> it"
> -                          " should\n");
>          case 0x41:
> +        case 0x42:              /* FT2 sets output freq with this, go
> figure */
>              s->freq = dsp_get_hilo (s);
>              ldebug ("set freq %d\n", s->freq);
>              break;
> diff --git a/hw/display/cg3.c b/hw/display/cg3.c
> index 6fff4852c5..1c199ab369 100644
> --- a/hw/display/cg3.c
> +++ b/hw/display/cg3.c
> @@ -232,6 +232,7 @@ static void cg3_reg_write(void *opaque, hwaddr addr,
> uint64_t val,
>                  s->b[s->dac_index] = regval;
>                  /* Index autoincrement */
>                  s->dac_index = (s->dac_index + 1) & 0xff;
> +                /* fall through */
>              default:
>                  s->dac_state = 0;
>                  break;
> diff --git a/hw/display/cirrus_vga.c b/hw/display/cirrus_vga.c
> index 7583b18c29..04c87c8e8d 100644
> --- a/hw/display/cirrus_vga.c
> +++ b/hw/display/cirrus_vga.c
> @@ -1426,7 +1426,8 @@ static void cirrus_vga_write_sr(CirrusVGAState * s,
> uint32_t val)
>          s->vga.hw_cursor_y = (val << 3) | (s->vga.sr_index >> 5);
>         break;
>      case 0x07:                 // Extended Sequencer Mode
> -    cirrus_update_memory_access(s);
> +        cirrus_update_memory_access(s);
> +        /* fall through */
>      case 0x08:                 // EEPROM Control
>      case 0x09:                 // Scratch Register 0
>      case 0x0a:                 // Scratch Register 1
> diff --git a/hw/timer/sh_timer.c b/hw/timer/sh_timer.c
> index 5f8736cf10..91b18ba312 100644
> --- a/hw/timer/sh_timer.c
> +++ b/hw/timer/sh_timer.c
> @@ -74,6 +74,7 @@ static uint32_t sh_timer_read(void *opaque, hwaddr
> offset)
>      case OFFSET_TCPR:
>          if (s->feat & TIMER_FEAT_CAPT)
>              return s->tcpr;
> +        /* fall through */
>      default:
>          hw_error("sh_timer_read: Bad offset %x\n", (int)offset);
>          return 0;
> diff --git a/target/arm/helper.c b/target/arm/helper.c
> index 66afb08ee0..12735ff089 100644
> --- a/target/arm/helper.c
> +++ b/target/arm/helper.c
> @@ -12277,6 +12277,7 @@ int arm_rmode_to_sf(int rmode)
>          /* FIXME: add support for TIEAWAY and ODD */
>          qemu_log_mask(LOG_UNIMP, "arm: unimplemented rounding mode: %d\n",
>                        rmode);
> +        /* fall through for now */
>

This one looks weird, hidden bug?

For the rest:

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

     case FPROUNDING_TIEEVEN:
>      default:
>          rmode = float_round_nearest_even;
> diff --git a/target/i386/translate.c b/target/i386/translate.c
> index 07d185e7b6..1f9d1d9b24 100644
> --- a/target/i386/translate.c
> +++ b/target/i386/translate.c
> @@ -4689,6 +4689,7 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
>      case 0x82:
>          if (CODE64(s))
>              goto illegal_op;
> +        /* fall through */
>      case 0x80: /* GRP1 */
>      case 0x81:
>      case 0x83:
> @@ -8292,6 +8293,7 @@ static target_ulong disas_insn(DisasContext *s,
> CPUState *cpu)
>      case 0x10e ... 0x10f:
>          /* 3DNow! instructions, ignore prefixes */
>          s->prefix &= ~(PREFIX_REPZ | PREFIX_REPNZ | PREFIX_DATA);
> +        /* fall through */
>      case 0x110 ... 0x117:
>      case 0x128 ... 0x12f:
>      case 0x138 ... 0x13a:
> diff --git a/target/mips/translate.c b/target/mips/translate.c
> index 20b43c0337..60408dcda3 100644
> --- a/target/mips/translate.c
> +++ b/target/mips/translate.c
> @@ -19874,6 +19874,8 @@ static void decode_opc(CPUMIPSState *env,
> DisasContext *ctx)
>          case OPC_MTHC1:
>              check_cp1_enabled(ctx);
>              check_insn(ctx, ISA_MIPS32R2);
> +            gen_cp1(ctx, op1, rt, rd);
> +            break;
>          case OPC_MFC1:
>          case OPC_CFC1:
>          case OPC_MTC1:
> --
> 2.17.1
>
>
>
Re: [Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports
Posted by Paolo Bonzini 7 years, 3 months ago
On 01/08/2018 17:25, Philippe Mathieu-Daudé wrote:
> 
>     @@ -12277,6 +12277,7 @@ int arm_rmode_to_sf(int rmode)
>              /* FIXME: add support for TIEAWAY and ODD */
>              qemu_log_mask(LOG_UNIMP, "arm: unimplemented rounding mode:
>     %d\n",
>                            rmode);
>     +        /* fall through for now */
> 
> 
> This one looks weird, hidden bug?

There is already a FIXME comment.

Paolo

> For the rest:
> 
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org
> <mailto:f4bug@amsat.org>>


Re: [Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports
Posted by Peter Maydell 7 years, 3 months ago
On 1 August 2018 at 16:14, Paolo Bonzini <pbonzini@redhat.com> wrote:
> Many of these are marked as "intentional/fix required" because they
> just need adding a fall through comment.  This is exactly what this
> patch does, except for target/mips/translate.c where it is easier to
> duplicate the code, and hw/audio/sb16.c where I consulted the DOSBox
> sources and decide to just remove the LOG_UNIMP before the fallthrough.
>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

> diff --git a/hw/audio/sb16.c b/hw/audio/sb16.c
> index 5a4d32364e..665a7e75c5 100644
> --- a/hw/audio/sb16.c
> +++ b/hw/audio/sb16.c
> @@ -741,10 +741,8 @@ static void complete (SB16State *s)
>              ldebug ("set time const %d\n", s->time_const);
>              break;
>
> -        case 0x42:              /* FT2 sets output freq with this, go figure */
> -            qemu_log_mask(LOG_UNIMP, "cmd 0x42 might not do what it think it"
> -                          " should\n");
>          case 0x41:
> +        case 0x42:              /* FT2 sets output freq with this, go figure */
>              s->freq = dsp_get_hilo (s);
>              ldebug ("set freq %d\n", s->freq);
>              break;

I agree with the outcome; see previous discussions
https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg02081.html
https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg02079.html

and this description of what the hardware does:
http://homepages.cae.wisc.edu/~brodskye/sb16doc/sb16doc.html#SamplingRate

We could improve the somewhat cryptic comment:
    /*
     * 0x41 is documented as setting the output sample rate,
     * and 0x42 the input sample rate, but in fact SB16 hardware
     * seems to have only a single sample rate under the hood,
     * and some (buggy) guest programs such as FT2 will set the
     * output rate using 0x42. Compare:
     * http://homepages.cae.wisc.edu/~brodskye/sb16doc/sb16doc.html#SamplingRate
     */

thanks
-- PMM

Re: [Qemu-devel] [PATCH] fix "Missing break in switch" coverity reports
Posted by Paolo Bonzini 7 years, 3 months ago
On 01/08/2018 17:59, Peter Maydell wrote:
> 
> We could improve the somewhat cryptic comment:
>     /*
>      * 0x41 is documented as setting the output sample rate,
>      * and 0x42 the input sample rate, but in fact SB16 hardware
>      * seems to have only a single sample rate under the hood,
>      * and some (buggy) guest programs such as FT2 will set the
>      * output rate using 0x42. Compare:
>      * http://homepages.cae.wisc.edu/~brodskye/sb16doc/sb16doc.html#SamplingRate
>      */

I sometimes enjoy keeping little bits of "old-style QEMU" in these more
historical devices, but your improvement is just too good, so I'll
replace it.  Thanks!

Paolo