diff mbox series

[PULL,06/26] target/ppc: Improve logging in Radix MMU

Message ID 20220104073121.3784280-7-clg@kaod.org
State New
Headers show
Series [PULL,01/26] ppc/pnv: Change the maximum of PHB3 devices for Power8NVL | expand

Commit Message

Cédric Le Goater Jan. 4, 2022, 7:31 a.m. UTC 
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211222071002.1568894-1-clg@kaod.org>
Signed-off-by: Cédric Le Goater <clg@kaod.org>
---
 target/ppc/mmu-radix64.c | 55 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 52 insertions(+), 3 deletions(-)

Comments

Peter Maydell Jan. 11, 2022, 4:51 p.m. UTC | #1 
On Tue, 4 Jan 2022 at 07:31, Cédric Le Goater <clg@kaod.org> wrote:
>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
> Message-Id: <20211222071002.1568894-1-clg@kaod.org>
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  target/ppc/mmu-radix64.c | 55 +++++++++++++++++++++++++++++++++++++---
>  1 file changed, 52 insertions(+), 3 deletions(-)

Hi; Coverity reports that this change introduces a use of
an uninitialized variable:

> @@ -306,6 +321,15 @@ static int ppc_radix64_partition_scoped_xlate(PowerPCCPU *cpu,
>      hwaddr pte_addr;
>      uint64_t pte;
>
> +    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
> +                  " mmu_idx %u (prot %c%c%c) 0x%"HWADDR_PRIx"\n",
> +                  __func__, access_str(access_type),
> +                  eaddr, mmu_idx,
> +                  *h_prot & PAGE_READ ? 'r' : '-',
> +                  *h_prot & PAGE_WRITE ? 'w' : '-',
> +                  *h_prot & PAGE_EXEC ? 'x' : '-',
> +                  g_raddr);

At the top of this function we now read the value at h_prot to
do this logging, but all the callsites pass in an uninitialized
value:

   int h_prot;
   ...
           ret = ppc_radix64_partition_scoped_xlate(cpu, 0, eaddr, prtbe_addr,
                                                 pate, &h_raddr, &h_prot, etc);


Are the callsites wrong (should be initializing h_prot), or is the
logging wrong (and it's this function itself which is supposed to
initialize *h_prot as an extra return value) ?

This is CID 1468942.

thanks
-- PMM
Cédric Le Goater Jan. 11, 2022, 5:28 p.m. UTC | #2 
On 1/11/22 17:51, Peter Maydell wrote:
> On Tue, 4 Jan 2022 at 07:31, Cédric Le Goater <clg@kaod.org> wrote:
>>
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
>> Message-Id: <20211222071002.1568894-1-clg@kaod.org>
>> Signed-off-by: Cédric Le Goater <clg@kaod.org>
>> ---
>>   target/ppc/mmu-radix64.c | 55 +++++++++++++++++++++++++++++++++++++---
>>   1 file changed, 52 insertions(+), 3 deletions(-)
> 
> Hi; Coverity reports that this change introduces a use of
> an uninitialized variable:
> 
>> @@ -306,6 +321,15 @@ static int ppc_radix64_partition_scoped_xlate(PowerPCCPU *cpu,
>>       hwaddr pte_addr;
>>       uint64_t pte;
>>
>> +    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
>> +                  " mmu_idx %u (prot %c%c%c) 0x%"HWADDR_PRIx"\n",
>> +                  __func__, access_str(access_type),
>> +                  eaddr, mmu_idx,
>> +                  *h_prot & PAGE_READ ? 'r' : '-',
>> +                  *h_prot & PAGE_WRITE ? 'w' : '-',
>> +                  *h_prot & PAGE_EXEC ? 'x' : '-',
>> +                  g_raddr);
> 
> At the top of this function we now read the value at h_prot to
> do this logging, but all the callsites pass in an uninitialized
> value:
>> 
>     int h_prot;
>     ...
>             ret = ppc_radix64_partition_scoped_xlate(cpu, 0, eaddr, prtbe_addr,
>                                                   pate, &h_raddr, &h_prot, etc);
> 
> 
> Are the callsites wrong (should be initializing h_prot), or is the
> logging wrong (and it's this function itself which is supposed to
> initialize *h_prot as an extra return value) ?>
> This is CID 1468942.

h_prot is initialized after the logging, in ppc_radix64_check_prot().
Logging is wrong.

Thanks,

C.
diff mbox series

Patch

diff --git a/target/ppc/mmu-radix64.c b/target/ppc/mmu-radix64.c
index 5b0e62e676dc..d10ae001d7c9 100644
--- a/target/ppc/mmu-radix64.c
+++ b/target/ppc/mmu-radix64.c
@@ -97,12 +97,22 @@  static void ppc_radix64_raise_segi(PowerPCCPU *cpu, MMUAccessType access_type,
     env->error_code = 0;
 }
 
+static inline const char *access_str(MMUAccessType access_type)
+{
+    return access_type == MMU_DATA_LOAD ? "reading" :
+        (access_type == MMU_DATA_STORE ? "writing" : "execute");
+}
+
 static void ppc_radix64_raise_si(PowerPCCPU *cpu, MMUAccessType access_type,
                                  vaddr eaddr, uint32_t cause)
 {
     CPUState *cs = CPU(cpu);
     CPUPPCState *env = &cpu->env;
 
+    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx" cause %08x\n",
+                  __func__, access_str(access_type),
+                  eaddr, cause);
+
     switch (access_type) {
     case MMU_INST_FETCH:
         /* Instruction Storage Interrupt */
@@ -130,6 +140,11 @@  static void ppc_radix64_raise_hsi(PowerPCCPU *cpu, MMUAccessType access_type,
     CPUState *cs = CPU(cpu);
     CPUPPCState *env = &cpu->env;
 
+    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx" 0x%"
+                  HWADDR_PRIx" cause %08x\n",
+                  __func__, access_str(access_type),
+                  eaddr, g_raddr, cause);
+
     switch (access_type) {
     case MMU_INST_FETCH:
         /* H Instruction Storage Interrupt */
@@ -306,6 +321,15 @@  static int ppc_radix64_partition_scoped_xlate(PowerPCCPU *cpu,
     hwaddr pte_addr;
     uint64_t pte;
 
+    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
+                  " mmu_idx %u (prot %c%c%c) 0x%"HWADDR_PRIx"\n",
+                  __func__, access_str(access_type),
+                  eaddr, mmu_idx,
+                  *h_prot & PAGE_READ ? 'r' : '-',
+                  *h_prot & PAGE_WRITE ? 'w' : '-',
+                  *h_prot & PAGE_EXEC ? 'x' : '-',
+                  g_raddr);
+
     *h_page_size = PRTBE_R_GET_RTS(pate.dw0);
     /* No valid pte or access denied due to protection */
     if (ppc_radix64_walk_tree(CPU(cpu)->as, g_raddr, pate.dw0 & PRTBE_R_RPDB,
@@ -343,6 +367,11 @@  static int ppc_radix64_process_scoped_xlate(PowerPCCPU *cpu,
     hwaddr h_raddr, pte_addr;
     int ret;
 
+    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
+                  " mmu_idx %u pid %"PRIu64"\n",
+                  __func__, access_str(access_type),
+                  eaddr, mmu_idx, pid);
+
     /* Index Process Table by PID to Find Corresponding Process Table Entry */
     offset = pid * sizeof(struct prtb_entry);
     size = 1ULL << ((pate.dw1 & PATE1_R_PRTS) + 12);
@@ -468,9 +497,10 @@  static int ppc_radix64_process_scoped_xlate(PowerPCCPU *cpu,
  *              | = On        | Process Scoped |    Scoped     |
  *              +-------------+----------------+---------------+
  */
-bool ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, MMUAccessType access_type,
-                       hwaddr *raddr, int *psizep, int *protp, int mmu_idx,
-                       bool guest_visible)
+static bool ppc_radix64_xlate_impl(PowerPCCPU *cpu, vaddr eaddr,
+                                   MMUAccessType access_type, hwaddr *raddr,
+                                   int *psizep, int *protp, int mmu_idx,
+                                   bool guest_visible)
 {
     CPUPPCState *env = &cpu->env;
     uint64_t lpid, pid;
@@ -588,3 +618,22 @@  bool ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, MMUAccessType access_type,
 
     return true;
 }
+
+bool ppc_radix64_xlate(PowerPCCPU *cpu, vaddr eaddr, MMUAccessType access_type,
+                       hwaddr *raddrp, int *psizep, int *protp, int mmu_idx,
+                       bool guest_visible)
+{
+    bool ret = ppc_radix64_xlate_impl(cpu, eaddr, access_type, raddrp,
+                                      psizep, protp, mmu_idx, guest_visible);
+
+    qemu_log_mask(CPU_LOG_MMU, "%s for %s @0x%"VADDR_PRIx
+                  " mmu_idx %u (prot %c%c%c) -> 0x%"HWADDR_PRIx"\n",
+                  __func__, access_str(access_type),
+                  eaddr, mmu_idx,
+                  *protp & PAGE_READ ? 'r' : '-',
+                  *protp & PAGE_WRITE ? 'w' : '-',
+                  *protp & PAGE_EXEC ? 'x' : '-',
+                  *raddrp);
+
+    return ret;
+}