diff mbox series

[v3,39/42] target/arm: Don't shift attrs in get_phys_addr_lpae

Message ID 20221001162318.153420-40-richard.henderson@linaro.org
State Superseded
Headers show
Series target/arm: Implement FEAT_HAFDBS | expand

Commit Message

Richard Henderson Oct. 1, 2022, 4:23 p.m. UTC 
Leave the upper and lower attributes in the place they originate
from in the descriptor.  Shifting them around is confusing, since
one cannot read the bit numbers out of the manual.  Also, new
attributes have been added which would alter the shifts.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/ptw.c | 31 +++++++++++++++----------------
 1 file changed, 15 insertions(+), 16 deletions(-)

Comments

Peter Maydell Oct. 7, 2022, 10:35 a.m. UTC | #1 
On Sat, 1 Oct 2022 at 17:49, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Leave the upper and lower attributes in the place they originate
> from in the descriptor.  Shifting them around is confusing, since
> one cannot read the bit numbers out of the manual.  Also, new
> attributes have been added which would alter the shifts.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/arm/ptw.c | 31 +++++++++++++++----------------
>  1 file changed, 15 insertions(+), 16 deletions(-)
>
> diff --git a/target/arm/ptw.c b/target/arm/ptw.c
> index 01a27b30fb..c68fd73617 100644
> --- a/target/arm/ptw.c
> +++ b/target/arm/ptw.c
> @@ -1071,7 +1071,7 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
>      hwaddr descaddr, indexmask, indexmask_grainsize;
>      uint32_t tableattrs;
>      target_ulong page_size;
> -    uint32_t attrs;
> +    uint64_t attrs;
>      int32_t stride;
>      int addrsize, inputsize, outputsize;
>      uint64_t tcr = regime_tcr(env, mmu_idx);
> @@ -1341,49 +1341,48 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
>      descaddr &= ~(page_size - 1);
>      descaddr |= (address & (page_size - 1));
>      /* Extract attributes from the descriptor */
> -    attrs = extract64(descriptor, 2, 10)
> -        | (extract64(descriptor, 52, 12) << 10);
> +    attrs = descriptor & (MAKE_64BIT_MASK(2, 10) | MAKE_64BIT_MASK(52, 12));

So bit positions for the lower-part bits need to have 2 added,
and bit positions for upper-part bits need to have 42 added.

>      if (mmu_idx == ARMMMUIdx_Stage2 || mmu_idx == ARMMMUIdx_Stage2_S) {
>          ns = mmu_idx == ARMMMUIdx_Stage2;
> -        xn = extract32(attrs, 11, 2);
> +        xn = extract64(attrs, 54, 2);

...so this one looks wrong, should be 53 ?

>          result->f.prot = get_S2prot(env, ap, xn, s1_is_el0);
>      } else {
> -        ns = extract32(attrs, 3, 1);
> -        xn = extract32(attrs, 12, 1);
> -        pxn = extract32(attrs, 11, 1);
> +        ns = extract32(attrs, 5, 1);
> +        xn = extract64(attrs, 54, 1);
> +        pxn = extract64(attrs, 53, 1);

Compare here where bit 11 in the old code is 53 in the new.

>          result->f.prot = get_S1prot(env, mmu_idx, aarch64, ap, ns, xn, pxn);
>      }
>

Otherwise
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

thanks
-- PMM
diff mbox series

Patch

diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index 01a27b30fb..c68fd73617 100644
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -1071,7 +1071,7 @@  static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
     hwaddr descaddr, indexmask, indexmask_grainsize;
     uint32_t tableattrs;
     target_ulong page_size;
-    uint32_t attrs;
+    uint64_t attrs;
     int32_t stride;
     int addrsize, inputsize, outputsize;
     uint64_t tcr = regime_tcr(env, mmu_idx);
@@ -1341,49 +1341,48 @@  static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
     descaddr &= ~(page_size - 1);
     descaddr |= (address & (page_size - 1));
     /* Extract attributes from the descriptor */
-    attrs = extract64(descriptor, 2, 10)
-        | (extract64(descriptor, 52, 12) << 10);
+    attrs = descriptor & (MAKE_64BIT_MASK(2, 10) | MAKE_64BIT_MASK(52, 12));
 
     if (mmu_idx == ARMMMUIdx_Stage2 || mmu_idx == ARMMMUIdx_Stage2_S) {
         /* Stage 2 table descriptors do not include any attribute fields */
         goto skip_attrs;
     }
     /* Merge in attributes from table descriptors */
-    attrs |= nstable << 3; /* NS */
+    attrs |= nstable << 5; /* NS */
     guarded = extract64(descriptor, 50, 1);  /* GP */
     if (param.hpd) {
         /* HPD disables all the table attributes except NSTable.  */
         goto skip_attrs;
     }
-    attrs |= extract32(tableattrs, 0, 2) << 11;     /* XN, PXN */
+    attrs |= extract64(tableattrs, 0, 2) << 53;     /* XN, PXN */
     /*
      * The sense of AP[1] vs APTable[0] is reversed, as APTable[0] == 1
      * means "force PL1 access only", which means forcing AP[1] to 0.
      */
-    attrs &= ~(extract32(tableattrs, 2, 1) << 4);   /* !APT[0] => AP[1] */
-    attrs |= extract32(tableattrs, 3, 1) << 5;      /* APT[1] => AP[2] */
+    attrs &= ~(extract64(tableattrs, 2, 1) << 6);   /* !APT[0] => AP[1] */
+    attrs |= extract32(tableattrs, 3, 1) << 7;      /* APT[1] => AP[2] */
  skip_attrs:
 
     /*
      * Here descaddr is the final physical address, and attributes
      * are all in attrs.
      */
-    if ((attrs & (1 << 8)) == 0) {
+    if ((attrs & (1 << 10)) == 0) {
         /* Access flag */
         fi->type = ARMFault_AccessFlag;
         goto do_fault;
     }
 
-    ap = extract32(attrs, 4, 2);
+    ap = extract32(attrs, 6, 2);
 
     if (mmu_idx == ARMMMUIdx_Stage2 || mmu_idx == ARMMMUIdx_Stage2_S) {
         ns = mmu_idx == ARMMMUIdx_Stage2;
-        xn = extract32(attrs, 11, 2);
+        xn = extract64(attrs, 54, 2);
         result->f.prot = get_S2prot(env, ap, xn, s1_is_el0);
     } else {
-        ns = extract32(attrs, 3, 1);
-        xn = extract32(attrs, 12, 1);
-        pxn = extract32(attrs, 11, 1);
+        ns = extract32(attrs, 5, 1);
+        xn = extract64(attrs, 54, 1);
+        pxn = extract64(attrs, 53, 1);
         result->f.prot = get_S1prot(env, mmu_idx, aarch64, ap, ns, xn, pxn);
     }
 
@@ -1408,10 +1407,10 @@  static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
 
     if (mmu_idx == ARMMMUIdx_Stage2 || mmu_idx == ARMMMUIdx_Stage2_S) {
         result->cacheattrs.is_s2_format = true;
-        result->cacheattrs.attrs = extract32(attrs, 0, 4);
+        result->cacheattrs.attrs = extract32(attrs, 2, 4);
     } else {
         /* Index into MAIR registers for cache attributes */
-        uint8_t attrindx = extract32(attrs, 0, 3);
+        uint8_t attrindx = extract32(attrs, 2, 3);
         uint64_t mair = env->cp15.mair_el[regime_el(env, mmu_idx)];
         assert(attrindx <= 7);
         result->cacheattrs.is_s2_format = false;
@@ -1426,7 +1425,7 @@  static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
     if (param.ds) {
         result->cacheattrs.shareability = param.sh;
     } else {
-        result->cacheattrs.shareability = extract32(attrs, 6, 2);
+        result->cacheattrs.shareability = extract32(attrs, 8, 2);
     }
 
     result->f.phys_addr = descaddr;