[Qemu-devel] [PATCH 2/8] target-xtensa: implement CACHEATTR SR

[Max Filippov <jcmvbkbc@gmail.com>]

In XEA1, the Options for Memory Protection and Translation and the
corresponding TLB management instructions are not available. Instead,
functionality similar to the Region Protection Option is available
through the cache attribute register. See ISA, A.2.14 for details.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 target-xtensa/cpu.c          |    1 +
 target-xtensa/cpu.h          |    2 ++
 target-xtensa/helper.c       |   21 ++++++++++++++++++++-
 target-xtensa/overlay_tool.h |    1 +
 target-xtensa/translate.c    |    1 +
 5 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/target-xtensa/cpu.c b/target-xtensa/cpu.c
index c6aa45e..035b07c 100644
--- a/target-xtensa/cpu.c
+++ b/target-xtensa/cpu.c
@@ -48,6 +48,7 @@ static void xtensa_cpu_reset(CPUState *s)
             XTENSA_OPTION_INTERRUPT) ? 0x1f : 0x10;
     env->sregs[VECBASE] = env->config->vecbase;
     env->sregs[IBREAKENABLE] = 0;
+    env->sregs[CACHEATTR] = 0x22222222;
     env->sregs[ATOMCTL] = xtensa_option_enabled(env->config,
             XTENSA_OPTION_ATOMCTL) ? 0x28 : 0x15;
 
diff --git a/target-xtensa/cpu.h b/target-xtensa/cpu.h
index d240ab7..068ad69 100644
--- a/target-xtensa/cpu.h
+++ b/target-xtensa/cpu.h
@@ -94,6 +94,7 @@ enum {
     XTENSA_OPTION_REGION_PROTECTION,
     XTENSA_OPTION_REGION_TRANSLATION,
     XTENSA_OPTION_MMU,
+    XTENSA_OPTION_CACHEATTR,
 
     /* Other */
     XTENSA_OPTION_WINDOWED_REGISTER,
@@ -129,6 +130,7 @@ enum {
     ITLBCFG = 91,
     DTLBCFG = 92,
     IBREAKENABLE = 96,
+    CACHEATTR = 98,
     ATOMCTL = 99,
     IBREAKA = 128,
     DBREAKA = 144,
diff --git a/target-xtensa/helper.c b/target-xtensa/helper.c
index ecd0182..200fb43 100644
--- a/target-xtensa/helper.c
+++ b/target-xtensa/helper.c
@@ -438,6 +438,24 @@ static unsigned region_attr_to_access(uint32_t attr)
     return access[attr & 0xf];
 }
 
+/*!
+ * Convert cacheattr to PAGE_{READ,WRITE,EXEC} mask.
+ * See ISA, A.2.14 The Cache Attribute Register
+ */
+static unsigned cacheattr_attr_to_access(uint32_t attr)
+{
+    static const unsigned access[16] = {
+         [0] = PAGE_READ | PAGE_WRITE             | PAGE_CACHE_WT,
+         [1] = PAGE_READ | PAGE_WRITE | PAGE_EXEC | PAGE_CACHE_WT,
+         [2] = PAGE_READ | PAGE_WRITE | PAGE_EXEC | PAGE_CACHE_BYPASS,
+         [3] =                          PAGE_EXEC | PAGE_CACHE_WB,
+         [4] = PAGE_READ | PAGE_WRITE | PAGE_EXEC | PAGE_CACHE_WB,
+        [14] = PAGE_READ | PAGE_WRITE             | PAGE_CACHE_ISOLATE,
+    };
+
+    return access[attr & 0xf];
+}
+
 static bool is_access_granted(unsigned access, int is_write)
 {
     switch (is_write) {
@@ -584,7 +602,8 @@ int xtensa_get_physical_addr(CPUXtensaState *env, bool update_tlb,
     } else {
         *paddr = vaddr;
         *page_size = TARGET_PAGE_SIZE;
-        *access = PAGE_READ | PAGE_WRITE | PAGE_EXEC | PAGE_CACHE_BYPASS;
+        *access = cacheattr_attr_to_access(
+                env->sregs[CACHEATTR] >> ((vaddr & 0xe0000000) >> 27));
         return 0;
     }
 }
diff --git a/target-xtensa/overlay_tool.h b/target-xtensa/overlay_tool.h
index 50bf573..45205b8 100644
--- a/target-xtensa/overlay_tool.h
+++ b/target-xtensa/overlay_tool.h
@@ -91,6 +91,7 @@
     XCHAL_OPTION(XCHAL_HAVE_XLT_CACHEATTR, \
             XTENSA_OPTION_REGION_TRANSLATION) | \
     XCHAL_OPTION(XCHAL_HAVE_PTP_MMU, XTENSA_OPTION_MMU) | \
+    XCHAL_OPTION(XCHAL_HAVE_CACHEATTR, XTENSA_OPTION_CACHEATTR) | \
     /* Other, TODO */ \
     XCHAL_OPTION(XCHAL_HAVE_WINDOWED, XTENSA_OPTION_WINDOWED_REGISTER) | \
     XCHAL_OPTION(XCHAL_HAVE_DEBUG, XTENSA_OPTION_DEBUG))
diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index 2ba2360..c246fcb 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -99,6 +99,7 @@ static const char * const sregnames[256] = {
     [ITLBCFG] = "ITLBCFG",
     [DTLBCFG] = "DTLBCFG",
     [IBREAKENABLE] = "IBREAKENABLE",
+    [CACHEATTR] = "CACHEATTR",
     [ATOMCTL] = "ATOMCTL",
     [IBREAKA] = "IBREAKA0",
     [IBREAKA + 1] = "IBREAKA1",
-- 
1.7.7.6