[Xen-devel] [PATCH v4 3/9] arm/mem_access: Add short-descriptor pte typedefs

[Sergej Proskurin <proskurin@xxxxxxxxxxxxx>]

The current implementation does not provide appropriate types for
short-descriptor translation table entries. As such, this commit adds new
types, which simplify managing the respective translation table entries.

Signed-off-by: Sergej Proskurin <proskurin@xxxxxxxxxxxxx>
---
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Julien Grall <julien.grall@xxxxxxx>
---
v3: Add more short-descriptor related pte typedefs that will be used by
    the following commits.

v4: Move short-descriptor pte typedefs out of page.h into short-desc.h.

    Change the type unsigned int to bool of every bitfield in
    short-descriptor related data-structures that holds only one bit.

    Change the typedef names from pte_sd_* to short_desc_*.
---
 xen/include/asm-arm/short-desc.h | 108 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 xen/include/asm-arm/short-desc.h

diff --git a/xen/include/asm-arm/short-desc.h b/xen/include/asm-arm/short-desc.h
new file mode 100644
index 0000000000..6e2ab09d24
--- /dev/null
+++ b/xen/include/asm-arm/short-desc.h
@@ -0,0 +1,108 @@
+#ifndef __ARM_SHORT_DESC_H__
+#define __ARM_SHORT_DESC_H__
+
+/*
+ * Comprises bits of the level 1 short-descriptor format representing
+ * a section.
+ */
+typedef struct __packed {
+    bool pxn:1;                 /* Privileged Execute Never */
+    bool sec:1;                 /* == 1 if section or supersection */
+    bool b:1;                   /* Bufferable */
+    bool c:1;                   /* Cacheable */
+    bool xn:1;                  /* Execute Never */
+    unsigned int dom:4;         /* Domain field */
+    bool impl:1;                /* Implementation defined */
+    unsigned int ap:2;          /* AP[1:0] */
+    unsigned int tex:3;         /* TEX[2:0] */
+    bool ro:1;                  /* AP[2] */
+    bool s:1;                   /* Shareable */
+    bool ng:1;                  /* Non-global */
+    bool supersec:1;            /* Must be 0 for sections */
+    bool ns:1;                  /* Non-secure */
+    unsigned int base:12;       /* Section base address */
+} short_desc_l1_sec_t;
+
+/*
+ * Comprises bits of the level 1 short-descriptor format representing
+ * a supersection.
+ */
+typedef struct __packed {
+    bool pxn:1;                 /* Privileged Execute Never */
+    bool sec:1;                 /* == 1 if section or supersection */
+    bool b:1;                   /* Bufferable */
+    bool c:1;                   /* Cacheable */
+    bool xn:1;                  /* Execute Never */
+    unsigned int extbase2:4;    /* Extended base address, PA[39:36] */
+    bool impl:1;                /* Implementation defined */
+    unsigned int ap:2;          /* AP[1:0] */
+    unsigned int tex:3;         /* TEX[2:0] */
+    bool ro:1;                  /* AP[2] */
+    bool s:1;                   /* Shareable */
+    bool ng:1;                  /* Non-global */
+    bool supersec:1;            /* Must be 0 for sections */
+    bool ns:1;                  /* Non-secure */
+    unsigned int extbase1:4;    /* Extended base address, PA[35:32] */
+    unsigned int base:8;        /* Supersection base address */
+} short_desc_l1_supersec_t;
+
+/*
+ * Comprises bits of the level 2 short-descriptor format representing
+ * a small page.
+ */
+typedef struct __packed {
+    bool xn:1;                  /* Execute Never */
+    bool page:1;                /* ==1 if small page */
+    bool b:1;                   /* Bufferable */
+    bool c:1;                   /* Cacheable */
+    unsigned int ap:2;          /* AP[1:0] */
+    unsigned int tex:3;         /* TEX[2:0] */
+    bool ro:1;                  /* AP[2] */
+    bool s:1;                   /* Shareable */
+    bool ng:1;                  /* Non-global */
+    unsigned int base:20;       /* Small page base address */
+} short_desc_l2_page_t;
+
+/*
+ * Comprises bits of the level 2 short-descriptor format representing
+ * a large page.
+ */
+typedef struct __packed {
+    bool lpage:1;               /* ==1 if large page */
+    bool page:1;                /* ==0 if large page */
+    bool b:1;                   /* Bufferable */
+    bool c:1;                   /* Cacheable */
+    unsigned int ap:2;          /* AP[1:0] */
+    unsigned int sbz:3;         /* Should be zero */
+    bool ro:1;                  /* AP[2] */
+    bool s:1;                   /* Shareable */
+    bool ng:1;                  /* Non-global */
+    unsigned int tex:3;         /* TEX[2:0] */
+    bool xn:1;                  /* Execute Never */
+    unsigned int base:16;       /* Large page base address */
+} short_desc_l2_lpage_t;
+
+/*
+ * Comprises the bits required to walk page tables adhering to the
+ * short-descriptor translation table format.
+ */
+typedef struct __packed {
+    unsigned int dt:2;          /* Descriptor type */
+    unsigned int pad1:8;
+    unsigned int base:22;       /* Base address of block or next table */
+} short_desc_walk_t;
+
+/*
+ * Represents page table entries adhering to the short-descriptor translation
+ * table format.
+ */
+typedef union {
+    uint32_t bits;
+    short_desc_walk_t walk;
+    short_desc_l1_sec_t sec;
+    short_desc_l1_supersec_t supersec;
+    short_desc_l2_page_t pg;
+    short_desc_l2_lpage_t lpg;
+} short_desc_t;
+
+#endif /* __ARM_SHORT_DESC_H__ */
-- 
2.12.2


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