On 16/11/2024 10:30, Julien Grall wrote:
Hi Ayan,
Hi Julien,
On 07/11/2024 15:03, Ayan Kumar Halder wrote:
+/*
+ * Macro to prepare and set a EL2 MPU memory region.
+ * We will also create an according MPU memory region entry, which
+ * is a structure of pr_t, in table \prmap.
+ *
+ * Inputs:
This needs to be removed as some parameters are both input and output
(eg sel) and some parameters are for temporary storage (eg prbar, prlar).
+ * sel: region selector
``sel`` is now also an output. But looking at the description, we
don't seem to say which registers are preserved or not. For instance,
both ..
+ * base: reg storing base address (should be page-aligned) >
+ * limit: reg storing limit address
... the two registers above will be clobbered. On the other hand...
+ * prbar: store computed PRBAR_EL2 value
+ * prlar: store computed PRLAR_EL2 value
+ * maxcount: maximum number of EL2 regions supported
... this will be preserved. So I think we need to clarify it. For
instance, this is the description of create_table_entry_from_paddr:
Actually prbar, prlar are similar to tmp1, tmp2 (ie scratch registers).
I used the names so as to make it more meaningful.
/*
* Macro to create a page table entry in \ptbl to \tbl
* ptbl: table symbol where the entry will be created
* tbl: physical address of the table to point to
* virt: virtual address
* lvl: page-table level
* tmp1: scratch register
* tmp2: scratch register
*
* Preserves \virt
* Clobbers \tbl, \tmp1, \tmp2
*
* Note that all parameters using registers should be distinct.
*/
In our case, it will be
/*
* Macro to prepare and set a EL2 MPU memory region.
* We will also create an according MPU memory region entry, which
* is a structure of pr_t, in table \prmap.
*
* sel: region selector
* base: reg storing base address
* limit: reg storing limit address
* prbar: store computed PRBAR_EL2 value
* prlar: store computed PRLAR_EL2 value
* maxcount: maximum number of EL2 regions supported
* attr_prbar: PRBAR_EL2-related memory attributes. If not specified
it will be
* REGION_DATA_PRBAR
* attr_prlar: PRLAR_EL2-related memory attributes. If not specified
it will be
* REGION_NORMAL_PRLAR
*
* Preserves \maxcount
* Clobbers \sel, \base, \limit, \prbar, \prlar
*
* Note that all parameters using registers should be distinct.
*/
- Ayan
