Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 198 insertions, 0 deletions

diff --git a/Documentation/xtensa/mmu.rst b/Documentation/xtensa/mmu.rst
new file mode 100644
index 000000000..450573afa
--- /dev/null
+++ b/Documentation/xtensa/mmu.rst
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+=============================
+MMUv3 initialization sequence
+=============================
+
+The code in the initialize_mmu macro sets up MMUv3 memory mapping
+identically to MMUv2 fixed memory mapping. Depending on
+CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX symbol this code is
+located in addresses it was linked for (symbol undefined), or not
+(symbol defined), so it needs to be position-independent.
+
+The code has the following assumptions:
+
+  - This code fragment is run only on an MMU v3.
+  - TLBs are in their reset state.
+  - ITLBCFG and DTLBCFG are zero (reset state).
+  - RASID is 0x04030201 (reset state).
+  - PS.RING is zero (reset state).
+  - LITBASE is zero (reset state, PC-relative literals); required to be PIC.
+
+TLB setup proceeds along the following steps.
+
+  Legend:
+
+    - VA = virtual address (two upper nibbles of it);
+    - PA = physical address (two upper nibbles of it);
+    - pc = physical range that contains this code;
+
+After step 2, we jump to virtual address in the range 0x40000000..0x5fffffff
+or 0x00000000..0x1fffffff, depending on whether the kernel was loaded below
+0x40000000 or above. That address corresponds to next instruction to execute
+in this code. After step 4, we jump to intended (linked) address of this code.
+The scheme below assumes that the kernel is loaded below 0x40000000.
+
+ ====== =====  =====  =====  =====   ====== =====  =====
+ -      Step0  Step1  Step2  Step3          Step4  Step5
+
+   VA      PA     PA     PA     PA     VA      PA     PA
+ ====== =====  =====  =====  =====   ====== =====  =====
+ E0..FF -> E0  -> E0  -> E0          F0..FF -> F0  -> F0
+ C0..DF -> C0  -> C0  -> C0          E0..EF -> F0  -> F0
+ A0..BF -> A0  -> A0  -> A0          D8..DF -> 00  -> 00
+ 80..9F -> 80  -> 80  -> 80          D0..D7 -> 00  -> 00
+ 60..7F -> 60  -> 60  -> 60
+ 40..5F -> 40         -> pc  -> pc   40..5F -> pc
+ 20..3F -> 20  -> 20  -> 20
+ 00..1F -> 00  -> 00  -> 00
+ ====== =====  =====  =====  =====   ====== =====  =====
+
+The default location of IO peripherals is above 0xf0000000. This may be changed
+using a "ranges" property in a device tree simple-bus node. See the Devicetree
+Specification, section 4.5 for details on the syntax and semantics of
+simple-bus nodes. The following limitations apply:
+
+1. Only top level simple-bus nodes are considered
+
+2. Only one (first) simple-bus node is considered
+
+3. Empty "ranges" properties are not supported
+
+4. Only the first triplet in the "ranges" property is considered
+
+5. The parent-bus-address value is rounded down to the nearest 256MB boundary
+
+6. The IO area covers the entire 256MB segment of parent-bus-address; the
+   "ranges" triplet length field is ignored
+
+
+MMUv3 address space layouts.
+============================
+
+Default MMUv2-compatible layout::
+
+                        Symbol                   VADDR       Size
+  +------------------+
+  | Userspace        |                           0x00000000  TASK_SIZE
+  +------------------+                           0x40000000
+  +------------------+
+  | Page table       |  XCHAL_PAGE_TABLE_VADDR   0x80000000  XCHAL_PAGE_TABLE_SIZE
+  +------------------+
+  | KASAN shadow map |  KASAN_SHADOW_START       0x80400000  KASAN_SHADOW_SIZE
+  +------------------+                           0x8e400000
+  +------------------+
+  | VMALLOC area     |  VMALLOC_START            0xc0000000  128MB - 64KB
+  +------------------+  VMALLOC_END
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_1           0xc8000000  DCACHE_WAY_SIZE
+  | remap area 1     |
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_2                       DCACHE_WAY_SIZE
+  | remap area 2     |
+  +------------------+
+  +------------------+
+  | KMAP area        |  PKMAP_BASE                           PTRS_PER_PTE *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  |                  |                                       (4MB * DCACHE_N_COLORS)
+  +------------------+
+  | Atomic KMAP area |  FIXADDR_START                        KM_TYPE_NR *
+  |                  |                                       NR_CPUS *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  +------------------+  FIXADDR_TOP              0xcffff000
+  +------------------+
+  | Cached KSEG      |  XCHAL_KSEG_CACHED_VADDR  0xd0000000  128MB
+  +------------------+
+  | Uncached KSEG    |  XCHAL_KSEG_BYPASS_VADDR  0xd8000000  128MB
+  +------------------+
+  | Cached KIO       |  XCHAL_KIO_CACHED_VADDR   0xe0000000  256MB
+  +------------------+
+  | Uncached KIO     |  XCHAL_KIO_BYPASS_VADDR   0xf0000000  256MB
+  +------------------+
+
+
+256MB cached + 256MB uncached layout::
+
+                        Symbol                   VADDR       Size
+  +------------------+
+  | Userspace        |                           0x00000000  TASK_SIZE
+  +------------------+                           0x40000000
+  +------------------+
+  | Page table       |  XCHAL_PAGE_TABLE_VADDR   0x80000000  XCHAL_PAGE_TABLE_SIZE
+  +------------------+
+  | KASAN shadow map |  KASAN_SHADOW_START       0x80400000  KASAN_SHADOW_SIZE
+  +------------------+                           0x8e400000
+  +------------------+
+  | VMALLOC area     |  VMALLOC_START            0xa0000000  128MB - 64KB
+  +------------------+  VMALLOC_END
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_1           0xa8000000  DCACHE_WAY_SIZE
+  | remap area 1     |
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_2                       DCACHE_WAY_SIZE
+  | remap area 2     |
+  +------------------+
+  +------------------+
+  | KMAP area        |  PKMAP_BASE                           PTRS_PER_PTE *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  |                  |                                       (4MB * DCACHE_N_COLORS)
+  +------------------+
+  | Atomic KMAP area |  FIXADDR_START                        KM_TYPE_NR *
+  |                  |                                       NR_CPUS *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  +------------------+  FIXADDR_TOP              0xaffff000
+  +------------------+
+  | Cached KSEG      |  XCHAL_KSEG_CACHED_VADDR  0xb0000000  256MB
+  +------------------+
+  | Uncached KSEG    |  XCHAL_KSEG_BYPASS_VADDR  0xc0000000  256MB
+  +------------------+
+  +------------------+
+  | Cached KIO       |  XCHAL_KIO_CACHED_VADDR   0xe0000000  256MB
+  +------------------+
+  | Uncached KIO     |  XCHAL_KIO_BYPASS_VADDR   0xf0000000  256MB
+  +------------------+
+
+
+512MB cached + 512MB uncached layout::
+
+                        Symbol                   VADDR       Size
+  +------------------+
+  | Userspace        |                           0x00000000  TASK_SIZE
+  +------------------+                           0x40000000
+  +------------------+
+  | Page table       |  XCHAL_PAGE_TABLE_VADDR   0x80000000  XCHAL_PAGE_TABLE_SIZE
+  +------------------+
+  | KASAN shadow map |  KASAN_SHADOW_START       0x80400000  KASAN_SHADOW_SIZE
+  +------------------+                           0x8e400000
+  +------------------+
+  | VMALLOC area     |  VMALLOC_START            0x90000000  128MB - 64KB
+  +------------------+  VMALLOC_END
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_1           0x98000000  DCACHE_WAY_SIZE
+  | remap area 1     |
+  +------------------+
+  | Cache aliasing   |  TLBTEMP_BASE_2                       DCACHE_WAY_SIZE
+  | remap area 2     |
+  +------------------+
+  +------------------+
+  | KMAP area        |  PKMAP_BASE                           PTRS_PER_PTE *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  |                  |                                       (4MB * DCACHE_N_COLORS)
+  +------------------+
+  | Atomic KMAP area |  FIXADDR_START                        KM_TYPE_NR *
+  |                  |                                       NR_CPUS *
+  |                  |                                       DCACHE_N_COLORS *
+  |                  |                                       PAGE_SIZE
+  +------------------+  FIXADDR_TOP              0x9ffff000
+  +------------------+
+  | Cached KSEG      |  XCHAL_KSEG_CACHED_VADDR  0xa0000000  512MB
+  +------------------+
+  | Uncached KSEG    |  XCHAL_KSEG_BYPASS_VADDR  0xc0000000  512MB
+  +------------------+
+  | Cached KIO       |  XCHAL_KIO_CACHED_VADDR   0xe0000000  256MB
+  +------------------+
+  | Uncached KIO     |  XCHAL_KIO_BYPASS_VADDR   0xf0000000  256MB
+  +------------------+