git: 48ba9b2669e6 - main - Use L2 blocks when in the identity map
Andrew Turner
andrew at FreeBSD.org
Wed Mar 3 14:26:50 UTC 2021
The branch main has been updated by andrew:
URL: https://cgit.FreeBSD.org/src/commit/?id=48ba9b2669e6a92a3254ec34461d0d86fb20b9f4
commit 48ba9b2669e6a92a3254ec34461d0d86fb20b9f4
Author: Andrew Turner <andrew at FreeBSD.org>
AuthorDate: 2020-12-24 11:02:34 +0000
Commit: Andrew Turner <andrew at FreeBSD.org>
CommitDate: 2021-03-03 14:18:03 +0000
Use L2 blocks when in the identity map
This reduces the memory mapped to be closer to the minimal memory
needed to enable the MMU.
Reviewed by: mmel
Sponsored by: Innovate UK
Differential Revision:://reviews.freebsd.org/D27765
---
sys/arm64/arm64/locore.S | 101 ++++++++++++++++++--------------------------
sys/arm64/include/machdep.h | 8 ++++
sys/conf/options.arm64 | 1 -
3 files changed, 49 insertions(+), 61 deletions(-)
diff --git a/sys/arm64/arm64/locore.S b/sys/arm64/arm64/locore.S
index b340041eb163..4d356e8897f0 100644
--- a/sys/arm64/arm64/locore.S
+++ b/sys/arm64/arm64/locore.S
@@ -466,35 +466,58 @@ common:
add x27, x24, #PAGE_SIZE
mov x6, x27 /* The initial page table */
-#if defined(SOCDEV_PA) && defined(SOCDEV_VA)
+
+ /* Create the VA = PA map */
+ mov x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_WRITE_BACK))
+ adrp x16, _start
+ and x16, x16, #(~L2_OFFSET)
+ mov x9, x16 /* PA start */
+ mov x8, x16 /* VA start (== PA start) */
+ mov x10, #1
+ bl build_l2_block_pagetable
+
+#if defined(SOCDEV_PA)
/* Create a table for the UART */
mov x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_DEVICE))
- mov x8, #(SOCDEV_VA) /* VA start */
- mov x9, #(SOCDEV_PA) /* PA start */
+ add x16, x16, #(L2_SIZE) /* VA start */
+ mov x8, x16
+
+ /* Store the socdev virtual address */
+ add x17, x8, #(SOCDEV_PA & L2_OFFSET)
+ adrp x9, socdev_va
+ str x17, [x9, :lo12:socdev_va]
+
+ mov x9, #(SOCDEV_PA & ~L2_OFFSET) /* PA start */
mov x10, #1
- bl build_l1_block_pagetable
+ bl build_l2_block_pagetable
#endif
#if defined(LINUX_BOOT_ABI)
/* Map FDT data ? */
cbz x19, 1f
- /* Create the identity mapping for FDT data (2 MiB max) */
+ /* Create the mapping for FDT data (2 MiB max) */
mov x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_WRITE_BACK))
- mov x9, x0
- mov x8, x0 /* VA start (== PA start) */
+ add x16, x16, #(L2_SIZE) /* VA start */
+ mov x8, x16
+ mov x9, x0 /* PA start */
+ /* Update the module pointer to point at the allocated memory */
+ and x0, x0, #(L2_OFFSET) /* Keep the lower bits */
+ add x0, x0, x8 /* Add the aligned virtual address */
+
mov x10, #1
- bl build_l1_block_pagetable
+ bl build_l2_block_pagetable
1:
#endif
- /* Create the VA = PA map */
- mov x7, #(ATTR_S1_nG | ATTR_S1_IDX(VM_MEMATTR_WRITE_BACK))
- mov x9, x28
- mov x8, x9 /* VA start (== PA start) */
- mov x10, #1
- bl build_l1_block_pagetable
+ /* Move to the l1 table */
+ add x27, x27, #PAGE_SIZE
+
+ /* Link the l1 -> l2 table */
+ mov x9, x6
+ mov x6, x27
+ bl link_l1_pagetable
/* Move to the l0 table */
add x27, x27, #PAGE_SIZE
@@ -513,13 +536,10 @@ LEND(create_pagetables)
/*
* Builds an L0 -> L1 table descriptor
*
- * This is a link for a 512GiB block of memory with up to 1GiB regions mapped
- * within it by build_l1_block_pagetable.
- *
* x6 = L0 table
* x8 = Virtual Address
* x9 = L1 PA (trashed)
- * x10 = Entry count
+ * x10 = Entry count (trashed)
* x11, x12 and x13 are trashed
*/
LENTRY(link_l0_pagetable)
@@ -551,9 +571,6 @@ LEND(link_l0_pagetable)
/*
* Builds an L1 -> L2 table descriptor
*
- * This is a link for a 1GiB block of memory with up to 2MiB regions mapped
- * within it by build_l2_block_pagetable.
- *
* x6 = L1 table
* x8 = Virtual Address
* x9 = L2 PA (trashed)
@@ -580,51 +597,13 @@ LENTRY(link_l1_pagetable)
ret
LEND(link_l1_pagetable)
-/*
- * Builds count 1 GiB page table entry
- * x6 = L1 table
- * x7 = Variable lower block attributes
- * x8 = VA start
- * x9 = PA start (trashed)
- * x10 = Entry count
- * x11, x12 and x13 are trashed
- */
-LENTRY(build_l1_block_pagetable)
- /*
- * Build the L1 table entry.
- */
- /* Find the table index */
- lsr x11, x8, #L1_SHIFT
- and x11, x11, #Ln_ADDR_MASK
-
- /* Build the L1 block entry */
- orr x12, x7, #L1_BLOCK
- orr x12, x12, #(ATTR_DEFAULT)
-
- /* Only use the output address bits */
- lsr x9, x9, #L1_SHIFT
-
- /* Set the physical address for this virtual address */
-1: orr x13, x12, x9, lsl #L1_SHIFT
-
- /* Store the entry */
- str x13, [x6, x11, lsl #3]
-
- sub x10, x10, #1
- add x11, x11, #1
- add x9, x9, #1
- cbnz x10, 1b
-
- ret
-LEND(build_l1_block_pagetable)
-
/*
* Builds count 2 MiB page table entry
* x6 = L2 table
* x7 = Type (0 = Device, 1 = Normal)
* x8 = VA start
* x9 = PA start (trashed)
- * x10 = Entry count
+ * x10 = Entry count (trashed)
* x11, x12 and x13 are trashed
*/
LENTRY(build_l2_block_pagetable)
@@ -778,6 +757,8 @@ pagetable_l1_ttbr1:
.space PAGE_SIZE
pagetable_l0_ttbr1:
.space PAGE_SIZE
+pagetable_l2_ttbr0_bootstrap:
+ .space PAGE_SIZE
pagetable_l1_ttbr0_bootstrap:
.space PAGE_SIZE
pagetable_l0_ttbr0_boostrap:
diff --git a/sys/arm64/include/machdep.h b/sys/arm64/include/machdep.h
index 54ffcbd46c81..45ff0065930a 100644
--- a/sys/arm64/include/machdep.h
+++ b/sys/arm64/include/machdep.h
@@ -60,6 +60,14 @@ void parse_fdt_bootargs(void);
int memory_mapping_mode(vm_paddr_t pa);
extern void (*pagezero)(void *);
+#ifdef SOCDEV_PA
+/*
+ * The virtual address SOCDEV_PA is mapped at.
+ * Only valid while the early pagetables are valid.
+ */
+extern uintptr_t socdev_va;
+#endif
+
#endif /* _KERNEL */
#endif /* _MACHINE_MACHDEP_H_ */
diff --git a/sys/conf/options.arm64 b/sys/conf/options.arm64
index 5a97fd6b3ef6..5185a301e55e 100644
--- a/sys/conf/options.arm64
+++ b/sys/conf/options.arm64
@@ -3,7 +3,6 @@
ARM64 opt_global.h
INTRNG opt_global.h
SOCDEV_PA opt_global.h
-SOCDEV_VA opt_global.h
THUNDERX_PASS_1_1_ERRATA opt_global.h
VFP opt_global.h
LINUX_BOOT_ABI opt_global.h
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