Now that deliberate writes to swapper_pg_dir are made via the fixmap, we
can defend against errant writes by moving it into the rodata section.
Since tramp_pg_dir and reserved_ttbr0 must be at a fixed offset from
swapper_pg_dir, and are not modified at runtime, these are also moved
into the rodata section. Likewise, idmap_pg_dir is not modified at
runtime, and is moved into rodata.
Signed-off-by: Jun Yao <yaojun8558363@gmail.com>
Reviewed-by: James Morse <james.morse@arm.com>
[Mark: simplify linker script, commit message]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
mov x28, lr
/*
- * Invalidate the idmap and swapper page tables to avoid potential
- * dirty cache lines being evicted.
+ * Invalidate the init page tables to avoid potential dirty cache lines
+ * being evicted. Other page tables are allocated in rodata as part of
+ * the kernel image, and thus are clean to the PoC per the boot
+ * protocol.
*/
- adrp x0, idmap_pg_dir
+ adrp x0, init_pg_dir
adrp x1, init_pg_end
sub x1, x1, x0
bl __inval_dcache_area
/*
- * Clear the idmap and swapper page tables.
+ * Clear the init page tables.
*/
- adrp x0, idmap_pg_dir
+ adrp x0, init_pg_dir
adrp x1, init_pg_end
sub x1, x1, x0
1: stp xzr, xzr, [x0], #16
EXCEPTION_TABLE(8) /* __init_begin will be marked RO NX */
NOTES
+ . = ALIGN(PAGE_SIZE);
+ idmap_pg_dir = .;
+ . += IDMAP_DIR_SIZE;
+
+#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
+ tramp_pg_dir = .;
+ . += PAGE_SIZE;
+#endif
+
+#ifdef CONFIG_ARM64_SW_TTBR0_PAN
+ reserved_ttbr0 = .;
+ . += RESERVED_TTBR0_SIZE;
+#endif
+ swapper_pg_dir = .;
+ . += PAGE_SIZE;
+ swapper_pg_end = .;
+
. = ALIGN(SEGMENT_ALIGN);
__init_begin = .;
__inittext_begin = .;
BSS_SECTION(0, 0, 0)
. = ALIGN(PAGE_SIZE);
- idmap_pg_dir = .;
- . += IDMAP_DIR_SIZE;
-
-#ifdef CONFIG_UNMAP_KERNEL_AT_EL0
- tramp_pg_dir = .;
- . += PAGE_SIZE;
-#endif
-
-#ifdef CONFIG_ARM64_SW_TTBR0_PAN
- reserved_ttbr0 = .;
- . += RESERVED_TTBR0_SIZE;
-#endif
- swapper_pg_dir = .;
- . += PAGE_SIZE;
- swapper_pg_end = .;
-
init_pg_dir = .;
. += INIT_DIR_SIZE;
init_pg_end = .;