diff options
| -rw-r--r-- | Documentation/arm64/booting.txt | 10 | ||||
| -rw-r--r-- | arch/arm64/kernel/head.S | 30 | ||||
| -rw-r--r-- | arch/arm64/mm/cache.S | 9 |
3 files changed, 45 insertions, 4 deletions
diff --git a/Documentation/arm64/booting.txt b/Documentation/arm64/booting.txt index a9691cc48fe3..beb754e87c65 100644 --- a/Documentation/arm64/booting.txt +++ b/Documentation/arm64/booting.txt @@ -111,8 +111,14 @@ Before jumping into the kernel, the following conditions must be met: - Caches, MMUs The MMU must be off. Instruction cache may be on or off. - Data cache must be off and invalidated. - External caches (if present) must be configured and disabled. + The address range corresponding to the loaded kernel image must be + cleaned to the PoC. In the presence of a system cache or other + coherent masters with caches enabled, this will typically require + cache maintenance by VA rather than set/way operations. + System caches which respect the architected cache maintenance by VA + operations must be configured and may be enabled. + System caches which do not respect architected cache maintenance by VA + operations (not recommended) must be configured and disabled. - Architected timers CNTFRQ must be programmed with the timer frequency and CNTVOFF must diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 61035d6814cb..26109682d2fa 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -26,6 +26,7 @@ #include <asm/assembler.h> #include <asm/ptrace.h> #include <asm/asm-offsets.h> +#include <asm/cache.h> #include <asm/cputype.h> #include <asm/memory.h> #include <asm/thread_info.h> @@ -229,7 +230,11 @@ ENTRY(set_cpu_boot_mode_flag) cmp w20, #BOOT_CPU_MODE_EL2 b.ne 1f add x1, x1, #4 -1: str w20, [x1] // This CPU has booted in EL1 +1: dc cvac, x1 // Clean potentially dirty cache line + dsb sy + str w20, [x1] // This CPU has booted in EL1 + dc civac, x1 // Clean&invalidate potentially stale cache line + dsb sy ret ENDPROC(set_cpu_boot_mode_flag) @@ -240,8 +245,9 @@ ENDPROC(set_cpu_boot_mode_flag) * This is not in .bss, because we set it sufficiently early that the boot-time * zeroing of .bss would clobber it. */ - .pushsection .data + .pushsection .data..cacheline_aligned ENTRY(__boot_cpu_mode) + .align L1_CACHE_SHIFT .long BOOT_CPU_MODE_EL2 .long 0 .popsection @@ -408,6 +414,15 @@ ENDPROC(__calc_phys_offset) */ __create_page_tables: pgtbl x25, x26, x24 // idmap_pg_dir and swapper_pg_dir addresses + mov x27, lr + + /* + * Invalidate the idmap and swapper page tables to avoid potential + * dirty cache lines being evicted. + */ + mov x0, x25 + add x1, x26, #SWAPPER_DIR_SIZE + bl __inval_cache_range /* * Clear the idmap and swapper page tables. @@ -470,6 +485,17 @@ __create_page_tables: add x0, x26, #2 * PAGE_SIZE // section table address create_pgd_entry x26, x0, x5, x6, x7 #endif + + /* + * Since the page tables have been populated with non-cacheable + * accesses (MMU disabled), invalidate the idmap and swapper page + * tables again to remove any speculatively loaded cache lines. + */ + mov x0, x25 + add x1, x26, #SWAPPER_DIR_SIZE + bl __inval_cache_range + + mov lr, x27 ret ENDPROC(__create_page_tables) .ltorg diff --git a/arch/arm64/mm/cache.S b/arch/arm64/mm/cache.S index c46f48b33c14..e803a62e0e45 100644 --- a/arch/arm64/mm/cache.S +++ b/arch/arm64/mm/cache.S @@ -168,6 +168,14 @@ ENTRY(__flush_dcache_area) ENDPROC(__flush_dcache_area) /* + * __inval_cache_range(start, end) + * - start - start address of region + * - end - end address of region + */ +ENTRY(__inval_cache_range) + /* FALLTHROUGH */ + +/* * __dma_inv_range(start, end) * - start - virtual start address of region * - end - virtual end address of region @@ -183,6 +191,7 @@ __dma_inv_range: b.lo 1b dsb sy ret +ENDPROC(__inval_cache_range) ENDPROC(__dma_inv_range) /* |