diff options
| author | Catalin Marinas <catalin.marinas@arm.com> | 2014-03-26 22:25:55 +0400 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2014-04-05 13:06:18 +0400 |
| commit | c218bca74eeafa2f8528b6bbb34d112075fcf40a (patch) | |
| tree | 29b3e350efca77e073436df3cf78b818bf57cc34 /arch | |
| parent | 35a86976924a9eda7775b5b02ad47268dca1a5b4 (diff) | |
| download | linux-c218bca74eeafa2f8528b6bbb34d112075fcf40a.tar.xz | |
arm64: Relax the kernel cache requirements for boot
With system caches for the host OS or architected caches for guest OS we
cannot easily guarantee that there are no dirty or stale cache lines for
the areas of memory written by the kernel during boot with the MMU off
(therefore non-cacheable accesses).
This patch adds the necessary cache maintenance during boot and relaxes
the booting requirements.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arm64/kernel/head.S | 30 | ||||
| -rw-r--r-- | arch/arm64/mm/cache.S | 9 |
2 files changed, 37 insertions, 2 deletions
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) /* |