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-rw-r--r--Documentation/arm64/booting.txt10
-rw-r--r--arch/arm64/kernel/head.S30
-rw-r--r--arch/arm64/mm/cache.S9
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)
/*