arm64: fix invalidation of wrong __early_cpu_boot_status cacheline

In head.S, the str_l macro, which takes a source register, a symbol name
and a temp register, is used to store a status value to the variable
__early_cpu_boot_status. Subsequently, the value of the temp register is
reused to invalidate any cachelines covering this variable.

However, since str_l resolves to

      adrp    \tmp, \sym
      str     \src, [\tmp, :lo12:\sym]

the temp register never actually holds the address of the variable but
only of the 4 KB window that covers it, and reusing it leads to the
wrong cacheline being invalidated. So instead, take the address
explicitly before doing the store, and reuse that value to perform
the cache invalidation.

Fixes: bb9052744f4b ("arm64: Handle early CPU boot failures")
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Suzuki K Poulose <Suzuki.Poulose@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S
index 4203d5f..80a709a 100644 (file)
--- a/arch/arm64/kernel/head.S
+++ b/arch/arm64/kernel/head.S
@@ -734,7 +734,8 @@ ENDPROC(__secondary_switched)
 
        .macro  update_early_cpu_boot_status status, tmp1, tmp2
        mov     \tmp2, #\status
-       str_l   \tmp2, __early_cpu_boot_status, \tmp1
+       adr_l   \tmp1, __early_cpu_boot_status
+       str     \tmp2, [\tmp1]
        dmb     sy
        dc      ivac, \tmp1                     // Invalidate potentially stale cache line
        .endm