Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm

Pull ARM fixes from Russell King:
 "A small number of ARM fixes

   - Fix function tracer and unwinder dependencies so that we don't end
     up building kernels that will crash

   - Fix ARMv7M nommu initialisation (missing register initialisation)

   - Fix EFI decompressor entry (ensuring barrier instructions are
     enabled prior to use)"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  ARM: 8857/1: efi: enable CP15 DMB instructions before cleaning the cache
  ARM: 8856/1: NOMMU: Fix CCR register faulty initialization when MPU is disabled
  ARM: fix function graph tracer and unwinder dependencies

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 850b480..9aed25a 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -73,7 +73,7 @@ config ARM
        select HAVE_EFFICIENT_UNALIGNED_ACCESS if (CPU_V6 || CPU_V6K || CPU_V7) && MMU
        select HAVE_EXIT_THREAD
        select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL
-       select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL
+       select HAVE_FUNCTION_GRAPH_TRACER if !THUMB2_KERNEL && !CC_IS_CLANG
        select HAVE_FUNCTION_TRACER if !XIP_KERNEL
        select HAVE_GCC_PLUGINS
        select HAVE_HW_BREAKPOINT if PERF_EVENTS && (CPU_V6 || CPU_V6K || CPU_V7)

diff --git a/arch/arm/Kconfig.debug b/arch/arm/Kconfig.debug
index 6d6e033..e388af4 100644 (file)
--- a/arch/arm/Kconfig.debug
+++ b/arch/arm/Kconfig.debug
@@ -47,8 +47,8 @@ config DEBUG_WX
 
 choice
        prompt "Choose kernel unwinder"
-       default UNWINDER_ARM if AEABI && !FUNCTION_GRAPH_TRACER
-       default UNWINDER_FRAME_POINTER if !AEABI || FUNCTION_GRAPH_TRACER
+       default UNWINDER_ARM if AEABI
+       default UNWINDER_FRAME_POINTER if !AEABI
        help
          This determines which method will be used for unwinding kernel stack
          traces for panics, oopses, bugs, warnings, perf, /proc/<pid>/stack,
@@ -65,7 +65,7 @@ config UNWINDER_FRAME_POINTER
 
 config UNWINDER_ARM
        bool "ARM EABI stack unwinder"
-       depends on AEABI
+       depends on AEABI && !FUNCTION_GRAPH_TRACER
        select ARM_UNWIND
        help
          This option enables stack unwinding support in the kernel

diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 6c7ccb4..7135820 100644 (file)
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -1438,7 +1438,21 @@ ENTRY(efi_stub_entry)
 
                @ Preserve return value of efi_entry() in r4
                mov     r4, r0
-               bl      cache_clean_flush
+
+               @ our cache maintenance code relies on CP15 barrier instructions
+               @ but since we arrived here with the MMU and caches configured
+               @ by UEFI, we must check that the CP15BEN bit is set in SCTLR.
+               @ Note that this bit is RAO/WI on v6 and earlier, so the ISB in
+               @ the enable path will be executed on v7+ only.
+               mrc     p15, 0, r1, c1, c0, 0   @ read SCTLR
+               tst     r1, #(1 << 5)           @ CP15BEN bit set?
+               bne     0f
+               orr     r1, r1, #(1 << 5)       @ CP15 barrier instructions
+               mcr     p15, 0, r1, c1, c0, 0   @ write SCTLR
+ ARM(          .inst   0xf57ff06f              @ v7+ isb       )
+ THUMB(                isb                                             )
+
+0:             bl      cache_clean_flush
                bl      cache_off
 
                @ Set parameters for booting zImage according to boot protocol

diff --git a/arch/arm/kernel/head-nommu.S b/arch/arm/kernel/head-nommu.S
index c08d2d8..b38bbd0 100644 (file)
--- a/arch/arm/kernel/head-nommu.S
+++ b/arch/arm/kernel/head-nommu.S
@@ -133,9 +133,9 @@ __secondary_data:
  */
        .text
 __after_proc_init:
-#ifdef CONFIG_ARM_MPU
 M_CLASS(movw   r12, #:lower16:BASEADDR_V7M_SCB)
 M_CLASS(movt   r12, #:upper16:BASEADDR_V7M_SCB)
+#ifdef CONFIG_ARM_MPU
 M_CLASS(ldr    r3, [r12, 0x50])
 AR_CLASS(mrc   p15, 0, r3, c0, c1, 4)          @ Read ID_MMFR0
        and     r3, r3, #(MMFR0_PMSA)           @ PMSA field