Re: [U-Boot] [PATCH v2] armv8: aarch64: Fix the warning about x1-x3 nonzero issue

On 16 January 2017 at 08:34, Alexander Graf agraf@suse.de wrote:

On 16/01/2017 07:16, Alison Wang wrote:

...

For 64-bit kernel, there is a warning about x1-x3 nonzero in violation of boot protocol. To fix this issue, input argument 4 is added for armv8_switch_to_el2 and armv8_switch_to_el1. The input argument 4 will be set to the right value, such as zero.

Signed-off-by: Alison Wang alison.wang@nxp.com

Thanks Alison, this removes the warning for me now and still boots fine. I tested with Juno R0/1/2 and FVP Foundation and AEMv8 models.

Tested-by: Ryan Harkin ryan.harkin@linaro.org

...

---

Changes in v2:

• Add another input argument 4 for armv8_switch_to_el2 and

armv8_switch_to_el1.

• Give up the previous way to adjust the parameters to transfer and make

sure x3 is zero.

arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S | 28 ++++++++++++++-------------- arch/arm/cpu/armv8/sec_firmware_asm.S | 5 +++-- arch/arm/cpu/armv8/start.S | 8 ++++---- arch/arm/cpu/armv8/transition.S | 22 +++++++++++----------- arch/arm/include/asm/system.h | 8 +++++--- arch/arm/lib/bootm.c | 10 +++++----- arch/arm/mach-rmobile/lowlevel_init_gen3.S | 8 ++++---- cmd/bootefi.c | 2 +- 8 files changed, 47 insertions(+), 44 deletions(-)

diff --git a/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S b/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S index 72f2c11..63215f0 100644 --- a/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S +++ b/arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S @@ -378,29 +378,29 @@ cpu_is_le: b.eq 1f

#ifdef CONFIG_ARMV8_SWITCH_TO_EL1

•   adr     x3, secondary_switch_to_el1
  

•   ldr     x4, =ES_TO_AARCH64
  

•   adr     x4, secondary_switch_to_el1
  

•   ldr     x5, =ES_TO_AARCH64
  

#else

•   ldr     x3, [x11]
  

•   ldr     x4, =ES_TO_AARCH32
  

•   ldr     x4, [x11]
  

•   ldr     x5, =ES_TO_AARCH32
  

#endif bl secondary_switch_to_el2

1: #ifdef CONFIG_ARMV8_SWITCH_TO_EL1

•   adr     x3, secondary_switch_to_el1
  

•   adr     x4, secondary_switch_to_el1
  

#else

•   ldr     x3, [x11]
  

•   ldr     x4, [x11]
  

#endif

•   ldr     x4, =ES_TO_AARCH64
  

•   ldr     x5, =ES_TO_AARCH64
    bl      secondary_switch_to_el2
  
  

ENDPROC(secondary_boot_func)

ENTRY(secondary_switch_to_el2)

•   switch_el x5, 1f, 0f, 0f
  

•   switch_el x6, 1f, 0f, 0f
  

0: ret -1: armv8_switch_to_el2_m x3, x4, x5 +1: armv8_switch_to_el2_m x4, x5, x6 ENDPROC(secondary_switch_to_el2)

ENTRY(secondary_switch_to_el1) @@ -414,22 +414,22 @@ ENTRY(secondary_switch_to_el1) /* physical address of this cpus spin table element */ add x11, x1, x0

•   ldr     x3, [x11]
  

•   ldr     x4, [x11]
  
    ldr     x5, [x11, #24]
    ldr     x6, =IH_ARCH_DEFAULT
    cmp     x6, x5
    b.eq    2f
  
  

•   ldr     x4, =ES_TO_AARCH32
  

•   ldr     x5, =ES_TO_AARCH32
    bl      switch_to_el1
  
  

-2: ldr x4, =ES_TO_AARCH64 +2: ldr x5, =ES_TO_AARCH64

switch_to_el1:

•   switch_el x5, 0f, 1f, 0f
  

•   switch_el x6, 0f, 1f, 0f
  

0: ret -1: armv8_switch_to_el1_m x3, x4, x5 +1: armv8_switch_to_el1_m x4, x5, x6 ENDPROC(secondary_switch_to_el1)

    /* Ensure that the literals used by the secondary boot code are

diff --git a/arch/arm/cpu/armv8/sec_firmware_asm.S b/arch/arm/cpu/armv8/sec_firmware_asm.S index 903195d..747b53f 100644 --- a/arch/arm/cpu/armv8/sec_firmware_asm.S +++ b/arch/arm/cpu/armv8/sec_firmware_asm.S @@ -57,7 +57,8 @@ ENDPROC(_sec_firmware_support_psci_version)

• x0: argument, zero
• x1: machine nr
• x2: fdt address

• • x3: kernel entry point

• • x3: input argument
• • x4: kernel entry point
  • @param outputs for secure firmware:
  • x0: function id
  • x1: kernel entry point

@@ -65,7 +66,7 @@ ENDPROC(_sec_firmware_support_psci_version)

• x3: fdt address

*/ ENTRY(armv8_el2_to_aarch32)

•   mov     x0, x3
  

•   mov     x0, x4
  

You no longer need x0 as scratch register. Just write ...

...

    mov     x3, x2
    mov     x2, x1
    mov     x1, x0

... x4 directly into x1 here.

Otherwise looks good to me. So with the change above you can add my

Reviewed-by: Alexander Graf agraf@suse.de

tag in the next version.

Alex