Am 13.01.2017 um 08:50 schrieb Alison Wang b18965@freescale.com:
For 64-bit kernel, there is a warning about x1-x3 nonzero in
violation
of boot protocol. x3 should be reset to zero before jumping to the kernel.
This patch will adjust the parameters to transfer and make sure x3 is zero.
Signed-off-by: Alison Wang alison.wang@nxp.com
If x3 is part of the boot protocol, please treat it as function argument rather than hard code it to 0.
[Alison Wang] I think x3 need to set to 0. Refer to the codes for the warning in kernel,
if (boot_args[1] || boot_args[2] || boot_args[3]) { pr_err("WARNING: x1-x3 nonzero in violation of boot protocol:\n" "\tx1: %016llx\n\tx2: %016llx\n\tx3: %016llx\n" "This indicates a broken bootloader or old kernel\n", boot_args[1], boot_args[2], boot_args[3]); }
arch/arm/cpu/armv8/transition.S | 44 +++++++++++++++++++++++++++++++++++++---- 1 file changed, 40 insertions(+), 4 deletions(-)
diff --git a/arch/arm/cpu/armv8/transition.S b/arch/arm/cpu/armv8/transition.S index adb9f35..06b6664 100644 --- a/arch/arm/cpu/armv8/transition.S +++ b/arch/arm/cpu/armv8/transition.S @@ -26,9 +26,27 @@ ENTRY(armv8_switch_to_el2) * if CONFIG_ARMV8_SWITCH_TO_EL1 is defined. * When running in EL2 now, jump to the * address saved in x3.
** For 64-bit kernel, there is a warning about* x1-x3 nonzero in violation of boot protocol.* x3 should be reset to zero before jumping to* the kernel. Use x4 instead of x3 as parameter.
- br x3
-1: armv8_switch_to_el2_m x3, x4, x5
- mov x4, x3
- mov x3, #0
- br x4
+1:
- /*
* For 64-bit kernel, there is a warning about* x1-x3 nonzero in violation of boot protocol.* x3 should be reset to zero before jumping to* the kernel. Use x4, x5, x6 instead of x3, x4,* x5 as parameters.*/- mov x5, x4
- mov x4, x3
- mov x3, #0
- armv8_switch_to_el2_m x4, x5, x6
ENDPROC(armv8_switch_to_el2)
ENTRY(armv8_switch_to_el1) @@ -36,9 +54,27 @@ ENTRY(armv8_switch_to_el1) 0: /* x3 is kernel entry point. When running in EL1 * now, jump to the address saved in x3.
** For 64-bit kernel, there is a warning about* x1-x3 nonzero in violation of boot protocol.* x3 should be reset to zero before jumping to* the kernel. Use x4 instead of x3 as parameter.*/- mov x4, x3
- mov x3, #0
- br x4
+1:
- /*
* For 64-bit kernel, there is a warning about* x1-x3 nonzero in violation of boot protocol.* x3 should be reset to zero before jumping to* the kernel. Use x4, x5, x6 instead of x3, x4,* x5 as parameters.
- br x3
-1: armv8_switch_to_el1_m x3, x4, x5
- mov x5, x4
- mov x4, x3
- mov x3, #0
- armv8_switch_to_el1_m x4, x5, x6
ENDPROC(armv8_switch_to_el1)
WEAK(armv8_el2_to_aarch32)
2.1.0.27.g96db324
Best Regards, Alison Wang