The standard boot protocol on ARM requires CPUs to be entered in the ARM state, unless they don't support the ARM instruction set (see Documentation/arm/Booting). On THUMB2 kernels, we assume the firmware can determine what state to enter the kernel in, but some firmwares don't honor the thumb bit. Make the cpu_resume symbol an ARM symbol, so that firmwares that honor the thumb bit will enter the kernel in ARM state and firmwares that don't honor the thumb bit will be able to enter the kernel in ARM state without more changes. This fixes a problem reported by Kevin Hilman where the ifc6410 fails to boot for THUMB2 kernels because the platform's firmware always enters the kernel in ARM mode from deep idle states. Reported-by: Kevin Hilman <khilman@xxxxxxxxxx> Suggested-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> Cc: Lina Iyer <lina.iyer@xxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> --- arch/arm/kernel/sleep.S | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/arm/kernel/sleep.S b/arch/arm/kernel/sleep.S index 76bb3128e135..7c289ebb0b45 100644 --- a/arch/arm/kernel/sleep.S +++ b/arch/arm/kernel/sleep.S @@ -118,7 +118,12 @@ ENDPROC(cpu_resume_after_mmu) .text .align + .arm ENTRY(cpu_resume) + THUMB( badr r9, 1f ) @ Kernel is entered in ARM. + THUMB( bx r9 ) @ If this is a Thumb-2 kernel, + THUMB( .thumb ) @ switch to Thumb now. + THUMB(1: ) ARM_BE8(setend be) @ ensure we are in BE mode #ifdef CONFIG_ARM_VIRT_EXT bl __hyp_stub_install_secondary -- The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
