On 12/10/16 17:57, Nicholas Piggin wrote:
> This adds a config option that can help exercise the case when
> the kernel is not running at PAGE_OFFSET.
>
> Signed-off-by: Nicholas Piggin <npig...@gmail.com>
> ---
> arch/powerpc/Kconfig | 9 +++++++++
> arch/powerpc/kernel/head_64.S | 4 ++++
> arch/powerpc/kernel/setup-common.c | 3 +++
> 3 files changed, 16 insertions(+)
>
> diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> index 65fba4c..5d43cb8 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -478,6 +478,15 @@ config RELOCATABLE
> setting can still be useful to bootwrappers that need to know the
> load address of the kernel (eg. u-boot/mkimage).
>
> +config RELOCATABLE_TEST
> + bool "Test relocatable kernel"
> + depends on (PPC64 && RELOCATABLE)
> + default n
> + help
> + This runs the relocatable kernel at the address it was initially
> + loaded at, which tends to be non-zero and therefore test the
> + relocation code.
> +
> config CRASH_DUMP
> bool "Build a kdump crash kernel"
> depends on PPC64 || 6xx || FSL_BOOKE || (44x && !SMP)
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index 79da0641..bc9ceac 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -111,8 +111,12 @@ __secondary_hold_acknowledge:
> .globl __run_at_load
> __run_at_load:
> DEFINE_FIXED_SYMBOL(__run_at_load)
> +#ifdef CONFIG_RELOCATABLE_TEST
> + .long 0x1 /* Test relocation, do not relocate to 0 */
> +#else
> .long 0x72756e30 /* "run0" -- relocate to 0 by default */
> #endif
> +#endif
Could we do something like
config RELOCATION_VALUE
default 0x72756e30
default 1 if CONFIG_RELOCTABLE_TEST
and then get
.long CONFIG_RELOCATION_VALUE
>
> . = 0x60
> /*
> diff --git a/arch/powerpc/kernel/setup-common.c
> b/arch/powerpc/kernel/setup-common.c
> index dba265c..18e0f19 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -795,6 +795,9 @@ static __init void print_system_info(void)
> pr_info("mmu_features = 0x%08x\n", cur_cpu_spec->mmu_features);
> #ifdef CONFIG_PPC64
> pr_info("firmware_features = 0x%016lx\n", powerpc_firmware_features);
> +
> + if (get_paca()->kernelbase != PAGE_OFFSET)
> + pr_info("kernelbase = 0x%llx\n", get_paca()->kernelbase);
> #endif
>
Do we need this? We get physical_offset if we are relocated.
> #ifdef CONFIG_PPC_STD_MMU_64
>
Balbir Singh.
