On 5 May 2017 at 20:47, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>
> Commit 69bbf2ab20389418327484288d8730732e4f3dd0 upstream.
>
> Two files that get included when building the multi_v7_defconfig target
> fail to build when selecting THUMB2_KERNEL for this configuration.
>
> In both cases, we can just build the file as ARM code, as none of its
> symbols are exported to modules, so there are no interworking concerns.
> In the iwmmxt.S case, add ENDPROC() declarations so the symbols are
> annotated as functions, resulting in the linker to emit the appropriate
> mode switches.
>
> Acked-by: Nicolas Pitre <nico@xxxxxxxxxx>
> Tested-by: Olof Johansson <olof@xxxxxxxxx>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Signed-off-by: Russell King <rmk+kernel@xxxxxxxxxxxxxxxx>
> Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
I think you will want to take 5008efc83bf85b647aa1cbc44718b1675bbb7444
as well. This patch by itself caused problems with ftrace's
instruction patching IIRC.
> ---
> arch/arm/kernel/Makefile | 1 +
> arch/arm/kernel/iwmmxt.S | 13 +++++++++++++
> 2 files changed, 14 insertions(+)
>
> diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile
> index 03120e656aea..2ecc7d15bc09 100644
> --- a/arch/arm/kernel/Makefile
> +++ b/arch/arm/kernel/Makefile
> @@ -84,6 +84,7 @@ obj-$(CONFIG_CPU_PJ4B) += pj4-cp0.o
> obj-$(CONFIG_IWMMXT) += iwmmxt.o
> obj-$(CONFIG_PERF_EVENTS) += perf_regs.o
> obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o perf_event_cpu.o
> +CFLAGS_pj4-cp0.o := -marm
> AFLAGS_iwmmxt.o := -Wa,-mcpu=iwmmxt
> obj-$(CONFIG_ARM_CPU_TOPOLOGY) += topology.o
>
> diff --git a/arch/arm/kernel/iwmmxt.S b/arch/arm/kernel/iwmmxt.S
> index 2b32978ae905..d65bb940d797 100644
> --- a/arch/arm/kernel/iwmmxt.S
> +++ b/arch/arm/kernel/iwmmxt.S
> @@ -58,6 +58,7 @@
> #define MMX_SIZE (0x98)
>
> .text
> + .arm
>
> /*
> * Lazy switching of Concan coprocessor context
> @@ -182,6 +183,8 @@ concan_load:
> tmcr wCon, r2
> mov pc, lr
>
> +ENDPROC(iwmmxt_task_enable)
> +
> /*
> * Back up Concan regs to save area and disable access to them
> * (mainly for gdb or sleep mode usage)
> @@ -232,6 +235,8 @@ ENTRY(iwmmxt_task_disable)
> 1: msr cpsr_c, ip @ restore interrupt mode
> ldmfd sp!, {r4, pc}
>
> +ENDPROC(iwmmxt_task_disable)
> +
> /*
> * Copy Concan state to given memory address
> *
> @@ -268,6 +273,8 @@ ENTRY(iwmmxt_task_copy)
> msr cpsr_c, ip @ restore interrupt mode
> mov pc, r3
>
> +ENDPROC(iwmmxt_task_copy)
> +
> /*
> * Restore Concan state from given memory address
> *
> @@ -304,6 +311,8 @@ ENTRY(iwmmxt_task_restore)
> msr cpsr_c, ip @ restore interrupt mode
> mov pc, r3
>
> +ENDPROC(iwmmxt_task_restore)
> +
> /*
> * Concan handling on task switch
> *
> @@ -335,6 +344,8 @@ ENTRY(iwmmxt_task_switch)
> mrc p15, 0, r1, c2, c0, 0
> sub pc, lr, r1, lsr #32 @ cpwait and return
>
> +ENDPROC(iwmmxt_task_switch)
> +
> /*
> * Remove Concan ownership of given task
> *
> @@ -353,6 +364,8 @@ ENTRY(iwmmxt_task_release)
> msr cpsr_c, r2 @ restore interrupts
> mov pc, lr
>
> +ENDPROC(iwmmxt_task_release)
> +
> .data
> concan_owner:
> .word 0
> --
> 2.9.0
>