Hi,
On Mon, Jan 18, 2021 at 11:40:40PM +0530, Manivannan Sadhasivam wrote:
> On Qualcomm ARM32 platforms, the SMC call can return before it has
> completed. If this occurs, the call can be restarted, but it requires
> using the returned session ID value from the interrupted SMC call.
>
> The ARM32 SMCC code already has the provision to add platform specific
> quirks for things like this. So let's make use of it and add the
> Qualcomm specific quirk (ARM_SMCCC_QUIRK_QCOM_A6) used by the QCOM_SCM
> driver.
>
> This change is similar to the below one added for ARM64 a while ago:
> commit 82bcd087029f ("firmware: qcom: scm: Fix interrupted SCM calls")
>
> Without this change, the Qualcomm ARM32 platforms like SDX55 will return
> -EINVAL for SMC calls used for modem firmware loading and validation.
>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
A gentle ping on this patch!
Thanks,
Mani
> ---
>
> Changes in v2:
>
> * Preserved callee saved registers and used the registers r4, r5 which
> are getting pushed onto the stack.
>
> arch/arm/kernel/asm-offsets.c | 3 +++
> arch/arm/kernel/smccc-call.S | 11 ++++++++++-
> 2 files changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
> index a1570c8bab25..2e2fa6fc2d4f 100644
> --- a/arch/arm/kernel/asm-offsets.c
> +++ b/arch/arm/kernel/asm-offsets.c
> @@ -23,6 +23,7 @@
> #include <asm/vdso_datapage.h>
> #include <asm/hardware/cache-l2x0.h>
> #include <linux/kbuild.h>
> +#include <linux/arm-smccc.h>
> #include "signal.h"
>
> /*
> @@ -147,6 +148,8 @@ int main(void)
> DEFINE(SLEEP_SAVE_SP_PHYS, offsetof(struct sleep_save_sp, save_ptr_stash_phys));
> DEFINE(SLEEP_SAVE_SP_VIRT, offsetof(struct sleep_save_sp, save_ptr_stash));
> #endif
> + DEFINE(ARM_SMCCC_QUIRK_ID_OFFS, offsetof(struct arm_smccc_quirk, id));
> + DEFINE(ARM_SMCCC_QUIRK_STATE_OFFS, offsetof(struct arm_smccc_quirk, state));
> BLANK();
> DEFINE(DMA_BIDIRECTIONAL, DMA_BIDIRECTIONAL);
> DEFINE(DMA_TO_DEVICE, DMA_TO_DEVICE);
> diff --git a/arch/arm/kernel/smccc-call.S b/arch/arm/kernel/smccc-call.S
> index 00664c78faca..931df62a7831 100644
> --- a/arch/arm/kernel/smccc-call.S
> +++ b/arch/arm/kernel/smccc-call.S
> @@ -3,7 +3,9 @@
> * Copyright (c) 2015, Linaro Limited
> */
> #include <linux/linkage.h>
> +#include <linux/arm-smccc.h>
>
> +#include <asm/asm-offsets.h>
> #include <asm/opcodes-sec.h>
> #include <asm/opcodes-virt.h>
> #include <asm/unwind.h>
> @@ -27,7 +29,14 @@ UNWIND( .fnstart)
> UNWIND( .save {r4-r7})
> ldm r12, {r4-r7}
> \instr
> - pop {r4-r7}
> + ldr r4, [sp, #36]
> + cmp r4, #0
> + beq 1f // No quirk structure
> + ldr r5, [r4, #ARM_SMCCC_QUIRK_ID_OFFS]
> + cmp r5, #ARM_SMCCC_QUIRK_QCOM_A6
> + bne 1f // No quirk present
> + str r6, [r4, #ARM_SMCCC_QUIRK_STATE_OFFS]
> +1: pop {r4-r7}
> ldr r12, [sp, #(4 * 4)]
> stm r12, {r0-r3}
> bx lr
> --
> 2.25.1
>
