Commit 57ac5166 authored by Manivannan Sadhasivam's avatar Manivannan Sadhasivam Committed by Russell King
Browse files

ARM: 9075/1: kernel: Fix interrupted SMC calls 



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 82bcd087 ("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: default avatarManivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: default avatarRussell King <rmk+kernel@armlinux.org.uk>
parent 5fafafe7

arch/arm/kernel/asm-offsets.c

+3 −0
Original line number Diff line number Diff line
@@ -24,6 +24,7 @@ 
#include <asm/vdso_datapage.h>

#include <asm/hardware/cache-l2x0.h>

#include <linux/kbuild.h>

#include <linux/arm-smccc.h>

#include "signal.h"



/*
@@ -148,6 +149,8 @@ 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);

arch/arm/kernel/smccc-call.S

+10 −1
Original line number Diff line number Diff line
@@ -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