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 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@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c
index be8050b..70993af 100644 (file)
--- a/arch/arm/kernel/asm-offsets.c
+++ b/arch/arm/kernel/asm-offsets.c
@@ -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);

diff --git a/arch/arm/kernel/smccc-call.S b/arch/arm/kernel/smccc-call.S
index 00664c7..931df62 100644 (file)
--- 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