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Commit ab9cb420 authored by Taniya Das's avatar Taniya Das Committed by Kyle Yan
Browse files

qcom: scm: Support register r6 to pass the session id 



Non-atomic scm call which could be interrupted, trustzone will store
the session id in a register(r6) which will be used when trustzone resumes
the call.
To avoid r6 being used by compiler, HLOS now uses it to send a zero before
making scm call.

Change-Id: I2927efe04fd019d551aae5e6548da3fb5c18b655
Signed-off-by: default avatarTaniya Das <tdas@codeaurora.org>
parent 123357f5

drivers/soc/qcom/scm.c

+5 −2
Original line number Diff line number Diff line 
/* Copyright (c) 2010-2016, The Linux Foundation. All rights reserved.

/* Copyright (c) 2010-2017, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and
@@ -134,6 +134,7 @@ struct scm_response { 
#define R3_STR "r3"

#define R4_STR "r4"

#define R5_STR "r5"

#define R6_STR "r6"



#endif
@@ -481,6 +482,7 @@ static int __scm_call_armv8_32(u32 w0, u32 w1, u32 w2, u32 w3, u32 w4, u32 w5, 
	register u32 r3 asm("r3") = w3;

	register u32 r4 asm("r4") = w4;

	register u32 r5 asm("r5") = w5;

	register u32 r6 asm("r6") = 0;



	do {

		asm volatile(
@@ -494,13 +496,14 @@ static int __scm_call_armv8_32(u32 w0, u32 w1, u32 w2, u32 w3, u32 w4, u32 w5, 
			__asmeq("%7", R3_STR)

			__asmeq("%8", R4_STR)

			__asmeq("%9", R5_STR)

			__asmeq("%10", R6_STR)

#ifdef REQUIRES_SEC

			".arch_extension sec\n"

#endif

			"smc	#0\n"

			: "=r" (r0), "=r" (r1), "=r" (r2), "=r" (r3)

			: "r" (r0), "r" (r1), "r" (r2), "r" (r3), "r" (r4),

			 "r" (r5));

			 "r" (r5), "r" (r6));



	} while (r0 == SCM_INTERRUPTED);