Commit 8b9c550e authored by Alex Elder's avatar Alex Elder Committed by Matt Porter
Browse files

ARM: bcm: use inline assembly for "smc" request 



Move the code that implements the "smc" call into a C function that
uses inline assembly.  This allows us to make that function private,
and enables us to get rid of "arch/arm/mach-bcm/bcm_kona_smc_asm.S".
Rename what had been the "buffer_addr" argument to be "buffer_phys"
so it's consistent with other usage in this file.

Since it's now easy to do, verify that r12 contains SEC_EXIT_NORMAL
upon completion of the SMC.  There really isn't a good way to handle
the abnormal completion of a secure monitor request.

Since "bcm_kona_smc.h" is now only included from C files, eliminate
the #ifndef __ASSEMBLY__.

Signed-off-by: default avatarAlex Elder <elder@linaro.org>
Reviewed-by: default avatarTim Kryger <tim.kryger@linaro.org>
Reviewed-by: default avatarMarkus Mayer <markus.mayer@linaro.org>
Reviewed-by: default avatarMatt Porter <mporter@linaro.org>
Signed-off-by: default avatarMatt Porter <mporter@linaro.org>
parent d5c627b5

arch/arm/mach-bcm/Makefile

+4 −3
Original line number Diff line number Diff line
@@ -20,9 +20,10 @@ obj-$(CONFIG_ARCH_BCM_21664) += board_bcm21664.o 
obj-$(CONFIG_ARCH_BCM_MOBILE_L2_CACHE) += kona.o



# Support for secure monitor traps

obj-$(CONFIG_ARCH_BCM_MOBILE_SMC) += bcm_kona_smc.o bcm_kona_smc_asm.o

plus_sec := $(call as-instr,.arch_extension sec,+sec)

AFLAGS_bcm_kona_smc_asm.o	:=-Wa,-march=armv7-a$(plus_sec)

obj-$(CONFIG_ARCH_BCM_MOBILE_SMC) += bcm_kona_smc.o

ifeq ($(call as-instr,.arch_extension sec,as_has_sec),as_has_sec)

CFLAGS_bcm_kona_smc.o		+= -Wa,-march=armv7-a+sec -DREQUIRES_SEC

endif



# BCM2835

obj-$(CONFIG_ARCH_BCM2835)	+= board_bcm2835.o

arch/arm/mach-bcm/bcm_kona_smc.c

+45 −1
Original line number Diff line number Diff line
@@ -76,6 +76,50 @@ int __init bcm_kona_smc_init(void) 
	return 0;

}



/*

 * Since interrupts are disabled in the open mode, we must keep

 * interrupts disabled in secure mode by setting R5=0x3. If interrupts

 * are enabled in open mode, we can set R5=0x0 to allow interrupts in

 * secure mode.  If we did this, the secure monitor would return back

 * control to the open mode to handle the interrupt prior to completing

 * the secure service. If this happened, R12 would not be

 * SEC_EXIT_NORMAL and we would need to call SMC again after resetting

 * R5 (it gets clobbered by the secure monitor) and setting R4 to

 * SSAPI_RET_FROM_INT_SERV to indicate that we want the secure monitor

 * to finish up the previous uncompleted secure service.

 */

static int bcm_kona_do_smc(u32 service_id, u32 buffer_phys)

{

	register u32 ip asm("ip");	/* Also called r12 */

	register u32 r0 asm("r0");

	register u32 r4 asm("r4");

	register u32 r5 asm("r5");

	register u32 r6 asm("r6");



	r4 = service_id;

	r5 = 0x3;		/* Keep IRQ and FIQ off in SM */

	r6 = buffer_phys;



	asm volatile (

		/* Make sure we got the registers we want */

		__asmeq("%0", "ip")

		__asmeq("%1", "r0")

		__asmeq("%2", "r4")

		__asmeq("%3", "r5")

		__asmeq("%4", "r6")

#ifdef REQUIRES_SEC

		".arch_extension sec\n"

#endif

		"	smc    #0\n"

		: "=r" (ip), "=r" (r0)

		: "r" (r4), "r" (r5), "r" (r6)

		: "r1", "r2", "r3", "r7", "lr");



	BUG_ON(ip != SEC_EXIT_NORMAL);



	return r0;

}



/* __bcm_kona_smc() should only run on CPU 0, with pre-emption disabled */

static void __bcm_kona_smc(void *info)

{
@@ -95,7 +139,7 @@ static void __bcm_kona_smc(void *info) 
	flush_cache_all();



	/* Trap into Secure Monitor and record the request result */

	data->result = bcm_kona_smc_asm(data->service_id, bcm_smc_buffer_phys);

	data->result = bcm_kona_do_smc(data->service_id, bcm_smc_buffer_phys);

}



unsigned bcm_kona_smc(unsigned service_id, unsigned arg0, unsigned arg1,

arch/arm/mach-bcm/bcm_kona_smc.h

+0 −6
Original line number Diff line number Diff line
@@ -21,7 +21,6 @@ 
#define SEC_ROM_RET_OK			0x00000001

#define SEC_EXIT_NORMAL			0x1



#ifndef	__ASSEMBLY__

extern int __init bcm_kona_smc_init(void);



extern unsigned bcm_kona_smc(unsigned service_id,
@@ -30,9 +29,4 @@ extern unsigned bcm_kona_smc(unsigned service_id, 
			     unsigned arg2,

			     unsigned arg3);



extern int bcm_kona_smc_asm(u32 service_id,

			    u32 buffer_addr);



#endif	/* __ASSEMBLY__ */



#endif /* BCM_KONA_SMC_H */

arch/arm/mach-bcm/bcm_kona_smc_asm.S

deleted100644 → 0
+0 −41
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2013 Broadcom Corporation

 *

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

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/linkage.h>

#include "bcm_kona_smc.h"



/*

 * int bcm_kona_smc_asm(u32 service_id, u32 buffer_addr)

 */



ENTRY(bcm_kona_smc_asm)

	stmfd	sp!, {r4-r12, lr}

	mov	r4, r0		@ service_id

	mov	r5, #3		@ Keep IRQ and FIQ off in SM

	/*

	 * Since interrupts are disabled in the open mode, we must keep

	 * interrupts disabled in secure mode by setting R5=0x3. If interrupts

	 * are enabled in open mode, we can set R5=0x0 to allow interrupts in

	 * secure mode.  If we did this, the secure monitor would return back

	 * control to the open mode to handle the interrupt prior to completing

	 * the secure service. If this happened, R12 would not be

	 * SEC_EXIT_NORMAL and we would need to call SMC again after resetting

	 * R5 (it gets clobbered by the secure monitor) and setting R4 to

	 * SSAPI_RET_FROM_INT_SERV to indicate that we want the secure monitor

	 * to finish up the previous uncompleted secure service.

	 */

	mov	r6, r1		@ buffer_addr

	smc	#0

	/* Check r12 for SEC_EXIT_NORMAL here if interrupts are enabled */

	ldmfd	sp!, {r4-r12, pc}

ENDPROC(bcm_kona_smc_asm)

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