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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: Alex Elder <elder@linaro.org>
Reviewed-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Matt Porter <mporter@linaro.org>
Signed-off-by: Matt Porter <mporter@linaro.org>
This commit is contained in:
Alex Elder 2014-04-21 16:53:09 -05:00 committed by Matt Porter
parent d5c627b575
commit 8b9c550e37
4 changed files with 49 additions and 51 deletions
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7
arch/arm/mach-bcm/Makefile
View File

@ -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

46
arch/arm/mach-bcm/bcm_kona_smc.c
View File

@ -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,

6
arch/arm/mach-bcm/bcm_kona_smc.h
View File

@ -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 */

41
arch/arm/mach-bcm/bcm_kona_smc_asm.S
View File

@ -1,41 +0,0 @@
/*
* 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)