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authorVadzim Dambrouski <pftbest@gmail.com>2015-10-19 19:40:14 +0300
committerAlbert ARIBAUD <albert.u.boot@aribaud.net>2015-11-10 09:45:33 +0100
commit432a6241bdb70b98ead8f58bbf717d3f7fe699a8 (patch)
treec1dc8eedb96b9c3248e71ce4141ee630a6070501 /arch/arm/lib
parente490ad25eb3dc4f075ed33b4b00b1f97071fcf3d (diff)
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arm: add support for semihosting for ARMv7M targets
If you enable CONFIG_SEMIHOSTING for STM32F429 target, you will get compile error looking like this: arch/arm/lib/semihosting.c: In function 'smh_read': {standard input}: Assembler messages: {standard input}:34: Error: invalid swi expression {standard input}:34: Error: value of 1193046 too large for field of 2 bytes at 0 scripts/Makefile.build:277: recipe for target 'arch/arm/lib/semihosting.o' failed The source of the problem is "svc #0x123456" instruction. This instruction can not be encoded using Thumb2 instruction set used by ARMv7M CPUs. ARM documentation suggests using "bkpt #0xAB" instruction instead [1]. This patch fixes compile errors and adds support for semihosting for STM32F429 or any other ARMv7M target. This change was sested on STM32F429-DISCOVERY board using OpenOCD and "smhload" u-boot command. [1] http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0471c/Bgbjhiea.html Signed-off-by: Vadzim Dambrouski <pftbest@gmail.com>
Diffstat (limited to 'arch/arm/lib')
-rw-r--r--arch/arm/lib/semihosting.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
index c3e964eabc..ed5e8e426e 100644
--- a/arch/arm/lib/semihosting.c
+++ b/arch/arm/lib/semihosting.c
@@ -31,6 +31,8 @@ static noinline long smh_trap(unsigned int sysnum, void *addr)
register long result asm("r0");
#if defined(CONFIG_ARM64)
asm volatile ("hlt #0xf000" : "=r" (result) : "0"(sysnum), "r"(addr));
+#elif defined(CONFIG_CPU_V7M)
+ asm volatile ("bkpt #0xAB" : "=r" (result) : "0"(sysnum), "r"(addr));
#else
/* Note - untested placeholder */
asm volatile ("svc #0x123456" : "=r" (result) : "0"(sysnum), "r"(addr));