die() when attempting to use bounce buffer on non-i386.

Only i386 has code to support bounce buffer. For others coreboot
would silently discard part of binary which doesn't work and is a hell to debug.

Instead just die.

Change-Id: I37ae24ea5d13aae95f9856a896700a0408747233
Signed-off-by: Vladimir Serbinenko <phcoder@gmail.com>
Reviewed-on: https://review.coreboot.org/13750
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/arch/arm/boot.c

@@ -25,3 +25,8 @@ void arch_prog_run(struct prog *prog)
 	doit = prog_entry(prog);
 	doit(prog_entry_arg(prog));
 }
+
+int arch_supports_bounce_buffer(void)
+{
+	return 0;
+}

src/arch/arm64/boot.c

@@ -72,6 +72,11 @@ void arch_prog_run(struct prog *prog)
 	doit(prog_entry_arg(prog));
 }
 
+int arch_supports_bounce_buffer(void)
+{
+	return 0;
+}
+
 /* Generic stage entry point. Can be overridden by board/SoC if needed. */
 __attribute__((weak)) void stage_entry(void)
 {

src/arch/mips/boot.c

@@ -23,3 +23,8 @@ void arch_prog_run(struct prog *prog)
 
 	doit(cb_tables);
 }
+
+int arch_supports_bounce_buffer(void)
+{
+	return 0;
+}

src/arch/power8/boot.c

@@ -21,3 +21,8 @@ void arch_prog_run(struct prog *prog)
 
 	doit(prog_entry_arg(prog));
 }
+
+int arch_supports_bounce_buffer(void)
+{
+	return 0;
+}

src/arch/riscv/boot.c

@@ -30,3 +30,8 @@ void arch_prog_run(struct prog *prog)
 		doit(prog_entry_arg(prog));
 	}
 }
+
+int arch_supports_bounce_buffer(void)
+{
+	return 0;
+}

src/arch/x86/boot.c

@@ -192,6 +192,11 @@ static void jmp_payload(void *entry, unsigned long buffer, unsigned long size)
 		);
 }
 
+int arch_supports_bounce_buffer(void)
+{
+	return 1;
+}
+
 static void try_payload(struct prog *prog)
 {
 	if (prog_type(prog) == PROG_PAYLOAD) {

src/include/program_loading.h

@@ -41,6 +41,9 @@ enum prog_type {
  * set on the last segment loaded. */
 void arch_segment_loaded(uintptr_t start, size_t size, int flags);
 
+/* Return true if arch supports bounce buffer.  */
+int arch_supports_bounce_buffer(void);
+
 /* Representation of a program. */
 struct prog {
 	/* The region_device is the source of program content to load. After

src/lib/selfboot.c

@@ -114,6 +114,9 @@ static int relocate_segment(unsigned long buffer, struct segment *seg)
 	if (!overlaps_coreboot(seg))
 		return 0;
 
+	if (!arch_supports_bounce_buffer())
+		die ("bounce buffer not supported");
+
 	start = seg->s_dstaddr;
 	middle = start + seg->s_filesz;
 	end = start + seg->s_memsz;