Add the hvcall for putchar and use it in puts. That, along with a
couple more lines in start to prepare for C code, and a branch to
main(), gets us "hello world". Run with
qemu-system-ppc64 -M pseries \
-bios powerpc/boot_rom.bin \
-display none -serial stdio \
-kernel powerpc/selftest.elf
(We're still not relocating yet, that comes in a later patch. Thus,
testing hello-world at this point requires a hacked QEMU and linking
the unit test at QEMU's kernel load address.)
Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
---
lib/powerpc/io.c | 15 +++++++++++++--
powerpc/Makefile.common | 1 +
powerpc/cstart64.S | 27 +++++++++++++++++++++++++++
3 files changed, 41 insertions(+), 2 deletions(-)
diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c
index cf3b6347e1e46..a7eaafeca9205 100644
--- a/lib/powerpc/io.c
+++ b/lib/powerpc/io.c
@@ -6,15 +6,26 @@
* This work is licensed under the terms of the GNU LGPL, version 2.
*/
#include <libcflat.h>
+#include <asm/spinlock.h>
+
+extern void halt(int code);
+extern void putchar(int c);
+
+static struct spinlock uart_lock;
void io_init(void)
{
}
-void puts(const char *s __unused)
+void puts(const char *s)
{
+ spin_lock(&uart_lock);
+ while (*s)
+ putchar(*s++);
+ spin_unlock(&uart_lock);
}
-void exit(int code __unused)
+void exit(int code)
{
+ halt(code);
}
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 5cd3ea8085038..d6356540918a5 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -26,6 +26,7 @@ CFLAGS += -ffreestanding
CFLAGS += -Wextra
CFLAGS += -O2
CFLAGS += -I lib -I lib/libfdt
+CFLAGS += -Wa,-mregnames
asm-offsets = lib/$(ARCH)/asm-offsets.h
include scripts/asm-offsets.mak
diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index d9b77f44f9e0e..d7c51cd352ee4 100644
--- a/powerpc/cstart64.S
+++ b/powerpc/cstart64.S
@@ -6,14 +6,41 @@
* This work is licensed under the terms of the GNU LGPL, version 2.
*/
+#define HVSC .long 0x44000022
+#define H_PUT_TERM_CHAR 0x58
+
+#define LOAD_REG_IMMEDIATE(reg,expr) \
+ lis reg,(expr)@highest; \
+ ori reg,reg,(expr)@higher; \
+ rldicr reg,reg,32,31; \
+ oris reg,reg,(expr)@h; \
+ ori reg,reg,(expr)@l;
+
+#define LOAD_REG_ADDR(reg,name) \
+ ld reg,name@got(r2)
+
.section .init
.globl start
start:
+ LOAD_REG_IMMEDIATE(r1, stackptr)
+ LOAD_REG_IMMEDIATE(r2, tocptr)
+ bl .main
+ bl .exit
b halt
.text
+.align 3
.globl halt
halt:
1: b 1b
+
+.globl putchar
+putchar:
+ sldi r6, r3, 56
+ li r3, H_PUT_TERM_CHAR
+ li r4, 0 /* vty-reg 0 means to use the default vty */
+ li r5, 1 /* sending just 1 byte */
+ HVSC
+ blr
--
2.4.3
--
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