Add broken sc1 detection and patching and an hcall for putchar,
to use 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/asm/hcall.h | 43 +++++++++++++++++++++++++++
lib/powerpc/hcall.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++
lib/powerpc/io.c | 15 ++++++++--
lib/ppc64/asm/hcall.h | 1 +
powerpc/Makefile.common | 2 ++
powerpc/cstart64.S | 21 +++++++++++++
6 files changed, 159 insertions(+), 2 deletions(-)
create mode 100644 lib/powerpc/asm/hcall.h
create mode 100644 lib/powerpc/hcall.c
create mode 100644 lib/ppc64/asm/hcall.h
diff --git a/lib/powerpc/asm/hcall.h b/lib/powerpc/asm/hcall.h
new file mode 100644
index 0000000000000..75eac456c49eb
--- /dev/null
+++ b/lib/powerpc/asm/hcall.h
@@ -0,0 +1,43 @@
+#ifndef _ASMPOWERPC_HCALL_H_
+#define _ASMPOWERPC_HCALL_H_
+/*
+ * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+
+#define SC1 0x44000022
+#define SC1_REPLACEMENT 0x7c000268
+
+#define H_SUCCESS 0
+#define H_HARDWARE -1
+
+#define H_SET_DABR 0x28
+#define H_PUT_TERM_CHAR 0x58
+
+#ifndef __ASSEMBLY__
+#include <libcflat.h>
+
+/*
+ * hcall_have_broken_sc1 checks if we're on a host with a broken sc1.
+ * Returns true if we are.
+ */
+extern bool hcall_have_broken_sc1(void);
+
+/*
+ * hcall_patch_broken_sc1 patches hcall's sc1 instruction, if needed,
+ * allowing all hypercalls built on it to work.
+ */
+extern void hcall_patch_broken_sc1(void);
+
+/*
+ * hcall is the hypercall wrapper function. unittests may do what
+ * they like, but the framework should make all hypercalls through
+ * here to ensure they use a working sc1 instruction, and properly
+ * handle clobbered registers. @nr is the hypercall number.
+ */
+extern unsigned long
+hcall(unsigned long nr, unsigned long *in, unsigned long *out);
+
+#endif /* !__ASSEMBLY__ */
+#endif /* _ASMPOWERPC_HCALL_H_ */
diff --git a/lib/powerpc/hcall.c b/lib/powerpc/hcall.c
new file mode 100644
index 0000000000000..4c42b18ef9901
--- /dev/null
+++ b/lib/powerpc/hcall.c
@@ -0,0 +1,79 @@
+/*
+ * Hypercall helpers
+ *
+ * broken_sc1 probing/patching inspired by SLOF, see
+ * SLOF:lib/libhvcall/brokensc1.c
+ *
+ * hcall() implementation inspired by Linux's epapr_hypercall, see
+ * arch/powerpc/include/asm/epapr_hcalls.h
+ *
+ * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.
+ */
+#include <libcflat.h>
+#include <asm/hcall.h>
+
+static u32 sc1[];
+
+bool hcall_have_broken_sc1(void)
+{
+ register unsigned long r3 asm("r3") = H_SET_DABR;
+ register unsigned long r4 asm("r4") = 0;
+
+ asm volatile("sc 1"
+ : "=r" (r3)
+ : "r" (r3), "r" (r4)
+ : "r5", "r6", "r7", "r8", "r9", "r10", "r11", "r12");
+
+ return !(r3 == H_SUCCESS || r3 == (unsigned long)H_HARDWARE);
+}
+
+void hcall_patch_broken_sc1(void)
+{
+ if (!hcall_have_broken_sc1())
+ return;
+ sc1[0] = SC1_REPLACEMENT;
+}
+
+unsigned long hcall(unsigned long nr, unsigned long *in, unsigned long *out)
+{
+ register unsigned long r3 asm("r3") = nr;
+ register unsigned long r4 asm("r4") = in[0];
+ register unsigned long r5 asm("r5") = in[1];
+ register unsigned long r6 asm("r6") = in[2];
+ register unsigned long r7 asm("r7") = in[3];
+ register unsigned long r8 asm("r8") = in[4];
+ register unsigned long r9 asm("r9") = in[5];
+ register unsigned long r10 asm("r10") = in[6];
+ register unsigned long r11 asm("r11") = in[7];
+
+ asm volatile("bl sc1"
+ : "=r"(r3), "=r"(r4), "=r"(r5), "=r"(r6), "=r"(r7),
+ "=r"(r8), "=r"(r9), "=r"(r10), "=r"(r11)
+ : "r"(r3), "r"(r4), "r"(r5), "r"(r6), "r"(r7),
+ "r"(r8), "r"(r9), "r"(r10), "r"(r11)
+ : "r12", "memory", "lr");
+
+ out[0] = r4;
+ out[1] = r5;
+ out[2] = r6;
+ out[3] = r7;
+ out[4] = r8;
+ out[5] = r9;
+ out[6] = r10;
+ out[7] = r11;
+
+ return r3;
+}
+
+void putchar(int c)
+{
+ unsigned long in[8], out[8];
+
+ in[0] = 0; /* default vty */
+ in[1] = 1; /* just 1 byte */
+ in[2] = (unsigned long)c << 56;
+
+ hcall(H_PUT_TERM_CHAR, in, out);
+}
diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c
index 0af45742fc900..5e1fa8dd96ab6 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/lib/ppc64/asm/hcall.h b/lib/ppc64/asm/hcall.h
new file mode 100644
index 0000000000000..daabaca510cd4
--- /dev/null
+++ b/lib/ppc64/asm/hcall.h
@@ -0,0 +1 @@
+#include "../../powerpc/asm/hcall.h"
diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
index 0c3eaba0d3aab..89610b525f0c1 100644
--- a/powerpc/Makefile.common
+++ b/powerpc/Makefile.common
@@ -21,6 +21,7 @@ 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
@@ -29,6 +30,7 @@ cflatobjs += lib/util.o
cflatobjs += lib/alloc.o
cflatobjs += lib/devicetree.o
cflatobjs += lib/powerpc/io.o
+cflatobjs += lib/powerpc/hcall.o
libgcc := $(shell $(CC) $(machine) --print-libgcc-file-name)
start_addr := $(shell printf "%x\n" $$(( $(phys_base) + $(kernel_offset) )))
diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S
index f90828dee1c19..623fd693b02d1 100644
--- a/powerpc/cstart64.S
+++ b/powerpc/cstart64.S
@@ -7,13 +7,34 @@
*/
#define __ASSEMBLY__
+#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 hcall_patch_broken_sc1
+ bl main
+ bl exit
b halt
.text
+.align 3
+
+.globl sc1
+sc1:
+ sc 1
+ blr
.globl halt
halt:
--
2.4.3
--
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