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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH 4/4] xen/ppc: Implement early serial console on PowerNV
Implement the OPAL firmware calls required to write to the serial
console on PowerNV systems. Unlike pseries/Open Firmware, the OPAL
firmware interface can be used past early boot and as such the relevant
functions are not marked as __init.
Signed-off-by: Shawn Anastasio <sanastasio@xxxxxxxxxxxxxxxxxxxxx>
---
Changed in v2:
- Include asm-offsets in asm-defns.h
- Clean up assembly formatting in asm-defns.h
- Clean up formatting of opal.c
- Clean up stray semicolon in OPAL_CALL macro in opal-calls.S
xen/arch/ppc/include/asm/asm-defns.h | 18 ++++++-
xen/arch/ppc/opal.c | 28 +++++++++-
xen/arch/ppc/ppc64/Makefile | 1 +
xen/arch/ppc/ppc64/asm-offsets.c | 4 ++
xen/arch/ppc/ppc64/opal-calls.S | 81 ++++++++++++++++++++++++++++
5 files changed, 129 insertions(+), 3 deletions(-)
create mode 100644 xen/arch/ppc/ppc64/opal-calls.S
diff --git a/xen/arch/ppc/include/asm/asm-defns.h
b/xen/arch/ppc/include/asm/asm-defns.h
index 5821f9024d..f1c49808bd 100644
--- a/xen/arch/ppc/include/asm/asm-defns.h
+++ b/xen/arch/ppc/include/asm/asm-defns.h
@@ -2,6 +2,8 @@
#ifndef _ASM_PPC_ASM_DEFNS_H
#define _ASM_PPC_ASM_DEFNS_H
+#include <asm/asm-offsets.h>
+
/*
* Load a 64-bit immediate value into the specified GPR.
*/
@@ -20,8 +22,20 @@
* Load the address of a symbol from the TOC into the specified GPR.
*/
#define LOAD_REG_ADDR(reg,name) \
- addis reg,%r2,name@toc@ha; \
- addi reg,reg,name@toc@l
+ addis reg, %r2, name@toc@ha; \
+ addi reg, reg, name@toc@l
+
+/*
+ * Declare a global assembly function with a proper TOC setup prologue
+ */
+#define _GLOBAL_TOC(name) \
+ .balign 4; \
+ .type name, @function; \
+ .globl name; \
+name: \
+0: addis %r2, %r12, (.TOC.-0b)@ha; \
+ addi %r2, %r2, (.TOC.-0b)@l; \
+ .localentry name, .-name
/*
* Depending on how we were booted, the CPU could be running in either
diff --git a/xen/arch/ppc/opal.c b/xen/arch/ppc/opal.c
index 251de8ac23..1183b7d5ef 100644
--- a/xen/arch/ppc/opal.c
+++ b/xen/arch/ppc/opal.c
@@ -8,9 +8,29 @@
#include <xen/init.h>
#include <xen/lib.h>
-/* Global OPAL struct containing entrypoint and base */
+/* Global OPAL struct containing entrypoint and base used by opal-calls.S */
struct opal opal;
+int64_t opal_console_write(int64_t term_number, uint64_t *length,
+ const void *buffer);
+int64_t opal_console_flush(int64_t term_number);
+int64_t opal_reinit_cpus(uint64_t flags);
+
+static void opal_putchar(char c)
+{
+ uint64_t len;
+
+ if ( c == '\n' )
+ {
+ char buf = '\r';
+ len = cpu_to_be64(1);
+ opal_console_write(0, &len, &buf);
+ }
+ len = cpu_to_be64(1);
+ opal_console_write(0, &len, &c);
+ opal_console_flush(0);
+}
+
void __init boot_opal_init(const void *fdt)
{
int opal_node;
@@ -45,4 +65,10 @@ void __init boot_opal_init(const void *fdt)
opal.base = be64_to_cpu(*opal_base);
opal.entry = be64_to_cpu(*opal_entry);
+
+ early_printk_init(opal_putchar);
+
+ /* Ask OPAL to set HID0 for Little Endian interrupts + Radix TLB support */
+ opal_reinit_cpus(OPAL_REINIT_CPUS_HILE_LE | OPAL_REINIT_CPUS_MMU_RADIX |
+ OPAL_REINIT_CPUS_MMU_HASH);
}
diff --git a/xen/arch/ppc/ppc64/Makefile b/xen/arch/ppc/ppc64/Makefile
index f4956daaa9..b9a91dc15f 100644
--- a/xen/arch/ppc/ppc64/Makefile
+++ b/xen/arch/ppc/ppc64/Makefile
@@ -1,2 +1,3 @@
obj-y += head.o
obj-y += of-call.o
+obj-y += opal-calls.o
diff --git a/xen/arch/ppc/ppc64/asm-offsets.c b/xen/arch/ppc/ppc64/asm-offsets.c
index e1129cb0f4..c15c1bf136 100644
--- a/xen/arch/ppc/ppc64/asm-offsets.c
+++ b/xen/arch/ppc/ppc64/asm-offsets.c
@@ -6,6 +6,7 @@
#include <xen/macros.h>
#include <asm/processor.h>
+#include <asm/boot.h>
#define DEFINE(_sym, _val) \
asm volatile ( "\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \
@@ -46,6 +47,9 @@ void __dummy__(void)
OFFSET(UREGS_cr, struct cpu_user_regs, cr);
OFFSET(UREGS_fpscr, struct cpu_user_regs, fpscr);
DEFINE(UREGS_sizeof, sizeof(struct cpu_user_regs));
+
+ OFFSET(OPAL_base, struct opal, base);
+ OFFSET(OPAL_entry, struct opal, entry);
}
/*
diff --git a/xen/arch/ppc/ppc64/opal-calls.S b/xen/arch/ppc/ppc64/opal-calls.S
new file mode 100644
index 0000000000..cc5de75c8a
--- /dev/null
+++ b/xen/arch/ppc/ppc64/opal-calls.S
@@ -0,0 +1,81 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Adapted from Linux's arch/powerpc/boot/opal-calls.S
+ *
+ * Copyright (c) 2016 IBM Corporation.
+ * Copyright Raptor Engineering, LLC
+ */
+
+#include <asm/asm-defns.h>
+#include <asm/opal-api.h>
+#include <asm/msr.h>
+
+ .text
+
+#define OPAL_CALL(name, token) \
+ .globl name; \
+name: \
+ li %r0, token; \
+ b opal_call
+
+ _GLOBAL_TOC(opal_call)
+ /* Back up LR, CR, r2 in caller's stack frame */
+ mflr %r11
+ mfcr %r12
+ std %r2, 24(%r1)
+ std %r11, 16(%r1)
+ stw %r12, 8(%r1)
+
+ /* Use r14 (non-volatile) to store the virtual address of opal_return_mmu
*/
+ std %r14, -8(%r1)
+ stdu %r1, -48(%r1)
+ LOAD_REG_ADDR(%r14, opal_return_mmu)
+
+ /*
+ * Setup new MSR without LE or MMU. Original MSR will be preserved across
+ * opal call in r13
+ */
+ mfmsr %r13
+ li %r11, MSR_LE | MSR_IR | MSR_DR
+ andc %r12, %r13, %r11
+ mthsrr1 %r12
+
+ LOAD_REG_ADDR(%r11, opal_return_real)
+ mtlr %r11
+
+ /* Load the opal call entry point and base */
+ LOAD_REG_ADDR(%r11, opal)
+ ld %r12, OPAL_entry(%r11)
+ ld %r2, OPAL_base(%r11)
+ mthsrr0 %r12
+ hrfid
+
+opal_return_real:
+ /*
+ * OPAL will always return to us in Big Endian mode. Since we are going
+ * to restore the old MSR with the correct endianness and MMU status set,
we
+ * can avoid an unnecessary FIXUP_ENDIAN trampoline by just encoding the
+ * required Big Endian instructions to restore the old MSR direclty.
+ */
+ .long 0xa64bbb7d /* mthsrr1 %r13 (Old MSR) */
+ .long 0xa64bda7d /* mthsrr0 %r14 (Virtual address of opal_return_mmu) */
+ .long 0x2402004c /* hrfid */
+
+opal_return_mmu:
+ /*
+ * We're back in the correct endianness and MMU mode, restore registers
+ * and return
+ */
+ addi %r1, %r1, 48
+ ld %r14, -8(%r1)
+ lwz %r11, 8(%r1)
+ ld %r12, 16(%r1)
+ ld %r2, 24(%r1)
+ mtcr %r11
+ mtlr %r12
+
+ blr
+
+OPAL_CALL(opal_console_write, OPAL_CONSOLE_WRITE)
+OPAL_CALL(opal_console_flush, OPAL_CONSOLE_FLUSH)
+OPAL_CALL(opal_reinit_cpus, OPAL_REINIT_CPUS)
--
2.30.2
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