[2/3] xen/ppc: Implement early serial printk on PaPR/pseries

Message ID	e9a4878544d264688578d7899867df7e8207aba5.1686148363.git.shawn@anastas.io (mailing list archive)
State	Superseded
Headers	show Return-Path: <xen-devel-bounces@lists.xenproject.org> Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" <xen-devel-bounces@lists.xenproject.org> From: Shawn Anastasio <shawn@anastas.io> To: xen-devel@lists.xenproject.org Cc: tpearson@raptorengineering.com, Shawn Anastasio <shawn@anastas.io>, Andrew Cooper <andrew.cooper3@citrix.com>, George Dunlap <george.dunlap@citrix.com>, Jan Beulich <jbeulich@suse.com>, Julien Grall <julien@xen.org>, Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>, Shawn Anastasio <shawnanastasio@raptorengineering.com> Subject: [PATCH 2/3] xen/ppc: Implement early serial printk on PaPR/pseries Date: Wed, 7 Jun 2023 10:06:33 -0500 Message-Id: <e9a4878544d264688578d7899867df7e8207aba5.1686148363.git.shawn@anastas.io> In-Reply-To: <cover.1686148363.git.shawn@anastas.io> References: <cover.1686148363.git.shawn@anastas.io> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit
Series	Initial support for Power \| expand [0/3] Initial support for Power [1/3] xen: Add files needed for minimal Power build [2/3] xen/ppc: Implement early serial printk on PaPR/pseries [3/3] maintainers: Add PPC64 maintainer

diff --git a/xen/arch/ppc/Kconfig.debug b/xen/arch/ppc/Kconfig.debug index e69de29bb2..3c25a446e8 100644 --- a/xen/arch/ppc/Kconfig.debug +++ b/xen/arch/ppc/Kconfig.debug @@ -0,0 +1,5 @@ +config EARLY_PRINTK + bool "Enable early printk" + default DEBUG + help + Enables early printk debug messages \ No newline at end of file diff --git a/xen/arch/ppc/Makefile b/xen/arch/ppc/Makefile index b3ad837d4b..00b3b7baf3 100644 --- a/xen/arch/ppc/Makefile +++ b/xen/arch/ppc/Makefile @@ -1,5 +1,6 @@ obj-$(CONFIG_PPC64) += ppc64/ -obj-y += setup.o +obj-y += setup.o boot_of.o +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o $(TARGET): $(TARGET)-syms cp -f $< $@ diff --git a/xen/arch/ppc/boot_of.c b/xen/arch/ppc/boot_of.c new file mode 100644 index 0000000000..9447d92661 --- /dev/null +++ b/xen/arch/ppc/boot_of.c @@ -0,0 +1,122 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + * + * Copyright IBM Corp. 2005, 2006, 2007 + * Copyright Raptor Engineering, LLC + * + * Authors: Jimi Xenidis <jimix@watson.ibm.com> + * Hollis Blanchard <hollisb@us.ibm.com> + * Shawn Anastasio <sanastasio@raptorengineering.com> + */ + +#include <xen/kernel.h> +#include <xen/init.h> +#include <xen/lib.h> +#include <asm/byteorder.h> +#include <asm/boot.h> + +#define ADDR(x) (uint32_t)(unsigned long)(x) + +/* OF entrypoint*/ +static unsigned long of_vec; + +/* OF device handles*/ +static int bof_chosen; +static int of_out; + +static int of_call(const char *service, uint32_t nargs, uint32_t nrets, + int32_t rets[], ...) +{ + int rc; + va_list args; + int i; + struct of_service s = { 0 }; + + s.ofs_service = cpu_to_be32(ADDR(service)); + s.ofs_nargs = cpu_to_be32(nargs); + s.ofs_nrets = cpu_to_be32(nrets); + + /* copy all the params into the args array */ + va_start(args, rets); + + for ( i = 0; i < nargs; i++ ) + { + s.ofs_args[i] = cpu_to_be32(va_arg(args, uint32_t)); + } + + va_end(args); + + rc = enter_prom(&s, of_vec); + + /* yes always to the copy, just in case */ + for ( i = 0; i < nrets; i++ ) + { + rets[i] = be32_to_cpu(s.ofs_args[i + nargs]); + } + + return rc; +} + +static int of_finddevice(const char *devspec) +{ + int rets[1] = { OF_FAILURE }; + + of_call("finddevice", 1, 1, rets, devspec); + if ( rets[0] == OF_FAILURE ) + return OF_FAILURE; + + return rets[0]; +} + +static int of_getprop(int ph, const char *name, void *buf, uint32_t buflen) +{ + int rets[1] = { OF_FAILURE }; + + of_call("getprop", 4, 1, rets, ph, ADDR(name), buf, buflen); + + if ( rets[0] == OF_FAILURE ) + return OF_FAILURE; + + return rets[0]; +} + +int of_write(int ih, const char *addr, uint32_t len) +{ + int rets[1] = { OF_FAILURE }; + + if ( of_call("write", 3, 1, rets, ih, addr, len) == OF_FAILURE ) + return OF_FAILURE; + + return rets[0]; +} + +void of_putchar(char c) +{ + if ( c == '\n' ) + { + char buf = '\r'; + (void) of_write(of_out, &buf, 1); + } + (void) of_write(of_out, &c, 1); +} + +void boot_of_init(unsigned long vec) +{ + of_vec = vec; + bof_chosen = of_finddevice("/chosen"); + of_getprop(bof_chosen, "stdout", &of_out, sizeof(of_out)); + of_out = be32_to_cpu(of_out); +} \ No newline at end of file diff --git a/xen/arch/ppc/configs/openpower_defconfig b/xen/arch/ppc/configs/openpower_defconfig index 8783eb3488..f7cc075e45 100644 --- a/xen/arch/ppc/configs/openpower_defconfig +++ b/xen/arch/ppc/configs/openpower_defconfig @@ -10,4 +10,5 @@ CONFIG_PPC64=y CONFIG_DEBUG=y CONFIG_DEBUG_INFO=y +CONFIG_EARLY_PRINTK=y CONFIG_EXPERT=y diff --git a/xen/arch/ppc/early_printk.c b/xen/arch/ppc/early_printk.c new file mode 100644 index 0000000000..ab9213d801 --- /dev/null +++ b/xen/arch/ppc/early_printk.c @@ -0,0 +1,36 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Power early printk using OpenFirmware or OPAL + * + * Copyright Raptor Engineering, LLC + * + * Authors: Shawn Anastasio <sanastasio@raptorengineering.com> + */ + +#include <xen/lib.h> +#include <asm/boot.h> + +static void (*putchar_func)(char); + +void early_printk_init(bool is_of) +{ + putchar_func = is_of ? of_putchar : NULL; +} + +void early_puts(const char *s, size_t nr) +{ + if ( !putchar_func ) + return; + + while ( nr-- > 0 ) + putchar_func(*s++); +} + +void early_printk(const char *s) +{ + if ( !putchar_func ) + return; + + while ( *s ) + putchar_func(*s++); +} \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/boot.h b/xen/arch/ppc/include/asm/boot.h new file mode 100644 index 0000000000..96d56f9650 --- /dev/null +++ b/xen/arch/ppc/include/asm/boot.h @@ -0,0 +1,31 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copyright Raptor Engineering, LLC + * + * Authors: Shawn Anastasio <@raptorengineering.com> + */ + +#ifndef _ASM_PPC_BOOT_H +#define _ASM_PPC_BOOT_H + +#include <xen/types.h> + +/* a collection of interfaces used during boot. */ +enum { + OF_FAILURE = -1, + OF_SUCCESS = 0, +}; + +struct of_service { + __be32 ofs_service; + __be32 ofs_nargs; + __be32 ofs_nrets; + __be32 ofs_args[10]; +}; + +extern int enter_prom(struct of_service *args, unsigned long entry); + +void boot_of_init(unsigned long); +void of_putchar(char c); + +#endif /* _ASM_PPC_BOOT_H */ \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/bug.h b/xen/arch/ppc/include/asm/bug.h new file mode 100644 index 0000000000..40022a757b --- /dev/null +++ b/xen/arch/ppc/include/asm/bug.h @@ -0,0 +1,6 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_PPC_BUG_H +#define _ASM_PPC_BUG_H + +#endif /* _ASM_PPC_BUG_H */ \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/byteorder.h b/xen/arch/ppc/include/asm/byteorder.h new file mode 100644 index 0000000000..ac840f9b1c --- /dev/null +++ b/xen/arch/ppc/include/asm/byteorder.h @@ -0,0 +1,74 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_POWERPC_BYTEORDER_H +#define _ASM_POWERPC_BYTEORDER_H + +#include <asm/types.h> +#include <xen/compiler.h> + +static inline __u16 ld_le16(const volatile __u16 *addr) +{ + __u16 val; + + asm volatile ("lhbrx %0,0,%1" : "=r" (val) : "r" (addr), "m" (*addr)); + return val; +} + +static inline void st_le16(volatile __u16 *addr, const __u16 val) +{ + asm volatile ("sthbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (addr)); +} + +static inline __u32 ld_le32(const volatile __u32 *addr) +{ + __u32 val; + + asm volatile ("lwbrx %0,0,%1" : "=r" (val) : "r" (addr), "m" (*addr)); + return val; +} + +static inline void st_le32(volatile __u32 *addr, const __u32 val) +{ + asm volatile ("stwbrx %1,0,%2" : "=m" (*addr) : "r" (val), "r" (addr)); +} + +static inline __attribute_const__ __u16 ___arch__swab16(__u16 value) +{ + __u16 result; + + asm("rlwimi %0,%1,8,16,23" + : "=r" (result) + : "r" (value), "0" (value >> 8)); + return result; +} + +static inline __attribute_const__ __u32 ___arch__swab32(__u32 value) +{ + __u32 result; + + asm("rlwimi %0,%1,24,16,23\n\t" + "rlwimi %0,%1,8,8,15\n\t" + "rlwimi %0,%1,24,0,7" + : "=r" (result) + : "r" (value), "0" (value >> 24)); + return result; +} + +#define __arch__swab16(x) ___arch__swab16(x) +#define __arch__swab32(x) ___arch__swab32(x) + +/* The same, but returns converted value from the location pointer by addr. */ +#define __arch__swab16p(addr) ld_le16(addr) +#define __arch__swab32p(addr) ld_le32(addr) + +/* The same, but do the conversion in situ, ie. put the value back to addr. */ +#define __arch__swab16s(addr) st_le16(addr,*addr) +#define __arch__swab32s(addr) st_le32(addr,*addr) + +#define __BYTEORDER_HAS_U64__ +#ifndef __powerpc64__ +#define __SWAB_64_THRU_32__ +#endif /* __powerpc64__ */ + +#include <xen/byteorder/little_endian.h> + +#endif /* _ASM_POWERPC_BYTEORDER_H */ diff --git a/xen/arch/ppc/include/asm/cache.h b/xen/arch/ppc/include/asm/cache.h new file mode 100644 index 0000000000..677a2b3915 --- /dev/null +++ b/xen/arch/ppc/include/asm/cache.h @@ -0,0 +1,6 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_PPC_CACHE_H +#define _ASM_PPC_CACHE_H + +#endif /* _ASM_PPC_CACHE_H */ \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/config.h b/xen/arch/ppc/include/asm/config.h index 7a2862ef7a..a3438de92b 100644 --- a/xen/arch/ppc/include/asm/config.h +++ b/xen/arch/ppc/include/asm/config.h @@ -52,6 +52,9 @@ /* size of minimum stack frame; C code can write into the caller's stack */ #define STACK_FRAME_OVERHEAD 32 +/* size of minimum stack frame that can hold an entire cpu_user_regs struct */ +#define STACK_SWITCH_FRAME_SIZE (UREGS_sizeof + STACK_FRAME_OVERHEAD) + #endif /* __PPC_CONFIG_H__ */ /* * Local variables: diff --git a/xen/arch/ppc/include/asm/early_printk.h b/xen/arch/ppc/include/asm/early_printk.h new file mode 100644 index 0000000000..a9566a1240 --- /dev/null +++ b/xen/arch/ppc/include/asm/early_printk.h @@ -0,0 +1,14 @@ +#ifndef __EARLY_PRINTK_H__ +#define __EARLY_PRINTK_H__ + +#include <xen/early_printk.h> + +#ifdef CONFIG_EARLY_PRINTK +void early_printk_init(bool is_of); +void early_printk(const char *str); +#else +static inline void early_printk_init(bool is_of) {} +static inline void early_printk(const char *s) {} +#endif + +#endif /* __EARLY_PRINTK_H__ */ \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/processor.h b/xen/arch/ppc/include/asm/processor.h index 0ab7bfc9df..63409f003a 100644 --- a/xen/arch/ppc/include/asm/processor.h +++ b/xen/arch/ppc/include/asm/processor.h @@ -114,7 +114,42 @@ #define PVR_970MP 0x0044 #define PVR_BE 0x0070 -#ifdef __ASSEMBLY__ +#ifndef __ASSEMBLY__ + +#include <xen/types.h> + +/* User-accessible registers: nost of these need to be saved/restored + * for every nested Xen invocation. */ +struct cpu_user_regs +{ + uint64_t gprs[32]; + uint64_t lr; + uint64_t ctr; + uint64_t srr0; + uint64_t srr1; + uint64_t pc; + uint64_t msr; + uint64_t fpscr; /* XXX Is this necessary */ + uint64_t xer; + uint64_t hid4; /* debug only */ + uint64_t dar; /* debug only */ + uint32_t dsisr; /* debug only */ + uint32_t cr; + uint32_t __pad; /* good spot for another 32bit reg */ + uint32_t entry_vector; +}; + +static __inline__ void sync(void) +{ + __asm__ __volatile__("sync"); +} + +static __inline__ void isync(void) +{ + __asm__ __volatile__("isync"); +} + +#else #define LOADADDR(rn, name) \ lis rn, name##@highest; \ @@ -152,6 +187,22 @@ .long 0xa6037b7d; /* mtsrr1 r11 */ \ .long 0x2400004c /* rfid */ +/* Taken from Linux kernel source (arch/powerpc/boot/crt0.S) */ +.macro OP_REGS op, width, start, end, base, offset + .Lreg=\start + .rept (\end - \start + 1) + \op .Lreg,\offset+\width*.Lreg(\base) + .Lreg=.Lreg+1 + .endr +.endm + +#define SAVE_GPRS(start, end, base) OP_REGS std, 8, start, end, base, 0 +#define REST_GPRS(start, end, base) OP_REGS ld, 8, start, end, base, 0 +#define SAVE_GPR(n, base) SAVE_GPRS(n, n, base) +#define REST_GPR(n, base) REST_GPRS(n, n, base) +#define SAVE_NVGPRS(base) SAVE_GPRS(14, 31, base) +#define REST_NVGPRS(base) REST_GPRS(14, 31, base) + #define _GLOBAL(name) \ .section ".text"; \ .align 2; \ @@ -167,7 +218,6 @@ #define _ENTRY(name) name -#else /* __ASSEMBLY__ */ #endif /* __ASSEMBLY__ */ #endif diff --git a/xen/arch/ppc/include/asm/string.h b/xen/arch/ppc/include/asm/string.h new file mode 100644 index 0000000000..aed83b0d47 --- /dev/null +++ b/xen/arch/ppc/include/asm/string.h @@ -0,0 +1,6 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_PPC_STRING_H +#define _ASM_PPC_STRING_H + +#endif /* _ASM_PPC_STRING_H */ \ No newline at end of file diff --git a/xen/arch/ppc/include/asm/types.h b/xen/arch/ppc/include/asm/types.h new file mode 100644 index 0000000000..44b5df49f2 --- /dev/null +++ b/xen/arch/ppc/include/asm/types.h @@ -0,0 +1,64 @@ +/* from xen/include/asm-x86/types.h */ + +#ifndef _PPC_TYPES_H +#define _PPC_TYPES_H + +#ifndef __ASSEMBLY__ +typedef unsigned short umode_t; + +/* + * __xx is ok: it doesn't pollute the POSIX namespace. Use these in the + * header files exported to user space + */ + +typedef __signed__ char __s8; +typedef unsigned char __u8; + +typedef __signed__ short __s16; +typedef unsigned short __u16; + +typedef __signed__ int __s32; +typedef unsigned int __u32; + +#if defined(__GNUC__) && !defined(__STRICT_ANSI__) +#if defined(__ppc__) +typedef __signed__ long long __s64; +typedef unsigned long long __u64; + +#elif defined(__PPC64__) +typedef __signed__ long __s64; +typedef unsigned long __u64; +#endif +#endif + +typedef signed char s8; +typedef unsigned char u8; + +typedef signed short s16; +typedef unsigned short u16; + +typedef signed int s32; +typedef unsigned int u32; + +#if defined(__ppc__) +typedef signed long long s64; +typedef unsigned long long u64; +typedef unsigned int size_t; +#elif defined(__PPC64__) +typedef signed long s64; +typedef unsigned long u64; +typedef unsigned long size_t; +#endif + +typedef unsigned long paddr_t; +#define PRIpaddr "08lx" + +/* DMA addresses come in generic and 64-bit flavours. */ + +typedef unsigned long dma_addr_t; +typedef u64 dma64_addr_t; + +typedef unsigned short xmem_bufctl_t; + +#endif /* __ASSEMBLY__ */ +#endif diff --git a/xen/arch/ppc/ppc64/asm-offsets.c b/xen/arch/ppc/ppc64/asm-offsets.c index e69de29bb2..a6de2b2768 100644 --- a/xen/arch/ppc/ppc64/asm-offsets.c +++ b/xen/arch/ppc/ppc64/asm-offsets.c @@ -0,0 +1,55 @@ +/* + * Generate definitions needed by assembly language modules. + * This code generates raw asm output which is post-processed + * to extract and format the required data. + */ + +#include <asm/processor.h> + +#define DEFINE(_sym, _val) \ + asm volatile ("\n.ascii\"==>#define " #_sym " %0 /* " #_val " */<==\"" \ + : : "i" (_val) ) +#define BLANK() \ + asm volatile ( "\n.ascii\"==><==\"" : : ) +#define OFFSET(_sym, _str, _mem) \ + DEFINE(_sym, offsetof(_str, _mem)); + +/* base-2 logarithm */ +#define __L2(_x) (((_x) & 0x00000002) ? 1 : 0) +#define __L4(_x) (((_x) & 0x0000000c) ? ( 2 + __L2( (_x)>> 2)) : __L2( _x)) +#define __L8(_x) (((_x) & 0x000000f0) ? ( 4 + __L4( (_x)>> 4)) : __L4( _x)) +#define __L16(_x) (((_x) & 0x0000ff00) ? ( 8 + __L8( (_x)>> 8)) : __L8( _x)) +#define LOG_2(_x) (((_x) & 0xffff0000) ? (16 + __L16((_x)>>16)) : __L16(_x)) + +void __dummy__(void) +{ + DEFINE(GPR_WIDTH, sizeof(unsigned long)); + DEFINE(FPR_WIDTH, sizeof(double)); + + OFFSET(UREGS_gprs, struct cpu_user_regs, gprs); + OFFSET(UREGS_r0, struct cpu_user_regs, gprs[0]); + OFFSET(UREGS_r1, struct cpu_user_regs, gprs[1]); + OFFSET(UREGS_r13, struct cpu_user_regs, gprs[13]); + OFFSET(UREGS_srr0, struct cpu_user_regs, srr0); + OFFSET(UREGS_srr1, struct cpu_user_regs, srr1); + OFFSET(UREGS_pc, struct cpu_user_regs, pc); + OFFSET(UREGS_msr, struct cpu_user_regs, msr); + OFFSET(UREGS_lr, struct cpu_user_regs, lr); + OFFSET(UREGS_ctr, struct cpu_user_regs, ctr); + OFFSET(UREGS_xer, struct cpu_user_regs, xer); + OFFSET(UREGS_hid4, struct cpu_user_regs, hid4); + OFFSET(UREGS_dar, struct cpu_user_regs, dar); + OFFSET(UREGS_dsisr, struct cpu_user_regs, dsisr); + OFFSET(UREGS_cr, struct cpu_user_regs, cr); + OFFSET(UREGS_fpscr, struct cpu_user_regs, fpscr); + DEFINE(UREGS_sizeof, sizeof(struct cpu_user_regs)); +} + +/* + * Local variables: + * mode: C + * c-file-style: "BSD" + * c-basic-offset: 4 + * indent-tabs-mode: nil + * End: + */ diff --git a/xen/arch/ppc/ppc64/head.S b/xen/arch/ppc/ppc64/head.S index d91b0972ae..d5ca1c08ad 100644 --- a/xen/arch/ppc/ppc64/head.S +++ b/xen/arch/ppc/ppc64/head.S @@ -65,3 +65,62 @@ cpu0_boot_stack_bottom: .space STACK_SIZE cpu0_boot_stack: .space STACK_FRAME_OVERHEAD + +/* Adapted from Linux kernel source (arch/powerpc/boot/crt0.S) */ +_GLOBAL(enter_prom) + mflr r0 + std r0,16(r1) + stdu r1,-STACK_SWITCH_FRAME_SIZE(r1) /* Save SP and create stack space */ + + /* Because PROM is running in 32b mode, it clobbers the high order half + * of all registers that it saves. We therefore save those registers + * PROM might touch to the stack. (r0, r3-r13 are caller saved) + */ + SAVE_GPR(2, r1) + SAVE_GPR(13, r1) + SAVE_NVGPRS(r1) + mfcr r10 + mfmsr r11 + std r10,UREGS_cr(r1) + std r11,UREGS_msr(r1) + + /* Put PROM address in SRR0 */ + mtsrr0 r4 + + /* Setup our trampoline return addr in LR */ + bcl 20,31,$+4 +0: mflr r4 + addi r4,r4,(1f - 0b) + mtlr r4 + + /* Prepare a 32-bit mode big endian MSR + */ + SET_REG_TO_CONST(r12, MSR_SF | MSR_LE) + andc r11,r11,r12 + mtsrr1 r11 + rfid + +1: /* Return from OF */ + FIXUP_ENDIAN + + /* Just make sure that r1 top 32 bits didn't get + * corrupt by OF + */ + rldicl r1,r1,0,32 + + /* Restore the MSR (back to 64 bits) */ + ld r0,UREGS_msr(r1) + mtmsrd r0 + isync + + /* Restore other registers */ + REST_GPR(2, r1) + REST_GPR(13, r1) + REST_NVGPRS(r1) + ld r4,UREGS_cr(r1) + mtcr r4 + + addi r1,r1,STACK_SWITCH_FRAME_SIZE + ld r0,16(r1) + mtlr r0 + blr diff --git a/xen/arch/ppc/setup.c b/xen/arch/ppc/setup.c index c9509fb6a6..fb12d4df34 100644 --- a/xen/arch/ppc/setup.c +++ b/xen/arch/ppc/setup.c @@ -1,9 +1,27 @@ /* SPDX-License-Identifier: GPL-2.0-or-later */ #include <xen/compile.h> #include <xen/init.h> +#include <asm/boot.h> +#include <asm/early_printk.h> -void __init noreturn start_xen(void) +void __init noreturn start_xen(unsigned long r3, unsigned long r4, + unsigned long r5, unsigned long r6, + unsigned long r7) { + if ( r5 ) + { + /* OF boot protocol */ + boot_of_init(r5); + early_printk_init(true); + } + else + { + /* kexec boot: Unimplemented */ + __builtin_trap(); + } + + early_printk("Hello, ppc64le!\n"); + for ( ;; ) { // Set current hardware thread to very low priority

[2/3] xen/ppc: Implement early serial printk on PaPR/pseries

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