| Message ID | 1455734459-31902-13-git-send-email-drjones@redhat.com |
|---|---|
| State | Superseded |
| Headers | show |
On Wed, Feb 17, 2016 at 07:40:53PM +0100, Andrew Jones wrote: > 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@redhat.com> > Tested-by: Laurent Vivier <lvivier@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > lib/powerpc/asm/hcall.h | 37 +++++++++++++++++++++++++++++++++++++ > lib/powerpc/hcall.c | 33 +++++++++++++++++++++++++++++++++ > lib/powerpc/io.c | 15 +++++++++++++-- > lib/ppc64/asm/hcall.h | 1 + > powerpc/Makefile.common | 2 ++ > powerpc/cstart64.S | 30 ++++++++++++++++++++++++++++++ > 6 files changed, 116 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..750c655562549 > --- /dev/null > +++ b/lib/powerpc/asm/hcall.h > @@ -0,0 +1,37 @@ > +#ifndef _ASMPOWERPC_HCALL_H_ > +#define _ASMPOWERPC_HCALL_H_ > +/* > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * 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_FUNCTION -2 > +#define H_PRIVILEGE -3 > +#define H_PARAMETER -4 > + > +#define H_SET_DABR 0x28 > +#define H_PUT_TERM_CHAR 0x58 > + > +#ifndef __ASSEMBLY__ > +/* > + * hcall_have_broken_sc1 checks if we're on a host with a broken sc1. > + * Returns 0 if we're not. > + */ > +extern int hcall_have_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. @nr is the > + * hypercall number. > + */ > +extern unsigned long hcall(unsigned long nr, ...); > + > +#endif /* !__ASSEMBLY__ */ > +#endif /* _ASMPOWERPC_HCALL_H_ */ > diff --git a/lib/powerpc/hcall.c b/lib/powerpc/hcall.c > new file mode 100644 > index 0000000000000..cd6d26680f7cd > --- /dev/null > +++ b/lib/powerpc/hcall.c > @@ -0,0 +1,33 @@ > +/* > + * Hypercall helpers > + * > + * broken_sc1 probing/patching inspired by SLOF, see > + * SLOF:lib/libhvcall/brokensc1.c > + * > + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> > + * > + * This work is licensed under the terms of the GNU LGPL, version 2. > + */ > +#include <asm/hcall.h> > + > +int 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 == (unsigned long)H_PRIVILEGE; > +} > + > +void putchar(int c) > +{ > + unsigned long vty = 0; /* 0 == default */ > + unsigned long nr_chars = 1; > + unsigned long chars = (unsigned long)c << 56; > + > + hcall(H_PUT_TERM_CHAR, vty, nr_chars, chars); > +} > diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c > index 0af45742fc900..ef90946fb1131 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 print_lock; > > void io_init(void) > { > } > > -void puts(const char *s __unused) > +void puts(const char *s) > { > + spin_lock(&print_lock); > + while (*s) > + putchar(*s++); > + spin_unlock(&print_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 06ec96c6e546b..b21e3933d0643 100644 > --- a/powerpc/Makefile.common > +++ b/powerpc/Makefile.common > @@ -16,6 +16,7 @@ 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 > @@ -24,6 +25,7 @@ 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) > > diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S > index f90828dee1c19..1884d79871ba5 100644 > --- a/powerpc/cstart64.S > +++ b/powerpc/cstart64.S > @@ -6,14 +6,44 @@ > * This work is licensed under the terms of the GNU LGPL, version 2. > */ > #define __ASSEMBLY__ > +#include <asm/hcall.h> > + > +#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) > + > + /* patch sc1 if needed */ > + bl hcall_have_broken_sc1 > + cmpwi r3, 0 > + beq 1f > + LOAD_REG_ADDR(r3, hcall) > + LOAD_REG_IMMEDIATE(r4, SC1_REPLACEMENT) > + stw r4, 0(r3) > + > +1: bl main > + bl exit > b halt > > .text > +.align 3 > + > +.globl hcall > +hcall: > + sc 1 > + blr > > .globl halt > halt:
diff --git a/lib/powerpc/asm/hcall.h b/lib/powerpc/asm/hcall.h new file mode 100644 index 0000000000000..750c655562549 --- /dev/null +++ b/lib/powerpc/asm/hcall.h @@ -0,0 +1,37 @@ +#ifndef _ASMPOWERPC_HCALL_H_ +#define _ASMPOWERPC_HCALL_H_ +/* + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> + * + * 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_FUNCTION -2 +#define H_PRIVILEGE -3 +#define H_PARAMETER -4 + +#define H_SET_DABR 0x28 +#define H_PUT_TERM_CHAR 0x58 + +#ifndef __ASSEMBLY__ +/* + * hcall_have_broken_sc1 checks if we're on a host with a broken sc1. + * Returns 0 if we're not. + */ +extern int hcall_have_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. @nr is the + * hypercall number. + */ +extern unsigned long hcall(unsigned long nr, ...); + +#endif /* !__ASSEMBLY__ */ +#endif /* _ASMPOWERPC_HCALL_H_ */ diff --git a/lib/powerpc/hcall.c b/lib/powerpc/hcall.c new file mode 100644 index 0000000000000..cd6d26680f7cd --- /dev/null +++ b/lib/powerpc/hcall.c @@ -0,0 +1,33 @@ +/* + * Hypercall helpers + * + * broken_sc1 probing/patching inspired by SLOF, see + * SLOF:lib/libhvcall/brokensc1.c + * + * Copyright (C) 2016, Red Hat Inc, Andrew Jones <drjones@redhat.com> + * + * This work is licensed under the terms of the GNU LGPL, version 2. + */ +#include <asm/hcall.h> + +int 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 == (unsigned long)H_PRIVILEGE; +} + +void putchar(int c) +{ + unsigned long vty = 0; /* 0 == default */ + unsigned long nr_chars = 1; + unsigned long chars = (unsigned long)c << 56; + + hcall(H_PUT_TERM_CHAR, vty, nr_chars, chars); +} diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c index 0af45742fc900..ef90946fb1131 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 print_lock; void io_init(void) { } -void puts(const char *s __unused) +void puts(const char *s) { + spin_lock(&print_lock); + while (*s) + putchar(*s++); + spin_unlock(&print_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 06ec96c6e546b..b21e3933d0643 100644 --- a/powerpc/Makefile.common +++ b/powerpc/Makefile.common @@ -16,6 +16,7 @@ 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 @@ -24,6 +25,7 @@ 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) diff --git a/powerpc/cstart64.S b/powerpc/cstart64.S index f90828dee1c19..1884d79871ba5 100644 --- a/powerpc/cstart64.S +++ b/powerpc/cstart64.S @@ -6,14 +6,44 @@ * This work is licensed under the terms of the GNU LGPL, version 2. */ #define __ASSEMBLY__ +#include <asm/hcall.h> + +#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) + + /* patch sc1 if needed */ + bl hcall_have_broken_sc1 + cmpwi r3, 0 + beq 1f + LOAD_REG_ADDR(r3, hcall) + LOAD_REG_IMMEDIATE(r4, SC1_REPLACEMENT) + stw r4, 0(r3) + +1: bl main + bl exit b halt .text +.align 3 + +.globl hcall +hcall: + sc 1 + blr .globl halt halt:
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@redhat.com> Tested-by: Laurent Vivier <lvivier@redhat.com> --- lib/powerpc/asm/hcall.h | 37 +++++++++++++++++++++++++++++++++++++ lib/powerpc/hcall.c | 33 +++++++++++++++++++++++++++++++++ lib/powerpc/io.c | 15 +++++++++++++-- lib/ppc64/asm/hcall.h | 1 + powerpc/Makefile.common | 2 ++ powerpc/cstart64.S | 30 ++++++++++++++++++++++++++++++ 6 files changed, 116 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