On Tue, Aug 04, 2015 at 02:03:24PM +1000, David Gibson wrote:
> On Mon, Aug 03, 2015 at 04:41:28PM +0200, Andrew Jones wrote:
> > Add enough RTAS support to support power-off, and apply it to
> > exit().
> >
> > Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
> > ---
> > lib/powerpc/asm/rtas.h | 27 ++++++++++++++++
> > lib/powerpc/io.c | 3 ++
> > lib/powerpc/rtas.c | 84 +++++++++++++++++++++++++++++++++++++++++++++++++
> > lib/ppc64/asm/rtas.h | 1 +
> > powerpc/Makefile.common | 1 +
> > powerpc/cstart64.S | 9 ++++++
> > 6 files changed, 125 insertions(+)
> > create mode 100644 lib/powerpc/asm/rtas.h
> > create mode 100644 lib/powerpc/rtas.c
> > create mode 100644 lib/ppc64/asm/rtas.h
> >
> > diff --git a/lib/powerpc/asm/rtas.h b/lib/powerpc/asm/rtas.h
> > new file mode 100644
> > index 0000000000000..53ce126c69a42
> > --- /dev/null
> > +++ b/lib/powerpc/asm/rtas.h
> > @@ -0,0 +1,27 @@
> > +#ifndef _ASMPOWERPC_RTAS_H_
> > +#define _ASMPOWERPC_RTAS_H_
> > +/*
> > + * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2.
> > + */
> > +#include <libcflat.h>
> > +
> > +#define RTAS_UNKNOWN_SERVICE (-1)
> > +
> > +struct rtas_args {
> > + u32 token;
> > + u32 nargs;
> > + u32 nret;
> > + u32 args[16];
> > + u32 *rets;
> > +};
> > +
> > +extern void rtas_init(void);
> > +extern void enter_rtas(unsigned long args);
> > +extern int rtas_token(const char *service);
> > +extern int rtas_call(int token, int nargs, int nret, int *outputs, ...);
> > +
> > +extern void rtas_power_off(void);
> > +
> > +#endif /* _ASMPOWERPC_RTAS_H_ */
> > diff --git a/lib/powerpc/io.c b/lib/powerpc/io.c
> > index a7eaafeca9205..25cdd0ad961ee 100644
> > --- a/lib/powerpc/io.c
> > +++ b/lib/powerpc/io.c
> > @@ -7,6 +7,7 @@
> > */
> > #include <libcflat.h>
> > #include <asm/spinlock.h>
> > +#include <asm/rtas.h>
> >
> > extern void halt(int code);
> > extern void putchar(int c);
> > @@ -15,6 +16,7 @@ static struct spinlock uart_lock;
> >
> > void io_init(void)
> > {
> > + rtas_init();
> > }
> >
> > void puts(const char *s)
> > @@ -27,5 +29,6 @@ void puts(const char *s)
> >
> > void exit(int code)
> > {
> > + rtas_power_off();
> > halt(code);
> > }
> > diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
> > new file mode 100644
> > index 0000000000000..39f7d4428ee77
> > --- /dev/null
> > +++ b/lib/powerpc/rtas.c
> > @@ -0,0 +1,84 @@
> > +/*
> > + * powerpc RTAS
> > + *
> > + * Copyright (C) 2015, Red Hat Inc, Andrew Jones <drjones@xxxxxxxxxx>
> > + *
> > + * This work is licensed under the terms of the GNU LGPL, version 2.
> > + */
> > +#include <libcflat.h>
> > +#include <libfdt/libfdt.h>
> > +#include <devicetree.h>
> > +#include <asm/spinlock.h>
> > +#include <asm/io.h>
> > +#include <asm/rtas.h>
> > +
> > +static struct spinlock lock;
> > +struct rtas_args rtas_args;
> > +static int rtas_node;
> > +
> > +void rtas_init(void)
> > +{
> > + if (!dt_available()) {
> > + printf("%s: No device tree!\n", __func__);
> > + abort();
> > + }
> > +
> > + rtas_node = fdt_path_offset(dt_fdt(), "/rtas");
> > + if (rtas_node < 0) {
> > + printf("%s: /rtas node: %s\n", __func__,
> > + fdt_strerror(rtas_node));
> > + abort();
> > + }
> > +}
> > +
> > +int rtas_token(const char *service)
> > +{
> > + const struct fdt_property *prop;
> > + u32 *token;
> > +
> > + prop = fdt_get_property(dt_fdt(), rtas_node, service, NULL);
> > + if (prop) {
> > + token = (u32 *)prop->data;
> > + return fdt32_to_cpu(*token);
> > + }
> > + return RTAS_UNKNOWN_SERVICE;
> > +}
> > +
> > +int rtas_call(int token, int nargs, int nret, int *outputs, ...)
> > +{
> > + va_list list;
> > + int ret, i;
> > +
> > + spin_lock(&lock);
> > +
> > + rtas_args.token = cpu_to_be32(token);
> > + rtas_args.nargs = cpu_to_be32(nargs);
> > + rtas_args.nret = cpu_to_be32(nret);
> > + rtas_args.rets = &rtas_args.args[nargs];
> > +
> > + va_start(list, outputs);
> > + for (i = 0; i < nargs; ++i)
> > + rtas_args.args[i] = cpu_to_be32(va_arg(list, u32));
> > + va_end(list);
> > +
> > + for (i = 0; i < nret; ++i)
> > + rtas_args.rets[i] = 0;
> > +
> > + enter_rtas(__pa(&rtas_args));
> > +
> > + if (nret > 1 && outputs != NULL)
> > + for (i = 0; i < nret - 1; ++i)
> > + outputs[i] = be32_to_cpu(rtas_args.rets[i + 1]);
> > +
> > + ret = nret > 0 ? be32_to_cpu(rtas_args.rets[0]) : 0;
> > +
> > + spin_unlock(&lock);
> > + return ret;
> > +}
> > +
> > +void rtas_power_off(void)
> > +{
> > + printf("RTAS power-off returned %d\n",
> > + rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1));
> > + assert(0);
> > +}
> > diff --git a/lib/ppc64/asm/rtas.h b/lib/ppc64/asm/rtas.h
> > new file mode 100644
> > index 0000000000000..fe77f635cd860
> > --- /dev/null
> > +++ b/lib/ppc64/asm/rtas.h
> > @@ -0,0 +1 @@
> > +#include "../../powerpc/asm/rtas.h"
> > diff --git a/powerpc/Makefile.common b/powerpc/Makefile.common
> > index b130342dee60e..f4eff7f8eccb4 100644
> > --- a/powerpc/Makefile.common
> > +++ b/powerpc/Makefile.common
> > @@ -39,6 +39,7 @@ cflatobjs += lib/powerpc/io.o
> > cflatobjs += lib/powerpc/setup.o
> > cflatobjs += lib/powerpc/mmu.o
> > cflatobjs += lib/powerpc/smp.o
> > +cflatobjs += lib/powerpc/rtas.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 8edaaa6e251fc..1c48083efa33c 100644
> > --- a/powerpc/cstart64.S
> > +++ b/powerpc/cstart64.S
> > @@ -8,6 +8,7 @@
> >
> > #define HVSC .long 0x44000022
> > #define H_PUT_TERM_CHAR 0x58
> > +#define KVMPPC_H_RTAS 0xf000
> >
> > #define LOAD_REG_IMMEDIATE(reg,expr) \
> > lis reg,(expr)@highest; \
> > @@ -85,3 +86,11 @@ putchar:
> > li r5, 1 /* sending just 1 byte */
> > HVSC
> > blr
> > +
> > +.globl enter_rtas
> > +enter_rtas:
> > + mr r4, r3
> > + lis r3, KVMPPC_H_RTAS@h
> > + ori r3, r3, KVMPPC_H_RTAS@l
> > + HVSC
> > + blr
>
> So, strictly speaking this isn't how a client program is supposed to
> access RTAS. Instead, you're supposed to call into SLOF to
> instantiate RTAS, then jump into the blob it gives you. Or, if you're
> replacing rather than using SLOF, then you're supposed to get the
> existing RTAS blob address from the device tree and jump into that (or
> copy it somewhere else yourself).
>
> In practice that RTAS blob will have the same 5 instructions as your
> enter_rtas, so it's probably ok to do this.
>
> What concerns me slightly, though, is that if we ever messed up the
> RTAS blob handling in qemu or SLOF, then bypassing it in the kvm tests
> like this means they wouldn't catch that breakage.
I'll look into doing this properly. It doesn't sound like it'd be much
effort.
Thanks,
drew
>
> --
> David Gibson | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
> | _way_ _around_!
> http://www.ozlabs.org/~dgibson
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