On Fri, Sep 21, 2007 at 06:05:30PM -0500, Milton Miller wrote:
> This code provides a console write that calls put-term-char.
>
> To avoid PIC relocation of the absolute rtas addresses, hide the
> actual call to rtas in assembly and declare all variables as int.
>
> An instantiated rtas will be protected by a reserved range in the
> device tree, so no explicit call to add_occupied_range is needed
> here.
>
> Signed-off-by: Milton Miller <[EMAIL PROTECTED]>
> ---
> vs 12176
> rtas_put_term_write now takes const char *buf
> rediff ops.h, Makefile
>
> Index: kernel/arch/powerpc/boot/rtas.c
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ kernel/arch/powerpc/boot/rtas.c 2007-09-21 01:43:08.000000000 -0500
> @@ -0,0 +1,146 @@
> +/*
> + * 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 2007 IBM Corporation.
> + *
> + * Authors: Milton Miller <[EMAIL PROTECTED]>
> + *
> + */
> +
> +#include "ops.h"
> +#include "stdio.h"
> +#include "flatdevtree.h"
> +
> +static int rtas_entry;
> +static int rtas_base;
> +static int rtas_size;
> +
> +static void find_rtas(void)
> +{
> + int rc;
> + void *devp;
> + char *str;
> +
> + devp = finddevice("/rtas");
> + if (! devp)
> + return;
> +
> + str = "linux,rtas-entry";
wtf? Just use the literals in the getprop() calls, this is pure
obfuscation.
> + rc = getprop(devp, str, &rtas_entry, sizeof(rtas_entry));
> + if (rc < 0)
> + return;
> + if (rc != sizeof(rtas_entry))
> + goto fail;
> +
> + str = "rtas-size";
> + rc = getprop(devp, str, &rtas_size, sizeof(rtas_size));
> + if (rc < 0)
> + return;
> + if (rc != sizeof(rtas_size))
> + goto fail;
> +
> + str = "linux,rtas-base";
> + rc = getprop(devp, str, &rtas_base, sizeof(rtas_base));
> + if (rc < 0) {
> + printf("rtas-size but no linux,rtas-base in /rtas. "
> + "disabling wrapper rtas interface\n\r");
> + rtas_entry = 0;
> + return;
> + }
> +
> + if (rc != sizeof(rtas_base))
> + goto fail;
> +
> + return;
> +
> +
> +fail:
> + printf("Unexpected length %d of %s property in /rtas.\n\r"
> + "disabling wrapper rtas interface\n\r", rc, str);
> + rtas_entry = 0;
> + return;
> +}
> +
> +/*
> + * PIC relocation of function pointers happens at call time.
> + * We have an absolute out-of-image address. So tell C they
> + * are just integers, and hide the call as an out-of-file
> + * function.
> + */
I don't get this. If we can call into the kernel using a function
pointer, you should be able to call into rtas without this weirdness.
> +__asm__ (
> + " .globl call_rtas\n"
> + " call_rtas: mtctr 5\n"
> + " bctr\n"
> + );
> +
> +void call_rtas(int args[], int base, int entry);
> +
> +
> +static int put_term_char;
> +
> +static void rtas_put_term_write(const char *buf, int len)
> +{
> + int i, args[5];
> +
> + args[0] = put_term_char;
> + args[1] = 1; /* num inputs */
> + args[2] = 1; /* num outputs */
> +
> + for (i=0; i < len; ) {
> + args[3] = buf[i];
> + args[4] = 0;
> +
> + call_rtas(args, rtas_base, rtas_entry);
> + if (args[4] == 0) /* SUCCESS */
> + i++;
> + else if (args[4] == -1) /* HARDWARE_ERROR */
> + break;
> + /* else retry */
> + }
> +}
> +
> +int rtas_console_init(void)
> +{
> + void *devp;
> + int rc;
> +
> +
> + devp = finddevice("/rtas");
> + if (!devp)
> + return -1;
> +
> + if (!rtas_entry)
> + find_rtas();
> + if (!rtas_entry)
> + return -1;
> +
> + rc = getprop(devp, "put-term-char", &put_term_char,
> + sizeof(put_term_char));
> + if (rc == sizeof(put_term_char))
> + console_ops.write = rtas_put_term_write;
> + else
> + put_term_char = -1;
> +
> + return put_term_char == -1 ? -1 : 0;
> +}
> +
> +/* for debug, hard code */
> +void use_rtas_console(int entry, int base, int tc)
> +{
> + rtas_entry = entry;
> + rtas_base = base;
> + put_term_char = tc;
> + console_ops.write = rtas_put_term_write;
> +}
> Index: kernel/arch/powerpc/boot/ops.h
> ===================================================================
> --- kernel.orig/arch/powerpc/boot/ops.h 2007-09-21 01:43:02.000000000
> -0500
> +++ kernel/arch/powerpc/boot/ops.h 2007-09-21 01:43:08.000000000 -0500
> @@ -99,6 +99,8 @@ void send_slaves_to_kernel(void *vmlinux
> void slaves_are_low(void);
> void wait_slaves_moved(void);
> void kexec_platform_init(struct boot_param_header *dt_blob);
> +int rtas_console_init(void);
> +void use_rtas_console(int entry, int base, int tc);
>
> int dt_xlate_reg(void *node, int res, unsigned long *addr, unsigned long
> *size);
> int dt_xlate_addr(void *node, u32 *buf, int buflen, unsigned long
> *xlated_addr);
> Index: kernel/arch/powerpc/boot/kexec.c
> ===================================================================
> --- kernel.orig/arch/powerpc/boot/kexec.c 2007-09-21 01:43:02.000000000
> -0500
> +++ kernel/arch/powerpc/boot/kexec.c 2007-09-21 01:43:08.000000000 -0500
> @@ -33,6 +33,9 @@ static void find_console_from_tree(void)
> {
> int rc = -1;
>
> + rc = rtas_console_init();
> + if (!rc)
> + return;
> if (rc) {
> /* no console, oh well */
> }
> Index: kernel/arch/powerpc/boot/Makefile
> ===================================================================
> --- kernel.orig/arch/powerpc/boot/Makefile 2007-09-21 01:43:02.000000000
> -0500
> +++ kernel/arch/powerpc/boot/Makefile 2007-09-21 01:43:08.000000000 -0500
> @@ -42,7 +42,7 @@ $(addprefix $(obj)/,$(zlib) gunzip_util.
> $(addprefix $(obj)/,$(zliblinuxheader)) $(addprefix
> $(obj)/,$(zlibheader))
>
> src-wlib := string.S crt0.S stdio.c main.c flatdevtree.c flatdevtree_misc.c \
> - flatdevtree_conv.c marshal.c memranges.c kexec.c \
> + flatdevtree_conv.c marshal.c memranges.c kexec.c rtas.c \
> ns16550.c serial.c simple_alloc.c div64.S util.S \
> gunzip_util.c elf_util.c $(zlib) devtree.c oflib.c ofconsole.c \
> 4xx.c ebony.c mv64x60.c mpsc.c mv64x60_i2c.c cuboot.c bamboo.c \
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
--
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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