[RFC] [PATCH] Write to HVC terminal from purgatory code
Michael Ellerman
michael at ellerman.id.au
Thu Sep 17 07:54:40 EDT 2009
On Mon, 2009-09-07 at 10:44 +0530, M. Mohan Kumar wrote:
> Write to HVC terminal from purgatory code
>
> Current x86/x86-64 kexec-tools print the message "I'm in purgatory" to
> serial console/VGA while executing the purgatory code. Implement this
> feature for POWERPC pseries platform by using the H_PUT_TERM_CHAR
> hypervisor call by printng to hvc console.
Hi Mohan, just a few comments ...
> diff --git a/kexec/arch/ppc64/fs2dt.c b/kexec/arch/ppc64/fs2dt.c
> index b01ff86..bd9d36c 100644
> --- a/kexec/arch/ppc64/fs2dt.c
> +++ b/kexec/arch/ppc64/fs2dt.c
> @@ -434,6 +434,9 @@ static void putnode(void)
> if (!strcmp(basename,"/chosen/")) {
> size_t cmd_len = 0;
> char *param = NULL;
> + char filename[MAXPATH];
> + char buff[64];
> + int fd;
>
> cmd_len = strlen(local_cmdline);
> if (cmd_len != 0) {
> @@ -446,7 +449,6 @@ static void putnode(void)
>
> /* ... if not, grab root= from the old command line */
> if (!param) {
> - char filename[MAXPATH];
> FILE *fp;
> char *last_cmdline = NULL;
> char *old_param;
> @@ -483,8 +485,51 @@ static void putnode(void)
> dt += (cmd_len + 3)/4;
>
> fprintf(stderr, "Modified cmdline:%s\n", local_cmdline);
> +
> + /*
> + * Determine the platform type/stdout type, so that purgatory
> + * code can print 'I'm in purgatory' message. Currently only
> + * pseries/hvcterminal is supported.
> + */
> + strcpy(filename, pathname);
> + strcat(filename, "linux,stdout-path");
strncat() ?
> + fd = open(filename, O_RDONLY);
> + if (fd == -1) {
> + printf("Unable to find linux,stdout-path, printing"
> + " from purgatory is diabled\n");
> + goto no_debug;
> + }
> + if (fstat(fd, &statbuf)) {
> + printf("Unable to stat linux,stdout-path, printing"
> + " from purgatory is diabled\n");
> + close(fd);
> + goto no_debug;
> + }
> + read(fd, buff, statbuf.st_size);
Be nice to check it's going to fit in buff here.
> + close(fd);
> + strcpy(filename, "/proc/device-tree/");
> + strcat(filename, buff);
> + strcat(filename, "/compatible");
strncpy / strncat.
> + fd = open(filename, O_RDONLY);
> + if (fd == -1) {
> + printf("Unable to find linux,stdout-path/compatible, "
> + " printing from purgatory is diabled\n");
You may as well print the actual path here, seeing as you have it.
> + goto no_debug;
> + }
> + if (fstat(fd, &statbuf)) {
> + printf("Unable to stat linux,stdout-path/compatible, "
> + " printing from purgatory is diabled\n");
> + close(fd);
> + goto no_debug;
> + }
> + read(fd, buff, statbuf.st_size);
> + if (!strcmp(buff, "hvterm1") ||
> + !strcmp(buff, "hvterm-protocol"))
> + my_debug = 1;
I have a personal hatred for variables called my_foo, but that's just
personal taste I guess :)
> + close(fd);
> }
>
> +no_debug:
> for (i=0; i < numlist; i++) {
> dp = namelist[i];
> strcpy(dn, dp->d_name);
> diff --git a/purgatory/arch/ppc64/console-ppc64.c b/purgatory/arch/ppc64/console-ppc64.c
> index d6da7b3..78a233b 100644
> --- a/purgatory/arch/ppc64/console-ppc64.c
> +++ b/purgatory/arch/ppc64/console-ppc64.c
> @@ -20,8 +20,22 @@
> */
>
> #include <purgatory.h>
> +#include "hvCall.h"
> +
> +extern int debug;
>
> void putchar(int c)
> {
> + char buff[16];
> + unsigned long *lbuf = (unsigned long *)buff;
> +
> + if (!debug) /* running on non pseries */
> + return;
> +
> + if (c == '\n')
> + putchar('\r');
> +
> + buff[0] = c;
> + plpar_hcall_norets(H_PUT_TERM_CHAR, 0, 1, lbuf[0], lbuf[1]);
> return;
> }
> diff --git a/purgatory/arch/ppc64/hvCall.S b/purgatory/arch/ppc64/hvCall.S
> new file mode 100644
> index 0000000..e401f81
> --- /dev/null
> +++ b/purgatory/arch/ppc64/hvCall.S
> @@ -0,0 +1,28 @@
> +/*
> + * This file contains the generic function to perform a call to the
> + * pSeries LPAR hypervisor.
> + *
> + * Created by M. Mohan Kumar (mohan at in.ibm.com)
> + * Copyright (C) IBM Corporation
> + * Taken from linux/arch/powerpc/platforms/pseries/hvCall.S
> + *
> + * 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.
> + */
> +
> +#define HVSC .long 0x44000022
> +.text
> + .machine ppc64
> +.globl .plpar_hcall_norets
> +.plpar_hcall_norets:
> + or 6,6,6 # medium low priority
> + mfcr 0
> + stw 0,8(1)
> +
> + HVSC /* invoke the hypervisor */
> +
> + lwz 0,8(1)
> + mtcrf 0xff,0
> + blr /* return r3 = status */
It's much easier to read if you use r0, r1 etc.
cheers
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