File 0001-Fix-PowerPC-CAS-reboot-to-evaluate-menu-context.patch of Package grub2
From cb72de6caff51b79c0e5ef13dbd7a79754e3de35 Mon Sep 17 00:00:00 2001
From: Michael Chang <mchang@suse.com>
Date: Thu, 17 Apr 2025 22:13:43 +0800
Subject: [PATCH] Fix PowerPC CAS reboot to evaluate menu context
The Client Architecture Support (CAS) negotiation between the firmware
and the operating system kernel can result in a reboot, allowing the
firmware to reinitialize itself to satisfy the request. In this case,
grub is expected to resume from the previous session by booting the
entry recorded in the boot-last-label OpenFirmware property.
However, the current implementation fails when a CAS-triggered reboot
originates from a menu entry within a submenu. For example, when booting
into a Btrfs snapshot. The root cause is that the menu context is not
evaluated. As a result, if the resumed boot entry relies on any
evaluated variables, the behavior becomes undefined.
This patch addresses the issue by storing both the entry ID and its
content in the boot-last-label property. The ID is used to descend into
the correct menu context, ensuring the entry is executed in the same
environment it was originally selected from.
A caret (^) is used to separate the entry ID from its content. The
resulting format in boot-last-label looks like this:
gnulinux-simple-2315b72a-17f2-4537-bc62-63da478ce1dd^setparams 'SLES 15-SP6'
set gfxpayload=text
insmod gzio
insmod part_gpt
insmod btrfs
search --no-floppy --fs-uuid --set=root 2315b72a-17f2- ...
echo 'Loading Linux 6.4.0-150600.23.25-default ...'
linux /boot/vmlinux-6.4.0-150600.23.25-default root=UUID= ...
echo 'Loading initial ramdisk ...'
initrd /boot/initrd-6.4.0-150600.23.25-default
Signed-off-by: Michael Chang <mchang@suse.com>
---
grub-core/normal/main.c | 60 ++++++++++++++++++++++--------
grub-core/normal/menu.c | 45 +++++++++++++++++++++-
grub-core/normal/menu_entry.c | 70 +++++++++++++++++++++++++++++++++--
grub-core/script/execute.c | 7 ----
4 files changed, 154 insertions(+), 28 deletions(-)
--- a/grub-core/normal/main.c
+++ b/grub-core/normal/main.c
@@ -365,21 +365,6 @@
{
menu = read_config_file (config);
-#ifdef GRUB_MACHINE_IEEE1275
- int boot;
- boot = 0;
- char *script = NULL;
- char *dummy[1] = { NULL };
- if (! grub_ieee1275_cas_reboot (&script) && script)
- {
- if (! grub_script_execute_new_scope (script, 0, dummy))
- boot = 1;
- }
- grub_free (script);
- if (boot)
- grub_command_execute ("boot", 0, 0);
-#endif
-
/* Ignore any error. */
grub_errno = GRUB_ERR_NONE;
}
@@ -393,7 +378,50 @@
{
if (menu && menu->size)
{
+#ifdef GRUB_MACHINE_IEEE1275
+ char *entry_id = NULL;
+ char *delim;
+ const char *chosen;
+ if (grub_ieee1275_cas_reboot (&entry_id) != 0)
+ goto enter_menu;
+
+ if ((delim = grub_strchr (entry_id, '^')) != NULL)
+ *delim = '\0';
+ else
+ goto enter_menu;
+
+ chosen = grub_env_get ("chosen") ? : "";
+ if (! grub_strlen (chosen))
+ {
+ grub_env_set ("default", entry_id);
+ grub_env_set ("timeout", "0");
+ }
+ else
+ {
+ delim = entry_id;
+ while ((delim = grub_strchr (delim, '>')) != NULL)
+ {
+ if (delim[1] == '>')
+ {
+ delim += 2;
+ continue;
+ }
+ *delim = '\0';
+ if (grub_strcmp (chosen, entry_id) == 0)
+ {
+ grub_env_set ("default", delim + 1);
+ grub_env_set ("timeout", "0");
+ break;
+ }
+ *delim++ = '>';
+ }
+ if (delim == NULL)
+ grub_dprintf ("normal", "CAS triggered but find no match: %s\n", entry_id);
+ }
+ enter_menu:
+ grub_free (entry_id);
+#endif
grub_boot_time ("Entering menu");
grub_show_menu (menu, nested, 0);
if (nested)
--- a/grub-core/normal/menu.c
+++ b/grub-core/normal/menu.c
@@ -32,6 +32,9 @@
#include <grub/script_sh.h>
#include <grub/gfxterm.h>
#include <grub/dl.h>
+#ifdef GRUB_MACHINE_IEEE1275
+#include <grub/ieee1275/ieee1275.h>
+#endif
/* Time to delay after displaying an error message about a default/fallback
entry failing to boot. */
@@ -317,8 +320,31 @@
grub_env_set ("default", ptr + 1);
else
grub_env_unset ("default");
+#ifdef GRUB_MACHINE_IEEE1275
+ char *cas_entry_id = NULL;
+ char *cas_entry_source;
+ const char *id;
+ const char *sourcecode = entry->sourcecode;
+ id = grub_env_get ("chosen") ? : "";
+
+ if (grub_ieee1275_cas_reboot (&cas_entry_id) != 0)
+ goto exec_new_scope;
+
+ if ((cas_entry_source = grub_strchr (cas_entry_id, '^')) != NULL)
+ *cas_entry_source++ = '\0';
+ else
+ goto exec_new_scope;
+
+ if (grub_strcmp (id, cas_entry_id) == 0)
+ sourcecode = cas_entry_source;
+
+ exec_new_scope:
+ grub_script_execute_new_scope (sourcecode, entry->argc, entry->args);
+ grub_free (cas_entry_id);
+#else
grub_script_execute_new_scope (entry->sourcecode, entry->argc, entry->args);
+#endif
if (errs_before != grub_err_printed_errors)
grub_wait_after_message ();
@@ -326,8 +352,23 @@
errs_before = grub_err_printed_errors;
if (grub_errno == GRUB_ERR_NONE && grub_loader_is_loaded ())
- /* Implicit execution of boot, only if something is loaded. */
- grub_command_execute ("boot", 0, 0);
+ {
+#ifdef GRUB_MACHINE_IEEE1275
+ char *entry_data;
+
+ entry_data = grub_xasprintf ("%s^%s", id, sourcecode);
+ if (entry_data)
+ grub_ieee1275_set_boot_last_label (entry_data);
+ else
+ grub_print_error ();
+ grub_free (entry_data);
+#endif
+ /* Implicit execution of boot, only if something is loaded. */
+ grub_command_execute ("boot", 0, 0);
+#ifdef GRUB_MACHINE_IEEE1275
+ grub_ieee1275_set_boot_last_label ("");
+#endif
+ }
if (errs_before != grub_err_printed_errors)
grub_wait_after_message ();
--- a/grub-core/normal/menu_entry.c
+++ b/grub-core/normal/menu_entry.c
@@ -29,6 +29,9 @@
#include <grub/charset.h>
#include <grub/safemath.h>
#include <grub/crypttab.h>
+#ifdef GRUB_MACHINE_IEEE1275
+#include <grub/ieee1275/ieee1275.h>
+#endif
enum update_mode
{
@@ -78,6 +81,9 @@
int completion_shown;
int submenu;
+#ifdef GRUB_MACHINE_IEEE1275
+ char *id;
+#endif
struct per_term_screen *terms;
unsigned nterms;
@@ -578,6 +584,9 @@
grub_free (screen->killed_text);
grub_free (screen->lines);
grub_free (screen->terms);
+#ifdef GRUB_MACHINE_IEEE1275
+ grub_free (screen->id);
+#endif
grub_free (screen);
}
@@ -599,6 +608,11 @@
screen->lines = grub_malloc (sizeof (struct line));
if (! screen->lines)
goto fail;
+#ifdef GRUB_MACHINE_IEEE1275
+ screen->id = grub_strdup (entry->id);
+ if (! screen->id)
+ goto fail;
+#endif
/* Initialize the first line which must be always present. */
if (! init_line (screen, screen->lines))
@@ -1215,14 +1229,64 @@
script[size] = '\0';
}
grub_script_execute_new_scope (script, 0, dummy);
- grub_free (script);
if (errs_before != grub_err_printed_errors)
grub_wait_after_message ();
if (grub_errno == GRUB_ERR_NONE && grub_loader_is_loaded ())
- /* Implicit execution of boot, only if something is loaded. */
- grub_command_execute ("boot", 0, 0);
+ {
+#ifdef GRUB_MACHINE_IEEE1275
+ char *entry_data = NULL;
+ const char *chosen;
+ const char *ptr;
+ grub_size_t sz = 0;
+ char *buf = NULL;
+ char *optr;
+
+ chosen = grub_env_get ("chosen") ? : "";
+ for (ptr = screen->id; *ptr; ptr++)
+ sz += (*ptr == '>') ? 2 : 1;
+ sz++;
+ sz += grub_strlen (chosen);
+ sz++;
+ buf = grub_malloc (sz);
+ if (!buf)
+ {
+ grub_print_error ();
+ goto exec_boot;
+ }
+ optr = buf;
+ if (*chosen != '\0')
+ {
+ optr = grub_stpcpy (optr, chosen);
+ *optr++ = '>';
+ }
+ for (ptr = screen->id; *ptr; ptr++)
+ {
+ if (*ptr == '>')
+ *optr++ = '>';
+ *optr++ = *ptr;
+ }
+ *optr = 0;
+ entry_data = grub_xasprintf ("%s^%s", buf, script);
+ if (entry_data)
+ grub_ieee1275_set_boot_last_label (entry_data);
+ else
+ grub_print_error ();
+ grub_free (entry_data);
+ grub_free (buf);
+ grub_free (script);
+ script = NULL;
+ exec_boot:
+#endif
+ /* Implicit execution of boot, only if something is loaded. */
+ grub_command_execute ("boot", 0, 0);
+#ifdef GRUB_MACHINE_IEEE1275
+ grub_ieee1275_set_boot_last_label ("");
+#endif
+ }
+
+ grub_free (script);
if (screen->submenu)
{
--- a/grub-core/script/execute.c
+++ b/grub-core/script/execute.c
@@ -28,9 +28,6 @@
#include <grub/extcmd.h>
#include <grub/i18n.h>
#include <grub/verify.h>
-#ifdef GRUB_MACHINE_IEEE1275
-#include <grub/ieee1275/ieee1275.h>
-#endif
/* Max digits for a char is 3 (0xFF is 255), similarly for an int it
is sizeof (int) * 3, and one extra for a possible -ve sign. */
@@ -886,10 +883,6 @@
grub_err_t ret = 0;
struct grub_script *parsed_script;
-#ifdef GRUB_MACHINE_IEEE1275
- grub_ieee1275_set_boot_last_label (source);
-#endif
-
while (source)
{
char *line;
