Re: [PATCH 2/3] Taint kernel on ACPI table override (format corrected)

["Éric Piel" <Eric.Piel@tremplin-utc.net>]

When an ACPI table is overridden (for now this can happen only for DSDT)
display a big warning and taint the kernel with flag A.

Signed-off-by: Eric Piel <eric.piel@tremplin-utc.net>
---
 drivers/acpi/osl.c     |    7 +++++++
 include/linux/kernel.h |    1 +
 kernel/panic.c         |    5 +++--
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
index 4568a59..549daea 100644
--- a/drivers/acpi/osl.c
+++ b/drivers/acpi/osl.c
@@ -392,6 +392,13 @@ acpi_os_table_override(struct acpi_table_header * existing_table,
 			*new_table = initrd_table;
 	}
 #endif
+	if (*new_table != NULL) {
+		printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], "
+			   "this is unsafe: tainting kernel\n",
+		       existing_table->signature,
+		       existing_table->oem_table_id);
+		add_taint(TAINT_OVERRIDDEN_ACPI_TABLE);
+	}
 	return AE_OK;
 }
 
diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index a7283c9..f51f8bd 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -240,6 +240,7 @@ extern enum system_states {
 #define TAINT_BAD_PAGE			(1<<5)
 #define TAINT_USER			(1<<6)
 #define TAINT_DIE			(1<<7)
+#define TAINT_OVERRIDDEN_ACPI_TABLE	(1<<8)
 
 extern void dump_stack(void) __cold;
 
diff --git a/kernel/panic.c b/kernel/panic.c
index da4d6ba..1b7a002 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -160,7 +160,7 @@ const char *print_tainted(void)
 {
 	static char buf[20];
 	if (tainted) {
-		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c",
+		snprintf(buf, sizeof(buf), "Tainted: %c%c%c%c%c%c%c%c%c",
 			tainted & TAINT_PROPRIETARY_MODULE ? 'P' : 'G',
 			tainted & TAINT_FORCED_MODULE ? 'F' : ' ',
 			tainted & TAINT_UNSAFE_SMP ? 'S' : ' ',
@@ -168,7 +168,8 @@ const char *print_tainted(void)
 			tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
 			tainted & TAINT_BAD_PAGE ? 'B' : ' ',
 			tainted & TAINT_USER ? 'U' : ' ',
-			tainted & TAINT_DIE ? 'D' : ' ');
+			tainted & TAINT_DIE ? 'D' : ' ',
+			tainted & TAINT_OVERRIDDEN_ACPI_TABLE ? 'A' : ' ');
 	}
 	else
 		snprintf(buf, sizeof(buf), "Not tainted");