[coreboot-gerrit] Patch set updated for coreboot: fdac806 CAR_GLOBAL: enforce compiler to check if _start != _end

Edward O'Callaghan (eocallaghan@alterapraxis.com) gerrit at coreboot.org
Wed Feb 19 15:52:33 CET 2014


Edward O'Callaghan (eocallaghan at alterapraxis.com) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/4719

-gerrit

commit fdac806240c2aa5da7820147bc3928920ff32e07
Author: Edward O'Callaghan <eocallaghan at alterapraxis.com>
Date:   Thu Feb 20 01:51:43 2014 +1100

    CAR_GLOBAL: enforce compiler to check if _start != _end
    
    There are some fun rules C compilers can use to optimize their code.
    One of them is the assumption that two symbols point to two different
    addresses.
    In this case this wasn't true, resulting in unintended code execution
    (and later, a crash) with a clang build.
    
    Change-Id: I1496b22e1d1869ed0610e321b6ec6a83252e9d8b
    Signed-off-by: Patrick Georgi <patrick at georgi-clan.de>
    Signed-off-by: Edward O'Callaghan <eocallaghan at alterapraxis.com>
---
 src/arch/x86/init/romstage.ld | 1 +
 src/cpu/x86/car.c             | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/arch/x86/init/romstage.ld b/src/arch/x86/init/romstage.ld
index f44185f..5458cfc 100644
--- a/src/arch/x86/init/romstage.ld
+++ b/src/arch/x86/init/romstage.ld
@@ -37,6 +37,7 @@ SECTIONS
 		. = ALIGN(16);
 		_car_migrate_start = .;
 		*(.car.migrate);
+		LONG(0);
 		_car_migrate_end = .;
 		. = ALIGN(16);
 		_erom = .;
diff --git a/src/cpu/x86/car.c b/src/cpu/x86/car.c
index 481153d..8f6a855 100644
--- a/src/cpu/x86/car.c
+++ b/src/cpu/x86/car.c
@@ -98,7 +98,7 @@ void car_migrate_variables(void)
 
 	/* Call all the migration functions. */
 	migrate_func = &_car_migrate_start;
-	while (migrate_func != &_car_migrate_end) {
+	while (*migrate_func != NULL) {
 		(*migrate_func)();
 		migrate_func++;
 	}



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