commit 293e6a96a9e19812f17bf6f925415e115612f607
author Jacob Garber <jgarber1@ualberta.ca> Wed Jul 17 11:47:19 2019 -0600
committer Patrick Georgi <pgeorgi@google.com> Tue Aug 20 15:30:47 2019 +0000
tree 16c898c77d69b32bbfa8c56ba8d2cefecf539572
parent 4f387e1240dc05d4eff59ae973ab4516cd588e1f

nb/amd/pi,sb/amd/sr5650: Remove unnecessary allocation

add_ivrs_device_entries() is a recursive function, and each recursive
call is passed a pointer to a root_level variable declared outside the
function. In an attempt to make the function self-contained, the initial
call is made with the root_level pointer set to NULL, and then the
function attempts to detect this and allocate a root_level variable for
the rest of the calls. This makes memory management very tricky - for
example, the pi code incorrectly attempts to free the root_level
variable at the end of *each* recursive call, which only avoids being a
double-free because free() in coreboot is currently a no-op. Let's
keep life simple and declare root_level as a local variable outside the
first function call instead.

Change-Id: Ifd63ee368fb89345b9b42ccb86cebcca64f32ac8
Signed-off-by: Jacob Garber <jgarber1@ualberta.ca>
Found-by: Coverity CID 1362811
Reviewed-on: https://review.coreboot.org/c/coreboot/+/34387
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/northbridge/amd/pi/00730F01/northbridge.c

diff --git a/src/northbridge/amd/pi/00730F01/northbridge.c b/src/northbridge/amd/pi/00730F01/northbridge.c
index 377d91e..ba17c61 100644
--- a/src/northbridge/amd/pi/00730F01/northbridge.c
+++ b/src/northbridge/amd/pi/00730F01/northbridge.c
@@ -491,11 +491,6 @@
 	unsigned int header_type;
 	unsigned int is_pcie;
 
-	if (!root_level) {
-		root_level = malloc(sizeof(int8_t));
-		*root_level = -1;
-	}
-
 	if (dev->path.type == DEVICE_PATH_PCI) {
 
 		if ((dev->bus->secondary == 0x0) &&
@@ -536,8 +531,6 @@
 		     sibling->sibling)
 			add_ivrs_device_entries(dev, sibling, depth + 1, depth,
 						root_level, current, length);
-
-	free(root_level);
 }
 
 unsigned long acpi_fill_ivrs_ioapic(acpi_ivrs_t *ivrs, unsigned long current)
@@ -643,7 +636,8 @@
 	current += 8;
 
 	/* Describe PCI devices */
-	add_ivrs_device_entries(NULL, all_devices, 0, -1, NULL, &current,
+	int8_t root_level = -1;
+	add_ivrs_device_entries(NULL, all_devices, 0, -1, &root_level, &current,
 				&ivrs->ivhd.length);
 
 	/* Describe IOAPICs */