[coreboot-gerrit] Change in coreboot[master]: nb/amd/pi,sr5650: Remove unnecessary memory allocation

[Jacob Garber (Code Review)]

Jacob Garber has uploaded this change for review. ( https://review.coreboot.org/c/coreboot/+/34387 )

Change subject: nb/amd/pi,sr5650: Remove unnecessary memory allocation
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nb/amd/pi,sr5650: Remove unnecessary memory 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
dispense with this memory weirdness and declare root_level as a local
variable outside the first function call instead.

Change-Id: Ifd63ee368fb89345b9b42ccb86cebcca64f32ac8
Signed-off-by: Jacob Garber 
Found-by: Coverity CID 1362811
---
M src/northbridge/amd/pi/00730F01/northbridge.c
M src/southbridge/amd/sr5650/sr5650.c
2 files changed, 4 insertions(+), 19 deletions(-)

git pull ssh://review.coreboot.org:29418/coreboot refs/changes/87/34387/1

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 */
diff --git a/src/southbridge/amd/sr5650/sr5650.c b/src/southbridge/amd/sr5650/sr5650.c
index 90ca564..8131e77 100644
--- a/src/southbridge/amd/sr5650/sr5650.c
+++ b/src/southbridge/amd/sr5650/sr5650.c
@@ -725,13 +725,6 @@
    struct device *sibling;
    struct bus *link;

-	if (!root_level) {
-		root_level = malloc(sizeof(int8_t));
-		if (root_level == NULL)
-			die("Error: Could not allocate a byte!\n");
-		*root_level = -1;
-	}
-
    if ((dev->path.type == DEVICE_PATH_PCI) &&
    	(dev->bus->secondary == 0x0) && (dev->path.pci.devfn == 0x0))
    	*root_level = depth;
@@ -798,9 +791,6 @@
    		sibling = sibling->sibling)
    		add_ivrs_device_entries(dev, sibling, depth + 1,
    			depth, root_level, current, length);
-
-	if (depth == 0)
-		free(root_level);
 }

unsigned long acpi_fill_mcfg(unsigned long current)
@@ -879,7 +869,8 @@
    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 */