[05/18] x86: qemu: Avoid accessing BSS too early

Commit Message

Simon Glass Nov. 12, 2024, 1:58 p.m. UTC

BSS is placed in DRAM which is actually available early with QEMU. But
it is cleared by the init sequence, so values stored there are lost.

Move the system-type flag into a function, instead.

Signed-off-by: Simon Glass <[e-mail]>
---

 arch/x86/cpu/qemu/qemu.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

Patch

diff --git a/arch/x86/cpu/qemu/qemu.c b/arch/x86/cpu/qemu/qemu.c
index 563f63e2bc8..e846ccd44aa 100644
--- a/arch/x86/cpu/qemu/qemu.c
+++ b/arch/x86/cpu/qemu/qemu.c
@@ -15,14 +15,21 @@ 
 #include <asm/arch/qemu.h>
 #include <asm/u-boot-x86.h>
 
-static bool i440fx;
-
 #if CONFIG_IS_ENABLED(QFW_PIO)
 U_BOOT_DRVINFO(x86_qfw_pio) = {
 	.name = "qfw_pio",
 };
 #endif
 
+static bool is_i440fx(void)
+{
+	u16 device;
+
+	pci_read_config16(PCI_BDF(0, 0, 0), PCI_DEVICE_ID, &device);
+
+	return device == PCI_DEVICE_ID_INTEL_82441;
+}
+
 static void enable_pm_piix(void)
 {
 	u8 en;
@@ -50,16 +57,17 @@  static void enable_pm_ich9(void)
 
 void qemu_chipset_init(void)
 {
-	u16 device, xbcs;
+	bool i440fx;
+	u16 xbcs;
 	int pam, i;
 
+	i440fx = is_i440fx();
+
 	/*
 	 * i440FX and Q35 chipset have different PAM register offset, but with
 	 * the same bitfield layout. Here we determine the offset based on its
 	 * PCI device ID.
 	 */
-	pci_read_config16(PCI_BDF(0, 0, 0), PCI_DEVICE_ID, &device);
-	i440fx = (device == PCI_DEVICE_ID_INTEL_82441);
 	pam = i440fx ? I440FX_PAM : Q35_PAM;
 
 	/*
@@ -123,7 +131,7 @@  int mp_determine_pci_dstirq(int bus, int dev, int func, int pirq)
 {
 	u8 irq;
 
-	if (i440fx) {
+	if (is_i440fx()) {
 		/*
 		 * Not like most x86 platforms, the PIRQ[A-D] on PIIX3 are not
 		 * connected to I/O APIC INTPIN#16-19. Instead they are routed