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-rw-r--r--arch/x86/pci/pcbios.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/pci/pcbios.c b/arch/x86/pci/pcbios.c
index 10ac8c316c4..2f7109ac4c1 100644
--- a/arch/x86/pci/pcbios.c
+++ b/arch/x86/pci/pcbios.c
@@ -198,6 +198,11 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
+ /*
+ * Zero-extend the result beyond 8 bits, do not trust the
+ * BIOS having done it:
+ */
+ *value &= 0xff;
break;
case 2:
__asm__("lcall *(%%esi); cld\n\t"
@@ -210,6 +215,11 @@ static int pci_bios_read(unsigned int seg, unsigned int bus,
"b" (bx),
"D" ((long)reg),
"S" (&pci_indirect));
+ /*
+ * Zero-extend the result beyond 16 bits, do not trust the
+ * BIOS having done it:
+ */
+ *value &= 0xffff;
break;
case 4:
__asm__("lcall *(%%esi); cld\n\t"