From: Tomas Hruby <thruby@few.vu.nl>
Date: Thu, 29 Mar 2012 07:53:38 +0000 (-0700)
Subject: ioapic - missing volatiles
X-Git-Tag: v3.2.1~632
X-Git-Url: http://zhaoyanbai.com/repos/%7B%24global.css%7D?a=commitdiff_plain;h=5ab87a6c387c591c4a1386fa706b6ca79c4a66a9;p=minix.git

ioapic - missing volatiles

leads to a kernel panic when using clang and SMP

reported by trd <trdempsey.201201@gmail.com>
---

diff --git a/kernel/arch/i386/apic.c b/kernel/arch/i386/apic.c
index cdb601e4a..69f7c4d94 100644
--- a/kernel/arch/i386/apic.c
+++ b/kernel/arch/i386/apic.c
@@ -178,14 +178,14 @@ static u32_t lapic_bus_freq[CONFIG_MAX_CPUS];
 
 static u32_t ioapic_read(u32_t ioa_base, u32_t reg)
 {
-	*((u32_t *)(ioa_base + IOAPIC_IOREGSEL)) = (reg & 0xff);
-	return *(u32_t *)(ioa_base + IOAPIC_IOWIN);
+	*((volatile u32_t *)(ioa_base + IOAPIC_IOREGSEL)) = (reg & 0xff);
+	return *(volatile u32_t *)(ioa_base + IOAPIC_IOWIN);
 }
 
 static void ioapic_write(u32_t ioa_base, u8_t reg, u32_t val)
 {
-	*((u32_t *)(ioa_base + IOAPIC_IOREGSEL)) = reg;
-	*((u32_t *)(ioa_base + IOAPIC_IOWIN)) = val;
+	*((volatile u32_t *)(ioa_base + IOAPIC_IOREGSEL)) = reg;
+	*((volatile u32_t *)(ioa_base + IOAPIC_IOWIN)) = val;
 }
 
 void lapic_microsec_sleep(unsigned count);