Reset code and vector handling from Linux

f3f8c351 · Silas Boyd-Wickizer · 7a34e712 · f3f8c351 · f3f8c351 · f3f8c351
--- a/kernel/main.cc
+++ b/kernel/main.cc
@@ -43,6 +43,8 @@ void initfutex(void);
 void initcmdline(void);
 void idleloop(void);

+#define IO_RTC  0x70
+
 static volatile int bstate;

 void
@@ -59,6 +61,34 @@ mpboot(void)
 }

 static void
+warmreset(u32 addr)
+{
+  volatile u16 *wrv;
+
+  // "The BSP must initialize CMOS shutdown code to 0AH
+  // and the warm reset vector (DWORD based at 40:67) to point at
+  // the AP startup code prior to the [universal startup algorithm]."
+  outb(IO_RTC, 0xF);  // offset 0xF is shutdown code
+  outb(IO_RTC+1, 0x0A);
+  wrv = (u16*)(0x40<<4 | 0x67);  // Warm reset vector
+  wrv[0] = 0;
+  wrv[1] = addr >> 4;
+}
+
+static void
+rstrreset(void)
+{
+  volatile u16 *wrv;
+  
+  // Paranoid: set warm reset code and vector back to defaults
+  outb(IO_RTC, 0xF);
+  outb(IO_RTC+1, 0);
+  wrv = (u16*)(0x40<<4 | 0x67);
+  wrv[0] = 0;
+  wrv[1] = 0;
+}
+
+static void
 bootothers(void)
 {
  extern u8 _bootother_start[];
@@ -78,6 +108,8 @@ bootothers(void)
    if(c == cpus+myid())  // We've started already.
      continue;

+    warmreset(v2p(code));
+
    // Tell bootother.S what stack to use and the address of apstart;
    // it expects to find these two addresses stored just before
    // its first instruction.
@@ -92,6 +124,7 @@ bootothers(void)
    // Wait for cpu to finish mpmain()
    while(bstate == 0)
      ;
+    rstrreset();
  }
 }


--- a/kernel/x2apic.cc
+++ b/kernel/x2apic.cc
@@ -33,8 +33,6 @@
 #define TCCR    0x839   // Timer Current Count
 #define TDCR    0x83e   // Timer Divide Configuration

-#define IO_RTC  0x70
-
 static u64 x2apichz;

 static int
@@ -65,16 +63,6 @@ void
 x2apicstartap(hwid_t id, u32 addr)
 {
  int i;
-  volatile u16 *wrv;
-
-  // "The BSP must initialize CMOS shutdown code to 0AH
-  // and the warm reset vector (DWORD based at 40:67) to point at
-  // the AP startup code prior to the [universal startup algorithm]."
-  outb(IO_RTC, 0xF);  // offset 0xF is shutdown code
-  outb(IO_RTC+1, 0x0A);
-  wrv = (u16*)(0x40<<4 | 0x67);  // Warm reset vector
-  wrv[0] = 0;
-  wrv[1] = addr >> 4;

  // Be paranoid about clearing APIC errors
  writemsr(ESR, 0);

--- a/kernel/xapic.cc
+++ b/kernel/xapic.cc
@@ -187,16 +187,6 @@ void
 xapicstartap(hwid hwid, u32 addr)
 {
  int i;
-  volatile u16 *wrv;
-
-  // "The BSP must initialize CMOS shutdown code to 0AH
-  // and the warm reset vector (DWORD based at 40:67) to point at
-  // the AP startup code prior to the [universal startup algorithm]."
-  outb(IO_RTC, 0xF);  // offset 0xF is shutdown code
-  outb(IO_RTC+1, 0x0A);
-  wrv = (u16*)(0x40<<4 | 0x67);  // Warm reset vector
-  wrv[0] = 0;
-  wrv[1] = addr >> 4;

  // "Universal startup algorithm."
  // Send INIT (level-triggered) interrupt to reset other CPU.