svn commit: r333363 - head/sys/powerpc/pseries

[Justin Hibbits]

Author: jhibbits
Date: Tue May  8 13:23:39 2018
New Revision: 333363
URL: https://svnweb.freebsd.org/changeset/base/333363

Log:
  Fix wrong cpu0 identification
  
  Summary:
  chrp_cpuref_init() was relying on the boot strap processor to be
  the first child of /cpus. That was not always the case, specially
  on pseries with FDT.
  
  This change uses the "reg" property of each CPU instead and also
  adds several sanity checks to avoid unexpected behavior (maybe
  too many panics?).
  
  The main observed symptom was interrupts being missed by the main
  processor, leading to timeouts and the kernel aborting the boot.
  
  Submitted by:	Leandro Lupori
  Reviewed by:	nwhitehorn
  Differential Revision: https://reviews.freebsd.org/D15174

Modified:
  head/sys/powerpc/pseries/platform_chrp.c

Modified: head/sys/powerpc/pseries/platform_chrp.c
==============================================================================
--- head/sys/powerpc/pseries/platform_chrp.c	Tue May  8 11:39:01 2018	(r333362)
+++ head/sys/powerpc/pseries/platform_chrp.c	Tue May  8 13:23:39 2018	(r333363)
@@ -350,14 +350,26 @@ chrp_smp_get_bsp(platform_t plat, struct cpuref *cpure
 	return (0);
 }
 
+static void
+get_cpu_reg(phandle_t cpu, cell_t *reg)
+{
+	int res;
+
+	res = OF_getproplen(cpu, "reg");
+	if (res != sizeof(cell_t))
+		panic("Unexpected length for CPU property reg on Open Firmware\n");
+	OF_getencprop(cpu, "reg", reg, res);
+}
+
 static int
 chrp_cpuref_init(void)
 {
-	phandle_t cpu, dev;
+	phandle_t cpu, dev, chosen, pbsp;
+	ihandle_t ibsp;
 	char buf[32];
-	int a, res;
-	cell_t interrupt_servers[32];
-	uint64_t bsp;
+	int a, bsp, res, res2, tmp_cpuref_cnt;
+	static struct cpuref tmp_cpuref[MAXCPU];
+	cell_t interrupt_servers[32], addr_cells, size_cells, reg, bsp_reg;
 
 	if (platform_cpuref_valid)
 		return (0);
@@ -371,25 +383,77 @@ chrp_cpuref_init(void)
 		dev = OF_peer(dev);
 	}
 
-	bsp = 0;
+	/* Make sure that cpus reg property have 1 address cell and 0 size cells */
+	res = OF_getproplen(dev, "#address-cells");
+	res2 = OF_getproplen(dev, "#size-cells");
+	if (res != res2 || res != sizeof(cell_t))
+		panic("CPU properties #address-cells and #size-cells not found on Open Firmware\n");
+	OF_getencprop(dev, "#address-cells", &addr_cells, sizeof(addr_cells));
+	OF_getencprop(dev, "#size-cells", &size_cells, sizeof(size_cells));
+	if (addr_cells != 1 || size_cells != 0)
+		panic("Unexpected values for CPU properties #address-cells and #size-cells on Open Firmware\n");
+
+	/* Look for boot CPU in /chosen/cpu and /chosen/fdtbootcpu */
+
+	chosen = OF_finddevice("/chosen");
+	if (chosen == -1)
+		panic("Device /chosen not found on Open Firmware\n");
+
+	bsp_reg = -1;
+
+	/* /chosen/cpu */
+	if (OF_getproplen(chosen, "cpu") == sizeof(ihandle_t)) {
+		OF_getprop(chosen, "cpu", &ibsp, sizeof(ibsp));
+		pbsp = OF_instance_to_package(ibsp);
+		if (pbsp != -1)
+			get_cpu_reg(pbsp, &bsp_reg);
+	}
+
+	/* /chosen/fdtbootcpu */
+	if (bsp_reg == -1) {
+		if (OF_getproplen(chosen, "fdtbootcpu") == sizeof(cell_t))
+			OF_getprop(chosen, "fdtbootcpu", &bsp_reg, sizeof(bsp_reg));
+	}
+
+	if (bsp_reg == -1)
+		panic("Boot CPU not found on Open Firmware\n");
+
+	bsp = -1;
+	tmp_cpuref_cnt = 0;
 	for (cpu = OF_child(dev); cpu != 0; cpu = OF_peer(cpu)) {
 		res = OF_getprop(cpu, "device_type", buf, sizeof(buf));
 		if (res > 0 && strcmp(buf, "cpu") == 0) {
 			res = OF_getproplen(cpu, "ibm,ppc-interrupt-server#s");
 			if (res > 0) {
-
-
 				OF_getencprop(cpu, "ibm,ppc-interrupt-server#s",
 				    interrupt_servers, res);
 
-				for (a = 0; a < res/sizeof(cell_t); a++) {
-					platform_cpuref[platform_cpuref_cnt].cr_hwref = interrupt_servers[a];
-					platform_cpuref[platform_cpuref_cnt].cr_cpuid = platform_cpuref_cnt;
+				get_cpu_reg(cpu, &reg);
+				if (reg == bsp_reg)
+					bsp = tmp_cpuref_cnt;
 
-					platform_cpuref_cnt++;
+				for (a = 0; a < res/sizeof(cell_t); a++) {
+					tmp_cpuref[tmp_cpuref_cnt].cr_hwref = interrupt_servers[a];
+					tmp_cpuref[tmp_cpuref_cnt].cr_cpuid = tmp_cpuref_cnt;
+					tmp_cpuref_cnt++;
 				}
 			}
 		}
+	}
+
+	if (bsp == -1)
+		panic("Boot CPU not found\n");
+
+	/* Map IDs, so BSP has CPUID 0 regardless of hwref */
+	for (a = bsp; a < tmp_cpuref_cnt; a++) {
+		platform_cpuref[platform_cpuref_cnt].cr_hwref = tmp_cpuref[a].cr_hwref;
+		platform_cpuref[platform_cpuref_cnt].cr_cpuid = platform_cpuref_cnt;
+		platform_cpuref_cnt++;
+	}
+	for (a = 0; a < bsp; a++) {
+		platform_cpuref[platform_cpuref_cnt].cr_hwref = tmp_cpuref[a].cr_hwref;
+		platform_cpuref[platform_cpuref_cnt].cr_cpuid = platform_cpuref_cnt;
+		platform_cpuref_cnt++;
 	}
 
 	platform_cpuref_valid = 1;