powerpc/iseries: Fix early init access to lppaca

The combination of commit

8154c5d22d91cd16bd9985b0638c8957e4688d0e and
93c22703efa72c7527dbd586d1951c1f4a85fd70

Broke boot on iSeries.

The problem is that iSeries very early boot code, which generates
the device-tree and runs before our normal early initializations
does need access the lppaca's very early, before the PACA array is
initialized, and in fact even before the boot PACA has been
initialized (it contains all 0's at this stage).

However, the first patch above makes that code use the new
llpaca_of(cpu) accessor, which itself is changed by the second patch to
use the PACA array.

We fix that by reverting iSeries to directly dereferencing the array. In
addition, we fix all iterators in the iSeries code to always skip CPU
whose number is above 63 which is the maximum size of that array and
the maximum number of supported CPUs on these machines.

Additionally, we make sure the boot_paca is properly initialized
in our early startup code.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

diff --git a/arch/powerpc/include/asm/lppaca.h b/arch/powerpc/include/asm/lppaca.h
index 380d48bacd16d0047cd1cb5006853ff4adf9506c..26b8c807f8f12d5ee5e3b06f7f2ec0a1523d559c 100644 (file)
--- a/arch/powerpc/include/asm/lppaca.h
+++ b/arch/powerpc/include/asm/lppaca.h
@@ -33,9 +33,25 @@
 //
 //----------------------------------------------------------------------------
 #include <linux/cache.h>
+#include <linux/threads.h>
 #include <asm/types.h>
 #include <asm/mmu.h>
 
+/*
+ * We only have to have statically allocated lppaca structs on
+ * legacy iSeries, which supports at most 64 cpus.
+ */
+#ifdef CONFIG_PPC_ISERIES
+#if NR_CPUS < 64
+#define NR_LPPACAS     NR_CPUS
+#else
+#define NR_LPPACAS     64
+#endif
+#else /* not iSeries */
+#define NR_LPPACAS     1
+#endif
+
+
 /* The Hypervisor barfs if the lppaca crosses a page boundary.  A 1k
  * alignment is sufficient to prevent this */
 struct lppaca {

diff --git a/arch/powerpc/kernel/paca.c b/arch/powerpc/kernel/paca.c
index ebf9846f3c3b30b7cf2d61d48a8a96c37b702c1c..f4adf89d7614150a73c44ad8251ae13ad7934b16 100644 (file)
--- a/arch/powerpc/kernel/paca.c
+++ b/arch/powerpc/kernel/paca.c
@@ -26,20 +26,6 @@ extern unsigned long __toc_start;
 
 #ifdef CONFIG_PPC_BOOK3S
 
-/*
- * We only have to have statically allocated lppaca structs on
- * legacy iSeries, which supports at most 64 cpus.
- */
-#ifdef CONFIG_PPC_ISERIES
-#if NR_CPUS < 64
-#define NR_LPPACAS     NR_CPUS
-#else
-#define NR_LPPACAS     64
-#endif
-#else /* not iSeries */
-#define NR_LPPACAS     1
-#endif
-
 /*
  * The structure which the hypervisor knows about - this structure
  * should not cross a page boundary.  The vpa_init/register_vpa call

diff --git a/arch/powerpc/platforms/iseries/dt.c b/arch/powerpc/platforms/iseries/dt.c
index fdb7384c0c4f3fe372207d4ad8bdc48a364a97c0..f0491cc2890004167a58ebefcdf24a37dd87534b 100644 (file)
--- a/arch/powerpc/platforms/iseries/dt.c
+++ b/arch/powerpc/platforms/iseries/dt.c
@@ -242,8 +242,8 @@ static void __init dt_cpus(struct iseries_flat_dt *dt)
        pft_size[0] = 0; /* NUMA CEC cookie, 0 for non NUMA  */
        pft_size[1] = __ilog2(HvCallHpt_getHptPages() * HW_PAGE_SIZE);
 
-       for (i = 0; i < NR_CPUS; i++) {
-               if (lppaca_of(i).dyn_proc_status >= 2)
+       for (i = 0; i < NR_LPPACAS; i++) {
+               if (lppaca[i].dyn_proc_status >= 2)
                        continue;
 
                snprintf(p, 32 - (p - buf), "@%d", i);
@@ -251,7 +251,7 @@ static void __init dt_cpus(struct iseries_flat_dt *dt)
 
                dt_prop_str(dt, "device_type", device_type_cpu);
 
-               index = lppaca_of(i).dyn_hv_phys_proc_index;
+               index = lppaca[i].dyn_hv_phys_proc_index;
                d = &xIoHriProcessorVpd[index];
 
                dt_prop_u32(dt, "i-cache-size", d->xInstCacheSize * 1024);

diff --git a/arch/powerpc/platforms/iseries/setup.c b/arch/powerpc/platforms/iseries/setup.c
index b0863410517f517129d111c4891cec990736abb4..2946ae10fbfdba2ea2eb2cc1e730eedf1cc4ad8b 100644 (file)
--- a/arch/powerpc/platforms/iseries/setup.c
+++ b/arch/powerpc/platforms/iseries/setup.c
@@ -680,6 +680,7 @@ void * __init iSeries_early_setup(void)
         * on but calling this function multiple times is fine.
         */
        identify_cpu(0, mfspr(SPRN_PVR));
+       initialise_paca(&boot_paca, 0);
 
        powerpc_firmware_features |= FW_FEATURE_ISERIES;
        powerpc_firmware_features |= FW_FEATURE_LPAR;