Merge tag 'powerpc-3.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux

Pull powerpc fixes from Michael Ellerman:

- Wire up sys_execveat(). Tested on 32 & 64 bit.

- Fix for kdump on LE systems with cpus hot unplugged.

- Revert Anton's fix for "kernel BUG at kernel/smpboot.c:134!", this
broke other platforms, we'll do a proper fix for 3.20.

* tag 'powerpc-3.19-3' of git://git.kernel.org/pub/scm/linux/kernel/git/mpe/linux:
Revert "powerpc: Secondary CPUs must set cpu_callin_map after setting active and online"
powerpc/kdump: Ignore failure in enabling big endian exception during crash
powerpc: Wire up sys_execveat() syscall

arch/powerpc/include/asm/kexec.h

···
 extern void reserve_crashkernel(void);
 extern void machine_kexec_mask_interrupts(void);
 
+static inline bool kdump_in_progress(void)
+{
+	return crashing_cpu >= 0;
+}
+
 #else /* !CONFIG_KEXEC */
 static inline void crash_kexec_secondary(struct pt_regs *regs) { }
 
···
 static inline int crash_shutdown_unregister(crash_shutdown_t handler)
 {
 	return 0;
+}
+
+static inline bool kdump_in_progress(void)
+{
+	return false;
 }
 
 #endif /* CONFIG_KEXEC */

arch/powerpc/include/asm/systbl.h

···
 SYSCALL_SPU(getrandom)
 SYSCALL_SPU(memfd_create)
 SYSCALL_SPU(bpf)
+COMPAT_SYS(execveat)

arch/powerpc/include/asm/unistd.h

···
 #include <uapi/asm/unistd.h>
 
 
-#define __NR_syscalls		362
+#define __NR_syscalls		363
 
 #define __NR__exit __NR_exit
 #define NR_syscalls	__NR_syscalls

arch/powerpc/include/uapi/asm/unistd.h

···
 #define __NR_getrandom		359
 #define __NR_memfd_create	360
 #define __NR_bpf		361
+#define __NR_execveat		362
 
 #endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */

arch/powerpc/kernel/machine_kexec_64.c

···
         * using debugger IPI.
         */
 
-	if (crashing_cpu == -1)
+	if (!kdump_in_progress())
 		kexec_prepare_cpus();
 
 	pr_debug("kexec: Starting switchover sequence.\n");

arch/powerpc/kernel/smp.c

···
 	smp_store_cpu_info(cpu);
 	set_dec(tb_ticks_per_jiffy);
 	preempt_disable();
+	cpu_callin_map[cpu] = 1;
 
 	if (smp_ops->setup_cpu)
 		smp_ops->setup_cpu(cpu);
···
 	smp_wmb();
 	notify_cpu_starting(cpu);
 	set_cpu_online(cpu, true);
-
-	/*
-	 * CPU must be marked active and online before we signal back to the
-	 * master, because the scheduler needs to see the cpu_online and
-	 * cpu_active bits set.
-	 */
-	smp_wmb();
-	cpu_callin_map[cpu] = 1;
 
 	local_irq_enable();
 

arch/powerpc/platforms/pseries/lpar.c

···
 #include <asm/trace.h>
 #include <asm/firmware.h>
 #include <asm/plpar_wrappers.h>
+#include <asm/kexec.h>
 #include <asm/fadump.h>
 
 #include "pseries.h"
···
 		 * out to the user, but at least this will stop us from
 		 * continuing on further and creating an even more
 		 * difficult to debug situation.
+		 *
+		 * There is a known problem when kdump'ing, if cpus are offline
+		 * the above call will fail. Rather than panicking again, keep
+		 * going and hope the kdump kernel is also little endian, which
+		 * it usually is.
 		 */
-		if (rc)
+		if (rc && !kdump_in_progress())
 			panic("Could not enable big endian exceptions");
 	}
 #endif