[PATCH] powerpc: Fix kdump copy regs and dynamic allocate per-cpu crash notes

- This contains the arch specific changes for the following the
kdump generic fixes which were already accepted in the upstream.
. Capturing CPU registers (for the case of 'panic' and invoking
the dump using 'sysrq-trigger') from a function (stack frame) which will
be not be available during the kdump boot. Hence, might result in
invalid stack trace.
. Dynamically allocating per cpu ELF notes section instead of
statically for NR_CPUS.

- Fix the compiler warning in prom_init.c.

Signed-off-by: Haren Myneni <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/kernel/crash.c

···
 	 * squirrelled away.  ELF notes happen to provide
 	 * all of that that no need to invent something new.
 	 */
-	buf = &crash_notes[cpu][0];
+	buf = (u32*)per_cpu_ptr(crash_notes, cpu);
+	if (!buf) 
+		return;
+
 	memset(&prstatus, 0, sizeof(prstatus));
 	prstatus.pr_pid = current->pid;
 	elf_core_copy_regs(&prstatus.pr_reg, regs);
 	buf = append_elf_note(buf, "CORE", NT_PRSTATUS, &prstatus,
 			sizeof(prstatus));
 	final_note(buf);
-}
-
-/* FIXME Merge this with xmon_save_regs ?? */
-static inline void crash_get_current_regs(struct pt_regs *regs)
-{
-	unsigned long tmp1, tmp2;
-
-	__asm__ __volatile__ (
-		"std    0,0(%2)\n"
-		"std    1,8(%2)\n"
-		"std    2,16(%2)\n"
-		"std    3,24(%2)\n"
-		"std    4,32(%2)\n"
-		"std    5,40(%2)\n"
-		"std    6,48(%2)\n"
-		"std    7,56(%2)\n"
-		"std    8,64(%2)\n"
-		"std    9,72(%2)\n"
-		"std    10,80(%2)\n"
-		"std    11,88(%2)\n"
-		"std    12,96(%2)\n"
-		"std    13,104(%2)\n"
-		"std    14,112(%2)\n"
-		"std    15,120(%2)\n"
-		"std    16,128(%2)\n"
-		"std    17,136(%2)\n"
-		"std    18,144(%2)\n"
-		"std    19,152(%2)\n"
-		"std    20,160(%2)\n"
-		"std    21,168(%2)\n"
-		"std    22,176(%2)\n"
-		"std    23,184(%2)\n"
-		"std    24,192(%2)\n"
-		"std    25,200(%2)\n"
-		"std    26,208(%2)\n"
-		"std    27,216(%2)\n"
-		"std    28,224(%2)\n"
-		"std    29,232(%2)\n"
-		"std    30,240(%2)\n"
-		"std    31,248(%2)\n"
-		"mfmsr  %0\n"
-		"std    %0, 264(%2)\n"
-		"mfctr  %0\n"
-		"std    %0, 280(%2)\n"
-		"mflr   %0\n"
-		"std    %0, 288(%2)\n"
-		"bl     1f\n"
-	"1:      mflr   %1\n"
-		"std    %1, 256(%2)\n"
-		"mtlr   %0\n"
-		"mfxer  %0\n"
-		"std    %0, 296(%2)\n"
-		: "=&r" (tmp1), "=&r" (tmp2)
-		: "b" (regs));
-}
-
-/* We may have saved_regs from where the error came from
- * or it is NULL if via a direct panic().
- */
-static void crash_save_self(struct pt_regs *saved_regs)
-{
-	struct pt_regs regs;
-	int cpu;
-
-	cpu = smp_processor_id();
-	if (saved_regs)
-		memcpy(&regs, saved_regs, sizeof(regs));
-	else
-		crash_get_current_regs(&regs);
-	crash_save_this_cpu(&regs, cpu);
 }
 
 #ifdef CONFIG_SMP
···
 	 */
 	crashing_cpu = smp_processor_id();
 	crash_kexec_prepare_cpus();
-	crash_save_self(regs);
+	crash_save_this_cpu(regs, crashing_cpu);
 }

arch/powerpc/kernel/prom_init.c

···
 	opt = strstr(RELOC(prom_cmd_line), RELOC("crashkernel="));
 	if (opt) {
 		opt += 12;
-		RELOC(prom_crashk_size) = prom_memparse(opt, &opt);
+		RELOC(prom_crashk_size) = 
+			prom_memparse(opt, (const char **)&opt);
 
 		if (ALIGN(RELOC(prom_crashk_size), 0x1000000) !=
 			RELOC(prom_crashk_size)) {

include/asm-powerpc/kexec.h

···
 #define KEXEC_ARCH KEXEC_ARCH_PPC
 #endif
 
-#define HAVE_ARCH_COPY_OLDMEM_PAGE
-
-#ifndef __ASSEMBLY__
-
 #ifdef CONFIG_KEXEC
 
+#ifdef __powerpc64__
+/*
+ * This function is responsible for capturing register states if coming
+ * via panic or invoking dump using sysrq-trigger.
+ */
+static inline void crash_setup_regs(struct pt_regs *newregs,
+					struct pt_regs *oldregs)
+{
+	if (oldregs)
+		memcpy(newregs, oldregs, sizeof(*newregs));
+	else {
+		/* FIXME Merge this with xmon_save_regs ?? */
+		unsigned long tmp1, tmp2;
+		__asm__ __volatile__ (
+			"std    0,0(%2)\n"
+			"std    1,8(%2)\n"
+			"std    2,16(%2)\n"
+			"std    3,24(%2)\n"
+			"std    4,32(%2)\n"
+			"std    5,40(%2)\n"
+			"std    6,48(%2)\n"
+			"std    7,56(%2)\n"
+			"std    8,64(%2)\n"
+			"std    9,72(%2)\n"
+			"std    10,80(%2)\n"
+			"std    11,88(%2)\n"
+			"std    12,96(%2)\n"
+			"std    13,104(%2)\n"
+			"std    14,112(%2)\n"
+			"std    15,120(%2)\n"
+			"std    16,128(%2)\n"
+			"std    17,136(%2)\n"
+			"std    18,144(%2)\n"
+			"std    19,152(%2)\n"
+			"std    20,160(%2)\n"
+			"std    21,168(%2)\n"
+			"std    22,176(%2)\n"
+			"std    23,184(%2)\n"
+			"std    24,192(%2)\n"
+			"std    25,200(%2)\n"
+			"std    26,208(%2)\n"
+			"std    27,216(%2)\n"
+			"std    28,224(%2)\n"
+			"std    29,232(%2)\n"
+			"std    30,240(%2)\n"
+			"std    31,248(%2)\n"
+			"mfmsr  %0\n"
+			"std    %0, 264(%2)\n"
+			"mfctr  %0\n"
+			"std    %0, 280(%2)\n"
+			"mflr   %0\n"
+			"std    %0, 288(%2)\n"
+			"bl     1f\n"
+		"1:     mflr   %1\n"
+			"std    %1, 256(%2)\n"
+			"mtlr   %0\n"
+			"mfxer  %0\n"
+			"std    %0, 296(%2)\n"
+			: "=&r" (tmp1), "=&r" (tmp2)
+			: "b" (newregs));
+	}
+}
+#else
+/*
+ * Provide a dummy definition to avoid build failures. Will remain
+ * empty till crash dump support is enabled.
+ */
+static inline void crash_setup_regs(struct pt_regs *newregs,
+					struct pt_regs *oldregs) { }
+#endif /* !__powerpc64 __ */
+
+#ifndef __ASSEMBLY__
 #define MAX_NOTE_BYTES 1024
 
 #ifdef __powerpc64__
···
 extern int default_machine_kexec_prepare(struct kimage *image);
 extern void default_machine_crash_shutdown(struct pt_regs *regs);
 
-#endif /* !CONFIG_KEXEC */
-
-/*
- * Provide a dummy definition to avoid build failures. Will remain
- * empty till crash dump support is enabled.
- */
-static inline void crash_setup_regs(struct pt_regs *newregs,
-					struct pt_regs *oldregs) { }
 #endif /* ! __ASSEMBLY__ */
+#endif /* CONFIG_KEXEC */
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_KEXEC_H */