fadump: Register for firmware assisted dump.

On 2012-02-20 11:02:51 Mon, Paul Mackerras wrote:
> On Thu, Feb 16, 2012 at 04:44:30PM +0530, Mahesh J Salgaonkar wrote:
>
> If I have read the code correctly, we are going to get this printk on
> non-pSeries machines or on older pSeries machines, even if the user
> has not put the fadump=on option on the kernel command line.  The
> printk will be annoying since there is no actual error condition.  It
> seems to me that the condition for the printk should include
> fw_dump.fadump_enabled.  In other words you should probably add
>
> 	if (!fw_dump.fadump_enabled)
> 		return 0;
>
> at the beginning of the function.

Hi Paul,

Thanks for pointing it out. Please find the updated patch below.

The existing patches above this (4/10 through 10/10) cleanly applies
on this update.

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

arch/powerpc/include/asm/fadump.h

@@ -48,6 +48,58 @@
 #define FADUMP_HPTE_REGION	0x0002
 #define FADUMP_REAL_MODE_REGION	0x0011
 
+/* Dump request flag */
+#define FADUMP_REQUEST_FLAG	0x00000001
+
+/* FAD commands */
+#define FADUMP_REGISTER		1
+#define FADUMP_UNREGISTER	2
+#define FADUMP_INVALIDATE	3
+
+/* Kernel Dump section info */
+struct fadump_section {
+	u32	request_flag;
+	u16	source_data_type;
+	u16	error_flags;
+	u64	source_address;
+	u64	source_len;
+	u64	bytes_dumped;
+	u64	destination_address;
+};
+
+/* ibm,configure-kernel-dump header. */
+struct fadump_section_header {
+	u32	dump_format_version;
+	u16	dump_num_sections;
+	u16	dump_status_flag;
+	u32	offset_first_dump_section;
+
+	/* Fields for disk dump option. */
+	u32	dd_block_size;
+	u64	dd_block_offset;
+	u64	dd_num_blocks;
+	u32	dd_offset_disk_path;
+
+	/* Maximum time allowed to prevent an automatic dump-reboot. */
+	u32	max_time_auto;
+};
+
+/*
+ * Firmware Assisted dump memory structure. This structure is required for
+ * registering future kernel dump with power firmware through rtas call.
+ *
+ * No disk dump option. Hence disk dump path string section is not included.
+ */
+struct fadump_mem_struct {
+	struct fadump_section_header	header;
+
+	/* Kernel dump sections */
+	struct fadump_section		cpu_state_data;
+	struct fadump_section		hpte_region;
+	struct fadump_section		rmr_region;
+};
+
+/* Firmware-assisted dump configuration details. */
 struct fw_dump {
 	unsigned long	cpu_state_data_size;
 	unsigned long	hpte_region_size;
@@ -62,10 +114,15 @@ struct fw_dump {
 	unsigned long	fadump_enabled:1;
 	unsigned long	fadump_supported:1;
 	unsigned long	dump_active:1;
+	unsigned long	dump_registered:1;
 };
 
 extern int early_init_dt_scan_fw_dump(unsigned long node,
 		const char *uname, int depth, void *data);
 extern int fadump_reserve_mem(void);
+extern int setup_fadump(void);
+extern int is_fadump_active(void);
+#else	/* CONFIG_FA_DUMP */
+static inline int is_fadump_active(void) { return 0; }
 #endif
 #endif

arch/powerpc/kernel/iommu.c

@@ -39,6 +39,7 @@
 #include <asm/pci-bridge.h>
 #include <asm/machdep.h>
 #include <asm/kdump.h>
+#include <asm/fadump.h>
 
 #define DBG(...)
 
@@ -445,7 +446,12 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
 
 static void iommu_table_clear(struct iommu_table *tbl)
 {
-	if (!is_kdump_kernel()) {
+	/*
+	 * In case of firmware assisted dump system goes through clean
+	 * reboot process at the time of system crash. Hence it's safe to
+	 * clear the TCE entries if firmware assisted dump is active.
+	 */
+	if (!is_kdump_kernel() || is_fadump_active()) {
 		/* Clear the table in case firmware left allocations in it */
 		ppc_md.tce_free(tbl, tbl->it_offset, tbl->it_size);
 		return;

arch/powerpc/mm/hash_utils_64.c

@@ -55,6 +55,7 @@
 #include <asm/spu.h>
 #include <asm/udbg.h>
 #include <asm/code-patching.h>
+#include <asm/fadump.h>
 
 #ifdef DEBUG
 #define DBG(fmt...) udbg_printf(fmt)
@@ -625,6 +626,16 @@ static void __init htab_initialize(void)
 		/* Using a hypervisor which owns the htab */
 		htab_address = NULL;
 		_SDR1 = 0; 
+#ifdef CONFIG_FA_DUMP
+		/*
+		 * If firmware assisted dump is active firmware preserves
+		 * the contents of htab along with entire partition memory.
+		 * Clear the htab if firmware assisted dump is active so
+		 * that we dont end up using old mappings.
+		 */
+		if (is_fadump_active() && ppc_md.hpte_clear_all)
+			ppc_md.hpte_clear_all();
+#endif
 	} else {
 		/* Find storage for the HPT.  Must be contiguous in
 		 * the absolute address space. On cell we want it to be