powerpc/fadump: Do not allow hot-remove memory from fadump reserved area.

For fadump to work successfully there should not be any holes in reserved
memory ranges where kernel has asked firmware to move the content of old
kernel memory in event of crash. Now that fadump uses CMA for reserved
area, this memory area is now not protected from hot-remove operations
unless it is cma allocated. Hence, fadump service can fail to re-register
after the hot-remove operation, if hot-removed memory belongs to fadump
reserved region. To avoid this make sure that memory from fadump reserved
area is not hot-removable if fadump is registered.

However, if user still wants to remove that memory, he can do so by
manually stopping fadump service before hot-remove operation.

Signed-off-by: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/include/asm/fadump.h b/arch/powerpc/include/asm/fadump.h
index 0a4e37159276cc6631ab4c65290437ba6424501f..188776befaf9b834031f1f04a90ef9ed5b58f1d5 100644 (file)
--- a/arch/powerpc/include/asm/fadump.h
+++ b/arch/powerpc/include/asm/fadump.h
@@ -205,7 +205,7 @@ struct fad_crash_memory_ranges {
        unsigned long long      size;
 };
 
-extern int is_fadump_boot_memory_area(u64 addr, ulong size);
+extern int is_fadump_memory_area(u64 addr, ulong size);
 extern int early_init_dt_scan_fw_dump(unsigned long node,
                const char *uname, int depth, void *data);
 extern int fadump_reserve_mem(void);

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index b7f83d6eb697b3650df490c3f1d2c38ee9afb5f5..45a8d0be1c96daf89ebea7b3c5e10853ee619cb2 100644 (file)
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -183,13 +183,19 @@ int __init early_init_dt_scan_fw_dump(unsigned long node,
 
 /*
  * If fadump is registered, check if the memory provided
- * falls within boot memory area.
+ * falls within boot memory area and reserved memory area.
  */
-int is_fadump_boot_memory_area(u64 addr, ulong size)
+int is_fadump_memory_area(u64 addr, ulong size)
 {
+       u64 d_start = fw_dump.reserve_dump_area_start;
+       u64 d_end = d_start + fw_dump.reserve_dump_area_size;
+
        if (!fw_dump.dump_registered)
                return 0;
 
+       if (((addr + size) > d_start) && (addr <= d_end))
+               return 1;
+
        return (addr + size) > RMA_START && addr <= fw_dump.boot_memory_size;
 }
 

diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 3b881ac66d9a2ae112b046032c89b778f571cf6e..be8a6db3558e5a7bd662355f4cbce7b346ea5cf5 100644 (file)
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -353,8 +353,11 @@ static bool lmb_is_removable(struct drmem_lmb *lmb)
        phys_addr = lmb->base_addr;
 
 #ifdef CONFIG_FA_DUMP
-       /* Don't hot-remove memory that falls in fadump boot memory area */
-       if (is_fadump_boot_memory_area(phys_addr, block_sz))
+       /*
+        * Don't hot-remove memory that falls in fadump boot memory area
+        * and memory that is reserved for capturing old kernel memory.
+        */
+       if (is_fadump_memory_area(phys_addr, block_sz))
                return false;
 #endif