[PATCH v3 3/3] m68k: rework BI_VIRT_RNG_SEED as BI_RNG_SEED

["Jason A. Donenfeld" <Jason@zx2c4.com>]

This is useful on !virt platforms for kexec, so change things from
BI_VIRT_RNG_SEED to be BI_RNG_SEED, and simply remove BI_VIRT_RNG_SEED
because it only ever lasted one release, and nothing is broken by not
having it. At the same time, keep a comment noting that it's been
removed, so that ID isn't reused.

Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Laurent Vivier <laurent@vivier.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 arch/m68k/include/asm/bootinfo.h           |  2 ++
 arch/m68k/include/uapi/asm/bootinfo-virt.h |  9 ++-------
 arch/m68k/include/uapi/asm/bootinfo.h      |  8 +++++++-
 arch/m68k/kernel/process.c                 | 10 ++++++++++
 arch/m68k/kernel/setup_mm.c                | 14 ++++++++++++++
 arch/m68k/virt/config.c                    | 21 ---------------------
 6 files changed, 35 insertions(+), 29 deletions(-)

diff --git a/arch/m68k/include/asm/bootinfo.h b/arch/m68k/include/asm/bootinfo.h
index 81c91af8ec6c..71103530839a 100644
--- a/arch/m68k/include/asm/bootinfo.h
+++ b/arch/m68k/include/asm/bootinfo.h
@@ -28,6 +28,8 @@ void process_uboot_commandline(char *commandp, int size);
 static inline void process_uboot_commandline(char *commandp, int size) {}
 #endif
 
+extern const struct bi_record *rng_seed_record;
+
 #endif /* __ASSEMBLY__ */
 
 
diff --git a/arch/m68k/include/uapi/asm/bootinfo-virt.h b/arch/m68k/include/uapi/asm/bootinfo-virt.h
index b091ee9b06e0..4032a14cc5c2 100644
--- a/arch/m68k/include/uapi/asm/bootinfo-virt.h
+++ b/arch/m68k/include/uapi/asm/bootinfo-virt.h
@@ -13,13 +13,8 @@
 #define BI_VIRT_VIRTIO_BASE	0x8004
 #define BI_VIRT_CTRL_BASE	0x8005
 
-/*
- * A random seed used to initialize the RNG. Record format:
- *
- *   - length       [ 2 bytes, 16-bit big endian ]
- *   - seed data    [ `length` bytes, padded to preserve 2-byte alignment ]
- */
-#define BI_VIRT_RNG_SEED	0x8006
+/* No longer used -- replaced with BI_RNG_SEED -- but don't reuse this index:
+ * 	#define BI_VIRT_RNG_SEED	0x8006 */
 
 #define VIRT_BOOTI_VERSION	MK_BI_VERSION(2, 0)
 
diff --git a/arch/m68k/include/uapi/asm/bootinfo.h b/arch/m68k/include/uapi/asm/bootinfo.h
index 95ecf3ae4c49..387f2a61e908 100644
--- a/arch/m68k/include/uapi/asm/bootinfo.h
+++ b/arch/m68k/include/uapi/asm/bootinfo.h
@@ -64,7 +64,13 @@ struct mem_info {
 					/* (struct mem_info) */
 #define BI_COMMAND_LINE		0x0007	/* kernel command line parameters */
 					/* (string) */
-
+/*
+ * A random seed used to initialize the RNG. Record format:
+ *
+ *   - length       [ 2 bytes, 16-bit big endian ]
+ *   - seed data    [ `length` bytes, padded to preserve 2-byte alignment ]
+ */
+#define BI_RNG_SEED		0x0008
 
     /*
      *  Linux/m68k Architectures (BI_MACHTYPE)
diff --git a/arch/m68k/kernel/process.c b/arch/m68k/kernel/process.c
index 2cb4a61bcfac..f40cc6f47f09 100644
--- a/arch/m68k/kernel/process.c
+++ b/arch/m68k/kernel/process.c
@@ -29,6 +29,7 @@
 #include <linux/reboot.h>
 #include <linux/init_task.h>
 #include <linux/mqueue.h>
+#include <linux/random.h>
 #include <linux/rcupdate.h>
 #include <linux/syscalls.h>
 #include <linux/uaccess.h>
@@ -36,6 +37,7 @@
 #include <asm/traps.h>
 #include <asm/machdep.h>
 #include <asm/setup.h>
+#include <asm/bootinfo.h>
 
 
 asmlinkage void ret_from_fork(void);
@@ -51,8 +53,16 @@ void arch_cpu_idle(void)
 #endif
 }
 
+const struct bi_record *rng_seed_record;
+
 void machine_restart(char * __unused)
 {
+	if (rng_seed_record && rng_seed_record->size > sizeof(*rng_seed_record) + 2) {
+		u16 len = rng_seed_record->size - sizeof(*rng_seed_record) - 2;
+		get_random_bytes((u8 *)rng_seed_record->data + 2, len);
+		*(u16 *)rng_seed_record->data = cpu_to_be16(len);
+	}
+
 	if (mach_reset)
 		mach_reset();
 	for (;;);
diff --git a/arch/m68k/kernel/setup_mm.c b/arch/m68k/kernel/setup_mm.c
index 7e7ef67cff8b..eacf734bea0e 100644
--- a/arch/m68k/kernel/setup_mm.c
+++ b/arch/m68k/kernel/setup_mm.c
@@ -25,6 +25,7 @@
 #include <linux/module.h>
 #include <linux/nvram.h>
 #include <linux/initrd.h>
+#include <linux/random.h>
 
 #include <asm/bootinfo.h>
 #include <asm/byteorder.h>
@@ -151,6 +152,19 @@ static void __init m68k_parse_bootinfo(const struct bi_record *record)
 				sizeof(m68k_command_line));
 			break;
 
+		case BI_RNG_SEED: {
+			u16 len = be16_to_cpup(data);
+			add_bootloader_randomness(data + 2, len);
+			/*
+			 * Zero the data to preserve forward secrecy, and zero the
+			 * length to prevent kexec from using it.
+			 */
+			memzero_explicit((void *)data, len + 2);
+			/* Store a reference to be filled in on reboot. */
+			rng_seed_record = record;
+			break;
+		}
+
 		default:
 			if (MACH_IS_AMIGA)
 				unknown = amiga_parse_bootinfo(record);
diff --git a/arch/m68k/virt/config.c b/arch/m68k/virt/config.c
index d4627840e35b..632ba200ad42 100644
--- a/arch/m68k/virt/config.c
+++ b/arch/m68k/virt/config.c
@@ -2,7 +2,6 @@
 
 #include <linux/reboot.h>
 #include <linux/serial_core.h>
-#include <linux/random.h>
 #include <clocksource/timer-goldfish.h>
 
 #include <asm/bootinfo.h>
@@ -45,18 +44,10 @@ static void virt_halt(void)
 		;
 }
 
-static const struct bi_record *rng_seed_record;
-
 static void virt_reset(void)
 {
 	void __iomem *base = (void __iomem *)virt_bi_data.ctrl.mmio;
 
-	if (rng_seed_record && rng_seed_record->size > sizeof(*rng_seed_record) + 2) {
-		u16 len = rng_seed_record->size - sizeof(*rng_seed_record) - 2;
-		get_random_bytes((u8 *)rng_seed_record->data + 2, len);
-		*(u16 *)rng_seed_record->data = cpu_to_be16(len);
-	}
-
 	iowrite32be(CMD_RESET, base + VIRT_CTRL_REG_CMD);
 	local_irq_disable();
 	while (1)
@@ -101,18 +92,6 @@ int __init virt_parse_bootinfo(const struct bi_record *record)
 		data += 4;
 		virt_bi_data.virtio.irq = be32_to_cpup(data);
 		break;
-	case BI_VIRT_RNG_SEED: {
-		u16 len = be16_to_cpup(data);
-		add_bootloader_randomness(data + 2, len);
-		/*
-		 * Zero the data to preserve forward secrecy, and zero the
-		 * length to prevent kexec from using it.
-		 */
-		memzero_explicit((void *)data, len + 2);
-		/* Store a reference to be filled in on reboot. */
-		rng_seed_record = record;
-		break;
-	}
 	default:
 		unknown = 1;
 		break;
-- 
2.37.3