sysctl: add boot_reason and cold_boot sysctl entries for arm64

Define boot_reason and cold_boot variables in the arm64 version
of setup.c so that arm64 targets can export the boot_reason and
cold_boot sysctl entries.

This feature is required by the qpnp-power-on driver.

Change-Id: Id2d4ff5b8caa2e6a35d4ac61e338963d602c8b84
Signed-off-by: David Collins <collinsd@codeaurora.org>
[osvaldob: resolved trival merge conflicts]
Signed-off-by: Osvaldo Banuelos <osvaldob@codeaurora.org>

Documentation/sysctl/kernel.txt

@@ -23,8 +23,10 @@ show up in /proc/sys/kernel:
 - auto_msgmni
 - bootloader_type	     [ X86 only ]
 - bootloader_version	     [ X86 only ]
+- boot_reason		     [ ARM and ARM64 only ]
 - callhome		     [ S390 only ]
 - cap_last_cap
+- cold_boot		     [ ARM and ARM64 only ]
 - core_pattern
 - core_pipe_limit
 - core_uses_pid
@@ -158,6 +160,19 @@ Documentation/x86/boot.txt for additional information.
 
 ==============================================================
 
+boot_reason:
+
+ARM and ARM64 -- reason for device boot
+
+A single bit will be set in the unsigned integer value to identify the
+reason the device was booted / powered on. The value will be zero if this
+feature is not supported on the ARM device being booted.
+
+See the power-on-status field definitions in
+Documentation/arm/msm/boot.txt for Qualcomm's family of devices.
+
+==============================================================
+
 callhome:
 
 Controls the kernel's callhome behavior in case of a kernel panic.
@@ -178,6 +193,16 @@ cap_last_cap
 Highest valid capability of the running kernel.  Exports
 CAP_LAST_CAP from the kernel.
 
+===============================================================
+
+cold_boot
+
+ARM and ARM64 -- indicator for system cold boot
+
+A single bit will be set in the unsigned integer value to identify
+whether the device was booted from a cold or warm state. Zero
+indicating a warm boot and one indicating a cold boot.
+
 ==============================================================
 
 core_pattern:

arch/arm64/include/asm/processor.h

@@ -49,6 +49,9 @@ extern phys_addr_t arm64_dma_phys_limit;
 #define ARCH_LOW_ADDRESS_LIMIT	(arm64_dma_phys_limit - 1)
 #endif /* __KERNEL__ */
 
+extern unsigned int boot_reason;
+extern unsigned int cold_boot;
+
 struct debug_info {
 	/* Have we suspended stepping by a debugger? */
 	int			suspended_step;

arch/arm64/kernel/setup.c

@@ -64,6 +64,12 @@
 #include <asm/efi.h>
 #include <asm/xen/hypervisor.h>
 
+unsigned int boot_reason;
+EXPORT_SYMBOL(boot_reason);
+
+unsigned int cold_boot;
+EXPORT_SYMBOL(cold_boot);
+
 static const char *machine_name;
 phys_addr_t __fdt_pointer __initdata;
 

kernel/sysctl.c

@@ -1173,6 +1173,27 @@ static struct ctl_table kern_table[] = {
 		.extra2		= &one,
 	},
 #endif
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+	{
+		.procname	= "boot_reason",
+		.data		= &boot_reason,
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+
+	{
+		.procname	= "cold_boot",
+		.data		= &cold_boot,
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+#endif
+/*
+ * NOTE: do not add new entries to this table unless you have read
+ * Documentation/sysctl/ctl_unnumbered.txt
+ */
 	{ }
 };