powerpc/dscr: Add some in-code documentation (d3cb06e0) · Commits · 戴 / test

arch/powerpc/include/asm/processor.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -295,6 +295,15 @@ struct thread_struct {
		#endif
		#ifdef CONFIG_PPC64
		unsigned long dscr;
		/*
		* This member element dscr_inherit indicates that the process
		* has explicitly attempted and changed the DSCR register value
		* for itself. Hence kernel wont use the default CPU DSCR value
		* contained in the PACA structure anymore during process context
		* switch. Once this variable is set, this behaviour will also be
		* inherited to all the children of this process from that point
		* onwards.
		*/
		int dscr_inherit;
		unsigned long ppr; /* used to save/restore SMT priority */
		#endif

arch/powerpc/kernel/sysfs.c

+38 −0

Original line number	Diff line number	Diff line
		@@ -496,13 +496,34 @@ static DEVICE_ATTR(spurr, 0400, show_spurr, NULL);
		static DEVICE_ATTR(purr, 0400, show_purr, store_purr);
		static DEVICE_ATTR(pir, 0400, show_pir, NULL);

		/*
		* This is the system wide DSCR register default value. Any
		* change to this default value through the sysfs interface
		* will update all per cpu DSCR default values across the
		* system stored in their respective PACA structures.
		*/
		static unsigned long dscr_default;

		/**
		* read_dscr() - Fetch the cpu specific DSCR default
		* @val: Returned cpu specific DSCR default value
		*
		* This function returns the per cpu DSCR default value
		* for any cpu which is contained in it's PACA structure.
		*/
		static void read_dscr(void *val)
		{
		(unsigned long )val = get_paca()->dscr_default;
		}


		/**
		* write_dscr() - Update the cpu specific DSCR default
		* @val: New cpu specific DSCR default value to update
		*
		* This function updates the per cpu DSCR default value
		* for any cpu which is contained in it's PACA structure.
		*/
		static void write_dscr(void *val)
		{
		get_paca()->dscr_default = (unsigned long )val;
		@@ -520,12 +541,29 @@ static void add_write_permission_dev_attr(struct device_attribute *attr)
		attr->attr.mode \|= 0200;
		}

		/**
		* show_dscr_default() - Fetch the system wide DSCR default
		* @dev: Device structure
		* @attr: Device attribute structure
		* @buf: Interface buffer
		*
		* This function returns the system wide DSCR default value.
		*/
		static ssize_t show_dscr_default(struct device *dev,
		struct device_attribute attr, char buf)
		{
		return sprintf(buf, "%lx\n", dscr_default);
		}

		/**
		* store_dscr_default() - Update the system wide DSCR default
		* @dev: Device structure
		* @attr: Device attribute structure
		* @buf: Interface buffer
		* @count: Size of the update
		*
		* This function updates the system wide DSCR default value.
		*/
		static ssize_t __used store_dscr_default(struct device *dev,
		struct device_attribute attr, const char buf,
		size_t count)

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