x86: cpuid: allow querying %ecx-sensitive CPUID levels (2347d933) · Commits · 戴 / test

arch/x86/kernel/cpuid.c

+20 −25

Original line number	Diff line number	Diff line
		/* ----------------------------------------------------------------------- *
		*
		* Copyright 2000 H. Peter Anvin - All Rights Reserved
		* Copyright 2000-2008 H. Peter Anvin - All Rights Reserved
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License as published by
		@@ -17,6 +17,10 @@
		* and then read in chunks of 16 bytes. A larger size means multiple
		* reads of consecutive levels.
		*
		* The lower 32 bits of the file position is used as the incoming %eax,
		* and the upper 32 bits of the file position as the incoming %ecx,
		* the latter intended for "counting" eax levels like eax=4.
		*
		* This driver uses /dev/cpu/%d/cpuid where %d is the minor number, and on
		* an SMP box will direct the access to CPU %d.
		*/
		@@ -43,27 +47,16 @@

		static struct class *cpuid_class;

		struct cpuid_command {
		u32 reg;
		u32 *data;
		struct cpuid_regs {
		u32 eax, ebx, ecx, edx;
		};

		static void cpuid_smp_cpuid(void *cmd_block)
		{
		struct cpuid_command *cmd = cmd_block;

		cpuid(cmd->reg, &cmd->data[0], &cmd->data[1], &cmd->data[2],
		&cmd->data[3]);
		}

		static inline void do_cpuid(int cpu, u32 reg, u32 * data)
		{
		struct cpuid_command cmd;

		cmd.reg = reg;
		cmd.data = data;
		struct cpuid_regs cmd = (struct cpuid_regs )cmd_block;

		smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
		cpuid_count(cmd->eax, cmd->ecx,
		&cmd->eax, &cmd->ebx, &cmd->ecx, &cmd->edx);
		}

		static loff_t cpuid_seek(struct file *file, loff_t offset, int orig)
		@@ -93,19 +86,21 @@ static ssize_t cpuid_read(struct file file, char __user buf,
		size_t count, loff_t * ppos)
		{
		char __user *tmp = buf;
		u32 data[4];
		u32 reg = *ppos;
		struct cpuid_regs cmd;
		int cpu = iminor(file->f_path.dentry->d_inode);
		u64 pos = *ppos;

		if (count % 16)
		return -EINVAL; /* Invalid chunk size */

		for (; count; count -= 16) {
		do_cpuid(cpu, reg, data);
		if (copy_to_user(tmp, &data, 16))
		cmd.eax = pos;
		cmd.ecx = pos >> 32;
		smp_call_function_single(cpu, cpuid_smp_cpuid, &cmd, 1, 1);
		if (copy_to_user(tmp, &cmd, 16))
		return -EFAULT;
		tmp += 16;
		*ppos = reg++;
		*ppos = ++pos;
		}

		return tmp - buf;

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