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Commit 13bfd47a authored by Qiaowei Ren's avatar Qiaowei Ren Committed by Ingo Molnar
Browse files

x86/tboot: Provide debugfs interfaces to access TXT log 



These logs come from tboot (Trusted Boot, an open source,
pre-kernel/VMM module that uses Intel TXT to perform a
measured and verified launch of an OS kernel/VMM.).

Signed-off-by: default avatarQiaowei Ren <qiaowei.ren@intel.com>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Cc: Gang Wei <gang.wei@intel.com>
Link: http://lkml.kernel.org/r/1372053333-21788-1-git-send-email-qiaowei.ren@intel.com


[ Beautified the code a bit. ]
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 5a802e15

arch/x86/kernel/tboot.c

+73 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/pfn.h>

#include <linux/mm.h>

#include <linux/tboot.h>

#include <linux/debugfs.h>



#include <asm/realmode.h>

#include <asm/processor.h>
@@ -338,6 +339,73 @@ static struct notifier_block tboot_cpu_notifier __cpuinitdata = 
	.notifier_call = tboot_cpu_callback,

};



#ifdef CONFIG_DEBUG_FS



#define TBOOT_LOG_UUID	{ 0x26, 0x25, 0x19, 0xc0, 0x30, 0x6b, 0xb4, 0x4d, \

			  0x4c, 0x84, 0xa3, 0xe9, 0x53, 0xb8, 0x81, 0x74 }



#define TBOOT_SERIAL_LOG_ADDR	0x60000

#define TBOOT_SERIAL_LOG_SIZE	0x08000

#define LOG_MAX_SIZE_OFF	16

#define LOG_BUF_OFF		24



static uint8_t tboot_log_uuid[16] = TBOOT_LOG_UUID;



static ssize_t tboot_log_read(struct file *file, char __user *user_buf, size_t count, loff_t *ppos)

{

	void __iomem *log_base;

	u8 log_uuid[16];

	u32 max_size;

	void *kbuf;

	int ret = -EFAULT;



	log_base = ioremap_nocache(TBOOT_SERIAL_LOG_ADDR, TBOOT_SERIAL_LOG_SIZE);

	if (!log_base)

		return ret;



	memcpy_fromio(log_uuid, log_base, sizeof(log_uuid));

	if (memcmp(&tboot_log_uuid, log_uuid, sizeof(log_uuid)))

		goto err_iounmap;



	max_size = readl(log_base + LOG_MAX_SIZE_OFF);

	if (*ppos >= max_size) {

		ret = 0;

		goto err_iounmap;

	}



	if (*ppos + count > max_size)

		count = max_size - *ppos;



	kbuf = kmalloc(count, GFP_KERNEL);

	if (!kbuf) {

		ret = -ENOMEM;

		goto err_iounmap;

	}



	memcpy_fromio(kbuf, log_base + LOG_BUF_OFF + *ppos, count);

	if (copy_to_user(user_buf, kbuf, count))

		goto err_kfree;



	*ppos += count;



	ret = count;



err_kfree:

	kfree(kbuf);



err_iounmap:

	iounmap(log_base);



	return ret;

}



static const struct file_operations tboot_log_fops = {

	.read	= tboot_log_read,

	.llseek	= default_llseek,

};



#endif /* CONFIG_DEBUG_FS */



static __init int tboot_late_init(void)

{

	if (!tboot_enabled())
@@ -348,6 +416,11 @@ static __init int tboot_late_init(void) 
	atomic_set(&ap_wfs_count, 0);

	register_hotcpu_notifier(&tboot_cpu_notifier);



#ifdef CONFIG_DEBUG_FS

	debugfs_create_file("tboot_log", S_IRUSR,

			arch_debugfs_dir, NULL, &tboot_log_fops);

#endif



	acpi_os_set_prepare_sleep(&tboot_sleep);

	return 0;

}