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x86/tboot: Provide debugfs interfaces to access TXT log

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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: Qiaowei Ren <qiaowei.ren@intel.com>
Acked-by: H. 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Qiaowei Ren 2013-06-24 13:55:33 +08:00 committed by Ingo Molnar
parent 5a802e1530
commit 13bfd47a0e
1 changed files with 73 additions and 0 deletions
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73
arch/x86/kernel/tboot.c
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@ -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;
}