[GIT PULL] x86/debug changes for v3.11

From: Ingo Molnar
Date: Mon Jul 01 2013 - 06:10:10 EST


Linus,

Please pull the latest x86-debug-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-debug-for-linus

HEAD: 13bfd47a0ef68fc8b21e67873dbdf269c7db6b59 x86/tboot: Provide debugfs interfaces to access TXT log

Misc debuggability improvements:

- Optimize the x86 CPU register printout a bit

- Expose the tboot TXT log via debugfs

- Small do_debug() cleanup

Thanks,

Ingo

------------------>
Dave Jones (1):
x86/debug: Only print out DR registers if they are not power-on defaults

Qiaowei Ren (1):
x86/tboot: Provide debugfs interfaces to access TXT log

Rusty Russell (1):
x86: Remove weird PTR_ERR() in do_debug


arch/x86/kernel/process_32.c | 11 +++++--
arch/x86/kernel/process_64.c | 9 +++++-
arch/x86/kernel/tboot.c | 73 ++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kernel/traps.c | 2 +-
4 files changed, 90 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 7305f7d..f84cfd1 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -110,11 +110,16 @@ void __show_regs(struct pt_regs *regs, int all)
get_debugreg(d1, 1);
get_debugreg(d2, 2);
get_debugreg(d3, 3);
- printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
- d0, d1, d2, d3);
-
get_debugreg(d6, 6);
get_debugreg(d7, 7);
+
+ /* Only print out debug registers if they are in their non-default state. */
+ if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+ (d6 == DR6_RESERVED) && (d7 == 0x400))
+ return;
+
+ printk(KERN_DEFAULT "DR0: %08lx DR1: %08lx DR2: %08lx DR3: %08lx\n",
+ d0, d1, d2, d3);
printk(KERN_DEFAULT "DR6: %08lx DR7: %08lx\n",
d6, d7);
}
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 355ae06..a8b9abc 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -105,11 +105,18 @@ void __show_regs(struct pt_regs *regs, int all)
get_debugreg(d0, 0);
get_debugreg(d1, 1);
get_debugreg(d2, 2);
- printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
get_debugreg(d3, 3);
get_debugreg(d6, 6);
get_debugreg(d7, 7);
+
+ /* Only print out debug registers if they are in their non-default state. */
+ if ((d0 == 0) && (d1 == 0) && (d2 == 0) && (d3 == 0) &&
+ (d6 == DR6_RESERVED) && (d7 == 0x400))
+ return;
+
+ printk(KERN_DEFAULT "DR0: %016lx DR1: %016lx DR2: %016lx\n", d0, d1, d2);
printk(KERN_DEFAULT "DR3: %016lx DR6: %016lx DR7: %016lx\n", d3, d6, d7);
+
}

void release_thread(struct task_struct *dead_task)
diff --git a/arch/x86/kernel/tboot.c b/arch/x86/kernel/tboot.c
index f84fe00..3ff42d2 100644
--- a/arch/x86/kernel/tboot.c
+++ b/arch/x86/kernel/tboot.c
@@ -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;
}
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 772e2a8..9340dfb 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -437,7 +437,7 @@ dotraplinkage void __kprobes do_debug(struct pt_regs *regs, long error_code)
/* Store the virtualized DR6 value */
tsk->thread.debugreg6 = dr6;

- if (notify_die(DIE_DEBUG, "debug", regs, PTR_ERR(&dr6), error_code,
+ if (notify_die(DIE_DEBUG, "debug", regs, (long)&dr6, error_code,
SIGTRAP) == NOTIFY_STOP)
goto exit;

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