[PATCH v2] x86, boot: add hex output for debugging

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* [PATCH v2] x86, boot: add hex output for debugging
@ 2014-10-31 20:58 Kees Cook
  2014-10-31 21:34 ` Andy Lutomirski
  2014-10-31 23:31 ` Yinghai Lu
  0 siblings, 2 replies; 5+ messages in thread
From: Kees Cook @ 2014-10-31 20:58 UTC (permalink / raw)
  To: linux-kernel
  Cc: H. Peter Anvin, Thomas Gleixner, Ingo Molnar, x86, Vivek Goyal,
	Josh Triplett, Junjie Mao, Andi Kleen

This is useful for reporting various addresses or other values while
debugging early boot. For example, when CONFIG_X86_VERBOSE_BOOTUP is set,
this is now visible at boot time:

	early console in setup code
	early console in decompress_kernel
	input_data: 0x0000000001e1526e
	input_len: 0x0000000000732236
	output: 0x0000000001000000
	output_len: 0x0000000001535640
	run_size: 0x00000000021fb000
	KASLR using RDTSC...

Signed-off-by: Kees Cook <keescook@chromium.org>
---
Since this displays run_size, this patch depends on Junjie Mao's patch
"x86, kaslr: Prevent .bss from overlaping initrd"

---
 arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++
 arch/x86/boot/compressed/misc.h | 11 +++++++++++
 2 files changed, 35 insertions(+)

diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 30dd59a9f0b4..2aefc8a63655 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -220,6 +220,23 @@ void __putstr(const char *s)
 	outb(0xff & (pos >> 1), vidport+1);
 }
 
+void __puthex(unsigned long value)
+{
+	char alpha[2] = "0";
+	int bits;
+
+	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
+		unsigned long digit = (value >> bits) & 0xf;
+
+		if (digit < 0xA)
+			alpha[0] = '0' + digit;
+		else
+			alpha[0] = 'a' + (digit - 0xA);
+
+		__putstr(alpha);
+	}
+}
+
 static void error(char *x)
 {
 	error_putstr("\n\n");
@@ -382,6 +399,13 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
 	free_mem_ptr     = heap;	/* Heap */
 	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
 
+	/* Report initial kernel position details. */
+	debug_putaddr(input_data);
+	debug_putaddr(input_len);
+	debug_putaddr(output);
+	debug_putaddr(output_len);
+	debug_putaddr(run_size);
+
 	/*
 	 * The memory hole needed for the kernel is the larger of either
 	 * the entire decompressed kernel plus relocation table, or the
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 24e3e569a13c..70472ae98a73 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -34,16 +34,27 @@ extern memptr free_mem_ptr;
 extern memptr free_mem_end_ptr;
 extern struct boot_params *real_mode;		/* Pointer to real-mode data */
 void __putstr(const char *s);
+void __puthex(unsigned long value);
 #define error_putstr(__x)  __putstr(__x)
+#define error_puthex(__x)  __puthex(__x)
 
 #ifdef CONFIG_X86_VERBOSE_BOOTUP
 
 #define debug_putstr(__x)  __putstr(__x)
+#define debug_puthex(__x)  __puthex(__x)
+#define debug_putaddr(__x) { \
+		debug_putstr(#__x ": 0x"); \
+		debug_puthex((unsigned long)(__x)); \
+		debug_putstr("\n"); \
+	}
 
 #else
 
 static inline void debug_putstr(const char *s)
 { }
+static inline void debug_puthex(const char *s)
+{ }
+#define debug_putaddr(x) /* */
 
 #endif
 
-- 
1.9.1


-- 
Kees Cook
Chrome OS Security

^ permalink raw reply related	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] x86, boot: add hex output for debugging
  2014-10-31 20:58 [PATCH v2] x86, boot: add hex output for debugging Kees Cook
@ 2014-10-31 21:34 ` Andy Lutomirski
  2014-10-31 23:31 ` Yinghai Lu
  1 sibling, 0 replies; 5+ messages in thread
From: Andy Lutomirski @ 2014-10-31 21:34 UTC (permalink / raw)
  To: Kees Cook, linux-kernel
  Cc: H. Peter Anvin, Thomas Gleixner, Ingo Molnar, x86, Vivek Goyal,
	Josh Triplett, Junjie Mao, Andi Kleen

On 10/31/2014 01:58 PM, Kees Cook wrote:
> This is useful for reporting various addresses or other values while
> debugging early boot. For example, when CONFIG_X86_VERBOSE_BOOTUP is set,
> this is now visible at boot time:
> 
> 	early console in setup code
> 	early console in decompress_kernel
> 	input_data: 0x0000000001e1526e
> 	input_len: 0x0000000000732236
> 	output: 0x0000000001000000
> 	output_len: 0x0000000001535640
> 	run_size: 0x00000000021fb000
> 	KASLR using RDTSC...
> 
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Since this displays run_size, this patch depends on Junjie Mao's patch
> "x86, kaslr: Prevent .bss from overlaping initrd"
> 

This reminds me: I have a patch to add an early-boot IDT that can report
#GP and #PF in this code if CONFIG_X86_VERBOSE_BOOTUP is set.  I can
dust it off if anyone thinks it'll be useful, even though I won't end up
needed it for the thing I wrote it for.

--Andy

> ---
>  arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++
>  arch/x86/boot/compressed/misc.h | 11 +++++++++++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
> index 30dd59a9f0b4..2aefc8a63655 100644
> --- a/arch/x86/boot/compressed/misc.c
> +++ b/arch/x86/boot/compressed/misc.c
> @@ -220,6 +220,23 @@ void __putstr(const char *s)
>  	outb(0xff & (pos >> 1), vidport+1);
>  }
>  
> +void __puthex(unsigned long value)
> +{
> +	char alpha[2] = "0";
> +	int bits;
> +
> +	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {
> +		unsigned long digit = (value >> bits) & 0xf;
> +
> +		if (digit < 0xA)
> +			alpha[0] = '0' + digit;
> +		else
> +			alpha[0] = 'a' + (digit - 0xA);
> +
> +		__putstr(alpha);
> +	}
> +}
> +
>  static void error(char *x)
>  {
>  	error_putstr("\n\n");
> @@ -382,6 +399,13 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
>  	free_mem_ptr     = heap;	/* Heap */
>  	free_mem_end_ptr = heap + BOOT_HEAP_SIZE;
>  
> +	/* Report initial kernel position details. */
> +	debug_putaddr(input_data);
> +	debug_putaddr(input_len);
> +	debug_putaddr(output);
> +	debug_putaddr(output_len);
> +	debug_putaddr(run_size);
> +
>  	/*
>  	 * The memory hole needed for the kernel is the larger of either
>  	 * the entire decompressed kernel plus relocation table, or the
> diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
> index 24e3e569a13c..70472ae98a73 100644
> --- a/arch/x86/boot/compressed/misc.h
> +++ b/arch/x86/boot/compressed/misc.h
> @@ -34,16 +34,27 @@ extern memptr free_mem_ptr;
>  extern memptr free_mem_end_ptr;
>  extern struct boot_params *real_mode;		/* Pointer to real-mode data */
>  void __putstr(const char *s);
> +void __puthex(unsigned long value);
>  #define error_putstr(__x)  __putstr(__x)
> +#define error_puthex(__x)  __puthex(__x)
>  
>  #ifdef CONFIG_X86_VERBOSE_BOOTUP
>  
>  #define debug_putstr(__x)  __putstr(__x)
> +#define debug_puthex(__x)  __puthex(__x)
> +#define debug_putaddr(__x) { \
> +		debug_putstr(#__x ": 0x"); \
> +		debug_puthex((unsigned long)(__x)); \
> +		debug_putstr("\n"); \
> +	}
>  
>  #else
>  
>  static inline void debug_putstr(const char *s)
>  { }
> +static inline void debug_puthex(const char *s)
> +{ }
> +#define debug_putaddr(x) /* */
>  
>  #endif
>  
> 


^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] x86, boot: add hex output for debugging
  2014-10-31 20:58 [PATCH v2] x86, boot: add hex output for debugging Kees Cook
  2014-10-31 21:34 ` Andy Lutomirski
@ 2014-10-31 23:31 ` Yinghai Lu
  2014-10-31 23:45   ` Josh Triplett
  1 sibling, 1 reply; 5+ messages in thread
From: Yinghai Lu @ 2014-10-31 23:31 UTC (permalink / raw)
  To: Kees Cook
  Cc: Linux Kernel Mailing List, H. Peter Anvin, Thomas Gleixner,
	Ingo Molnar, the arch/x86 maintainers, Vivek Goyal, Josh Triplett,
	Junjie Mao, Andi Kleen

[-- Attachment #1: Type: text/plain, Size: 4073 bytes --]

On Fri, Oct 31, 2014 at 1:58 PM, Kees Cook <keescook@chromium.org> wrote:
> This is useful for reporting various addresses or other values while
> debugging early boot. For example, when CONFIG_X86_VERBOSE_BOOTUP is set,
> this is now visible at boot time:
>
>         early console in setup code
>         early console in decompress_kernel
>         input_data: 0x0000000001e1526e
>         input_len: 0x0000000000732236
>         output: 0x0000000001000000
>         output_len: 0x0000000001535640
>         run_size: 0x00000000021fb000
>         KASLR using RDTSC...
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Since this displays run_size, this patch depends on Junjie Mao's patch
> "x86, kaslr: Prevent .bss from overlaping initrd"
>
> ---
>  arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++
>  arch/x86/boot/compressed/misc.h | 11 +++++++++++
>  2 files changed, 35 insertions(+)
...

We can reuse printf.c in arch/x86/boot.

I had attached one in local tree for a while. or even sent it before
several years ago.

Thanks

Yinghai


Subject: [PATCH] x86, boot: Add printf support for early console in
compressed/misc.c

Reuse printf.c in x86 setup code.
And print out decompress_kernel input and output info.

Later decompresser code could print out more info for debug info.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/x86/boot/compressed/Makefile |    2 +-
 arch/x86/boot/compressed/misc.c   |    8 ++++++++
 arch/x86/boot/compressed/misc.h   |    7 +++++++
 arch/x86/boot/compressed/printf.c |    5 +++++
 4 files changed, 21 insertions(+), 1 deletion(-)

Index: linux-2.6/arch/x86/boot/compressed/Makefile
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/Makefile
+++ linux-2.6/arch/x86/boot/compressed/Makefile
@@ -28,7 +28,7 @@ HOST_EXTRACFLAGS += -I$(srctree)/tools/i

 vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \
     $(obj)/string.o $(obj)/cmdline.o \
-    $(obj)/piggy.o $(obj)/cpuflags.o
+    $(obj)/printf.o $(obj)/piggy.o $(obj)/cpuflags.o

 vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
 vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/aslr.o
Index: linux-2.6/arch/x86/boot/compressed/printf.c
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/boot/compressed/printf.c
@@ -0,0 +1,5 @@
+#include "misc.h"
+
+#define puts(__x)  __putstr(__x)
+
+#include "../printf.c"
Index: linux-2.6/arch/x86/boot/compressed/misc.c
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/misc.c
+++ linux-2.6/arch/x86/boot/compressed/misc.c
@@ -390,6 +390,14 @@ asmlinkage __visible void *decompress_ke
     output = choose_kernel_location(input_data, input_len,
                     output, output_len);

+    debug_putstr("decompress_kernel:\n");
+    debug_printf("  input: [0x%lx-0x%lx], output: 0x%lx, heap:
[0x%lx-0x%lx]\n",
+         (unsigned long)input_data,
+         (unsigned long)input_data + input_len - 1,
+         (unsigned long)output,
+         (unsigned long)heap,
+         (unsigned long)heap + BOOT_HEAP_SIZE - 1);
+
     /* Validate memory location choices. */
     if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
         error("Destination address inappropriately aligned");
Index: linux-2.6/arch/x86/boot/compressed/misc.h
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/misc.h
+++ linux-2.6/arch/x86/boot/compressed/misc.h
@@ -36,14 +36,21 @@ extern struct boot_params *real_mode;        /
 void __putstr(const char *s);
 #define error_putstr(__x)  __putstr(__x)

+/* printf.c */
+int sprintf(char *buf, const char *fmt, ...);
+int printf(const char *fmt, ...);
+
 #ifdef CONFIG_X86_VERBOSE_BOOTUP

 #define debug_putstr(__x)  __putstr(__x)
+#define debug_printf printf

 #else

 static inline void debug_putstr(const char *s)
 { }
+static inline int debug_printf(const char *fmt, ...)
+{ }

 #endif

[-- Attachment #2: early_console_more_2_2x.patch --]
[-- Type: text/x-patch, Size: 2932 bytes --]

Subject: [PATCH] x86, boot: Add printf support for early console in compressed/misc.c

Reuse printf.c in x86 setup code.
And print out decompress_kernel input and output info.

Later decompresser code could print out more info for debug info.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/x86/boot/compressed/Makefile |    2 +-
 arch/x86/boot/compressed/misc.c   |    8 ++++++++
 arch/x86/boot/compressed/misc.h   |    7 +++++++
 arch/x86/boot/compressed/printf.c |    5 +++++
 4 files changed, 21 insertions(+), 1 deletion(-)

Index: linux-2.6/arch/x86/boot/compressed/Makefile
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/Makefile
+++ linux-2.6/arch/x86/boot/compressed/Makefile
@@ -28,7 +28,7 @@ HOST_EXTRACFLAGS += -I$(srctree)/tools/i
 
 vmlinux-objs-y := $(obj)/vmlinux.lds $(obj)/head_$(BITS).o $(obj)/misc.o \
 	$(obj)/string.o $(obj)/cmdline.o \
-	$(obj)/piggy.o $(obj)/cpuflags.o
+	$(obj)/printf.o $(obj)/piggy.o $(obj)/cpuflags.o
 
 vmlinux-objs-$(CONFIG_EARLY_PRINTK) += $(obj)/early_serial_console.o
 vmlinux-objs-$(CONFIG_RANDOMIZE_BASE) += $(obj)/aslr.o
Index: linux-2.6/arch/x86/boot/compressed/printf.c
===================================================================
--- /dev/null
+++ linux-2.6/arch/x86/boot/compressed/printf.c
@@ -0,0 +1,5 @@
+#include "misc.h"
+
+#define puts(__x)  __putstr(__x)
+
+#include "../printf.c"
Index: linux-2.6/arch/x86/boot/compressed/misc.c
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/misc.c
+++ linux-2.6/arch/x86/boot/compressed/misc.c
@@ -390,6 +390,14 @@ asmlinkage __visible void *decompress_ke
 	output = choose_kernel_location(input_data, input_len,
 					output, output_len);
 
+	debug_putstr("decompress_kernel:\n");
+	debug_printf("  input: [0x%lx-0x%lx], output: 0x%lx, heap: [0x%lx-0x%lx]\n",
+		 (unsigned long)input_data,
+		 (unsigned long)input_data + input_len - 1,
+		 (unsigned long)output,
+		 (unsigned long)heap,
+		 (unsigned long)heap + BOOT_HEAP_SIZE - 1);
+
 	/* Validate memory location choices. */
 	if ((unsigned long)output & (MIN_KERNEL_ALIGN - 1))
 		error("Destination address inappropriately aligned");
Index: linux-2.6/arch/x86/boot/compressed/misc.h
===================================================================
--- linux-2.6.orig/arch/x86/boot/compressed/misc.h
+++ linux-2.6/arch/x86/boot/compressed/misc.h
@@ -36,14 +36,21 @@ extern struct boot_params *real_mode;		/
 void __putstr(const char *s);
 #define error_putstr(__x)  __putstr(__x)
 
+/* printf.c */
+int sprintf(char *buf, const char *fmt, ...);
+int printf(const char *fmt, ...);
+
 #ifdef CONFIG_X86_VERBOSE_BOOTUP
 
 #define debug_putstr(__x)  __putstr(__x)
+#define debug_printf printf
 
 #else
 
 static inline void debug_putstr(const char *s)
 { }
+static inline int debug_printf(const char *fmt, ...)
+{ }
 
 #endif
 

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] x86, boot: add hex output for debugging
  2014-10-31 23:31 ` Yinghai Lu
@ 2014-10-31 23:45   ` Josh Triplett
  2014-11-01  0:03     ` Joe Perches
  0 siblings, 1 reply; 5+ messages in thread
From: Josh Triplett @ 2014-10-31 23:45 UTC (permalink / raw)
  To: Yinghai Lu
  Cc: Kees Cook, Linux Kernel Mailing List, H. Peter Anvin,
	Thomas Gleixner, Ingo Molnar, the arch/x86 maintainers,
	Vivek Goyal, Junjie Mao, Andi Kleen

On Fri, Oct 31, 2014 at 04:31:32PM -0700, Yinghai Lu wrote:
> On Fri, Oct 31, 2014 at 1:58 PM, Kees Cook <keescook@chromium.org> wrote:
> > This is useful for reporting various addresses or other values while
> > debugging early boot. For example, when CONFIG_X86_VERBOSE_BOOTUP is set,
> > this is now visible at boot time:
> >
> >         early console in setup code
> >         early console in decompress_kernel
> >         input_data: 0x0000000001e1526e
> >         input_len: 0x0000000000732236
> >         output: 0x0000000001000000
> >         output_len: 0x0000000001535640
> >         run_size: 0x00000000021fb000
> >         KASLR using RDTSC...
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > Since this displays run_size, this patch depends on Junjie Mao's patch
> > "x86, kaslr: Prevent .bss from overlaping initrd"
> >
> > ---
> >  arch/x86/boot/compressed/misc.c | 24 ++++++++++++++++++++++++
> >  arch/x86/boot/compressed/misc.h | 11 +++++++++++
> >  2 files changed, 35 insertions(+)
> ...
> 
> We can reuse printf.c in arch/x86/boot.
> 
> I had attached one in local tree for a while. or even sent it before
> several years ago.

I don't think we need the full generality of printf in the decompression
stub.  I prefer Kees' patch, though I'd still like to see __puthex made
conditional.

- Josh Triplett

^ permalink raw reply	[flat|nested] 5+ messages in thread

* Re: [PATCH v2] x86, boot: add hex output for debugging
  2014-10-31 23:45   ` Josh Triplett
@ 2014-11-01  0:03     ` Joe Perches
  0 siblings, 0 replies; 5+ messages in thread
From: Joe Perches @ 2014-11-01  0:03 UTC (permalink / raw)
  To: Josh Triplett
  Cc: Yinghai Lu, Kees Cook, Linux Kernel Mailing List, H. Peter Anvin,
	Thomas Gleixner, Ingo Molnar, the arch/x86 maintainers,
	Vivek Goyal, Junjie Mao, Andi Kleen

On Fri, 2014-10-31 at 16:45 -0700, Josh Triplett wrote:
> I don't think we need the full generality of printf in the decompression
> stub.  I prefer Kees' patch, though I'd still like to see __puthex made
> conditional.

Maybe use a statement expression macro instead?
Something like this could emit the right number of bits for any type

#define __puthex(val)							\
({									\
	typeof(val) value = val;					\
	char alpha[2] = {};						\
	int bits;							\
									\
	__putstr("0x");							\
	for (bits = sizeof(value) * 8 - 4; bits >= 0; bits -= 4) {	\
		int digit = (value >> bits) & 0xf;			\
									\
		if (digit < 10)						\
			alpha[0] = '0' + digit;				\
		else							\
			alpha[0] = 'a' + (digit - 10);			\
									\
		__putstr(alpha);					\
	}								\
})



^ permalink raw reply	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2014-11-01  0:03 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
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2014-10-31 20:58 [PATCH v2] x86, boot: add hex output for debugging Kees Cook
2014-10-31 21:34 ` Andy Lutomirski
2014-10-31 23:31 ` Yinghai Lu
2014-10-31 23:45   ` Josh Triplett
2014-11-01  0:03     ` Joe Perches

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