Hello Keir,
You code does not work. When each byte string is more than 0x7f, sign bit is
extended and produce wrong value.
diff -r 8a9f81672c76 xen/common/gdbstub.c
--- a/xen/common/gdbstub.c Wed Aug 12 14:27:52 2009 +0100
+++ b/xen/common/gdbstub.c Wed Aug 12 19:49:12 2009 -0700
@@ -93,7 +93,7 @@
return -1;
}
-char
+unsigned char
str2hex(const char *str)
{
return (char2hex(str[0]) << 4) | char2hex(str[1]);
@@ -127,7 +127,7 @@
x <<= 8;
x += str2hex(*str);
#elif defined(__LITTLE_ENDIAN)
- x += (unsigned long)str2hex(*str) << (i*8);
+ x += (unsigned long)str2hex(str) << (i*8);
#else
# error unknown endian
#endif
diff -r 8a9f81672c76 xen/include/xen/gdbstub.h
--- a/xen/include/xen/gdbstub.h Wed Aug 12 14:27:52 2009 +0100
+++ b/xen/include/xen/gdbstub.h Wed Aug 12 19:49:12 2009 -0700
@@ -29,7 +29,7 @@
/* value <-> char (de)serialzers for arch specific gdb backends */
char hex2char(unsigned long x);
int char2hex(unsigned char c);
-char str2hex(const char *str);
+unsigned char str2hex(const char *str);
unsigned long str2ulong(const char *str, unsigned long bytes);
struct gdb_context {
-caz
-----Original Message-----
From: Caz Yokoyama [mailto:caz@xxxxxxxxxxx]
Sent: Wednesday, August 12, 2009 2:03 PM
To: 'Keir Fraser'; 'xen-devel@xxxxxxxxxxxxxxxxxxx'
Subject: RE: [Xen-devel] [PATCH] fix the bug of gdb which debugs xen.
Probably, you mean.
diff -r 8a9f81672c76 xen/common/gdbstub.c
--- a/xen/common/gdbstub.c Wed Aug 12 14:27:52 2009 +0100
+++ b/xen/common/gdbstub.c Wed Aug 12 14:00:20 2009 -0700
@@ -127,7 +127,7 @@
x <<= 8;
x += str2hex(*str);
#elif defined(__LITTLE_ENDIAN)
- x += (unsigned long)str2hex(*str) << (i*8);
+ x += (unsigned long)str2hex(str) << (i*8);
#else
# error unknown endian
#endif
-caz
-----Original Message-----
From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
Sent: Wednesday, August 12, 2009 6:30 AM
To: Caz Yokoyama; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] [PATCH] fix the bug of gdb which debugs xen.
I rewrote it some more. Take a look at changeset 20054.
-- Keir
On 12/08/2009 13:52, "Caz Yokoyama" <cazyokoyama@xxxxxxxxx> wrote:
> Hello Keir,
> You are right and good points. Thank you. I did not aware them because
only
> environment I test is x86_64. How about this? I am glad if you check in. I
> regularly update my local source code by "hg pull; hg up".
> -caz
>
> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> Sent: Wednesday, August 12, 2009 12:58 AM
> To: Caz Yokoyama; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] [PATCH] fix the bug of gdb which debugs xen.
>
> I don't know whether you intend this for immediate checkin, but anyway:
>
> * Don't delete the sysenter logic in traps.c, leave it.
> * I'm not sure about swap64() in gdbstub.c. The value may not be 64 bits
> (e.g., running on i386), or the system may not be little endian. Might be
> better to define an alternative to str2ulong() which is endian aware, like
> gdb_write_to_packet_hex().
>
> -- Keir
>
> On 12/08/2009 03:15, "Caz Yokoyama" <cazyokoyama@xxxxxxxxx> wrote:
>
>> Hello,
>> This patch fixes the bug of gdb which debugs Xen hypervisor, i.e. not
> domU. As
>> Emre Can Sezer reported in
>> http://lists.xensource.com/archives/html/xen-devel/2009-01/msg00885.html,
> once
>> break point is hit, continue command produces SIGTRAP at
> restore_all_xen().
>> This patch makes continue command resume Xen running. I still see other
> bugs
>> like backtrace command does not show function name. But I hope this helps
> your
>> debug.
>> FYI, related postings.
>> http://lists.xensource.com/archives/html/xen-devel/2007-12/msg00678.html
>>
>
http://www.filewatcher.com/p/xen_2.0.6.orig.tar.gz.2456215/xen-2.0/docs/misc
> /X
>> enDebugger-HOWTO.html
>>
>> connect gdb on step command
>> --- a/xen/arch/x86/traps.c Thu Aug 06 13:27:53 2009 +0100
>> +++ b/xen/arch/x86/traps.c Tue Aug 11 18:15:25 2009 -0700
>> @@ -2977,13 +2977,7 @@
>> if ( regs->eflags & EF_TF )
>> {
>> #ifdef __x86_64__
>> - void sysenter_entry(void);
>> - void sysenter_eflags_saved(void);
>> - /* In SYSENTER entry path we can't zap TF until EFLAGS is
> saved.
>> */
>> - if ( (regs->rip >= (unsigned long)sysenter_entry) &&
>> - (regs->rip < (unsigned long)sysenter_eflags_saved) )
>> - goto out;
>> - WARN_ON(regs->rip != (unsigned long)sysenter_eflags_saved);
>> + debugger_trap_fatal(TRAP_debug, regs);
>> #else
>> WARN_ON(1);
>> #endif
>>
>> Value of gdb command is little endian.
>> diff -r 13fe7f07df15 xen/common/gdbstub.c
>> --- a/xen/common/gdbstub.c Thu Aug 06 13:27:53 2009 +0100
>> +++ b/xen/common/gdbstub.c Tue Aug 11 18:15:25 2009 -0700
>> @@ -53,6 +53,10 @@
>>
>> #define GDB_RETRY_MAX 10
>>
>> +#define swap16(_v) ((((u16)(_v)>>8)&0xff)|(((u16)(_v)&0xff)<<8))
>> +#define swap32(_v)
>> (((u32)swap16((u16)(_v))<<16)|(u32)swap16((u32)((_v)>>16)))
>> +#define swap64(_v)
>> (((u64)swap32((u32)(_v))<<32)|(u64)swap32((u32)((_v)>>32)))
>> +
>> struct gdb_cpu_info
>> {
>> atomic_t paused;
>> @@ -489,6 +493,7 @@
>> }
>> ptr++;
>> val = str2ulong(ptr, sizeof(unsigned long));
>> + val = swap64(val);
>> gdb_arch_write_reg(addr, val, regs, ctx);
>> break;
>> case 'D':
>>
>> Thank you.
>> -Caz Yokoyama, caz at caztech dot com. 503-804-1028(m).
>>
>>
>
str_to_native_ulong.patch
Description: Binary data
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