Re: [XenPPC] [PATCH] Print backtrace on BUG
hmm, this brings up an interesting issues. We curently do not print a regdump or backtrace is gdb is enabled, this is the reason why this patch exists. We obviously do not want this noise with gdb because breakpoint will become seriously annoying and may even prohibit gdb from even working (tho TB's O-patch will help with this). But I think on BUG() and Machine check we should always dump this info even before the debugger. Thoughts? -JX On Sep 21, 2006, at 9:18 AM, Jimi Xenidis wrote: hey Amos, Please see how __warn() calls backtrace. Also lets make this a full binding and call it __full_crash that way the backtrace will be labeled and useful since the first frames are dubious. -JX On Sep 20, 2006, at 11:41 PM, Amos Waterland wrote: This makes Xen/PPC dump a backtrace when a BUG() is triggered. Signed-off-by: Amos Waterland <[EMAIL PROTECTED]> --- config.h | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff -r 5418062d2da8 xen/include/asm-powerpc/powerpc64/config.h --- a/xen/include/asm-powerpc/powerpc64/config.h +++ b/xen/include/asm-powerpc/powerpc64/config.h @@ -38,7 +38,15 @@ #ifndef __ASSEMBLY__ -#define FORCE_CRASH() __asm__ __volatile__ ( "trap" ) +#define FORCE_CRASH () \ +do { \ +unsigned long sp, lr, pc, tp; \ +asm("mr %0, 1" : "=r" (sp)); \ +asm("mflr %0" : "=r" (lr)); \ +asm("mflr %0; bl 1f; 1: mflr %1; mtlr %0" : "=r" (tp), "=r" (pc));\ +show_backtrace(sp, lr, pc); \ +__asm__ __volatile__ ( "trap" ); \ +} while ( 0 ) #endif /* __ASSEMBLY__ */ ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
Re: [XenPPC] [PATCH] Print backtrace on BUG
hey Amos, Please see how __warn() calls backtrace. Also lets make this a full binding and call it __full_crash that way the backtrace will be labeled and useful since the first frames are dubious. -JX On Sep 20, 2006, at 11:41 PM, Amos Waterland wrote: This makes Xen/PPC dump a backtrace when a BUG() is triggered. Signed-off-by: Amos Waterland <[EMAIL PROTECTED]> --- config.h | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff -r 5418062d2da8 xen/include/asm-powerpc/powerpc64/config.h --- a/xen/include/asm-powerpc/powerpc64/config.h +++ b/xen/include/asm-powerpc/powerpc64/config.h @@ -38,7 +38,15 @@ #ifndef __ASSEMBLY__ -#define FORCE_CRASH() __asm__ __volatile__ ( "trap" ) +#define FORCE_CRASH () \ +do { \ +unsigned long sp, lr, pc, tp; \ +asm("mr %0, 1" : "=r" (sp)); \ +asm("mflr %0" : "=r" (lr)); \ +asm("mflr %0; bl 1f; 1: mflr %1; mtlr %0" : "=r" (tp), "=r" (pc));\ +show_backtrace(sp, lr, pc); \ +__asm__ __volatile__ ( "trap" ); \ +} while ( 0 ) #endif /* __ASSEMBLY__ */ ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
Re: [XenPPC] [PATCH] Print backtrace on BUG
Bah, it's too early for GCC asm: +asm("mr %0, 1" : "=r" (sp)); \ +asm("mflr %0" : "=r" (lr)); \ +asm("mflr %0; bl 1f; 1: mflr %1; mtlr %0" : "=r" (tp), "=r" (pc));\ asm("bl $+4 ; mflr %0; mtlr %1" : "=r"(pc) : "r"(lr));\ +show_backtrace(sp, lr, pc); \ +__asm__ __volatile__ ( "trap" ); \ +} while ( 0 ) ...and the one "asm" where you put "volatile" on is the only one that doesn't need it :-) (and no __ is needed either). Alternatively (and preferred), you can make a single statement out of the first three asm statements. In fact, you _have_ to make those three into one; even "volatile asm"s can be reordered by the compiler, if there's no data dependency. The "trap" asm is always volatile (it has no parameters); it can still be reordered though. You can use __builtin_trap() here instead. Segher ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
Re: [XenPPC] [PATCH] Print backtrace on BUG
Hi Amos, +do { \ +unsigned long sp, lr, pc, tp; \ You can do without "tp": +asm("mr %0, 1" : "=r" (sp)); \ +asm("mflr %0" : "=r" (lr)); \ +asm("mflr %0; bl 1f; 1: mflr %1; mtlr %0" : "=r" (tp), "=r" (pc));\ asm("bl $+4 ; mflr %0; mtlr %1" : "=r"(pc) : "r"(lr));\ +show_backtrace(sp, lr, pc); \ +__asm__ __volatile__ ( "trap" ); \ +} while ( 0 ) ...and the one "asm" where you put "volatile" on is the only one that doesn't need it :-) (and no __ is needed either). Alternatively (and preferred), you can make a single statement out of the first three asm statements. Segher ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel
[XenPPC] [PATCH] Print backtrace on BUG
This makes Xen/PPC dump a backtrace when a BUG() is triggered. Signed-off-by: Amos Waterland <[EMAIL PROTECTED]> --- config.h | 10 +- 1 file changed, 9 insertions(+), 1 deletion(-) diff -r 5418062d2da8 xen/include/asm-powerpc/powerpc64/config.h --- a/xen/include/asm-powerpc/powerpc64/config.h +++ b/xen/include/asm-powerpc/powerpc64/config.h @@ -38,7 +38,15 @@ #ifndef __ASSEMBLY__ -#define FORCE_CRASH() __asm__ __volatile__ ( "trap" ) +#define FORCE_CRASH() \ +do { \ +unsigned long sp, lr, pc, tp; \ +asm("mr %0, 1" : "=r" (sp)); \ +asm("mflr %0" : "=r" (lr)); \ +asm("mflr %0; bl 1f; 1: mflr %1; mtlr %0" : "=r" (tp), "=r" (pc));\ +show_backtrace(sp, lr, pc); \ +__asm__ __volatile__ ( "trap" ); \ +} while ( 0 ) #endif /* __ASSEMBLY__ */ ___ Xen-ppc-devel mailing list Xen-ppc-devel@lists.xensource.com http://lists.xensource.com/xen-ppc-devel