From: Jordan Niethe <jniethe5@gmail.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] powerpc: Allow relative pointers in bug table entries
Date: Mon, 30 Nov 2020 11:59:27 +1100 [thread overview]
Message-ID: <CACzsE9oLn55hfpWoxamUQmHks5uL8Euc2k6XhUavbVkhsRBhSQ@mail.gmail.com> (raw)
In-Reply-To: <5c997bc4-c859-0db6-f167-37ca37819059@csgroup.eu>
On Sun, Nov 29, 2020 at 6:00 AM Christophe Leroy
<christophe.leroy@csgroup.eu> wrote:
>
>
>
> Le 27/11/2020 à 04:02, Jordan Niethe a écrit :
> > This enables GENERIC_BUG_RELATIVE_POINTERS on Power so that 32-bit
> > offsets are stored in the bug entries rather than 64-bit pointers.
> >
> > Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
> > ---
> > arch/powerpc/Kconfig | 4 ++++
> > arch/powerpc/include/asm/bug.h | 37 ++++++++++++++++++++++++++++++++--
> > arch/powerpc/xmon/xmon.c | 17 ++++++++++++++--
> > 3 files changed, 54 insertions(+), 4 deletions(-)
> >
> > diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
> > index e9f13fe08492..294108e0e5c6 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -311,6 +311,10 @@ config GENERIC_BUG
> > default y
> > depends on BUG
> >
> > +config GENERIC_BUG_RELATIVE_POINTERS
> > + def_bool y
> > + depends on GENERIC_BUG
> > +
> > config SYS_SUPPORTS_APM_EMULATION
> > default y if PMAC_APM_EMU
> > bool
> > diff --git a/arch/powerpc/include/asm/bug.h b/arch/powerpc/include/asm/bug.h
> > index 338f36cd9934..d03d834042a1 100644
> > --- a/arch/powerpc/include/asm/bug.h
> > +++ b/arch/powerpc/include/asm/bug.h
> > @@ -12,7 +12,11 @@
> > #ifdef CONFIG_DEBUG_BUGVERBOSE
> > .macro EMIT_BUG_ENTRY addr,file,line,flags
> > .section __bug_table,"aw"
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> As far as I understand, as soon as CONFIG_BUG is selected, GENERIC_BUG is automatically selected so
> GENERIC_BUG_RELATIVE_POINTERS is selected as well. Therefore this #ifndef is never possible.
Thanks, you are right. I'll fix that up.
>
> > 5001: PPC_LONG \addr, 5002f
> > +#else
> > +5001: .4byte \addr - 5001b, 5002f - 5001b
> > +#endif /* CONFIG_GENERIC_BUG_RELATIVE_POINTERS */
> > .short \line, \flags
> > .org 5001b+BUG_ENTRY_SIZE
> > .previous
> > @@ -23,7 +27,11 @@
> > #else
> > .macro EMIT_BUG_ENTRY addr,file,line,flags
> > .section __bug_table,"aw"
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> Same
>
> > 5001: PPC_LONG \addr
> > +#else
> > +5001: .4byte \addr - 5001b
> > +#endif /* CONFIG_GENERIC_BUG_RELATIVE_POINTERS */
> > .short \flags
> > .org 5001b+BUG_ENTRY_SIZE
> > .previous
> > @@ -34,20 +42,45 @@
> > /* _EMIT_BUG_ENTRY expects args %0,%1,%2,%3 to be FILE, LINE, flags and
> > sizeof(struct bug_entry), respectively */
> > #ifdef CONFIG_DEBUG_BUGVERBOSE
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> Same
>
> > #define _EMIT_BUG_ENTRY \
> > ".section __bug_table,\"aw\"\n" \
> > "2:\t" PPC_LONG "1b, %0\n" \
> > "\t.short %1, %2\n" \
> > ".org 2b+%3\n" \
> > ".previous\n"
> > -#else
> > +
> > +#else /* relative pointers */
> > +
> > +#define _EMIT_BUG_ENTRY \
> > + ".section __bug_table,\"aw\"\n" \
> > + "2:\t.4byte 1b - 2b, %0 - 2b\n" \
> > + "\t.short %1, %2\n" \
> > + ".org 2b+%3\n" \
> > + ".previous\n"
> > +#endif /* relative pointers */
> > +
> > +#else /* verbose */
> > +
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> Same
>
> > #define _EMIT_BUG_ENTRY \
> > ".section __bug_table,\"aw\"\n" \
> > "2:\t" PPC_LONG "1b\n" \
> > "\t.short %2\n" \
> > ".org 2b+%3\n" \
> > ".previous\n"
> > -#endif
> > +
> > +#else /* relative pointers */
> > +
> > +#define _EMIT_BUG_ENTRY \
> > + ".section __bug_table,\"aw\"\n" \
> > + "2:\t.4byte 1b - 2b\n" \
> > + "\t.short %2\n" \
> > + ".org 2b+%3\n" \
> > + ".previous\n"
> > +
> > +#endif /* relative pointers */
> > +#endif /* verbose */
> >
> > #define BUG_ENTRY(insn, flags, ...) \
> > __asm__ __volatile__( \
> > diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> > index 55c43a6c9111..5f7cf7e95767 100644
> > --- a/arch/powerpc/xmon/xmon.c
> > +++ b/arch/powerpc/xmon/xmon.c
> > @@ -1731,6 +1731,9 @@ static void print_bug_trap(struct pt_regs *regs)
> > #ifdef CONFIG_BUG
> > const struct bug_entry *bug;
> > unsigned long addr;
> > +#ifdef CONFIG_DEBUG_BUGVERBOSE
> > + char *file;
> > +#endif
> >
> > if (regs->msr & MSR_PR)
> > return; /* not in kernel */
> > @@ -1744,10 +1747,20 @@ static void print_bug_trap(struct pt_regs *regs)
> > return;
> >
> > #ifdef CONFIG_DEBUG_BUGVERBOSE
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> Same
>
> > + file = bug->file;
> > +#else /* relative pointers */
> > + file = (char *)bug + bug->file_disp;
> > +#endif /* relative pointers */
> > printf("kernel BUG at %s:%u!\n",
> > - bug->file, bug->line);
> > + file, bug->line);
> > #else
> > - printf("kernel BUG at %px!\n", (void *)bug->bug_addr);
> > +#ifndef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
>
> Same
>
> > + addr = bug->addr;
> > +#else /* relative pointers */
> > + addr = (unsigned long)bug + bug->bug_addr_disp;
> > +#endif /* relative pointers */
> > + printf("kernel BUG at %px!\n", (void *)addr);
> > #endif
> > #endif /* CONFIG_BUG */
> > }
> >
>
> Christophe
next prev parent reply other threads:[~2020-11-30 1:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 3:02 [PATCH] powerpc: Allow relative pointers in bug table entries Jordan Niethe
2020-11-28 19:00 ` Christophe Leroy
2020-11-30 0:59 ` Jordan Niethe [this message]
2020-11-30 1:42 ` Michael Ellerman
2020-11-30 1:50 ` Jordan Niethe
2020-11-30 6:27 ` Christophe Leroy
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